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Sample records for base material reduces

  1. A nonlinear manifold-based reduced order model for multiscale analysis of heterogeneous hyperelastic materials

    Science.gov (United States)

    Bhattacharjee, Satyaki; Matouš, Karel

    2016-05-01

    A new manifold-based reduced order model for nonlinear problems in multiscale modeling of heterogeneous hyperelastic materials is presented. The model relies on a global geometric framework for nonlinear dimensionality reduction (Isomap), and the macroscopic loading parameters are linked to the reduced space using a Neural Network. The proposed model provides both homogenization and localization of the multiscale solution in the context of computational homogenization. To construct the manifold, we perform a number of large three-dimensional simulations of a statistically representative unit cell using a parallel finite strain finite element solver. The manifold-based reduced order model is verified using common principles from the machine-learning community. Both homogenization and localization of the multiscale solution are demonstrated on a large three-dimensional example and the local microscopic fields as well as the homogenized macroscopic potential are obtained with acceptable engineering accuracy.

  2. Effect of self-glazing on reducing the radioactivity levels of red mud based ceramic materials.

    Science.gov (United States)

    Qin, Shuo; Wu, Bolin

    2011-12-30

    Self-glazing red mud based ceramic materials (RMCM) were produced by normal pressure sintering process using the main raw materials of red mud. The properties of the RMCM samples were investigated by the measurements of mechanical properties, radiation measurement, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the self-glazing RMCM have good mechanical properties (water absorption and apparent porosity approached zero; bulk density, 2.94 g/cm(3); compressive strength, 78.12 MPa). The radiation level has clear change regularity that the radioactivity levels of red mud (6360 Bq) is obvious declined, and can be reduced to that of the natural radioactive background of Guilin Karst landform, China (3600 Bq). It will not only consume large quantities of red mud, but also decrease the production cost of self-glazing RMCM. And the statement of this paper will offer effective ways to reduce the radioactivity level of red mud.

  3. Effect of self-glazing on reducing the radioactivity levels of red mud based ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Shuo [College of Material Science and Engineering, Guilin University of Technology, Guilin, Guangxi 541004 (China); Wu, Bolin, E-mail: wubolin3211@gmail.com [College of Material Science and Engineering, Guilin University of Technology, Guilin, Guangxi 541004 (China)

    2011-12-30

    Graphical abstract: Self-glazing red mud based ceramic materials (RMCM) were produced by normal pressure sintering process using the main raw materials of red mud. The properties of the RMCM samples were investigated by the measurements of mechanical properties, radiation measurement, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the self-glazing RMCM have good mechanical properties (water absorption and apparent porosity approached zero; bulk density, 2.94 g/cm{sup 3}; compressive strength, 78.12 MPa). The radiation level has clear change regularity that the radioactivity levels of red mud (6360 Bq) are obvious declined, and can be reduced to that of the natural radioactive background of Guilin Karst landform, China (3600 Bq). It will not only consume large quantities of red mud, but also decrease the production cost of self-glazing RMCM. And the statement of this paper will offer effective ways to reduce the radioactivity level of red mud. Highlights: Black-Right-Pointing-Pointer The self-glazing phenomenon in red mud system was first discovered in our research. Black-Right-Pointing-Pointer Radiation levels of red mud can be reduced efficiently by self-glazing layer. Black-Right-Pointing-Pointer Red mud based ceramic materials will not cause harm to environment and humans. Black-Right-Pointing-Pointer This research possesses important economic significances to aluminum companies. - Abstract: Self-glazing red mud based ceramic materials (RMCM) were produced by normal pressure sintering process using the main raw materials of red mud. The properties of the RMCM samples were investigated by the measurements of mechanical properties, radiation measurement, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the self-glazing RMCM have good mechanical properties (water absorption and apparent porosity approached zero; bulk density, 2.94 g/cm{sup 3}; compressive strength, 78.12 MPa). The radiation

  4. Nutrient enrichment reduces constraints on material flows in a detritus-based food web.

    Science.gov (United States)

    Cross, Wyatt F; Wallace, J Bruce; Rosemond, Amy D

    2007-10-01

    predators (from -80% to 55%). Our results demonstrate that nutrient enrichment of detritus-based systems may reduce stoichiometric constraints on material flows, increase the contribution of consumers to C, N, and P cycling, alter the proportion of C inputs metabolized by consumers, and potentially lead to reduced ecosystem-level storage of C.

  5. Nanostructured hybrid materials based on reduced graphene oxide for solar energy conversion

    Science.gov (United States)

    Morais, Andreia; Amaral Carminati, Saulo do; Nogueira, Ana Flavia

    2016-09-01

    Research on carbon-based photocatalytic nanomaterials has been a field in continuous expansion in the last years. Graphene (or its derivatives) is currently one of the most studied materials due to its high surface area, photodegradation resistance, optical transparency and high charge mobility values. All of these excellent properties are highlighted for applications in various research areas. The incorporation of small amounts of reduced graphene oxide (RGO) sheets in semiconductors matrices is also a strategy widely used to improve the physicochemical properties, which cannot normally be achieved using conventional composites or pristine semiconductors. Most studies suggest that these twodimensional (2D) materials can facilitate electron injection and assist the electron transport in semiconductors. In this context, this manuscript will present examples of graphene-based semiconductor nanocomposites obtained by our research group and their application in the photodegradation of methylene blue (MB), photocatalytic conversion of CO2 to hydrocarbon fuels and photocatalytic water splitting reaction. Our results show the positive effect of coupling the RGO sheets with semiconductors for photocatalysis.

  6. Green Materials Science and Engineering Reduces Biofouling: Approaches for Medical and Membrane-based Technologies

    Directory of Open Access Journals (Sweden)

    Kerianne M Dobosz

    2015-03-01

    Full Text Available Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety.

  7. Green materials science and engineering reduces biofouling: approaches for medical and membrane-based technologies.

    Science.gov (United States)

    Dobosz, Kerianne M; Kolewe, Kristopher W; Schiffman, Jessica D

    2015-01-01

    Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime, and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials, and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety.

  8. Green materials science and engineering reduces biofouling: approaches for medical and membrane-based technologies

    Science.gov (United States)

    Dobosz, Kerianne M.; Kolewe, Kristopher W.; Schiffman, Jessica D.

    2015-01-01

    Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime, and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials, and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety. PMID:25852659

  9. Effect of palladium on the reducibility of Mn based materials: correlation with methane oxidation activity.

    Science.gov (United States)

    Baylet, A; Royer, S; Labrugère, C; Valencia, H; Marécot, P; Tatibouët, J M; Duprez, D

    2008-10-21

    Mn-based oxide supports were synthesized using different procedures: (i) carbonate co-precipitation method, leading to the formation of a hexaaluminate crystallized solid (La(0.2)Sr(0.3)Ba(0.5)MnAl(11)O(19)) and (ii) solid-solid diffusion method, leading to the formation of a doped theta-Al(2)O(3) crystallized solid (nominal composition: 60 wt% La(0.2)Sr(0.3)Ba(0.5)MnAl(11)O(19) + 40 wt% Al(2)O(3)). Impregnation of 1.0 wt%Pd was carried out on both oxides. The solids were tested for the catalytic methane combustion up to 700 degrees C. It was observed that adding palladium resulted in an important increase in the catalytic activity. The combined use of H(2)-TPR and XPS techniques reveals that only Mn(3+)/Mn(2+) redox "couple" is present in the solids, whatever the synthesis procedure used. The fraction Mn(3+)/Mn is proportional to the total Mn content in the solid support, whatever the sample structure (hexaaluminate or doped theta-Al(2)O(3)) and its morphology (large crystals or aggregates of small particles, respectively). Pd impregnation and further calcination at 650 degrees C has no significant effect on the Mn(3+)/Mn fraction. However, some changes in Mn(3+) reduction profile are observed, depending on the solid structure. Indeed, palladium addition strongly affects the manganese reducibility with an important shift of the reduction process to lower temperatures (approximately 100 degrees C). On the basis of redox properties observed for the different catalysts, a Mars-van-Krevelen redox mechanism, with oxygen transfer from support oxides to palladium particles, is proposed to explain the difference in terms of catalytic conversion and stability with respect to a 1.0 wt%Pd/Al(2)O(3) reference sample.

  10. The influence of reduced graphene oxide on electrical conductivity of LiFePO4-based composite as cathode material

    Science.gov (United States)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin; Iskandar, Ferry

    2016-02-01

    LiFePO4 is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g-1. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4-based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  11. Evaluation of the theoretical and clinical methods for reducing marginal leakage in resin-based composite restorative materials: A review

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Keshvad

    2016-11-01

    Full Text Available Resin-based composite restorative materials  have a substantial share in dental treatments. Their esthetic has made them patients’ first choice as restorative materials. Marginal leakage is one of their problems which leads to recurrent caries and post-operative hypersensitivity. Our aim was to evaluate the theoretical and clinical methods that have been proposed in the dental literature. Around 50 articles from Pubmed, SCOPUS and google scholar were selected and categorized in 4 groups based on the selected keywords. All the studies discussed in this paper have emphasized that there is no way to eliminate the microleakage but it can be reduced by means of some approaches. On the other hand, due to the multifactorial nature and difference of oral environment and laboratory conditions, there isn’t any certain way to define precisely. It seems that there is an absolute need for more research in this field to make the relation of theoretical results and clinical findings possible.

  12. On the use of crystalline admixtures in cement based construction materials: from porosity reducers to promoters of self healing

    Science.gov (United States)

    Ferrara, Liberato; Krelani, Visar; Moretti, Fabio

    2016-08-01

    The project detailed in this paper aims at a thorough characterization of the effects of crystalline admixtures, currently employed as porosity reducing admixtures, on the self-healing capacity of the cementitious composites, i.e. their capacity to completely or partially re-seal cracks and, in case, also exhibit recovery of mechanical properties. The problem has been investigated with reference to both a normal strength concrete (NSC) and a high performance fibre reinforced cementitious composite (HPFRCC). In the latter case, the influence of flow-induced fibre alignment has also been considered in the experimental investigation. With reference to either 3-point (for NSC) or 4-point (for HPFRCC) bending tests performed up to controlled crack opening and up to failure, respectively before and after exposure/conditioning recovery of stiffness and stress bearing capacity has been evaluated to assess the self-healing capacity. In a durability-based design framework, self-healing indices to quantify the recovery of mechanical properties will also be defined. In NSC, crystalline admixtures are able to promote up to 60% of crack sealing even under exposure to open air. In the case of HPFRCCs, which would already feature autogenous healing capacity because of their peculiar mix compositions, the synergy between the dispersed fibre reinforcement and the action of the crystalline admixture has resulted in a likely ‘chemical pre-stressing’ of the same reinforcement, from which the recovery of mechanical performance of the material has greatly benefited, up to levels even higher than the performance of the virgin un-cracked material.

  13. Reduced-graphene-oxide-and-strontium-titanate-based double-layered composite: an efficient microwave-absorbing material

    Indian Academy of Sciences (India)

    SUKANTA DAS; S K SAHU; RAMESH ORAON; P C ROUTRAY; H BASKEY; G C NAYAK

    2017-04-01

    Microwave-absorbing materials based on reduced graphene oxide (r-GO)/ strontium titanate were prepared by embedding in epoxy matrix. R-GO and strontium titanate were synthesized and characterized before composite fabrication. Microstructures of the constituent elements were studied by scanning electron microscopy and X-ray diffraction (XRD). Microwave absorption capabilities of the composite absorbers were investigated using a Vector Network Analyser in the range 8–12 GHz. A maximum reflection loss of $−$7.5 and $−$16.4 dB was obtained at 9.3 and 12.08 GHz, respectively, for 2% (w/w) r-GO-loaded epoxy composites. A maximum attenuation of $−$12.8 dB at 9.3 GHz was obtained for the strontium titanate/epoxy composite. However, double-layer composite with r-GO/strontium titanate/epoxy composition showed the maximum reflection loss of $−$15.1 dB at 9.47 GHz and $−$9.65 dB at 12.3 GHz. All the results are discussed in terms of complex permeability and permittivity. The study revealed that intrinsic conductivity and polarization of the r-GO particles and dielectric polarization of the strontium titanate within epoxy matrix contribute to the microwave absorption.

  14. Use of a chitosan based natural coating materials to reduce spoilage and pathogenic bacteria on poultry products

    Science.gov (United States)

    Chitosan is a natural compound with proven antimicrobial activity having GRAS status (generally recognized as safe) as determined by the United States Food and Drug Administration (Smith et al., 2014). Efforts are underway to develop and improve the use of chitosan based films as packaging material...

  15. Ultrahigh capacity anode material for lithium ion battery based on rod gold nanoparticles decorated reduced graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Atar, Necip, E-mail: necipatar@gmail.com [Department of Chemical Engineering, Pamukkale University, Denizli (Turkey); Eren, Tanju [Department of Chemical Engineering, Pamukkale University, Denizli (Turkey); Yola, Mehmet Lütfi [Department of Metallurgical and Materials Engineering, Sinop University, Sinop (Turkey)

    2015-09-01

    In this study, we report the synthesis of rod shaped gold nanoparticles/2-aminoethanethiol functionalized reduced graphene oxide composite (rdAuNPs/AETrGO) and its application as an anode material for lithium-ion batteries. The structure of the rdAuNPs/AETrGO composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The electrochemical performance was investigated at different current rates by using a coin-type cell. It was found that the rod shaped gold nanoparticles were highly dispersed on the reduced graphene oxide sheets. Moreover, the rdAuNPs/AETrGO composite showed a high specific gravimetric capacity of about 1320 mAh g{sup −1} and a long-term cycle stability. - Highlights: • We prepared rod shaped gold nanoparticles functionalized reduced graphene oxide. • The nanocomposite was used as an anode material for lithium-ion batteries. • The nanocomposite showed a high specific gravimetric capacity of about 1320 mAh g{sup −1}. • The nanocomposite exhibited a long-term cycle stability.

  16. Plasmonics-based detection of H2 and CO: discrimination between reducing gases facilitated by material control

    Directory of Open Access Journals (Sweden)

    Gnanaprakash Dharmalingam

    2012-10-01

    Full Text Available Monitoring emissions in high-temperature-combustion applications is very important for regulating the discharge of gases such as NO2 and CO as well as unburnt fuel into the environment. This work reports the detection of H2 and CO gases by employing a metal–metal oxide nanocomposite (gold–yttria stabilized zirconia (Au–YSZ film fabricated through layer-by-layer physical vapor deposition (PVD. The change in the peak position of the localized surface plasmon resonance (LSPR was monitored as a function of time and gas concentration. The responses of the films were preferential towards H2, as observed from the results of exposing the films to the gases at temperatures of 500 °C in a background of dry air. Characterization of the samples by XRD and SEM enabled the correlation of material properties with the differences in the CO- and H2-induced LSPR peak shifts, including the relative desensitization towards NO2. Sensing characteristics of films with varying support thicknesses and metal-particle diameters have been studied, and the results are presented. A comparison has been made to films fabricated through co-sputtered PVD, and the calibration curves of the sensing response show a preferential response towards H2. The distinction between H2 and CO responses is also seen through the use of principal-component analysis (PCA. Such material arrangements, which can be tuned for their selectivity by changing certain parameters such as particle size, support thickness, etc., have direct applications within optical chemical sensors for turbine engines, solid-oxide fuel cells, and other high-temperature applications.

  17. Reducible oxide based catalysts

    Science.gov (United States)

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  18. The influence of reduced graphene oxide on electrical conductivity of LiFePO{sub 4}-based composite as cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin [Physics of Electronic Materials Research Division, Department of Physics, Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia); Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id [Physics of Electronic Materials Research Division, Department of Physics, Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia); Research Center for Nanoscience and Nanotechnology Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia)

    2016-02-08

    LiFePO{sub 4} is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g{sup −1}. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO{sub 4}-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO{sub 4}−based composite by varying mass of rGO in composition. Vibration of LiFePO{sub 4}-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO{sub 4} nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  19. Graphene-based smart materials

    Science.gov (United States)

    Yu, Xiaowen; Cheng, Huhu; Zhang, Miao; Zhao, Yang; Qu, Liangti; Shi, Gaoquan

    2017-09-01

    The high specific surface area and the excellent mechanical, electrical, optical and thermal properties of graphene make it an attractive component for high-performance stimuli-responsive or 'smart' materials. Complementary to these inherent properties, functionalization or hybridization can substantially improve the performance of these materials. Typical graphene-based smart materials include mechanically exfoliated perfect graphene, chemical vapour deposited high-quality graphene, chemically modified graphene (for example, graphene oxide and reduced graphene oxide) and their macroscopic assemblies or composites. These materials are sensitive to a range of stimuli, including gas molecules or biomolecules, pH value, mechanical strain, electrical field, and thermal or optical excitation. In this Review, we outline different graphene-based smart materials and their potential applications in actuators, chemical or strain sensors, self-healing materials, photothermal therapy and controlled drug delivery. We also introduce the working mechanisms of graphene-based smart materials and discuss the challenges facing the realization of their practical applications.

  20. I. Synthesis, characterization, and base catalysis of novel zeolite supported super-basic materials II. Oxidative dehydrogenation of ethane over reduced heteropolyanion catalysts

    Science.gov (United States)

    Galownia, Jonathan M.

    This thesis is composed of two separate and unrelated projects. The first part of this thesis outlines an investigation into the synthesis and characterization of a novel zeolite supported super-base capable of carbon-carbon olefin addition to alkyl aromatics. A zeolite supported basic material capable of such reactions would benefit many fine chemical syntheses, as well as vastly improve the economics associated with production of the high performance thermoplastic polyester polyethylene naphthalate. The thermal decomposition of alkali---metal azides impregnated in zeolite X is investigated as a novel route to the synthesis of a zeolite supported super-base. Impregnation of the alkali---metal azide precursor is shown to result in azide species occluded within the pores of the zeolite support by using high speed, solid-state 23Na MAS and 2D MQMAS NMR, FTIR, and TGA characterization methods. Addition of alkali---metal azides to the zeolite results in redistribution of the extra-lattice cations in the zeolite framework. Thermal decomposition of impregnated azide species produces further cation redistribution, but no neutral metallic clusters are detected by high speed, solid-state 23Na MAS NMR following thermal activation of the materials. Instead, it is possible that inactive ionic clusters are formed. The thermally activated materials do not promote base catalysis for the isomerization of 1-butene, the ethylation of toluene and o-xylene, and the alkenylation of o-xylene with 1,3-butadiene to produce 5-ortho-tolyl-pent-2-ene (5-OTP). The lack of catalytic activity in the materials is attributed to failure of the materials to form neutral metallic clusters during thermal treatment, possibly due to preferential formation of NMR silent ionic clusters. The formation of neutral metallic clusters is found to be insensitive to synthesis technique and activation procedure. It is concluded that the impregnation of alkali---metal azides in zeolite X does not provide a

  1. Upscaled CTAB-based DNA extraction and real-time PCR assays for Fusarium culmorum and F. graminearum DNA in plant material with reduced sampling error.

    Science.gov (United States)

    Brandfass, Christoph; Karlovsky, Petr

    2008-11-01

    Fusarium graminearum Schwabe (Gibberella zeae Schwein. Petch.) and F. culmorum W.G. Smith are major mycotoxin producers in small-grain cereals afflicted with Fusarium head blight (FHB). Real-time PCR (qPCR) is the method of choice for species-specific, quantitative estimation of fungal biomass in plant tissue. We demonstrated that increasing the amount of plant material used for DNA extraction to 0.5-1.0 g considerably reduced sampling error and improved the reproducibility of DNA yield. The costs of DNA extraction at different scales and with different methods (commercial kits versus cetyltrimethylammonium bromide-based protocol) and qPCR systems (doubly labeled hybridization probes versus SYBR Green) were compared. A cost-effective protocol for the quantification of F. graminearum and F. culmorum DNA in wheat grain and maize stalk debris based on DNA extraction from 0.5-1.0 g material and real-time PCR with SYBR Green fluorescence detection was developed.

  2. LDEF materials data bases

    Science.gov (United States)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base.

  3. Bioelectricity Production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells Using Indigenous Anode-Reducing Bacterial Community from Wastewater of Rice-Based Industries

    Directory of Open Access Journals (Sweden)

    Shailesh Kumar Jadhav

    2017-03-01

    Full Text Available Microbial fuel cells (MFCs are the electrochemical systems that harness the electricity production capacity of certain microbes from the reduction of biodegradable compounds. The present study aimed to develop mediator-less MFC without using expensive proton exchange membrane. In the present study, a triplicate of dual-chamber, mediator-less MFCs was operated with two local rice based industrial wastewater to explore the potential of this wastewater as a fuel option in these electrochemical systems. 30 combinations of 6 electrodes viz. Carbon (14 cm × 1.5 cm, Zn (14.9 cm × 4.9 cm, Cu (14.9 cm × 4.9 cm, Sn (14.1cm × 4.5cm, Fe (14cm × 4cm and Al (14cm × 4.5 cm were evaluated for each of the wastewater samples. Zn-C as anode-cathode combination produced a maximum voltage that was 1.084±0.016V and 1.086±0.028 and current of 1.777±0.115mA and 1.503±0.120 for KRM and SSR, respectively. In the present study, thick biofilm has been observed growing in MFC anode. Total 14 bacterial isolates growing in anode were obtained from two of the wastewater. The dual chambered, membrane-less and mediator-less MFCs were employed successfully to improve the economic feasibility of these electrochemical systems to generate bioelectricity and wastewater treatment simultaneously. Keywords: Membrane-less, Microbial Fuel Cells, Biofilm, Wastewater, Electrogenic. Article History: Received June 25th 2016; Received in revised form Dec 15th 2016; Accepted January 5th 2017; Available online How to Cite This Article: Reena, M. and Jadhav, S. K. (2017 Bioelectricity production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells using Indigenous Anode-reducing Bacterial Community from Wastewater of Rice-based Industries. International Journal of Renewable Energy Develeopment, 6(1, 83-92. http://dx.doi.org/10.14710/ijred.6.1.83-92

  4. High-Performance Wireless Ammonia Gas Sensors Based on Reduced Graphene Oxide and Nano-Silver Ink Hybrid Material Loaded on a Patch Antenna.

    Science.gov (United States)

    Wu, Bian; Zhang, Xingfei; Huang, Beiju; Zhao, Yutong; Cheng, Chuantong; Chen, Hongda

    2017-09-09

    Reduced graphene oxide (rGO) has been studied as a resistive ammonia gas sensor at room temperature. The sensitive hybrid material composed of rGO and nano-silver ink (Ag-ink) was loaded on a microstrip patch antenna to realize high-performance wireless ammonia sensors. The material was investigated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Firstly, interdigital electrodes (IDEs) printed on the polyethylene terephthalate (PET) by direct printing were employed to measure the variation of resistance of the sensitive material with the ammonia concentration. The results indicated the response of sensor varied from 4.25% to 14.7% under 15-200 ppm ammonia concentrations. Furthermore, the hybrid material was loaded on a microstrip patch antenna fabricated by a conventional printed circuit board (PCB) process, and a 10 MHz frequency shift of the sensor antenna could be observed for 200 ppm ammonia gas. Finally, the wireless sensing property of the sensor antenna was successfully tested using the same emitted antenna outside the gas chamber with a high gain of 5.48 dBi, and an increased reflection magnitude of the emitted antenna due to the frequency mismatch of the sensor antenna was observed. Therefore, wireless ammonia gas sensors loaded on a patch antenna have significant application prospects in the field of Internet of Things (IoTs).

  5. Superlubricity in vehicles. New carbon-based materials reduce fuel consumption and wear; Supraschmierung im Automobil. Neue, kohlenstoffbasierte Werkstoffe mindern Kraftstoffverbrauch und Verschleiss

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Franz

    2012-07-01

    During the long development history of mechanical engineering, engineers have substantially exhausted the traditional methods of reducing friction. Further optimisations are mostly just a matter of a few per cent. Innovative coatings made of diamond-like, shiny black carbon compounds can now exploit their advantages. They combine extraordinary lubricity with anti-adhesive properties, chemical stability and extreme material hardness. In the Pegasus research project, scientists from research and industry are working on their large-scale use for drive trains in vehicles. (orig.)

  6. Experiments to investigate particulate materials in reduced gravity fields

    Science.gov (United States)

    Bowden, M.; Eden, H. F.; Felsenthal, P.; Glaser, P. E.; Wechsler, A. E.

    1967-01-01

    Study investigates agglomeration and macroscopic behavior in reduced gravity fields of particles of known properties by measuring and correlating thermal and acoustical properties of particulate materials. Experiment evaluations provide a basis for a particle behavior theory and measure bulk properties of particulate materials in reduced gravity.

  7. Visible-light-responsive photocatalysts toward water oxidation based on NiTi-layered double hydroxide/reduced graphene oxide composite materials.

    Science.gov (United States)

    Li, Bei; Zhao, Yufei; Zhang, Shitong; Gao, Wa; Wei, Min

    2013-10-23

    A visible-light responsive photocatalyst was fabricated by anchoring NiTi-layered double hydroxide (NiTi-LDH) nanosheets to the surface of reduced graphene oxide sheets (RGO) via an in situ growth method; the resulting NiTi-LDH/RGO composite displays excellent photocatalytic activity toward water splitting into oxygen with a rate of 1.968 mmol g(-1) h(-1) and a quantum efficiency as high as 61.2% at 500 nm, which is among the most effective visible-light photocatalysts. XRD patterns and SEM images indicate that the NiTi-LDH nanosheets (diameter: 100-200 nm) are highly dispersed on the surface of RGO. UV-vis absorption spectroscopy exhibits that the introduction of RGO enhances the visible-light absorption range of photocatalysts, which is further verified by the largely decreased band gap (∼1.78 eV) studied by cyclic voltammetry measurements. Moreover, photoluminescence (PL) measurements indicate a more efficient separation of electron-hole pairs; electron spin resonance (ESR) and Raman scattering spectroscopy confirm the electrons transfer from NiTi-LDH nanosheets to RGO, accounting for the largely enhanced carrier mobility and the resulting photocatalytic activity in comparison with pristine NiTi-LDH material. Therefore, this work demonstrates a facile approach for the fabrication of visible-light responsive NiTi-LDH/RGO composite photocatalysts, which can be used as a promising candidate in solar energy conversion and environmental science.

  8. Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

    KAUST Repository

    Bai, Yaocai

    2012-06-01

    Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different pH conditions. The pH values were found to have great influence on the reduction of graphene oxides. Acidic and neutral media yielded reduced graphene oxides with more oxygen-functional groups, lower specific surface areas but broader pore size distributions than those in basic medium. Variations induced by the pH changes resulted in great differences in the supercapacitor performance. The graphene produced in the basic solution presented mainly electric double layer behavior with specific capacitance of 185 F/g, while the other two showed additional pseudocapacitance behavior with specific capacitance of 225 F/g (acidic) and 230 F/g (neutral), all at a constant current density of 1A/g. The other one is that different reduced graphene oxides were prepared via solution based hydrazine reduction, low temperature thermal reduction, and hydrothermal reduction. The as- prepared samples were then investigated by UV-vis spectroscopy, X-ray diffraction, Raman spectroscopy, and Scanning electron microscope. The supercapacitor performances were also studied and the hydrothermally reduced graphene oxide exhibited the highest specific capacitance.

  9. Materials engineering data base

    Science.gov (United States)

    1995-01-01

    The various types of materials related data that exist at the NASA Marshall Space Flight Center and compiled into databases which could be accessed by all the NASA centers and by other contractors, are presented.

  10. Strategies for reducing material costs through implementation of clinical guidelines.

    Science.gov (United States)

    Vollman, K; Sprung, P; Posa, S; Ladin, D; Kachhal, S K

    1998-01-01

    This paper presents a case study where the efforts to improve clinical guidelines resulted in significant savings in material costs through the standardization of the supplies and negotiation of contracts with the suppliers. It also presents an approach that is now being used to standardize material and reduce supply costs in other areas of the health system.

  11. An investigation on phase change materials to reduce summer overheating

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, S.; Kornadt, O. [Bauhaus-University Weimar, Weimar (Germany). Dept. of Building Physics

    2006-07-01

    The overheating problem in office buildings can be partially attributed to modern architectural constructions with high glazing facades and light-weight constructions. One way to solve the problem is to use phase change materials (PCMs) which are heat accumulators that store and release heat during the phase change process. PCMs increase the thermal mass in buildings and help reduce peak temperatures during summer hot spells. This study examined the heat storing effect of PCMs and their potential use in the building sector. In particular, 2 PCMs were examined in full scale experiments at the Bauhaus-University Weimar. The study examined the effects of PCMs placed on the surface of inner partitioning, ceilings or floors that could be numerically treated as a separate layer with room-side heat transfer one side and heat conduction to the next layers on the other side. Experimental results led to the development of a numerical description of the phase change process with and without super-cooling. The numerical description was based on temperature dependent functions for heat capacity and thermal conductivity. This presentation described the validation, stability and accuracy of the model and proposed recommendations. Simulation results of PCM-plaster with micro-encapsulated paraffin show the potential of a marketable material. In addition to optimizing the melting temperature and layer thickness, an important criterion for PCM efficiency is the number of overheating hours that can be reduced. For a European climate, a 3 cm layer thick PCM plaster with optimized peak temperature can reduce overheating hours by 25 to 50 per cent. 15 refs., 1 tab., 8 figs.

  12. Forisome Based Smart Materials

    Science.gov (United States)

    2015-03-31

    to various conditions for crystallization . (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published...forced us to reduce the total volume for crystallization . However, purified protein is currently subjected to various conditions for slow crystal growth ...proteins in a cell free wheat germ system and crystallize the proteins for x-ray diffraction and electron microscopy. While expression of the proteins was

  13. Lignin-Based Thermoplastic Materials.

    Science.gov (United States)

    Wang, Chao; Kelley, Stephen S; Venditti, Richard A

    2016-04-21

    Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors.

  14. Technetium Sorption by Cementitious Materials Under Reducing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States); Estes, Shanna L. [Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC (United States); Powell, Brian A. [Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC (United States)

    2012-09-28

    slowly until the termination of the desorption experiment after 20 days. Although the cementitious materials investigated demonstrated the ability to strongly sequester aqueous {sup 99}Tc under anoxic conditions, the introduction of oxygen resulted in the rapid remobilization of {sup 99}Tc. These studies provide experimental support for the use of a solubility based model under reducing saltstone conditions where Tc(IV) is expected to be the dominant species. The existing Kd model would be appropriate for oxidized saltstone conditions (aged saltstone, not directly evaluated in this study) where Tc(VII) is expected to be the dominant species.

  15. Technetium Sorption By Cementitious Materials Under Reducing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel I. [Savannah River National Lab., Aiken, SC (United States); Estes, Shanna L. [Clemson Univ., SC (United States). Environmental Engineering and Earth Sciences; Arai, Yuji [Clemson Univ., SC (United States). College of Agriculture, Forestry and Life Sciences; Powell, Brian A. [Clemson Univ., SC (United States). Environmental Engineering and Earth Sciences

    2013-07-18

    The objective of this study was to measure Tc sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. Earlier studies were conducted and the experimental conditions were found not to simulate those of the facility. Through a five month subcontract with Clemson University, sorption of {sup 99}Tc to four cementitious materials was examined within an anaerobic glovebag targeting a 0.1% H{sub 2}(g)/ 99.9% N{sub 2}(g) atmosphere. Early experiments based on Tc sorption and Eh indicated that 0.1% H{sub 2}(g) (a reductant) was necessary to preclude experimental impacts from O{sub 2}(g) diffusion into the glovebag. Preliminary data to date (up to 56 days) indicates that sorption of {sup 99}Tc to cementitious materials increased with increasing slag content for simulated saltstone samples. This is consistent with the conceptual model that redox active sulfide groups within the reducing slag facilitate reduction of Tc(VII) to Tc(IV). These experiments differ from previous experiments where a 2% H{sub 2}(g) atmosphere was maintained (Kaplan et al., 2011 (SRNL-STI-2010-00668)). The impact of the 2% H{sub 2}(g) reducing atmosphere on this data was examined and determined to cause the reduction of Tc in experimental samples without slag. In the present ongoing study, after 56 days, Tc sorption by the 50-year old cement samples (no slag) was undetectable, whereas Tc sorption in the cementitious materials containing slag continues to increase with contact time (measured after 1, 4, 8, 19 and 56 days). Sorption was not consistent with spike concentrations and steady state has not been demonstrated after 56 days. The average conditional K{sub d} value for the Vault 2 cementitious material was 873 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K{sub d} was 168 mL/g, and for TR545 (90% slag) the conditional K{sub d} was 1,619 mL/g. It is anticipated that additional samples will be collected until steady state

  16. Polyphosphazine-based polymer materials

    Science.gov (United States)

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  17. Network-inspired design of broadband materials with reduced dimensionality

    CERN Document Server

    Yu, Sunkyu; Hong, Jiho; Park, Namkyoo

    2016-01-01

    A network picture has been applied to various physical and biological systems not only to explore their governing mechanisms but also to develop progressive functionalities. Utilizing discretization schemes, both electrical and optical materials can also be interpreted as abstract 'graph' networks composed of couplings (edges) between local elements (vertices), which define the correlation between material structures and wave flows. Nonetheless, the fertile structural degrees of freedom in graph theory have not been fully exploited in physics owing to the suppressed long-range interaction between far-off elements. Here, by exploiting the similarity between Hamiltonians in different dimensions, we propose the design of reduced-dimensional materials that preserve the level statistics of highly complex networks with significant long-range coupling. We show that the disorder-induced removal of the level degeneracy in high-degree networks allows their isospectral projection to one-dimensional structures without an...

  18. High-albedo materials for reducing building cooling energy use

    Energy Technology Data Exchange (ETDEWEB)

    Taha, H.; Sailor, D.; Akbari, H.

    1992-01-01

    One simple and effective way to mitigate urban heat islands, i.e., the higher temperatures in cities compared to those of the surrounds, and their negative impacts on cooling energy consumption is to use high-albedo materials on major urban surfaces such as rooftops, streets, sidewalks, school yards, and the exposed surfaces of parking lots. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building`s envelope (direct effect) and also by lowering the urban air temperature in the neighborhood of the building (indirect effect). This project is an attempt to address high-albedo materials for buildings and to perform measurements of roof coatings. We search for existing methods and materials to implement fighter colors on major building and urban surfaces. Their cost effectiveness are examined and the possible related technical, maintenance, and environmental problems are identified. We develop a method for measuring albedo in the field by studying the instrumentation aspects of such measurements. The surface temperature impacts of various albedo/materials in the actual outdoor environment are studied by measuring the surface temperatures of a variety of materials tested on an actual roof. We also generate an albedo database for several urban surfaces to serve as a reference for future use. The results indicate that high-albedo materials can have a large impact on the surface temperature regime. On clear sunny days, when the solar noon surface temperatures of conventional roofing materials were about 40{degrees}C (72{degrees}F) warmer than air, the surface temperature of high-albedo coatings were only about 5{degrees}C warmer than air. In the morning and in the late afternoon, the high-albedo materials were as cool as the air itself. While conventional roofing materials warm up by an average 0.055{degrees}C/(W m{sup {minus}2}), the high-albedo surfaces warm up by an average 0.015{degrees}C/(W m{sup {minus}2}).

  19. High-albedo materials for reducing building cooling energy use

    Energy Technology Data Exchange (ETDEWEB)

    Taha, H.; Sailor, D.; Akbari, H.

    1992-01-01

    One simple and effective way to mitigate urban heat islands, i.e., the higher temperatures in cities compared to those of the surrounds, and their negative impacts on cooling energy consumption is to use high-albedo materials on major urban surfaces such as rooftops, streets, sidewalks, school yards, and the exposed surfaces of parking lots. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building's envelope (direct effect) and also by lowering the urban air temperature in the neighborhood of the building (indirect effect). This project is an attempt to address high-albedo materials for buildings and to perform measurements of roof coatings. We search for existing methods and materials to implement fighter colors on major building and urban surfaces. Their cost effectiveness are examined and the possible related technical, maintenance, and environmental problems are identified. We develop a method for measuring albedo in the field by studying the instrumentation aspects of such measurements. The surface temperature impacts of various albedo/materials in the actual outdoor environment are studied by measuring the surface temperatures of a variety of materials tested on an actual roof. We also generate an albedo database for several urban surfaces to serve as a reference for future use. The results indicate that high-albedo materials can have a large impact on the surface temperature regime. On clear sunny days, when the solar noon surface temperatures of conventional roofing materials were about 40{degrees}C (72{degrees}F) warmer than air, the surface temperature of high-albedo coatings were only about 5{degrees}C warmer than air. In the morning and in the late afternoon, the high-albedo materials were as cool as the air itself. While conventional roofing materials warm up by an average 0.055{degrees}C/(W m{sup {minus}2}), the high-albedo surfaces warm up by an average 0.015{degrees}C/(W m{sup {minus}2}).

  20. Protein-based composite materials

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    2012-05-01

    Full Text Available Protein-based composite biomaterials have been actively pursued as they can encompass a range of physical properties to accommodate a broader spectrum of functional requirements, such as elasticity to support diverse tissues. By optimizing molecular interfaces between structural proteins, useful composite materials can be fabricated as films, gels, particles, and fibers, as well as for electrical and optical devices. Such systems provide analogies to more traditional synthetic polymers yet with expanded utility due to the material's tunability, mechanical properties, degradability, biocompatibility, and functionalization, such as for drug delivery, biosensors, and tissue regeneration.

  1. Conductive polymer-based material

    Science.gov (United States)

    McDonald, William F.; Koren, Amy B.; Dourado, Sunil K.; Dulebohn, Joel I.; Hanchar, Robert J.

    2007-04-17

    Disclosed are polymer-based coatings and materials comprising (i) a polymeric composition including a polymer having side chains along a backbone forming the polymer, at least two of the side chains being substituted with a heteroatom selected from oxygen, nitrogen, sulfur, and phosphorus and combinations thereof; and (ii) a plurality of metal species distributed within the polymer. At least a portion of the heteroatoms may form part of a chelation complex with some or all of the metal species. In many embodiments, the metal species are present in a sufficient concentration to provide a conductive material, e.g., as a conductive coating on a substrate. The conductive materials may be useful as the thin film conducting or semi-conducting layers in organic electronic devices such as organic electroluminescent devices and organic thin film transistors.

  2. Method of Reducing Consumption of 3 D Printing Materials Based on Model Structure Optimization%基于模型结构优化的降低3D打印材料消耗方法

    Institute of Scientific and Technical Information of China (English)

    王洁瑜; 董方敏

    2016-01-01

    3D printing technology is a new and high technology based on the principle of increasing material manufacturing,which is the continuation and development of rapid prototyping technology with increasing expansion and popularity. Currently,the research hotspot of 3D printing is concentrated on principle and structure for 3D printer,and free forming process,materials,costs for 3D printing. How to re-duce material consumption in order to lower the cost of 3D printing is one of the most important research. Optimizing the model structure and reducing material consumption is currently commonly used. From the viewpoint of using the model structure optimization method to lower the 3D printing costs,the basic principles of the model structure optimization is described,and several typical algorithms are intro-duced for reducing the material 3D printing consumption based on model structure optimization method. Then the characteristics of the al-gorithms and their application areas are analyzed. Finally,several possible future research directions in the area are pointed out.%3D打印技术是基于增材制造法原理的一种高新技术,是快速成型技术的延续与发展,其应用领域正在不断扩大和普及。目前,对3D打印方面的研究热点集中在3D打印机的原理和结构、3D打印自由成形工艺、3D打印材料、3D打印成本等方面。如何减少材料消耗来降低3D打印成本是其中重要的研究内容之一,而通过优化模型结构来减少材料的消耗是目前常用的方法。从采用对模型结构进行优化的方法来降低3D打印成本的角度,阐述了模型结构优化的基本原理,介绍了几类典型的基于模型结构优化技术降低3D打印材料消耗的算法,分析了各种算法的特点及适用领域,并指出了未来可能的研究内容和方向。

  3. Carbohydrate based materials for gamma radiation shielding

    Science.gov (United States)

    Tabbakh, F.; Babaee, V.; Naghsh-Nezhad, Z.

    2015-05-01

    Due to the limitation in using lead as a shielding material for its toxic properties and limitation in abundance, price or non-flexibility of other commonly used materials, finding new shielding materials and compounds is strongly required. In this conceptual study carbohydrate based compounds were considered as new shielding materials. The simulation of radiation attenuation is performed using MCNP and Geant4 with a good agreement in the results. It is found that, the thickness of 2 mm of the proposed compound may reduce up to 5% and 50% of 1 MeV and 35 keV gamma-rays respectively in comparison with 15% and 100% for the same thickness of lead.

  4. LONG-TERM TECHNETIUM INTERACTIONS WITH REDUCING CEMENTITIOUS MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D.; Lilley, M.; Almond, P.; Powell, B.

    2011-03-15

    Technetium is among the key risk drivers at the Saltstone Facility. The way that it is immobilized in this cementitious waste form is by converting its highly mobile Tc(VII) form to a much less mobile Tc(IV) form through reduction by the cement's blast furnace slag. This report includes a review of published data and experimental results dealing with Tc leaching from Portland cement waste forms. The objectives for the literature study were to document previous reports of Tc interactions with slag-containing cementitious materials. The objectives for the laboratory study were to measure Tc-saltstone Kd values under reducing conditions. From the literature it was concluded: (1) Spectroscopic evidence showed that when Tc(IV) in a slag-cement was exposed to an oxidizing environment, it will convert to the more mobile Tc(VII) species within a short time frame, 2.5 years. (2) SRS saltstone will reduce Tc(VII) in the absence of NaS or sodium dithionite in a reducing atmosphere. (3) Only trace concentrations of atmospheric oxygen (30 to 60 ppm O{sub 2}; Eh 120 mV) at the high pH levels of cementitious systems is required to maintain Tc as Tc(VII). (4) Experimental conditions must be responsible for wide variability of measured K{sub d} values, such that they are either very low, {approx}1 mL/g, or they are very high {approx}1000 mL/g, suggesting that Tc(VII) or Tc(IV) dominate the systems. Much of this variability appears to be the result of experimental conditions, especially direct controls of oxygen contact with the sample. (5) A field study conducted at SRS in the 1980s indicated that a slag-saltstone immobilized Tc for 2.5 years. Below background concentrations of Tc leached out of the slag-containing saltstone, whereas Tc leached out of the slag-free saltstone at the rate of nitrate loss. One possible explanation for the immobilization of Tc in this study was that the slag-saltstone maintained reducing conditions within the core of the 55-gallon sample, whereas

  5. Ground based materials science experiments

    Science.gov (United States)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  6. Ground based materials science experiments

    Science.gov (United States)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  7. Materials design data for reduced activation martensitic steel type EUROFER

    Science.gov (United States)

    Tavassoli, A.-A. F.; Alamo, A.; Bedel, L.; Forest, L.; Gentzbittel, J.-M.; Rensman, J.-W.; Diegele, E.; Lindau, R.; Schirra, M.; Schmitt, R.; Schneider, H. C.; Petersen, C.; Lancha, A.-M.; Fernandez, P.; Filacchioni, G.; Maday, M. F.; Mergia, K.; Boukos, N.; Baluc; Spätig, P.; Alves, E.; Lucon, E.

    2004-08-01

    Materials design limits derived so far from the data generated in Europe for the reduced activation ferritic/martensitic (RAFM) steel type Eurofer are presented. These data address the short-term needs of the ITER Test Blanket Modules and a DEMOnstration fusion reactor. Products tested include plates, bars, tubes, TIG and EB welds, as well as powder consolidated blocks and solid-solid HIP joints. Effects of thermal ageing and low dose neutron irradiation are also included. Results are sorted and screened according to design code requirements before being introduced in reference databases. From the physical properties databases, variations of magnetic properties, modulus of elasticity, density, thermal conductivity, thermal diffusivity, specific heat, mean and instantaneous linear coefficients of thermal expansion versus temperature are derived. From the tensile and creep properties databases design allowable stresses are derived. From the instrumented Charpy impact and fracture toughness databases, ductile to brittle transition temperature, toughness and behavior of materials in different fracture modes are evaluated. From the fatigue database, total strain range versus number of cycles to failure curves are plotted and used to derive fatigue design curves. Cyclic curves are also derived and compared with monotonic hardening curves. Finally, irradiated and aged materials data are compared to ensure that the safety margins incorporated in unirradiated design limits are not exceeded.

  8. Action Course and Mechanism of Shrinkage Reducing Admixture in Cement Based Materials%减缩剂在水泥基材料中的作用历程与机理研究

    Institute of Scientific and Technical Information of China (English)

    王智; 郭清春; 江楠; 钱觉时; 党玉栋

    2012-01-01

    研究了2种减缩剂被水泥熟料、矿渣和粉煤灰等固体颗粒吸附的性质及其对水溶液和模拟水泥石孔隙溶液表面张力、蒸发速率的影响.结果表明:水泥熟料、矿渣和粉煤灰等固体颗粒对2种减缩剂的平均吸附率小于10%,有90%以上减缩剂溶于溶液中;2种减缩剂溶于水或模拟水泥石孔隙溶液中均能有效降低溶液的表面张力和蒸发速率.减缩剂的作用历程和机理为:溶解于水泥石孔隙溶液中的减缩剂能长期稳定地降低溶液的表面张力,从而减少因毛细孔失水所产生的收缩应力,此外还能在一定程度上降低溶液的蒸发速率,这两方面的共同作用抑制了水泥基材料的收缩.%The adsorption of two shrinkage reducing admixtures(SRAs) on the surface of solid particles, such as cement clinker, slag and fly ash were investigated. Besides, the effect of SRA on surface tension and evaporation rate of water solution and simulated pore solution(SPS) were researched as well. The results indicate that the average adsorption rate of SRA on the surface of solid particles is less than 10% , so more than 90% of SRA remains in solution. The SRAs can significantly reduce the surface tension and e-vaporation of water solution and SPS. The action course and mechanism of SRA can be considered as the fact that the shrinkage reduction of cement based materials is resulted from the dissolution of SRA in the pore solution leading to significant reduction of surface tension of pore solution. Meanwhile, the SRA lowers the evaporation rate of the solution. These two effects may be the main causes of shrinkage reduction of cement based materials.

  9. Vanadium based materials as electrode materials for high performance supercapacitors

    Science.gov (United States)

    Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

    2016-10-01

    As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

  10. Chiral quantum dot based materials

    Science.gov (United States)

    Govan, Joseph; Loudon, Alexander; Baranov, Alexander V.; Fedorov, Anatoly V.; Gun'ko, Yurii

    2014-05-01

    Recently, the use of stereospecific chiral stabilising molecules has also opened another avenue of interest in the area of quantum dot (QD) research. The main goal of our research is to develop new types of technologically important quantum dot materials containing chiral defects, study their properties and explore their applications. The utilisation of chiral penicillamine stabilisers allowed the preparation of new water soluble white emitting CdS quantum nanostructures which demonstrated circular dichroism in the band-edge region of the spectrum. It was also demonstrated that all three types of QDs (D-, L-, and Rac penicillamine stabilised) show very broad emission bands between 400 and 700 nm due to defects or trap states on the surfaces of the nanocrystals. In this work the chiral CdS based quantum nanostructures have also been doped by copper metal ions and new chiral penicilamine stabilized CuS nanoparticles have been prepared and investigated. It was found that copper doping had a strong effect at low levels in the synthesis of chiral CdS nanostructures. We expect that this research will open new horizons in the chemistry of chiral nanomaterials and their application in biotechnology, sensing and asymmetric synthesis.

  11. Biocompatibility of Resin-based Dental Materials

    OpenAIRE

    Keyvan Moharamzadeh; Ian M. Brook; Richard van Noort

    2009-01-01

    Oral and mucosal adverse reactions to resin-based dental materials have been reported. Numerous studies have examined thebiocompatibility of restorative dental materials and their components, and a wide range of test systems for the evaluation of the biological effects of these materials have been developed. This article reviews the biological aspects of resin-based dental materials and discusses the conventional as well as the new techniques used for biocompatibility assessment of dental mat...

  12. Surface Functionalization of Graphene-based Materials

    Science.gov (United States)

    Mathkar, Akshay

    Graphene-based materials have generated tremendous interest in the past decade. Manipulating their characteristics using wet-chemistry methods holds distinctive value, as it provides a means towards scaling up, while not being limited by yield. The majority of this thesis focuses on the surface functionalization of graphene oxide (GO), which has drawn tremendous attention as a tunable precursor due to its readily chemically manipulable surface and richly functionalized basal plane. Firstly, a room-temperature based method is presented to reduce GO stepwise, with each organic moiety being removed sequentially. Characterization confirms the carbonyl group to be reduced first, while the tertiary alcohol is reduced last, as the optical gap decrease from 3.5 eV down to 1 eV. This provides greater control over GO, which is an inhomogeneous system, and is the first study to elucidate the order of removal of each functional group. In addition to organically manipulating GO, this thesis also reports a chemical methodology to inorganically functionalize GO and tune its wetting characteristics. A chemical method to covalently attach fluorine atoms in the form of tertiary alkyl fluorides is reported, and confirmed by MAS 13C NMR, as two forms of fluorinated graphene oxide (FGO) with varying C/F and C/O ratios are synthesized. Introducing C-F bonds decreases the overall surface free energy, which drastically reduces GO's wetting behavior, especially in its highly fluorinated form. Ease of solution processing leads to development of sprayable inks that are deposited on a range of porous and nonporous surfaces to impart amphiphobicity. This is the first report that tunes the wetting characteristics of GO. Lastly as a part of a collaboration with ConocoPhillips, another class of carbon nanomaterials - carbon nanotubes (CNTs), have been inorganically functionalized to repel 30 wt% MEA, a critical solvent in CO 2 recovery. In addition to improving the solution processability of CNTs

  13. Negative Dielectric Constant Material Based on Ion Conducting Materials

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2017-01-01

    Metamaterials or artificial negative index materials (NIMs) have generated great attention due to their unique and exotic electromagnetic properties. One exemplary negative dielectric constant material, which is an essential key for creating the NIMs, was developed by doping ions into a polymer, a protonated poly (benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at megahertz (MHz) frequencies due to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency were tunable by doping concentration. The highly doped PBI showed larger absolute magnitude of negative dielectric constant at just above its resonance frequency than the less doped PBI.

  14. Negative Dielectric Constant Material Based on Ion Conducting Materials

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2014-01-01

    Metamaterials or artificial negative index materials (NIMs) have generated great attention due to their unique and exotic electromagnetic properties. One exemplary negative dielectric constant material, which is an essential key for creating the NIMs, was developed by doping ions into a polymer, a protonated poly(benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at megahertz (MHz) frequencies due to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency were tunable by doping concentration. The highly doped PBI showed larger absolute magnitude of negative dielectric constant at just above its resonance frequency than the less doped PBI.

  15. Reduced graphene oxide based flexible organic charge trap memory devices

    Science.gov (United States)

    Rani, Adila; Song, Ji-Min; Jung Lee, Mi; Lee, Jang-Sik

    2012-12-01

    A nonvolatile organic transistor memory device was developed using layer-by-layer assembly of 3-aminopropyltriethoxysilane (APTES) and solution-processed, reduced graphene oxide (rGO) as the charge trapping layer on flexible substrates. Reduction of graphene oxide and successful adsorption of the rGO on APTES-covered substrates were confirmed. The organic memory devices based on rGO exhibited reliable programmable memory operations, confirmed by program/erase operations, data retention, and endurance properties. These methods can potentially play a significant role in the fabrication of next-generation flexible nonvolatile memory devices based on graphene materials.

  16. Development of starch-based materials

    NARCIS (Netherlands)

    Habeych Narvaez, E.A.

    2009-01-01

    Starch-based materials show potential as fully degradable plastics. However, the current applicability of these materials is limited due to their poor moisture tolerance and mechanical properties. Starch is therefore frequently blended with other polymers to make the material more suitable for sp

  17. Development of starch-based materials

    NARCIS (Netherlands)

    Habeych Narvaez, E.A.

    2009-01-01

    Starch-based materials show potential as fully degradable plastics. However, the current applicability of these materials is limited due to their poor moisture tolerance and mechanical properties. Starch is therefore frequently blended with other polymers to make the material more suitable for

  18. Improving material management to reduce greenhouse gas emissions

    NARCIS (Netherlands)

    Hekkert, Marko Peter

    2001-01-01

    Climate change due to greenhouse gas emissions caused by human actions is probably one of the major global environmental problems that we face today. In order to reduce the risk of climate change and the potential effects thereof, the emission of greenhouse gases like carbon dioxide (CO2) and methan

  19. Starch-based completely biodegradable polymer materials

    Directory of Open Access Journals (Sweden)

    2009-06-01

    Full Text Available Starch is a natural polymer which possesses many unique properties and some shortcoming simultaneously. Some synthetic polymers are biodegradable and can be tailor-made easily. Therefore, by combining the individual advantages of starch and synthetic polymers, starch-based completely biodegradable polymers (SCBP are potential for applications in biomedical and environmental fields. Therefore it received great attention and was extensively investigated. In this paper, the structure and characteristics of starch and some synthetic degradable polymers are briefly introduced. Then, the recent progress about the preparation of SCBP via physical blending and chemical modification is reviewed and discussed. At last, some examples have been presented to elucidate that SCBP are promising materials for various applications and their development is a good solution for reducing the consumption of petroleum resources and environmental problem.

  20. Nanoporous Silicon Based Energetic Materials

    Science.gov (United States)

    2008-12-01

    performed at SINTEF , Norway as shown in Figure 4 (line a). 3 Annealing PSi in air at different temperatures can be used to change the surface...3h (c)PSi annealed at 500C for 0.5 h (courtesy SINTEF ) e is C d magnification bright field TEM image of PSi-Fe2O3. The inset electron...Dr. Knut Thorshaug and Dr Diplos Spyros of SINTEF Norway for DRIFTS and XPS data. REFERENCES dvanced Energetics Materials, 2004; report byA ring

  1. LDEF materials special investigation group's data bases

    Science.gov (United States)

    Strickland, John W.; Funk, Joan G.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) was composed of and contained a wide array of materials, representing the largest collection of materials flown for space exposure and returned for ground-based analyses to date. The results and implications of the data from these materials are the foundation on which future space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been tasked with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the space user community in an easily accessed, user-friendly form. The format and content of the data bases developed or being developed to accomplish this task are discussed. The hardware and software requirements for each of the three data bases are discussed along with current availability of the data bases.

  2. Materiality in a practice-based approach

    DEFF Research Database (Denmark)

    Svabo, Connie

    2009-01-01

    The paper provides an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Common terms for materiality are 'artifact' and 'object'. The interaction between social and material realities is grasped as several processes: object-oriented a......The paper provides an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Common terms for materiality are 'artifact' and 'object'. The interaction between social and material realities is grasped as several processes: object......-oriented activity, symbolization, embodiment, performance, alignment and mediation. Material artifacts both stabilize and destabilize organizational action. They may ensure coordination, communication, and control, but they may also create disturbance and conflict....

  3. PDMAEMA based gene delivery materials

    Directory of Open Access Journals (Sweden)

    Seema Agarwal

    2012-09-01

    Full Text Available Gene transfection is the transfer of genetic material like DNA into cells. Cationic polymers which form nanocomplexes with DNA, so-called non-viral gene vectors, are a highly promising platform for efficient gene transfection. Despite intensive research efforts and some of the on-going clinical trials on gene transfection, none of the existing cationic polymer systems are generally acceptable for human gene therapy. Since the process of gene transfection is complex and puts different challenges and demands on the delivery system, there is a strong requirement for the design and development of a multifunctional system in a simple way. This review will discuss recent efforts in design, synthesis, and performance of poly(2-dimethylaminoethyl methacrylate (PDMAEMA nanocomplexes with DNA.

  4. New Cork-Based Materials and Applications

    Directory of Open Access Journals (Sweden)

    Luís Gil

    2015-02-01

    Full Text Available This review work is an update of a previous work reporting the new cork based materials and new applications of cork based materials. Cork is a material which has been used for multiple applications. The most known uses of cork are in stoppers (natural and agglomerated cork for alcoholic beverages, classic floor covering with composite cork tiles (made by the binding of cork particles with different binders, and thermal/acoustic/vibration insulation with expanded corkboard in buildings and some other industrial fields. Many recent developments have been made leading to new cork based materials. Most of these newly developed cork materials are not yet on the market, but they represent new possibilities for engineers, architects, designers and other professionals which must be known and considered, potentially leading to their industrialization. This paper is a review covering the last five years of innovative cork materials and applications also mentioning previous work not reported before.

  5. Whole Language-Based English Reading Materials

    Directory of Open Access Journals (Sweden)

    Dian Erlina

    2016-05-01

    Full Text Available This Research and Development (R&D aims at developing English reading materials for undergraduate EFL students of Universitas Islam Negeri (UIN Raden Fatah Palembang, Indonesia. Research data were obtained through questionnaires, tests, and documents. The results of the research show that the existing materials are not relevant to the students’ need, so there is a need for developing new materials based on whole language principles. In general, the new developed materials are considered reliable by the experts, students, and lecturers. The materials are also effective in improving students’ reading achievement. The final product of the materials consists of a course book entitled Whole Language Reading (WLR and a teacher’s manual. WLR provides rich input of reading strategies, variety of topics, concepts, texts, activities, tasks, and evaluations. Using this book makes reading more holistic and meaningful as it provides integration across language skills and subject areas. Keywords: materials development, reading materials, whole language

  6. REDUCED THROMBOGENICITY OF ARTIFICIAL MATERIALS BY COATING WITH ADPASE

    NARCIS (Netherlands)

    BAKKER, WW; VANDERLEI, B; NIEUWENHUIS, P; ROBINSON, P; Bartels, H.

    1991-01-01

    A novel coating solution for the improvement of biocompatibility of polyurethane-based vascular prostheses was tested in rabbits and rats in vivo. Segments of coated and uncoated vascular prostheses were implanted into the peritoneal cavity of rats, followed by induction of experimental haemorrhage;

  7. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  8. Research on the additives to reduce radioactive pollutants in the building materials containing fly ash.

    Science.gov (United States)

    He, Deng-liang; Yin, Guang-fu; Dong, Fa-qin; Liu, Lai-bao; Luo, Ya-jun

    2010-05-15

    Several kinds of functional additives such as barite, zeolite, ferric oxide, gypsum, and high alumina cement were introduced to prepare a low-radiation cement-based composite to reduce radioactive pollutants contained in fly ash. The effect of content and granularity of the functional additives on the release of radioactive pollutants were investigated. Composites were characterized by X-ray diffraction, Scan electron microscopy. The results indicate that the radioactive pollutants contained in the fly ash can be reduced by adding a proper amount of zeolite, ferric oxide, gypsum, and high alumina cement. The release of radon from fly ash decreases with a decrease in the granularity of additives. Compared with traditional cement-based composite containing fly ash, the release of radon can be reduced 64.8% in these composites, and the release of gamma-ray is decreased 45%. Based on the microstructure and phase analysis, we think that by added functional additives, there are favorable to form self-absorption of radioactivity in the interior composites. This cement-based composite will conducive to fly ash are large-scale applied in the field of building materials.

  9. Material Recognition for Content Based Image Retrieval

    NARCIS (Netherlands)

    Geusebroek, J.M.

    2002-01-01

    One of the open problems in content-based Image Retrieval is the recognition of material present in an image. Knowledge about the set of materials present gives important semantic information about the scene under consideration. For example, detecting sand, sky, and water certainly classifies the im

  10. Material Recognition for Content Based Image Retrieval

    NARCIS (Netherlands)

    Geusebroek, J.M.

    2002-01-01

    One of the open problems in content-based Image Retrieval is the recognition of material present in an image. Knowledge about the set of materials present gives important semantic information about the scene under consideration. For example, detecting sand, sky, and water certainly classifies the

  11. New nonlinear optical materials based on ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J P [Department of Physics, Fudan University, Shanghai 200433 (China); Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Institute of Theoretical Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Yu, K W [Department of Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Institute of Theoretical Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China)

    2006-01-01

    We exploit theoretically a new class of magneto-controlled nonlinear optical material based on ferrofluids in which ferromagnetic nanoparticles are coated with a nonmagnetic metallic nonlinear shell. Such an optical material can have anisotropic nonlinear optical properties and a giant enhancement of nonlinearity, as well as an attractive figure of merit.

  12. Materiality in a Practice-Based Approach

    Science.gov (United States)

    Svabo, Connie

    2009-01-01

    Purpose: The paper aims to provide an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Design/methodology/approach: The overview is theoretically generated and is based on the anthology Knowing in Organizations: A Practice-based Approach edited by Nicolini, Gherardi and Yanow. The…

  13. Effect of Modifying Prosthetic Socket Base Materials by Adding Nanodiamonds

    Directory of Open Access Journals (Sweden)

    Lifang Ma

    2015-01-01

    Full Text Available The curing process of prosthetic socket base materials requires attention owing to a series of associated problems that are yet to be addressed and solved. However, to date, few relevant studies have been reported. In this paper, nanodiamonds modified with a silane coupling agent were dispersed into a prosthetic socket base material, and the performance of the modified base materials was investigated. Adding a predetermined amount of nanodiamonds to the prosthetic socket base material increased the glass transition temperature, improved the mechanical properties of the cured base material, and reduced the influence of the volatile gas formed during the curing process on the environment. With increasing nanodiamond contents, the glass transition temperature increased and the mechanical properties improved slightly. Owing to the high thermal conductivity of the nanodiamonds, the localized heat, as a result of the curing process, could be dissipated and released. Thus, adding nanodiamonds led to a more uniform temperature field forming in the curing system. This improved the curing process and reduced the formation of volatile monomers, thereby decreasing the adverse impact of the generated volatile gases on the environment. All of these provide a potential strategy for modifying prosthetic socket base materials.

  14. Smart material-based radiation sources

    Science.gov (United States)

    Kovaleski, Scott

    2014-10-01

    From sensors to power harvesters, the unique properties of smart materials have been exploited in numerous ways to enable new applications and reduce the size of many useful devices. Smart materials are defined as materials whose properties can be changed in a controlled and often reversible fashion by use of external stimuli, such as electric and magnetic fields, temperature, or humidity. Smart materials have been used to make acceleration sensors that are ubiquitous in mobile phones, to make highly accurate frequency standards, to make unprecedentedly small actuators and motors, to seal and reduce friction of rotating shafts, and to generate power by conversion of either kinetic or thermal energy to electrical energy. The number of useful devices enabled by smart materials is large and continues to grow. Smart materials can also be used to generate plasmas and accelerate particles at small scales. The materials discussed in this talk are from non-centrosymmetric crystalline classes including piezoelectric, pyroelectric, and ferroelectric materials, which produce large electric fields in response to external stimuli such as applied electric fields or thermal energy. First, the use of ferroelectric, pyroelectric and piezoelectric materials for plasma generation and particle acceleration will be reviewed. The talk will then focus on the use of piezoelectric materials at the University of Missouri to construct plasma sources and electrostatic accelerators for applications including space propulsion, x-ray imaging, and neutron production. The basic concepts of piezoelectric transformers, which are analogous to conventional magnetic transformers, will be discussed, along with results from experiments over the last decade to produce micro-thrusters for space propulsion and particle accelerators for x-ray and neutron production. Support from ONR, AFOSR, and LANL.

  15. Status and key issues of reduced activation ferritic/martensitic steels as the structural material for a DEMO blanket

    Science.gov (United States)

    Tanigawa, H.; Shiba, K.; Möslang, A.; Stoller, R. E.; Lindau, R.; Sokolov, M. A.; Odette, G. R.; Kurtz, R. J.; Jitsukawa, S.

    2011-10-01

    The status and key issues of reduced activation ferritic/martensitic (RAFM) steels R&D are reviewed as the primary candidate structural material for fusion energy demonstration reactor blankets. This includes manufacturing technology, the as-fabricated and irradiates material database and joining technologies. The review indicated that the manufacturing technology, joining technology and database accumulation including irradiation data are ready for initial design activity, and also identifies various issues that remain to be solved for engineering design activity and qualification of the material for international fusion material irradiation facility (IFMIF) irradiation experiments that will validate the data base.

  16. Status and key issues of reduced activation ferritic/martensitic steels as the structural material for a DEMO blanket

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, Hiroyasu [ORNL; Stoller, Roger E [ORNL; Sokolov, Mikhail A [ORNL; Odette, G.R. [University of California, Santa Barbara; Jitsukawa, Shiro [Japan Atomic Energy Agency (JAEA); Shiba, K. [Japan Atomic Energy Agency (JAEA); Kurtz, Richard [Pacific Northwest National Laboratory (PNNL); Moeslang, A. [Forschungszentrum Karlsruhe, Karlsruhe, Germany; Lindau, R. [Forschungszentrum Karlsruhe, Karlsruhe, Germany

    2011-01-01

    The status and key issues of reduced activation ferritic/martensitic (RAFM) steels R&D are reviewed as the primary candidate structural material for fusion energy demonstration reactor blankets. This includes manufacturing technology, the as-fabricated and irradiates material database and joining technologies. The review indicated that the manufacturing technology, joining technology and database accumulation including irradiation data are ready for initial design activity, and also identifies various issues that remain to be solved for engineering design activity and qualification of the material for international fusion material irradiation facility (IFMIF) irradiation experiments that will validate the data base.

  17. Towards a Skill-Based Music Education in Reducing Poverty and ...

    African Journals Online (AJOL)

    Towards a Skill-Based Music Education in Reducing Poverty and Enacting Leadership Quality in Nigeria. ... research materials for effective teaching and learning of music education in secondary schools in order to inculcate in the students ...

  18. Electronics based on two-dimensional materials.

    Science.gov (United States)

    Fiori, Gianluca; Bonaccorso, Francesco; Iannaccone, Giuseppe; Palacios, Tomás; Neumaier, Daniel; Seabaugh, Alan; Banerjee, Sanjay K; Colombo, Luigi

    2014-10-01

    The compelling demand for higher performance and lower power consumption in electronic systems is the main driving force of the electronics industry's quest for devices and/or architectures based on new materials. Here, we provide a review of electronic devices based on two-dimensional materials, outlining their potential as a technological option beyond scaled complementary metal-oxide-semiconductor switches. We focus on the performance limits and advantages of these materials and associated technologies, when exploited for both digital and analog applications, focusing on the main figures of merit needed to meet industry requirements. We also discuss the use of two-dimensional materials as an enabling factor for flexible electronics and provide our perspectives on future developments.

  19. Triarylborane-Based Materials for OLED Applications

    Directory of Open Access Journals (Sweden)

    Gulsen Turkoglu

    2017-09-01

    Full Text Available Multidisciplinary research on organic fluorescent molecules has been attracting great interest owing to their potential applications in biomedical and material sciences. In recent years, electron deficient systems have been increasingly incorporated into fluorescent materials. Triarylboranes with the empty p orbital of their boron centres are electron deficient and can be used as strong electron acceptors in conjugated organic fluorescent materials. Moreover, their applications in optoelectronic devices, energy harvesting materials and anion sensing, due to their natural Lewis acidity and remarkable solid-state fluorescence properties, have also been investigated. Furthermore, fluorescent triarylborane-based materials have been commonly utilized as emitters and electron transporters in organic light emitting diode (OLED applications. In this review, triarylborane-based small molecules and polymers will be surveyed, covering their structure-property relationships, intramolecular charge transfer properties and solid-state fluorescence quantum yields as functional emissive materials in OLEDs. Also, the importance of the boron atom in triarylborane compounds is emphasized to address the key issues of both fluorescent emitters and their host materials for the construction of high-performance OLEDs.

  20. Reduced cost design of liquid lithium target for international fusion material irradiation facility (IFMIF)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hiroo; Ida, Mizuho; Sugimoto, Masayoshi; Takeuchi, Hiroshi [Department of Fussion Engineering Research, Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Yutani, Toshiaki [Toshiba Corp., Tokyo (Japan)

    2001-01-01

    The International Fusion Materials Irradiation Facility (IFMIF) is being jointly planned to provide an accelerator-based D-Li neutron source to produce intense high energy neutrons (2 MW/m{sup 2}) up to 200 dpa and a sufficient irradiation volume (500 cm{sup 3}) for testing the candidate materials and components up to about a full lifetime of their anticipated use in ITER and DEMO. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid lithium flow with a speed of 20 m/s. Following Conceptual Design Activity (1995-1998), a design study with focus on cost reduction without changing its original mission has been done in 1999. The following major changes to the CAD target design have been considered in the study and included in the new design: i) number of the Li target has been changed from 2 to 1, ii) spare of impurity traps of the Li loop was removed although the spare will be stored in a laboratory for quick exchange, iii) building volume was reduced via design changes in lithium loop length. This paper describes the reduced cost design of the lithium target system and recent status of Key Element Technology activities. (author)

  1. Finite Element Analysis of Functionally Graded Material to Reduce Crazing in Transparent Armor

    Science.gov (United States)

    2015-09-01

    UNCLASSIFIED AD-E403 681 Technical Report ARMET-TR-14042 FINITE ELEMENT ANALYSIS OF FUNCTIONALLY GRADED MATERIAL TO REDUCE...prevent disclosure of its contents or reconstruction of the document. Do not return to the originator. UNCLASSIFIED REPORT DOCUMENTATION PAGE Form...September 2012 to April 2013 4. TITLE AND SUBTITLE FINITE ELEMENT ANALYSIS OF FUNCTIONALLY GRADED MATERIAL TO REDUCE CRAZING IN TRANSPARENT ARMOR

  2. Study of New Materials Design based on Hadoop

    Directory of Open Access Journals (Sweden)

    Wu Jun

    2016-01-01

    Full Text Available With the rapid development of information technology, the scientific research shows that the data mining and other information technology could be used in the design of new materials. It is explicit that Intelligent Materials research focuses on using physical and chemical principles combined with computer techniques such as Big Data, Cloud computing and Intelligent modeling and simulation to solve chemical problems. In this paper, based on the cluster based outlier algorithm as the main body, this paper discusses the definition New Materials research In the Hadoop cloud platform, and the parallel processing of Map-Reduce model. The performance this model of new material was established by using the method of Map-Reduction provided the basis for the performance optimization.

  3. Doping To Reduce Base Resistances Of Bipolar Transistors

    Science.gov (United States)

    Lin, True-Lon

    1991-01-01

    Modified doping profile proposed to reduce base resistance of bipolar transistors. A p/p+ base-doping profile reduces base resistance without reducing current gain. Proposed low/high base-doping profile realized by such low-temperature deposition techniques as molecular-beam epitaxy, ultra-high-vacuum chemical-vapor deposition, and limited-reaction epitaxy. Produces desired doping profiles without excessive diffusion of dopant.

  4. Reduced order observer based identification of base isolated buildings

    Institute of Scientific and Technical Information of China (English)

    Satish Nagarajaiah; Prasad Dharap

    2003-01-01

    The objective of this study is to identify system parameters from the recorded response of base isolated buildings, such as USC hospital building, during the 1994 Northridge earthquake. Full state measurements are not available for identification. Additionally, the response is nonlinear due to the yielding of the lead-rubber bearings. Two new approaches are presented in this paper to solve the aforementioned problems. First, a reduced order observer is used to estimate the unmeasured states. Second, a least squares technique with time segments is developed to identify the piece-wise linear system properties. The observer is used to estimate the initial conditions needed for the time segmented identification. A series of equivalent linear system parameters are identified in different time segments. It is shown that the change in system parameters, such as frequencies and damping ratios, due to nonlinear behavior of the lead-rubber bearings, are reliably estimated using the presented technique. It is shown that the response was reduced due to yielding of the lead-rubber bearings and period lengthening.

  5. Microemulsion-based synthesis of nanocrystalline materials.

    Science.gov (United States)

    Ganguli, Ashok K; Ganguly, Aparna; Vaidya, Sonalika

    2010-02-01

    Microemulsion-based synthesis is found to be a versatile route to synthesize a variety of nanomaterials. The manipulation of various components involved in the formation of a microemulsion enables one to synthesize nanomaterials with varied size and shape. In this tutorial review several aspects of microemulsion based synthesis of nanocrystalline materials have been discussed which would be of interest to a cross-section of researchers working on colloids, physical chemistry, nanoscience and materials chemistry. The review focuses on the recent developments in the above area with current understanding on the various factors that control the structure and dynamics of microemulsions which can be effectively used to manipulate the size and shape of nanocrystalline materials.

  6. Ecotoxicological effects of graphene-based materials

    Science.gov (United States)

    Montagner, A.; Bosi, S.; Tenori, E.; Bidussi, M.; Alshatwi, A. A.; Tretiach, M.; Prato, M.; Syrgiannis, Z.

    2017-03-01

    Graphene-based materials (GBMs) are currently under careful examination due to their potential impact on health and environment. Over the last few years, ecotoxicology has started to analyze all the potential issues related to GBMs and their possible consequences on living organisms. These topics are critically considered in this comprehensive review along with some considerations about future perspectives.

  7. Morphology of polyethylene ski base materials.

    Science.gov (United States)

    Fischer, Jörg; Wallner, Gernot M; Pieber, Alois

    2010-03-01

    We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.

  8. Photodetectors based on two dimensional materials

    Science.gov (United States)

    Zheng, Lou; Zhongzhu, Liang; Guozhen, Shen

    2016-09-01

    Two-dimensional (2D) materials with unique properties have received a great deal of attention in recent years. This family of materials has rapidly established themselves as intriguing building blocks for versatile nanoelectronic devices that offer promising potential for use in next generation optoelectronics, such as photodetectors. Furthermore, their optoelectronic performance can be adjusted by varying the number of layers. They have demonstrated excellent light absorption, enabling ultrafast and ultrasensitive detection of light in photodetectors, especially in their single-layer structure. Moreover, due to their atomic thickness, outstanding mechanical flexibility, and large breaking strength, these materials have been of great interest for use in flexible devices and strain engineering. Toward that end, several kinds of photodetectors based on 2D materials have been reported. Here, we present a review of the state-of-the-art in photodetectors based on graphene and other 2D materials, such as the graphene, transition metal dichalcogenides, and so on. Project supported by the National Natural Science Foundation of China (Nos. 61377033, 61574132, 61504136) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

  9. The Effect of KOH Treatment on the Chemical Structure and Electrocatalytic Activity of Reduced Graphene Oxide Materials.

    Science.gov (United States)

    Kim, Sujin; Choi, Kwangrok; Shim, Yeonjun; Lee, Seungjun; Park, Sungjin

    2016-08-01

    Reduced graphene oxide (rG-O)-based materials have great potential as metal-free electrocatalysts for the oxygen reduction reaction (ORR) owing to their electrical and electrochemical properties and large surface area. Long-term durability and chemical stability of the catalysts in the presence of electrolytes such as aqueous KOH solution are important for their use in practical applications. In this study, three types of rG-O and rG-O-K (rG-O after reaction with KOH) materials were synthesized. The chemical structures, surface areas, and catalytic ORR performances of the rG-O materials were compared with those of the corresponding rG-O-K materials. The onset potentials of the rG-O materials for electrocatalytic reduction of oxygen are almost the same as those of the corresponding rG-O-K materials; however, the current density and the number of transferred electrons are significantly reduced. These data show that the catalytic ORR performance of rG-O-based materials can be altered by KOH.

  10. Nickel cobalt oxide nanowire-reduced graphite oxide composite material and its application for high performance supercapacitor electrode material.

    Science.gov (United States)

    Wang, Xu; Yan, Chaoyi; Sumboja, Afriyanti; Lee, Pooi See

    2014-09-01

    In this paper, we report a facile synthesis method of mesoporous nickel cobalt oxide (NiCo2O4) nanowire-reduced graphite oxide (rGO) composite material by urea induced hydrolysis reaction, followed by sintering at 300 degrees C. P123 was used to stabilize the GO during synthesis, which resulted in a uniform coating of NiCo2O4 nanowire on rGO sheet. The growth mechanism of the composite material is discussed in detail. The NiCo2O4-rGO composite material showed an outstanding electrochemical performance of 873 F g(-1) at 0.5 A g(-1) and 512 F g(-1) at 40 A g(-1). This method provides a promising approach towards low cost and large scale production of supercapacitor electrode material.

  11. Graphene-based materials for energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Nanda Gopal [Energy Research Institute, Nanyang Technological University (Singapore); Pan, Yongzheng; Li, Lin; Chan, Siew Hwa [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

    2012-08-08

    With the depletion of conventional energy sources, the demand for renewable energy and energy-efficient devices continues to grow. As a novel 2D nanomaterial, graphene attracts considerable research interest due to its unique properties and is a promising material for applications in energy conversion and storage devices. Recently, the fabrication of fuel cells and solar cells using graphene for various functional parts has been studied extensively. This research news summarizes and compares the advancements that have been made and are in progress in the utilization of graphene-based materials for energy conversion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Graphene based materials for biomedical applications

    Directory of Open Access Journals (Sweden)

    Yuqi Yang

    2013-10-01

    Full Text Available Graphene, a single layer 2-dimensional structure nanomaterial with unique physicochemical properties (e.g. high surface area, excellent electrical conductivity, strong mechanical strength, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization, has received increasing attention in physical, chemical and biomedical fields. This article selectively reviews current advances of graphene based materials for biomedical applications. In particular, graphene based biosensors for small biomolecules (glucose, dopamine etc., proteins and DNA detection have been summarized; graphene based bioimaging, drug delivery, and photothermal therapy applications have been described in detail. Future perspectives and possible challenges in this rapidly developing area are also discussed.

  13. Gas sensors based on nanostructured materials.

    Science.gov (United States)

    Jiménez-Cadena, Giselle; Riu, Jordi; Rius, F Xavier

    2007-11-01

    Gas detection is important for controlling industrial and vehicle emissions, household security and environmental monitoring. In recent decades many devices have been developed for detecting CO(2), CO, SO(2), O(2), O(3), H(2), Ar, N(2), NH(3), H(2)O and several organic vapours. However, the low selectivity or the high operation temperatures required when most gas sensors are used have prompted the study of new materials and the new properties that come about from using traditional materials in a nanostructured mode. In this paper, we have reviewed the main research studies that have been made of gas sensors that use nanomaterials. The main quality characteristics of these new sensing devices have enabled us to make a critical review of the possible advantages and drawbacks of these nanostructured material-based sensors.

  14. Protein-Based Drug-Delivery Materials

    Directory of Open Access Journals (Sweden)

    Dave Jao

    2017-05-01

    Full Text Available There is a pressing need for long-term, controlled drug release for sustained treatment of chronic or persistent medical conditions and diseases. Guided drug delivery is difficult because therapeutic compounds need to survive numerous transport barriers and binding targets throughout the body. Nanoscale protein-based polymers are increasingly used for drug and vaccine delivery to cross these biological barriers and through blood circulation to their molecular site of action. Protein-based polymers compared to synthetic polymers have the advantages of good biocompatibility, biodegradability, environmental sustainability, cost effectiveness and availability. This review addresses the sources of protein-based polymers, compares the similarity and differences, and highlights characteristic properties and functionality of these protein materials for sustained and controlled drug release. Targeted drug delivery using highly functional multicomponent protein composites to guide active drugs to the site of interest will also be discussed. A systematical elucidation of drug-delivery efficiency in the case of molecular weight, particle size, shape, morphology, and porosity of materials will then be demonstrated to achieve increased drug absorption. Finally, several important biomedical applications of protein-based materials with drug-delivery function—including bone healing, antibiotic release, wound healing, and corneal regeneration, as well as diabetes, neuroinflammation and cancer treatments—are summarized at the end of this review.

  15. Satellite Contamination and Materials Outgassing Knowledge base

    Science.gov (United States)

    Minor, Jody L.; Kauffman, William J. (Technical Monitor)

    2001-01-01

    Satellite contamination continues to be a design problem that engineers must take into account when developing new satellites. To help with this issue, NASA's Space Environments and Effects (SEE) Program funded the development of the Satellite Contamination and Materials Outgassing Knowledge base. This engineering tool brings together in one location information about the outgassing properties of aerospace materials based upon ground-testing data, the effects of outgassing that has been observed during flight and measurements of the contamination environment by on-orbit instruments. The knowledge base contains information using the ASTM Standard E- 1559 and also consolidates data from missions using quartz-crystal microbalances (QCM's). The data contained in the knowledge base was shared with NASA by government agencies and industry in the US and international space agencies as well. The term 'knowledgebase' was used because so much information and capability was brought together in one comprehensive engineering design tool. It is the SEE Program's intent to continually add additional material contamination data as it becomes available - creating a dynamic tool whose value to the user is ever increasing. The SEE Program firmly believes that NASA, and ultimately the entire contamination user community, will greatly benefit from this new engineering tool and highly encourages the community to not only use the tool but add data to it as well.

  16. Composite Materials and Films Based on Melanins, Polydopamine, and Other Catecholamine-Based Materials

    Directory of Open Access Journals (Sweden)

    Vincent Ball

    2017-07-01

    Full Text Available Polydopamine (PDA is related to eumelanins in its composition and structure. These pigments allow the design, inspired by natural materials, of composite nanoparticles and films for applications in the field of energy conversion and the design of biomaterials. This short review summarizes the main advances in the design of PDA-based composites with inorganic and organic materials.

  17. MULCHES AND OTHER COVER MATERIALS TO REDUCE WEED GROWTH IN CONTAINER-GROWN NURSERY STOCK.

    Science.gov (United States)

    Rys, F; Van Wesemael, D; Van Haecke, D; Mechant, E; Gobin, B

    2014-01-01

    Due to the recent EU-wide implementation of Integrated Pest Management (IPM), alternative methods to reduce weed growth in container-grown nursery stock are needed to cut back the use of herbicides. Covering the upper layer of the substrate is known as a potential method to prevent or reduce weed growth in plant containers. As a high variety of mulches and other cover materials are on the market, however, it is no longer clear for growers which cover material is most efficient for use in containers. Therefore, we examined the effect on weed growth of different mulches and other cover materials, including Pinus maritima, P. sylvestris, Bio-Top Basic, Bio-Top Excellent, coco chips fine, hemp fibres, straw pellets, coco disk 180LD and jute disk. Cover materials were applied immediately after repotting of Ligustrum ovalifolium or planting of Fagus sylvatica. At regular times, both weed growth and side effects (e.g., plant growth, water status of the substrate, occurrence of mushrooms, foraging of birds, complete cover of the substrate and fixation) were assessed. All examined mulches or other cover materials were able to reduce weed growth on the containers during the whole growing season. Weed suppression was even better than that of a chemical treated control. Although all materials showed some side effects, the impact on plant growth is most important to the grower and depends not only on material characteristics (e.g., biodegradation, nutrient leaching and N-immobilisation) but also on container size and climatic conditions. In conclusion, mulches and other cover materials can be a valuable tool within IPM to lower herbicide use. To enable a deliberate choice of which cover material is best used in a specific situation more research is needed on lifespan and stability as well as on economic characteristics of the materials.

  18. An ultraviolet photodetector fabricated from WO₃ nanodiscs/reduced graphene oxide composite material.

    Science.gov (United States)

    Shao, Dali; Yu, Mingpeng; Lian, Jie; Sawyer, Shayla

    2013-07-26

    A high sensitivity, fast ultraviolet (UV) photodetector was fabricated from WO₃ nanodiscs (NDs)/reduced graphene oxide (RGO) composite material. The WO₃ NDs/reduced GO composite material was synthesized using a facile three-step synthesis procedure. First, the Na₂WO₄/GO precursor was synthesized by homogeneous precipitation. Second, the Na₂WO₄/GO precursor was transformed into Na₂WO₄/GO composites by acidification. Finally, the Na₂WO₄/GO composites were reduced to WO₃ NDs/RGO via a hydrothermal reduction process. The UV photodetector showed a fast transient response and high responsivity, which are attributed to the improved carrier transport and collection efficiency through graphene. The excellent material properties of the WO₃ NDs/RGO composite demonstrated in this work may open up new possibilities for using WO₃ NDs/RGO for future optoelectronic applications.

  19. Brittle Destruction of Carbon Based Materials

    Science.gov (United States)

    Koza, Y.; Amouroux, S.; Bazylev, B. N.; Berthe, E.; Kuehnlein, W.; Linke, J.; Penkalla, H. J.; Singheiser, L.

    Erosion mechanisms for different carbon based materials (graphite, carbon fiber composites (CFCs), Si-doped CFC) have been studied under brittle destruction under intense transient thermal loads (ELMs, plasma disruptions, VDEs) with respect to material erosion in different particle emission regimes, characterization of emitted particles, and behavior of preheated samples. Furthermore, the experimental data were compared with 3-D numerical simulation on the onset of brittle destruction. From a morphological point of view, the resulting erosion patterns on the test samples and ejected particles differ significantly for the three materials. The isotropic graphite shows a homogeneous erosion profile with flat craters, while the CFC forms no crater and only preferential erosion in localized spots in the PAN fiber area while the pitch fiber strands remain almost undamaged. The particles originating from graphite samples which have been collected on TEM grids are composed of nano sized amorphous carbon. CFCs have been the source for sub Î 1/4 m sized agglomerated fragments of crystalline carbon or silicon particles with âe 1/4 50 nm diameter. Preheating of the test samples to 500 or 800°C results in a remarkable increase of the erosion depth and weight loss compared to the samples loaded at room temperature and identical heat fluxes. In particular, melting phenomena in the Si-doped CFC materials became essential at elevated temperatures.

  20. Experimental study of compatibility of reduced metal oxides with thermal energy storage lining materials

    Science.gov (United States)

    El-Leathy, Abdelrahman; Danish, Syed Noman; Al-Ansary, Hany; Jeter, Sheldon; Al-Suhaibani, Zeyad

    2016-05-01

    Solid particles have been shown to be able to operate at temperatures higher than 1000 °C in concentrated solar power (CSP) systems with thermal energy storage (TES). Thermochemical energy storage (TCES) using metal oxides have also found to be advantageous over sensible and latent heat storage concepts. This paper investigates the compatibility of the inner lining material of a TES tank with the reduced metal oxide. Two candidate metal oxides are investigated against six candidate lining materials. XRD results for both the materials are investigated and compared before and after the reduction of metal oxide at 1000°C in the presence of lining material. It is found that the lining material rich in zirconia is suitable for such application. Silicon Carbide is also found non-reacting with one of the metal oxides so it needs to be further investigated with other candidate metal oxides.

  1. Reducing Vehicle Weight and Improving U.S. Energy Efficiency Using Integrated Computational Materials Engineering

    Science.gov (United States)

    Joost, William J.

    2012-09-01

    Transportation accounts for approximately 28% of U.S. energy consumption with the majority of transportation energy derived from petroleum sources. Many technologies such as vehicle electrification, advanced combustion, and advanced fuels can reduce transportation energy consumption by improving the efficiency of cars and trucks. Lightweight materials are another important technology that can improve passenger vehicle fuel efficiency by 6-8% for each 10% reduction in weight while also making electric and alternative vehicles more competitive. Despite the opportunities for improved efficiency, widespread deployment of lightweight materials for automotive structures is hampered by technology gaps most often associated with performance, manufacturability, and cost. In this report, the impact of reduced vehicle weight on energy efficiency is discussed with a particular emphasis on quantitative relationships determined by several researchers. The most promising lightweight materials systems are described along with a brief review of the most significant technical barriers to their implementation. For each material system, the development of accurate material models is critical to support simulation-intensive processing and structural design for vehicles; improved models also contribute to an integrated computational materials engineering (ICME) approach for addressing technical barriers and accelerating deployment. The value of computational techniques is described by considering recent ICME and computational materials science success stories with an emphasis on applying problem-specific methods.

  2. Polyamide as a Denture Base Material: A Literature Review

    Directory of Open Access Journals (Sweden)

    Mahroo Vojdani

    2015-03-01

    Full Text Available The purpose of this article was to review the biocompatibility, physical, and mechanical properties of the polyamide denture base materials. An electronic search of scientific papers from 1990-2014 was carried out using PubMed, Scopus and Wiley Inter Science engines using the search terms “nylon denture base” and “polyamide denture base”. Searching the key words yielded a total of 82 articles. By application of inclusion criteria, the obtained results were further reduced to 24 citations recruited in this review. Several studies have evaluated various properties of polyamide (nylon denture base materials. According to the results of the studies, currently, thermo-injectable, high impact, flexible or semi-flexible polyamide is thought to be an alternative to the conventional acrylic resins due to its esthetic and functional characteristics and physicochemical qualities. It would be justifiable to use this material for denture fabrication in some cases such as severe soft/ hard tissue undercuts, unexplained repeated fracture of denture, in aesthetic-concerned patients, those who have allergy to other denture base materials, and in patients with microstomia. Although polyamide has some attractive advantages, they require modifications to produce consistently better properties than the current polymethyl methacrylate (PMMA materials. Moreover, since there is a very limited knowledge about their clinical performance, strict and careful follow-up evaluation of the patients rehabilitated with polyamide prosthesis is recommended.

  3. Polyamide as a Denture Base Material: A Literature Review

    Science.gov (United States)

    Vojdani, Mahroo; Giti, Rashin

    2015-01-01

    The purpose of this article was to review the biocompatibility, physical, and mechanical properties of the polyamide denture base materials. An electronic search of scientific papers from 1990-2014 was carried out using PubMed, Scopus and Wiley Inter Science engines using the search terms “nylon denture base” and “polyamide denture base”. Searching the key words yielded a total of 82 articles. By application of inclusion criteria, the obtained results were further reduced to 24 citations recruited in this review. Several studies have evaluated various properties of polyamide (nylon) denture base materials. According to the results of the studies, currently, thermo-injectable, high impact, flexible or semi-flexible polyamide is thought to be an alternative to the conventional acrylic resins due to its esthetic and functional characteristics and physicochemical qualities. It would be justifiable to use this material for denture fabrication in some cases such as severe soft/ hard tissue undercuts, unexplained repeated fracture of denture, in aesthetic-concerned patients, those who have allergy to other denture base materials, and in patients with microstomia.  Although polyamide has some attractive advantages, they require modifications to produce consistently better properties than the current polymethyl methacrylate (PMMA) materials. Moreover, since there is a very limited knowledge about their clinical performance, strict and careful follow-up evaluation of the patients rehabilitated with polyamide prosthesis is recommended. PMID:26106628

  4. Bibliographic data base for low activation materials

    Energy Technology Data Exchange (ETDEWEB)

    Alenina, M.V.; Kolotov, V.P. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation); Ivanov, L.I. [A.A. Baikov Institute of Metallurgy and Science of Materials, Russian Academy of Sciences, Moscow (Russian Federation)

    2007-07-01

    Full text of publication follows: The analysis of the publications dealing with development of low-activation materials for fusion technology demonstrates that the period of information doubling is about 5-6 years. Such high rate usually is characteristic of the actively developing field of science. To develop an useful instrument for analysis and systematization of the available data a computer based bibliographic system has been developed some time ago. Recently the engine of the system has been significantly modernized. The bibliographic system is based on using of MS SQL server data base which includes main bibliographic information including abstracts. The most important feature of the system is that full-text abstracts searching capabilities are appended with indexing of information by experts to increase its definition. The experts indexes cover the following topics: - Main problems; - Software and methods for calculation; - Libraries of nuclear data; - Spectrum of neutrons for different construction parts of fusion reactor; - Low activation materials; - Technology of production; - Radiation effects; - Utilization of radiation waste; - Estimation of risks; - Designs of fusion reactor; - Nuclear transmutations; - Equipment used for investigations. The primary data base is filling/appending by periodical queries to different bibliographic data bases (INIS, COMPEMDEX and others) via suitable Internet providers including strict analysis of the income information to remove a possible 'information noise' and following data indexing by experts. The data base contains references since 1976 year (when first works in this area have been fulfilled) and until now. The bibliographic system is accessible by means of Internet using different forms developed for queries (http://www.geokhi.ru/{approx}lam{sub d}b). (authors)

  5. Reduced content of chloroatranol and atranol in oak moss absolute significantly reduces the elicitation potential of this fragrance material

    DEFF Research Database (Denmark)

    Andersen, Flemming; Andersen, Kirsten H; Bernois, Armand;

    2015-01-01

    BACKGROUND: Oak moss absolute, an extract from the lichen Evernia prunastri, is a valued perfume ingredient but contains extreme allergens. OBJECTIVES: To compare the elicitation properties of two preparations of oak moss absolute: 'classic oak moss', the historically used preparation, and 'new oak...... moss', with reduced contents of the major allergens atranol and chloroatranol. PATIENTS/MATERIALS/METHODS: The two preparations were compared in randomized double-blinded repeated open application tests and serial dilution patch tests in 30 oak moss-sensitive volunteers and 30 non-allergic control...... subjects. RESULTS: In both test models, new oak moss elicited significantly less allergic contact dermatitis in oak moss-sensitive subjects than classic oak moss. The control subjects did not react to either of the preparations. CONCLUSIONS: New oak moss is still a fragrance allergen, but elicits less...

  6. A New Bio-based Dielectric Material.

    Science.gov (United States)

    Zhan, Mingjiang; Wool, Richard P.

    2007-03-01

    Low dielectric constant (low-k) materials are widely used in modern high-speed microelectronics, such as printed circuit boards. A new bio-based composite was developed from soybean oil and chicken feather fibers, which has the potential to replace currently used petroleum-based dielectrics. Feather fibers have a unique hollow structure which distinguishes them from glass fibers and give very attractive properties. Due to the retained air in the hollow fibers, the dielectric constant can be lower than conventional epoxy-based dielectrics at both low and high frequencies. The coefficients of thermal expansion (CTE) of the materials decrease with addition of feather fibers and even can be negative. By controlling the fraction of fibers, delamination caused by CTE mismatch between the dielectric and the metal lines can be avoided. The enhancement of adhesion between copper surface and polymer matrix was investigated. The tough structure of fibers significantly improved the mechanical properties of the composites, such as flexural properties and storage modulus. Supported by USDA

  7. A Room-Temperature Operation Formaldehyde Sensing Material Printed Using Blends of Reduced Graphene Oxide and Poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Wen-Yu Chuang

    2015-11-01

    Full Text Available This work demonstrates a printable blending material, i.e., reduced graphene oxide (RGO mixed with poly(methyl methacrylate (PMMA, for formaldehyde sensing. Based on experimental results, 2% RGO/10% PMMA is an optimal ratio for formaldehyde detection, which produced a 30.5% resistance variation in response to 1000 ppm formaldehyde and high selectivity compared to different volatile organic compounds (VOCs, humidity, CO, and NO. The demonstrated detection limit is 100 ppm with 1.51% resistance variation. Characterization of the developed formaldehyde sensing material was performed by Fourier-transform infrared (FTIR spectrometry, scanning electron microscopy (SEM, and Raman spectroscopy. Based on Raman spectroscopy, the basic sensing mechanism is the band distortion of RGO due to blending with PMMA and the adsorption of formaldehyde. This work establishes insights into the formaldehyde sensing mechanism and explores a potential printable sensing material for diverse applications.

  8. A Room-Temperature Operation Formaldehyde Sensing Material Printed Using Blends of Reduced Graphene Oxide and Poly(methyl methacrylate).

    Science.gov (United States)

    Chuang, Wen-Yu; Yang, Sung-Yuan; Wu, Wen-Jong; Lin, Chih-Ting

    2015-11-13

    This work demonstrates a printable blending material, i.e., reduced graphene oxide (RGO) mixed with poly(methyl methacrylate) (PMMA), for formaldehyde sensing. Based on experimental results, 2% RGO/10% PMMA is an optimal ratio for formaldehyde detection, which produced a 30.5% resistance variation in response to 1000 ppm formaldehyde and high selectivity compared to different volatile organic compounds (VOCs), humidity, CO, and NO. The demonstrated detection limit is 100 ppm with 1.51% resistance variation. Characterization of the developed formaldehyde sensing material was performed by Fourier-transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM), and Raman spectroscopy. Based on Raman spectroscopy, the basic sensing mechanism is the band distortion of RGO due to blending with PMMA and the adsorption of formaldehyde. This work establishes insights into the formaldehyde sensing mechanism and explores a potential printable sensing material for diverse applications.

  9. Laser materials based on transition metal ions

    Science.gov (United States)

    Moncorgé, Richard

    2017-01-01

    The purpose of this presentation is to review the spectroscopic properties of the main laser materials based on transition metal ions which lead to noticeable laser performance at room temperature and, for very few cases, because of unique properties, when they are operated at cryogenic temperatures. The description also includes the materials which are currently being used as saturable absorbers for passive-Q-switching of a variety of other near- and mid-infrared solid state lasers. A substantial part of the article is devoted first to the description of the energy levels and of the absorption and emission transitions of the transition metal ions in various types of environments by using the well-known Tanabe-Sugano diagrams. It is shown in particular how these diagrams can be used along with other theoretical considerations to understand and describe the spectroscopic properties of ions sitting in crystal field environments of near-octahedral or near-tetrahedral symmetry. The second part is then dedicated to the description (positions and intensities) of the main absorption and emission features which characterize the different types of materials.

  10. Tablet-Based Education to Reduce Depression-Related Stigma

    Science.gov (United States)

    Lu, Catherine; Winkelman, Megan; Wong, Shane Shucheng

    2016-01-01

    Objectives: This study investigated the efficacy of a tablet-based multimedia education application, the Project Not Alone Depression Module, in improving depression literacy and reducing depression stigma among a community-based mental health clinic population. Methods: A total of 93 participants completed either a tablet-based multimedia…

  11. XRD Investigation of Some Thermal Degraded Starch Based Materials

    Directory of Open Access Journals (Sweden)

    Mihai Todica

    2016-01-01

    Full Text Available The thermal degradation of some starch based materials was investigated using XRD method. The samples were obtained by thermal extrusion of mixtures of different proportions of starch, glycerol, and water. Such materials are suitable for the manufacturing of low pollutant packaging. Thermal degradation is one of the simplest ways to destroy such materials and this process is followed by structural modification of the local ordering of samples, water evaporation, crystallization, oxidation, or destruction of the chemical bonds. These modifications need to be studied in order to reduce to the minimum production of pollutant residues by burning process. XRD measurements show modification of the local ordering of the starch molecules depending on the temperature and initial composition of the samples. The molecular ordering perturbation is more pronounced in samples with low content of starch.

  12. Nanocellulose-Based Materials for Water Purification

    Directory of Open Access Journals (Sweden)

    Hugo Voisin

    2017-03-01

    Full Text Available Nanocellulose is a renewable material that combines a high surface area with high strength, chemical inertness, and versatile surface chemistry. In this review, we will briefly describe how nanocellulose is produced, and present—in particular, how nanocellulose and its surface modified versions affects the adsorption behavior of important water pollutants, e.g., heavy metal species, dyes, microbes, and organic molecules. The processing of nanocellulose-based membranes and filters for water purification will be described in detail, and the uptake capacity, selectivity, and removal efficiency will also be discussed. The processing and performance of nanocellulose-based membranes, which combine a high removal efficiency with anti-fouling properties, will be highlighted.

  13. Solution-based nanoengineering of materials.

    Energy Technology Data Exchange (ETDEWEB)

    Criscenti, Louise Jacqueline; Spoerke, Erik David; Liu, Jun; Voigt, James A.; Cygan, Randall Timothy; Machesky, Michael L. (Illinois State Water Survey, Champaign, IL); Tian, Zhengrong Ryan; McKenzie, Bonnie Beth

    2005-02-01

    Solution-based synthesis is a powerful approach for creating nano-structured materials. Although there have been significant recent successes in its application to fabricating nanomaterials, the general principles that control solution synthesis are not well understood. The purpose of this LDRD project was to develop the scientific principles required to design and build unique nanostructures in crystalline oxides and II/VI semiconductors using solution-based molecular self-assembly techniques. The ability to synthesize these materials in a range of different nano-architectures (from controlled morphology nanocrystals to surface templated 3-D structures) has provided the foundation for new opportunities in such areas as interactive interfaces for optics, electronics, and sensors. The homogeneous precipitation of ZnO in aqueous solution was used primarily as the model system for the project. We developed a low temperature, aqueous solution synthesis route for preparation of large arrays of oriented ZnO nanostructures. Through control of heterogeneous nucleation and growth, methods to predicatively alter the ZnO microstructures by tailoring the surface chemistry of the crystals were established. Molecular mechanics simulations, involving single point energy calculations and full geometry optimizations, were developed to assist in selecting appropriate chemical systems and understanding physical adsorption and ultimately growth mechanisms in the design of oxide nanoarrays. The versatility of peptide chemistry in controlling the formation of cadmium sulfide nanoparticles and zinc oxide/cadmium sulfide heterostructures was also demonstrated.

  14. Effects of sorbent materials on the cryofocusing analysis of gaseous reduced sulphur compounds.

    Science.gov (United States)

    Kim, Ki-Hyun; Pandey, Sudhir Kumar; Ahn, J H; Szulejko, J E; Sohn, Jong Ryeul

    2014-08-01

    The relative performance of different sorbent materials employed in the cryofocusing (e.g. in cold trap (CT) unit) stage was investigated at sub-ambient temperature by the thermal desorption (TD)-gas chromatography (GC)-pulsed flame photometric detector. To this end, the TD-based calibration of five reduced sulphur compounds (RSC: H2S, CH3SH, CS2, DMS and DMDS) and SO2 was carried out via the Peltier cooling system with five types of sorbent combinations such as two single-bed (Tenax TA and Silica gel) plus three multibed types (a combination of either two from the following three sorbents: Tenax TA, Silica gel and Carbopack B). Relative performance of each of all five CT options, if evaluated in terms of response factors for each compound, demonstrated that each CT composition acts as an important criterion to distinguish detection properties between light and heavy sulphur species. Although the relative response of H2S and CH3 SH was systematically distinguishable between the CT types, that of SO2 was the most complicated to interpret. According to this study, the two CT types consisting of Carbopack B and Silica gel (CS-0.4 and CS-0.6) were the optimum choices for sulphur gas analysis in terms of basic QA parameters (sensitivity, reproducibility and linearity).

  15. Enhance the figure of merit for flexible thermoelectric materials by reducing the screening effect

    Science.gov (United States)

    Ismail, Mukhlis M.; Hussein, Ahmed M.

    2017-06-01

    A flexible thermoelectric materials (FTEM) films based on Polydimethylsiloxane as the polymer matrix and (Zinc Oxide, Polyaniline and multi wall Carbon nanotube) as the fillers were prepared. The fillers were prepared using modified sol-gel method to enhance the distribution of the nanoparticles inside the polymer matrix and good performance. The Seebeck coefficient, electrical conductivity, thermal conductivity and dielectric measurements were carried out for all of the four films. The Seebeck coefficient results for the investigated films were -40, 220, -120, 280 μv/k° at 200 °C for FTEM 1, 2, 3, 4 alternatively. The sign and the value for the Seebeck measurements show a great dependent on the filler type add to the film. The electrical conductivity results for the films was varied from 2 × 10-8 to 0.14 S/m and strongly dependent on the fillers electrical conductivity. The less dependent on the thermal conductivity of the fillers and a slight change in the thermal conductivity value of the films were obtained. The figure of merit for the films was ranged from 1.14 × 10-16 to 3.134 × 10-8. The dielectric results ranged from 4 to 3500. Reducing the screening effect will increase the electrical conductivity and Seebeck coefficient values.

  16. Instruments to reduce the leaching of heavy metals from building materials in the Netherlands.

    Science.gov (United States)

    van Breemen, A J H; Vermij, P H M

    2007-01-01

    In the Netherlands the leaching of heavy metals from metal building and constructing materials results in serious contamination problems in the water system. The most common sources of these heavy metals in construction materials are copper waterworks and roofs, zinc roofs, gutters and rain pipes, zinced steel, stainless steel, and lead sealing material. In urban waters the surface water and sediment standards are often exceeded. Although building and construction materials are certainly not the only source of heavy metals, they are an important part of the problem. This article focuses on six instruments that are in use in the Netherlands to try to reduce impact on the surface waters. In addition to this, national as well as international, a reconsideration of the risks and surface water standards for several heavy metals is considered. A balanced use of instruments can be considered as the application of a best practice.

  17. Investigation on Using SBS and Active Carbon Filler to Reduce the VOC Emission from Bituminous Materials

    Directory of Open Access Journals (Sweden)

    Peiqiang Cui

    2014-08-01

    Full Text Available Bituminous materials are playing a vital role in pavement design and the roofing industry because of outstanding properties. Unfortunately, bituminous materials will release volatile organic compounds (VOC, making them non-environmentally friendly. Therefore, technologies that can be used to decrease the VOC emission are urgently required. In this research, the VOC emission and material behaviors were analyzed and compared to investigate the possibility of adding styrene butadiene styrene (SBS and active carbon filler into bituminous materials to develop environmentally-friendly materials. Thermal gravimetric analysis-mass spectrometry (TG-MS and ultraviolet-visible spectroscopy testing (UV-Vis were employed to characterize the VOC emission process. Temperature sweep testing and frequency sweep testing were conducted to evaluate the rheological properties of bituminous materials. Research results indicated that the combined introduction of 4 wt% styrene butadiene styrene (SBS and 4 wt% active carbon filler cannot only significantly lower the VOC emission speed and amount, but also improve the deformation resistance behavior at a higher temperature. SBS and active carbon filler can be used to reduce the VOC emission form bituminous materials.

  18. Mechanical properties of gangue-containing aluminosilicate based cementitious materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the major raw materials.The gangue was calcined at 500℃.The main constituent was calcined gangue, fly ash and slag, while alkali-silicate solutions were used as the diagenetic agent.The structure of gangue-containing aluminosilicate based cementitious materials was studied by the methods of IR, NMR and SEM.The results show that the mechanical properties are affected by the mass ratio between the gangue, slag and fly ash, the kind of activator and additional salt.For 28-day curing time, the compressive strength of the sample with a mass proportion of 2:1:1 (gangue: slag: fly ash) is 58.9 MPa, while the compressive strength of the sample containing 80wt%gangue can still be up to 52.3 MPa.The larger K+ favors the formation of large silicate oligomers with which Al(OH)4- prefers to bind.Therefore, in Na-K compounding activator solutions more oligomers exist which result in a stronger compressive strength of aluminosilicate-based cementitious materials than in the case of Na-containing activator.The reasons for this were found through IR and NMR analysis.Glauber's salt reduces the 3-day compressive strength of the paste, but increases its 7-day and 28-day compressive strengths.

  19. The Influence of Reduced Gravity on the Crystal Growth of Electronic Materials

    Science.gov (United States)

    Su, Ching-Hua; Gillies, D. C.; Szofran, F. R.; Watring, D. A.; Lehoczky, S. L.

    1996-01-01

    The imperfections in the grown crystals of electronic materials, such as compositional nonuniformity, dopant segregation and crystalline structural defects, are detrimental to the performance of the opto-electronic devices. Some of these imperfections can be attributed to effects caused by Earth gravity during crystal growth process and four areas have been identified as the uniqueness of material processing in reduced gravity environment. The significant results of early flight experiments, i.e. prior to space shuttle era, are briefly reviewed followed by an elaborated review on the recent flight experiments conducted on shuttle missions. The results are presented for two major growth methods of electronic materials: melt and vapor growth. The use of an applied magnetic field in the melt growth of electrically conductive melts on Earth to simulate the conditions of reduced gravity has been investigated and it is believed that the superimposed effect of moderate magnetic fields and the reduced gravity environment of space can result in reduction of convective intensities to the extent unreachable by the exclusive use of magnet on Earth or space processing. In the Discussions section each of the significant results of the flight experiments is attributed to one of the four effects of reduced gravity and the unresolved problems on the measured mass fluxes in some of the vapor transport flight experiments are discussed.

  20. Reducing discards without reducing profit: Free gear choice in a Danish result-based management trial

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Ulrich, Clara; Qvist Eliasen, Søren

    2016-01-01

    The 2013 Common Fisheries Policy introduced a landing obligation on a range of species. This is changing the fundamental principles on which EU fisheries management is based, with more focus on the full accountability of all catches (a move towards catch quota management) and less accountability ......, where unwanted catches could be reduced to some extent without negative effects on economic viability. Some practical implementation challenges were nevertheless encountered, which are discussed in the perspective of implementing results-based management at full scale....

  1. Highly explosive nanosilicon-based composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Clement, D.; Diener, J.; Gross, E.; Kuenzner, N.; Kovalev, D. [Technical University of Munich, Physics Department, James-Franck-Str., 85747 Garching (Germany); Timoshenko, V.Yu. [Moscow State M.V. Lomonosov University, Physics Department, 119899 Moscow (Russian Federation)

    2005-06-01

    We present a highly explosive binary system based on porous silicon layers with their pores filled with solid oxidizers. The porous layers are produced by a standard electrochemical etching process and exhibit properties that are different from other energetic materials. Its production is completely compatible with the standard silicon technology and full bulk silicon wafers can be processed and therefore a large number of explosive elements can be produced simultaneously. The application-relevant parameters: the efficiency and the long-term stability of various porous silicon/oxidizer systems have been studied in details. Structural properties of porous silicon, its surface termination, the atomic ratio of silicon to oxygen and the chosen oxidizers were optimized to achieve the highest efficiency of the explosive reaction. This explosive system reveals various possible applications in different industrial fields, e.g. as a novel, very fast airbag igniter. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Performance Analysis of Leaf Spring by Contact Mechanics Approach Based on the Nature of Material Properties

    OpenAIRE

    Sathish Gandhi, Veeramalai Chinnasamy; Kumaravelan, Radhakrishnan; Ramesh, Sengottuvelu; Joemax Agu, Maxwell Thompson

    2014-01-01

    In an automotive system, a curved leaf spring is used for the purpose of suspension and for reducing the transient vibration of the system. Composite materials are widely used in automobile industries as a replacement for steel to reduce the weight and to increase the strength of an automotive system. In this study, various materials have been considered for an analysis based on the Young modulus-to-yield strength ratio. The study has been carried out by considering the material properties. T...

  3. The realization of HITS algorithm based on MapReduce

    Directory of Open Access Journals (Sweden)

    YU Hui

    2013-10-01

    Full Text Available In this paper,we use Hadoop to redesign HITS algrothim according to the research of HITS algrothim and the cloud computing framework Hadoop which base on MapReduce progaming model.Meanwhile,we analysize the effect of diffenent blocksize and cluster scale in influent on the efficiency of the algrothim.The results shows that the efficiency reduced with the blocksize increased,while the efficiency increased gradually when cluster scale had been expanded properly.

  4. FDI report on adverse reactions to resin-based materials.

    Science.gov (United States)

    Fan, P L; Meyer, D M

    2007-02-01

    Resin-based restorative materials are considered safe for the vast majority of dental patients. Although constituent chemicals such as monomers, accelerators and initiators can potentially leach out of cured resin-based materials after placement, adverse reactions to these chemicals are rare and reaction symptoms commonly subside after removal of the materials. Dentists should be aware of the rare possibility that patients could have adverse reactions to constituents of resin-based materials and be vigilant in observing any adverse reactions after restoration placement. Dentists should also be cognisant of patient complaints about adverse reactions that may result from components of resin-based materials. To minimise monomer leaching and any potential risk of dermatological reactions, resin-based materials should be adequately cured. Dental health care workers should avoid direct skin contact with uncured resin-based materials. Latex and vinyl gloves do not provide adequate barrier protection to the monomers in resin-based materials.

  5. Materials And Processes Technical Information System (MAPTIS) LDEF materials data base

    Science.gov (United States)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    A preliminary Long Duration Exposure Facility (LDEF) Materials Data Base was developed by the LDEF Materials Special Investigation Group (MSIG). The LDEF Materials Data Base is envisioned to eventually contain the wide variety and vast quantity of materials data generated from LDEF. The data is searchable by optical, thermal, and mechanical properties, exposure parameters (such as atomic oxygen flux) and author(s) or principal investigator(s). Tne LDEF Materials Data Base was incorporated into the Materials and Processes Technical Information System (MAPTIS). MAPTIS is a collection of materials data which has been computerized and is available to engineers, designers, and researchers in the aerospace community involved in the design and development of spacecraft and related hardware. The LDEF Materials Data Base is described and step-by-step example searches using the data base are included. Information on how to become an authorized user of the system is included.

  6. Graphene-Based Materials for Biosensors: A Review

    Directory of Open Access Journals (Sweden)

    Phitsini Suvarnaphaet

    2017-09-01

    Full Text Available The advantages conferred by the physical, optical and electrochemical properties of graphene-based nanomaterials have contributed to the current variety of ultrasensitive and selective biosensor devices. In this review, we present the points of view on the intrinsic properties of graphene and its surface engineering concerned with the transduction mechanisms in biosensing applications. We explain practical synthesis techniques along with prospective properties of the graphene-based materials, which include the pristine graphene and functionalized graphene (i.e., graphene oxide (GO, reduced graphene oxide (RGO and graphene quantum dot (GQD. The biosensing mechanisms based on the utilization of the charge interactions with biomolecules and/or nanoparticle interactions and sensing platforms are also discussed, and the importance of surface functionalization in recent up-to-date biosensors for biological and medical applications.

  7. Possible causes of the change of dynamics in glass-forming materials subjected to reduced dimension

    Energy Technology Data Exchange (ETDEWEB)

    Ngai, K.L. [Naval Research Lab., Washington, DC (United States); Rizos, A.K. [Univ. of Crete (Greece)

    1997-12-31

    There is currently many ongoing investigations of the change in the glass transition temperature when a material is reduced in dimension from the normal bulk state. The reduction in dimension can be accomplished by casting the material as thin films with or without a substrate or putting it in nanometer size pores. In this work, the authors explore possible causes of the change in dynamics of the bulk material when the glass-former is subjected to such modifications. The existence of a growing cooperative length scale L(T) with decreasing temperature in bulk fragile glass-forming liquids reaching the size of approximately 1.5--2.0 nm at the glass transition temperature is the basis of the consideration. When the reduced dimension is comparable to L(T{sub g}), cooperative dynamics within a length scale equal to L(T{sub g}) can no longer be maintained in all three dimensions throughout the sample. The imposed reduction of the cooperative length scale speeds up the dynamics and causes a reduction of the glass transition temperature. For polymeric glass-formers particularly at higher molecular weights, reduction of one dimension in thin films engenders orientation of the polymer chains when their radius of gyration becomes comparable to the film thickness. The latter is known to cause also a reduction of the glass transition temperature.

  8. Polymers based on renewable raw materials

    Directory of Open Access Journals (Sweden)

    Jovanović Slobodan M.

    2002-01-01

    Full Text Available The basic raw materials for the chemical industry, which also means for polymer production, are mineral oil and natural gas. Mineral oil and natural gas resources are limited so that sooner or later they will be consumed. For this reason alternative, renewable raw materials for the chemical industry have become the object of intensive investigation all over the world. Some of the results of these investigations concerning renewable raw materials for the production of polymer materials are presented in this paper.

  9. Phosphorus speciation by coupled HPLC-ICPMS: low level determination of reduced phosphorus in natural materials

    Science.gov (United States)

    Atlas, Zachary; Pasek, Matthew; Sampson, Jacqueline

    2015-04-01

    Phosphorus is a geologically important minor element in the Earth's crust commonly found as relatively insoluble apatite. This constraint causes phosphorus to be a key limiting nutrient in biologic processes. Despite this, phosphorus plays a direct role in the formation of DNA, RNA and other cellular materials. Recent works suggest that since reduced phosphorus is considerably more soluble than oxidized phosphorus that it was integrally involved in the development of life on the early Earth and may continue to play a role in biologic productivity to this day. This work examines a new method for quantification and identification of reduced phosphorus as well as applications to the speciation of organo-phosphates separated by coupled HPLC - ICP-MS. We show that reduced phosphorus species (P1+, P3+ and P5+) are cleanly separated in the HPLC and coupled with the ICPMS reaction cell, using oxygen as a reaction gas to effectively convert elemental P to P-O. Analysis at M/Z= 47 producing lower background and flatter baseline chromatography than analyses performed at M/Z = 31. Results suggest very low detection limits (0.05 μM) for P species analyzed as P-O. Additionally we show that this technique has potential to speciate at least 5 other forms of phosphorus compounds. We verified the efficacy of method on numerous materials including leached Archean rocks, suburban retention pond waters, blood and urine samples and most samples show small but detectible levels of reduced phosphorus and or organo-phaospates. This finding in nearly all substances analyzed supports the assumption that the redox processing of phosphorus has played a significant role throughout the history of the Earth and it's presence in the present environment is nearly ubiquitous with the reduced oxidation state phosphorus compounds, phosphite and hypophosphite, potentially acting as significant constituents in the anaerobic environment.

  10. Evaluation of nitrogen containing reducing agents for the corrosion control of materials relevant to nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Padma S. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India); Mohan, D. [Department of Chemistry, Anna University, Chennai, Tamilnadu (India); Chandran, Sinu; Rajesh, Puspalata; Rangarajan, S. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India); Velmurugan, S., E-mail: svelu@igcar.gov.in [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India)

    2017-02-01

    Materials undergo enhanced corrosion in the presence of oxidants in aqueous media. Usually, hydrogen gas or water soluble reducing agents are used for inhibiting corrosion. In the present study, the feasibility of using alternate reducing agents such as hydrazine, aqueous ammonia, and hydroxylamine that can stay in the liquid phase was investigated. A comparative study of corrosion behavior of the structural materials of the nuclear reactor viz. carbon steel (CS), stainless steel (SS-304 LN), monel-400 and incoloy-800 in the oxidizing and reducing conditions was also made. In nuclear industry, the presence of radiation field adds to the corrosion problems. The radiolysis products of water such as oxygen and hydrogen peroxide create an oxidizing environment that enhances the corrosion. Electrochemical studies at 90 °C showed that the reducing agents investigated were efficient in controlling corrosion processes in the presence of oxygen and hydrogen peroxide. Evaluation of thermal stability of hydrazine and its effect on corrosion potential of SS-304 LN were also investigated in the temperature range of 200–280 °C. The results showed that the thermal decomposition of hydrazine followed a first order kinetics. Besides, a change in electrochemical corrosion potential (ECP) was observed from −0.4 V (Vs SHE) to −0.67 V (Vs SHE) on addition of 5 ppm of hydrazine at 240 °C. Investigations were also made to understand the distribution behavior of hydrogen peroxide and hydrazine in water-steam phases and it was found that both the phases showed identical behavior. - Highlights: • Hydrazine was found to be a promising reducing agent for oxidant control. • In presence of hydrazine corrosion potential of SS304 LN was well below −230 mV. • SS304LN could be protected from IGSCC by hydrazine addition. • Thermal and radiation stability of hydrazine at 285 °C was found satisfactory.

  11. Reducing Social Loafing in Group-Based Projects

    Science.gov (United States)

    Perron, Brian E.

    2011-01-01

    Social loafing in group-based projects is a common problem for college teachers. This problem has received great attention, including a Quick Fix article by Stevens (2007), whose recommendations remain useful today, particularly the mechanism for peer evaluations--a key strategy for reducing social loafing. Since the publication of Stevens's…

  12. The ETLMR MapReduce-Based ETL Framework

    DEFF Research Database (Denmark)

    Xiufeng, Liu; Thomsen, Christian; Pedersen, Torben Bach

    2011-01-01

    This paper presents ETLMR, a parallel Extract--Transform--Load (ETL) programming framework based on MapReduce. It has built-in support for high-level ETL-specific constructs including star schemas, snowflake schemas, and slowly changing dimensions (SCDs). ETLMR gives both high programming...

  13. Reducing Ultrasonic Signal Noise by Algorithms based on Wavelet Thresholding

    Directory of Open Access Journals (Sweden)

    M. Kreidl

    2002-01-01

    Full Text Available Traditional techniques for reducing ultrasonic signal noise are based on the optimum frequency of an acoustic wave, ultrasonic probe construction and low-noise electronic circuits. This paper describes signal processing methods for noise suppression using a wavelet transform. Computer simulations of the proposed testing algorithms are presented.

  14. Reducing discards without reducing profit: Free gear choice in a Danish result-based management trial

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Ulrich, Clara; Qvist Eliasen, Søren

    2017-01-01

    The 2013 Common Fisheries Policy introduced a landing obligation on a range of species. This is changing the fundamental principles on which EU fisheries management is based, with more focus on the full accountability of all catches (a move towards catch quota management) and less accountability......, where unwanted catches could be reduced to some extent without negative effects on economic viability. Some practical implementation challenges were nevertheless encountered, which are discussed in the perspective of implementing results-based management at full scale....... on the means used to obtain these catches (a move towards results-based management). To investigate the potentials and challenges that these paradigm shifts give rise to, a 6-months ‘unrestricted gear’ trial was performed in Denmark in 2015,. Twelve trawlers of different size, rigging, fishing area and target...

  15. The preliminary Long Duration Exposure Facility (LDEF) materials data base

    Science.gov (United States)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1992-01-01

    A preliminary Long Duration Exposure Facility (LDEF) Materials Data Base was developed by the LDEF Materials Special Investigation Group (MSIG). The LDEF Materials Data Base is envisioned to eventually contain the wide variety and vast quantity of materials data generated for LDEF. The data is searchable by optical, thermal, and mechanical properties, exposure parameters (such as atomic oxygen flux), and author(s) or principal investigator(s). The LDEF Materials Data Base was incorporated into the Materials and Processes Technical Information System (MAPTIS). MAPTIS is a collection of materials data which was computerized and is available to engineers, designers, and researchers in the aerospace community involved in the design and development of spacecraft and related hardware. This paper describes the LDEF Materials Data Base and includes step-by-step example searches using the data base. Information on how to become an authorized user of the system is included.

  16. Biofuels 2020: Biorefineries based on lignocellulosic materials.

    Science.gov (United States)

    Valdivia, Miguel; Galan, Jose Luis; Laffarga, Joaquina; Ramos, Juan-Luis

    2016-09-01

    The production of liquid biofuels to blend with gasoline is of worldwide importance to secure the energy supply while reducing the use of fossil fuels, supporting the development of rural technology with knowledge-based jobs and mitigating greenhouse gas emissions. Today, engineering for plant construction is accessible and new processes using agricultural residues and municipal solid wastes have reached a good degree of maturity and high conversion yields (almost 90% of polysaccharides are converted into monosaccharides ready for fermentation). For the complete success of the 2G technology, it is still necessary to overcome a number of limitations that prevent a first-of-a-kind plant from operating at nominal capacity. We also claim that the triumph of 2G technology requires the development of favourable logistics to guarantee biomass supply and make all actors (farmers, investors, industrial entrepreneurs, government, others) aware that success relies on agreement advances. The growth of ethanol production for 2020 seems to be secured with a number of 2G plants, but public/private investments are still necessary to enable 2G technology to move on ahead from its very early stages to a more mature consolidated technology. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  17. Research requirements to reduce empty weight of helicopters by use of advanced materials

    Science.gov (United States)

    Hoffstedt, D. J.

    1976-01-01

    Utilization of the new, lightweight, high-strength, aerospace structural-composite (filament/matrix) materials, when specifically designed into a new aircraft, promises reductions in structural empty weight of 12 percent at recurring costs competive with metals. A program of basic and applied research and demonstration is identified with the objective of advancing the state of the art to the point where civil helicopters are confidently designed, produced, certified, and marketed by 1985. A structural empty-weight reduction of 12 percent was shown to significantly reduce energy consumption in modern high-performance helicopters.

  18. Friction and wear in polymer-based materials

    CERN Document Server

    Bely, V A; Petrokovets, M I

    1982-01-01

    Friction and Wear in Polymer-Based Materials discusses friction and wear problems in polymer-based materials. The book is organized into three parts. The chapters in Part I cover the basic laws of friction and wear in polymer-based materials. Topics covered include frictional interaction during metal-polymer contact and the influence of operating conditions on wear in polymers. The chapters in Part II discuss the structure and frictional properties of polymer-based materials; the mechanism of frictional transfer when a polymer comes into contact with polymers, metals, and other materials; and

  19. Reducing cost of repair materials for automatic melt injection furnace. Jido chutoro no hoshuyo zairyohi no sakugen

    Energy Technology Data Exchange (ETDEWEB)

    Yasushita, Y.; Nouchi, T.; Nagano, T.; Tamaru, I.; Hasei, S.; Hamano, K.; Suimizu, T.; Okamoto, M. (Nippon Kokan Pipe Fitting Co. Ltd., Osaka (Japan))

    1992-08-25

    This paper summarizes discussion intended of reducing material cost implemented at a casting department which produces materials for pipe joints covering 600 to 650 models. Targets were placed on reducing the current material cost by 30%, the currently used repair jigs by 30%, as well as reducing repair works and manpower. First, a Pareto chart was sought on monetary amount of materials used, to identify items requiring sizable material costs. Items identified include reduction of amount of heat insulating materials used for sensor protection, slug removal cost, and refractories. With respect to the heat insulating materials, the cut sizes were discussed, and as a result , difference among individuals was eliminated molten face levels were prevented from being positioned too high , and the number of replacement due to damages was reduces. The rate of heat insulating material reduction was 39%. As regards the slug removal cost, the cost was reduced by reusing waste materials, the inductor channels were changed, and the method of operating the automatic molten metal pouring furnace was improved. With regard to the refractories, the shell width of troughs was covered with steel plates to reduce the use amount, the replacement manpower was reduced, and the use of expensive refractories was minimized. 10 figs., 5 tabs.

  20. Network-Based Material Requirements Planning (NBMRP) in ...

    African Journals Online (AJOL)

    Network-Based Material Requirements Planning (NBMRP) in Product Development Project. ... delays during the execution stage due to poor material supply programmes. ... and uninterrupted scheduled flow throughout the project life cycle.

  1. Biodegradable starch-based polymeric materials

    Science.gov (United States)

    Suvorova, Anna I.; Tyukova, Irina S.; Trufanova, Elena I.

    2000-05-01

    The effects of low-molecular-weight additives, temperature and mechanical action on the structure and properties of starch are discussed. Special attention is given to mixtures of starch with synthetic polymers, e.g., co-polymers of ethylene with vinyl acetate, vinyl alcohol, acrylic acid, cellulose derivatives and other natural polymers. These mixtures can be used in the development of novel environmentally safe materials (films, coatings, packaging materials) and various articles for short-term use. The bibliography includes 105 references.

  2. Optical Limiting Materials Based on Gold Nanoparticles

    Science.gov (United States)

    2014-04-30

    Murphy, University of Illinois at Urbana-Champaign (formerly University of South Carolina), Department of Chemistry Award Number: FA9550-09-1-0246...of the electromagnetic spectrum. 2. Functionalization of the surface of the gold nanoparticles with selected organic and inorganic materials, with...the thesis work of one Ph.D. student (Sean Sivapalan, Ph.D. in materials science and engineering, graduated in 2013, now employed at Intel

  3. Simulation and Experimental Study on Effect of Phase Change Material Thickness to Reduce Temperature of Photovoltaic Panel

    Science.gov (United States)

    Indartono, Y. S.; Prakoso, S. D.; Suwono, A.; Zaini, I. N.; Fernaldi, B.

    2015-09-01

    Solar energy is promising renewable energy which can be applied in Indonesia. Average solar radiation in the country is 4.8 kWh/day/m2. Weakness of silicon-based photovoltaic (PV) is efficiency reduction caused by temperature increase. Many attempts have been done to reduce PV temperature. In previous study, palm oil, which is widely available in Indonesia, is suitable to be used as phase change material (PCM) to reduce PV temperature. In this study, thickness of aluminium rectangular-tube containing phase change material oil is varied. The tube is placed at back part of PV. Numerical and experimental study was done to evaluate the effect of tube thickness to the temperature reduction of the PV. Variation of tube thickness used in the experiment is 50.8mm, 76.2 mm, 101.6 mm. Both studies show that increase of PCM thickness reduces PV temperature. Higher PCM thickness cause large reduction on PV temperature. Simulation result shows there is an optimum thickness of the PCM which is applied to the PV.

  4. Nitrogen-doped reduced graphene oxide as electrode material for high rate supercapacitors

    Science.gov (United States)

    Śliwak, Agata; Grzyb, Bartosz; Díez, Noel; Gryglewicz, Grażyna

    2017-03-01

    Nitrogen-doped reduced graphene oxides (N-rGOs) have been synthesized at various temperatures by a facile hydrothermal route involving the doping of an aqueous graphene oxide dispersion with amitrole. The N-rGOs had a nitrogen content ranging from 10.9 to 13.4 at%, which is among the highest reported for this type of material. The predominant nitrogen species were pyridinic followed by amide/amine, pyrrolic, and quaternary nitrogen. Cyclic voltammetry and impedance spectroscopy measurements performed on the N-doped and nitrogen-free samples revealed that nitrogen fixation provided the material with pseudocapacitive behaviour and improved ion diffusion and charge propagation. A high specific capacitance of 244 F g-1 was obtained at a high scan rate of 100 mV s-1 for the N-rGO with the highest nitrogen content. An outstanding rate capability for the N-rGO, with increasing scan rates, of 98% was obtained, while only 70% was obtained for the non-doped rGO. 92% of the initial capacitance was maintained over 5000 charge/discharge cycles due to the high stability of the electrochemically active nitrogen moieties. Hydrothermal synthesis using amitrole as a nitrogen dopant represents a simple route for the synthesis of graphene with very high nitrogen content and exceptional behaviour for use as electrode material in high-power supercapacitors.

  5. Highly Loaded Fe-MCM-41 Materials: Synthesis and Reducibility Studies

    Directory of Open Access Journals (Sweden)

    Malose P. Mokhonoana

    2009-12-01

    Full Text Available Fe-MCM-41 materials were prepared by different methods. The Fe was both incorporated into the structure and formed crystallites attached to the silica. High Fe content MCM-41 (~16 wt% with retention of mesoporosity and long-range order was achieved by a range of new synthetic methodologies: (i by delaying the addition of Fe3+(aq to the stirred synthesis gel by 2 h, (ii by addition of Fe3+ precursor as a freshlyprecipitated aqueous slurry, (iii by exploiting a secondary synthesis with Si-MCM-41 as SiO2 source. For comparative purposes the MCM-41 was also prepared by incipient wetness impregnation (IWI. Although all these synthesis methods preserved mesoporosity and long-range order of the SiO2 matrix, the hydrothermally-fabricated Fe materials prepared via the secondary synthesis route has the most useful properties for exploitation as a catalyst, in terms of hydrothermal stability of the resulting support. Temperatureprogrammed reduction (TPR studies revealed a three-peak reduction pattern for this material instead of the commonly observed two-peak reduction pattern. The three peaks showed variable intensity that related to the presence of two components: crystalline Fe2O3 and Fe embedded in the SiO2 matrix (on the basis of ESR studies. The role of secondary synthesis of Si-MCM-41 on the iron reducibility was also demonstrated in IWI of sec-Si-MCM-41.

  6. An experimental study of low velocity impacts into granular material in reduced gravity

    Science.gov (United States)

    Murdoch, Naomi; Avila Martinez, Iris; Sunday, Cecily; Cherrier, Olivier; Zenou, Emanuel; Janin, Tristan; Cadu, Alexandre; Gourinat, Yves; Mimoun, David

    2016-04-01

    The granular nature of asteroid surfaces, in combination with the low surface gravity, makes it difficult to predict lander - surface interactions from existing theoretical models. Nonetheless, an understanding of such interactions is particularly important for the deployment of a lander package. This was demonstrated by the Philae lander, which bounced before coming to rest roughly 1 kilometer away from its intended landing site on the surface of comet 67P/Churyumov-Gerasimenko before coming to rest (Biele et al., 2015). In addition to being important for planning the initial deployment, information about the acceleration profile upon impact is also important in the choice of scientific payloads that want to exploit the initial landing to study the asteroid surface mechanical properties (e.g., Murdoch et al., 2016). Using the ISAE-SUPAERO drop tower, we have performed a series of low-velocity collisions into granular material in low gravity. Reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use an Atwood machine, or a system of pulleys and counterweights. In reducing the effective surface acceleration of the granular material, the confining pressure will be reduced, and the properties of the granular material will become more representative of those on an asteroid's surface. In addition, since both the surface and projectile are falling, the projectile requires a minimum amount of time to catch the surface before the collision begins. This extended free-fall increases the experiment duration, making it easier to use accelerometers and high-speed cameras for data collection. The experiment is built into an existing 5.5 m drop-tower frame and has required the custom design of all components, including the projectile, surface sample container, release mechanism and deceleration system (Sunday et al., 2016

  7. Magnesium Based Materials and their Antimicrobial Activity

    Science.gov (United States)

    Robinson, Duane Allan

    that nMgO has similar effects. Incorporation of nMgO into a PCL composite was easily achieved and revealed similar, although not identical antimicrobial results. This work has provided a strong foundation and methodology for further evaluation of Mg based materials and their antimicrobial properties.

  8. New Materials for Chalcogenide Based Solar Cells

    Science.gov (United States)

    Tosun, Banu Selin

    Thin film solar cells based on copper indium gallium diselenide (CIGS) have achieved efficiencies exceeding 20 %. The p-n junction in these solar cells is formed between a p-type CIGS absorber layer and a composite n-type film that consists of a 50-100 nm thin n-type CdS followed by a 50-200 nm thin n-type ZnO. This dissertation focuses on developing materials for replacing CdS and ZnO films to improve the damp-heat stability of the solar cells and for minimizing the use of Cd. Specifically, I demonstrate a new CIGS solar cell with better damp heat stability wherein the ZnO layer is replaced with SnO2. The efficiency of solar cells made with SnO2 decreased less than 5 % after 120 hours at 85 °C and 85 % relative humidity while the efficiency of solar cells made with ZnO declined by more than 70 %. Moreover, I showed that a SnO2 film deposited on top of completed CIGS solar cells significantly increased the device lifetime by forming a barrier against water diffusion. Semicrystalline SnO2 films deposited at room temperature had nanocrystals embedded in an amorphous matrix, which resulted in films without grain boundaries. These films exhibited better damp-heat stability than ZnO and crystalline SnO2 films deposited at higher temperature and this difference is attributed to the lack of grain boundary water diffusion. In addition, I studied CBD of Zn1-xCdxS from aqueous solutions of thiourea, ethylenediaminetetraacetic acid and zinc and cadmium sulfate. I demonstrated that films with varying composition (x) can be deposited through CBD and studied the structure and composition variation along the films' thickness. However, this traditional chemical bath deposition (CBD) approach heats the entire solution and wastes most of the chemicals by homogenous particle formation. To overcome this problem, I designed and developed a continuous-flow CBD approach to utilize the chemicals efficiently and to eliminate homogenous particle formation. Only the substrate is heated to

  9. Carbon dioxide laser and bonding materials reduce enamel demineralization around orthodontic brackets.

    Science.gov (United States)

    de Souza-e-Silva, Cíntia Maria; Parisotto, Thaís Manzano; Steiner-Oliveira, Carolina; Kamiya, Regianne Umeko; Rodrigues, Lidiany Karla Azevedo; Nobre-dos-Santos, Marinês

    2013-01-01

    Altering the structure of the enamel surface around the orthodontic bracket by reducing its content of carbonate and phosphate resulting from application of CO(2) laser may represent a more effective strategy in preventing caries in this region. This study aimed at determining whether irradiation with a CO(2) laser combined with fluoride-releasing bonding material could reduce enamel demineralization around orthodontic brackets subjected to cariogenic challenge. Ninety bovine enamel slabs were divided into five groups (n = 18): non-inoculated brain-heart infusion broth group, non-fluoride-releasing composite resin (NFRCR--control group), resin-modified glass ionomer cement (RMGIC), CO(2) laser + Transbond (L+NFRCR) and CO(2) laser + Fuji (L+RMGIC). Slabs were submitted to a 5-day microbiological caries model. The Streptococcus mutans biofilm formed on the slabs was biochemically and microbiologically analysed, and the enamel Knoop hardness number (KHN) around the brackets was determined. The data were analysed by ANOVA and Tukey tests (α = 0.05). Biochemical and microbiological analyses of the biofilm revealed no statistically significant differences among the groups. Lased groups presented the highest KHN means, which statistically differed from NFRCR; however, no difference was found between these lased groups. RMGIC did not differ from NFRCR which presented the lowest KHN mean. The CO(2) laser (λ = 10.6 μm; 10.0 J/cm(2) per pulse) use with or without F-bonding materials was effective in inhibiting demineralization around orthodontic brackets. However, no additional effect was found when the enamel was treated with the combination of CO(2) laser and an F-releasing material.

  10. Projection-Based Reduced Order Modeling for Spacecraft Thermal Analysis

    Science.gov (United States)

    Qian, Jing; Wang, Yi; Song, Hongjun; Pant, Kapil; Peabody, Hume; Ku, Jentung; Butler, Charles D.

    2015-01-01

    This paper presents a mathematically rigorous, subspace projection-based reduced order modeling (ROM) methodology and an integrated framework to automatically generate reduced order models for spacecraft thermal analysis. Two key steps in the reduced order modeling procedure are described: (1) the acquisition of a full-scale spacecraft model in the ordinary differential equation (ODE) and differential algebraic equation (DAE) form to resolve its dynamic thermal behavior; and (2) the ROM to markedly reduce the dimension of the full-scale model. Specifically, proper orthogonal decomposition (POD) in conjunction with discrete empirical interpolation method (DEIM) and trajectory piece-wise linear (TPWL) methods are developed to address the strong nonlinear thermal effects due to coupled conductive and radiative heat transfer in the spacecraft environment. Case studies using NASA-relevant satellite models are undertaken to verify the capability and to assess the computational performance of the ROM technique in terms of speed-up and error relative to the full-scale model. ROM exhibits excellent agreement in spatiotemporal thermal profiles (<0.5% relative error in pertinent time scales) along with salient computational acceleration (up to two orders of magnitude speed-up) over the full-scale analysis. These findings establish the feasibility of ROM to perform rational and computationally affordable thermal analysis, develop reliable thermal control strategies for spacecraft, and greatly reduce the development cycle times and costs.

  11. Marine fungi: Degraders of poly-3-hydroxyalkanoate based plastic materials

    Directory of Open Access Journals (Sweden)

    Matavulj Milan

    2009-01-01

    Full Text Available The search for new biosynthetic and biodegradable materials to save nonrenewable resources and reduce global pollution problems is an urgent task. Recently, materials like thermoplastic poly-3-hydroxyalkanoates (PHA, have been found synthesized by bacteria as storage materials. The major PHAs synthesized are poly-b-hydroxybutyrate (PHB, poly-b-hydroxyvalerate (PHV and their copolymers. They are already commercially produced and used as BIOPOLTM (ICI, England. Their complete degradability by bacteria has already been shown. Today, oceans and estuaries serve as major landfills, and since fungi are an important part of the degrading microbiota, in order to prove their participation in the degradation process, a simple degradation test suitable for fungi and marine conditions had to be developed. Several solid media based on artificial sea water, differing in the content of non-alkanoate organics and supplemented with 0.1% PHA (or BIOPOLTM as a main source of carbon have been tested. The testing principle consists of clearing the turbid medium in test tube or plates caused by suspended granules of PHA. All media tested supported the growth of fungi. For the discrete and transparent clearing of zones, a mineral medium with 0.01% peptone, 0.01% yeast extract, and 0.1% PHB or BIOPOLTM was finally chosen where the fine and evenly distributed turbidity is accomplished by a specific procedure. This method allows the investigation of degradability of PHA-based plastic materials as well as screening for fungal ability to depolymerise pure PHA homopolymers. Using this medium, 32 strains of marine yeasts and 102 strains of marine mycelial fungi belonging to different systematic and ecological groups were tested for their ability to degrade PHAs. Only about 4% of the strains were able to degrade BIOPOLTM and about 6% depolymerised pure PHB homopolymer. This is in sharp contrast to the results of our previous experiments with 143 strains of terrestrial fungi

  12. SODIM: Service Oriented Data Integration based on MapReduce

    Directory of Open Access Journals (Sweden)

    Ghada ElSheikh

    2013-09-01

    Data integration systems can benefit from innovative dynamic infrastructure solutions such as Clouds, with its more agility, lower cost, device independency, location independency, and scalability. This study consolidates the data integration system, Service Orientation, and distributed processing to develop a new data integration system called Service Oriented Data Integration based on MapReduce (SODIM that improves the system performance, especially with large number of data sources, and that can efficiently be hosted on modern dynamic infrastructures as Clouds.

  13. Reducing discards without reducing profit: Free gear choice in a Danish result-based management trial

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Ulrich, Clara; Eliasen, Søren Qvist

    2016-01-01

    The 2013 Common Fisheries Policy introduced a landing obligation on a range of species. This is changing the fundamental principles on which EU fisheries management is based, with more focus on the full accountability of all catches (a move towards catch quota management) and less accountability ......, where unwanted catches could be reduced to some extent without negative effects on economic viability. Some practical implementation challenges were nevertheless encountered, which are discussed in the perspective of implementing results-based management at full scale.......The 2013 Common Fisheries Policy introduced a landing obligation on a range of species. This is changing the fundamental principles on which EU fisheries management is based, with more focus on the full accountability of all catches (a move towards catch quota management) and less accountability...... on the means used to obtain these catches (a move towards results-based management). To investigate the potentials and challenges that these paradigm shifts give rise to, a 6-months ‘unrestricted gear’ trial was performed in Denmark in 2015,. Twelve trawlers of different size, rigging, fishing area and target...

  14. Luminescent hybrid materials based on laponite clay.

    Science.gov (United States)

    Li, Huanrong; Li, Man; Wang, Yu; Zhang, Wenjun

    2014-08-11

    The spectroscopic behavior of ionic Eu(3+) or Tb(3+) complexes of an aromatic carboxyl-functionalized organic salt as well as those of the hybrid materials derived from adsorption of the ionic complexes on Laponite clay are reported. X-ray diffraction (XRD) patterns suggest that the complexes are mainly adsorbed on the outer surfaces of the Laponite disks rather than intercalated within the interlayer spaces. Photophysical data showed that the energy-transfer efficiency from the ligand to Eu(3+) ions in the hybrid material is increased remarkably with respect to the corresponding ionic complex. The hybrid material containing the Eu(3+) complex shows bright red emission from the prominent (5) D0 →(7) F2 transition of Eu(3+) ions, and that containing the Tb(3+) complex exhibits bright green emission due to the dominant (5) D4 →(7) F5 transition of Tb(3+) ions.

  15. Supercapacitors based on graphene/pseudocapacitive materials

    Directory of Open Access Journals (Sweden)

    Sačer Denis

    2017-01-01

    Full Text Available Composites of graphene and SnO2 were successfully prepared by a single step simultaneous synthesis of SnO2 and reduction of graphene oxide (GO. Three different compositions of precursor solution resulted in different composite materials containing graphene and SnO2. The reaction was realized by microwave-assisted hydrothermal synthesis. Scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDX gave insight into the morphology and composition of the obtained materials. Good capacitive/pseudocapacitive properties of the obtained material suitable for supercapacitor application were registered by cyclic voltammetry, from where specific capacitance values up to 93 F g-1 were determined. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172060

  16. Rhombohedral cubic semiconductor materials on trigonal substrate with single crystal properties and devices based on such materials

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    Growth conditions are developed, based on a temperature-dependent alignment model, to enable formation of cubic group IV, group II-V and group II-VI crystals in the [111] orientation on the basal (0001) plane of trigonal crystal substrates, controlled such that the volume percentage of primary twin crystal is reduced from about 40% to about 0.3%, compared to the majority single crystal. The control of stacking faults in this and other embodiments can yield single crystalline semiconductors based on these materials that are substantially without defects, or improved thermoelectric materials with twinned crystals for phonon scattering while maintaining electrical integrity. These methods can selectively yield a cubic-on-trigonal epitaxial semiconductor material in which the cubic layer is substantially either directly aligned, or 60 degrees-rotated from, the underlying trigonal material.

  17. Stretchable, curvilinear electronics based on inorganic materials.

    Science.gov (United States)

    Kim, Dae-Hyeong; Xiao, Jianliang; Song, Jizhou; Huang, Yonggang; Rogers, John A

    2010-05-18

    All commercial forms of electronic/optoelectronic technologies use planar, rigid substrates. Device possibilities that exploit bio-inspired designs or require intimate integration with the human body demand curvilinear shapes and/or elastic responses to large strain deformations. This article reviews progress in research designed to accomplish these outcomes with established, high-performance inorganic electronic materials and modest modifications to conventional, planar processing techniques. We outline the most well developed strategies and illustrate their use in demonstrator devices that exploit unique combinations of shape, mechanical properties and electronic performance. We conclude with an outlook on the challenges and opportunities for this emerging area of materials science and engineering.

  18. IFMIF (International Fusion Materials Irradiation Facility) conceptual design activity reduced cost report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-02-01

    This report describes the results of a preliminary reevaluation of the design and cost of the International Fusion Materials Irradiation Facility (IFMIF) Project in response to the request from the 28th FPCC meeting in January 1999. Two major ideas have been considered: 1) reduction of the total construction cost through elimination of the previously planned facility upgrade and 2) a facility deployment in 3 stages with capabilities for limited experiments in the first stage. As a result, the size and complexity of the facility could be significantly reduced, leading to substantial cost savings. In addition to these two ideas, this study also included a critical review of the original CDA specification with the objective of elimination of nonessential items. For example, the number of lithium targets was reduced from two to one. As a result of these changes in addition to the elimination of the upgrade, the total cost estimate was very substantially reduced from 797.2 MICF to 487.8 MICF, where 1 MICF = 1 Million of the IFMIF Conversion Units (approximately $1M US January, 1996). (author)

  19. INVESTIGATION OF DIFFERENT REDUCING AGENTS OF AZO DYES FROM TEXTILE MATERIALS

    Directory of Open Access Journals (Sweden)

    VARZARU Elena

    2017-05-01

    Full Text Available Toxicology of textiles is a subject of increasing interest, because of the presence of dangerous compounds in clothes generated from dyeing and finishing processes. In order to protect human health, numerous regulations (Oeko Tex Standard 100, REACH Regulation limit the presence of dangerous chemicals, such as aromatic amines, generated by reductive cleavage of azo dyes, by no more than 30 mg/kg of textile material. The objective of this work was to investigate different methods of azo dyes reduction from colored textile specimens, in order to determine the procedure with the highest selectivity and sensibility. Aromatic amines are generated by chemical degradation achieved by the cleavage of the azo linkage using reducing agents.Different alternatives to sodium dithionite, reducing agent recommended by standard method ISO/FDIS 14362-1 were tested, such as: sodium sulfite and tin chloride. Also, xylene extraction, the common procedure for synthetic fibers was also performed for cotton, dyed with azo dye Direct Blue 6, in order to assess the reliability of common simultaneously extraction and reduction of direct dyes from natural fibres. Sodium ditionite remains the popular choice for reducing agent, since it provides efficient cleavage of azo linkage, generating specifically carcinogenic amines. Both liquid and gas chromatography analytical techniques were used for precise quantitative determination of generated compounds.

  20. Acetylene-based materials in organic photovoltaics.

    Science.gov (United States)

    Silvestri, Fabio; Marrocchi, Assunta

    2010-04-08

    Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C(60), and their use as the active materials in photovoltaic devices.

  1. Acetylene-Based Materials in Organic Photovoltaics

    Directory of Open Access Journals (Sweden)

    Fabio Silvestri

    2010-04-01

    Full Text Available Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (polyarylacetylenes that have been used in the field. A general introduction to (polyarylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (copolymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices.

  2. Geotechnical characterization of peat-based landfill cover materials

    Institute of Scientific and Technical Information of China (English)

    Afshin Khoshand; Mamadou Fall

    2016-01-01

    Natural methane (CH4) oxidation that is carried out through the use of landfill covers (biocovers) is a promising method for reducing CH4 emissions from landfills. Previous studies on peat-based landfill covers have mainly focused on their biochemical properties (e.g. CH4 oxidation capacity). However, the utilization of peat as a cover material also requires a solid understanding of its geotechnical properties (thermal, hydraulic, and mechanical), which are critical to the performance of any biocover. Therefore, the objective of this context is to investigate and assess the geotechnical properties of peat-based cover materials (peat, peat-sand mixture), including compaction, consolidation, and hydraulic and thermal conductivities. The studied materials show high compressibility to the increase of vertical stress, with compression index (Cc) values ranging from 0.16 to 0.358. The compressibility is a function of sand content such that the peat-sand mixture (1:3) has the lowest Cc value. Both the thermal and hydraulic conductivities are functions of moisture content, dry density, and sand content. The hydraulic conduc-tivity varies from 1.74 × 10-9 m/s to 7.35 × 10-9 m/s, and increases with the increase in sand content. The thermal conductivity of the studied samples varies between 0.54 W/(m K) and 1.41 W/(m K) and it in-creases with the increases in moisture and sand contents. Increases in sand content generally increase the mechanical behavior of peat-based covers; however, they also cause relatively high hydraulic and thermal conductivities which are not favored properties for biocovers.

  3. A high energy output nanogenerator based on reduced graphene oxide

    Science.gov (United States)

    Li, Weiping; Zhang, Yupeng; Liu, Liangliang; Li, Delong; Liao, Lei; Pan, Chunxu

    2015-10-01

    In this paper, we report a novel graphene-based nanogenerator for high energy harvesting. Experimental and theoretical results revealed that the energy output mechanism is the joint action of the strain effect (band engineering) and the triboelectric effect of reduced graphene oxide. It was found that the current could be adjusted by experimental parameters, such as the electrolyte concentration and rotation rate. Furthermore, the voltage output could be amplified by series connection of the system. Compared with other nanogenerators, the present graphene-based nanogenerator provides advantages, such as simple assembly, flexibility and high structural stability. It is expected that this nanogenerator will be of potential application in active sensors and sustainable power sources.In this paper, we report a novel graphene-based nanogenerator for high energy harvesting. Experimental and theoretical results revealed that the energy output mechanism is the joint action of the strain effect (band engineering) and the triboelectric effect of reduced graphene oxide. It was found that the current could be adjusted by experimental parameters, such as the electrolyte concentration and rotation rate. Furthermore, the voltage output could be amplified by series connection of the system. Compared with other nanogenerators, the present graphene-based nanogenerator provides advantages, such as simple assembly, flexibility and high structural stability. It is expected that this nanogenerator will be of potential application in active sensors and sustainable power sources. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04971g

  4. A reduced graphene oxide based electrochemical biosensor for tyrosine detection.

    Science.gov (United States)

    Wei, Junhua; Qiu, Jingjing; Li, Li; Ren, Liqiang; Zhang, Xianwen; Chaudhuri, Jharna; Wang, Shiren

    2012-08-24

    In this paper, a 'green' and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10(-7) M to 2 × 10(-5) M with a detection limitation of 7.5 × 10(-8) M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.

  5. Bio-based amphiphilic materials development and applications

    Science.gov (United States)

    Farm-based raw materials are increasingly used in the development of amphiphilic materials that have potential applications in the production of a variety of consumer and industrial products, including lubricants. Raw materials of interest include: starches, proteins, fats, oils, and sugars. These ...

  6. Reduced graphene oxide film based highly responsive infrared detector

    Science.gov (United States)

    Khan, Mustaque A.; Nanda, Karuna K.; Krupanidhi, Saluru B.

    2017-08-01

    Due to the unique optical properties, graphene can effectively be used for the detection of infrared light. In this regard, reduced graphene oxide (RGO) has drawn considerable attention in scientific society because of simplicity of preparation and tunable properties. Here, we report the synthesis of RGO by solvothermal reduction of graphene oxide (GO) in ethanol and the detection of infrared light (1064 and 1550 nm) with metal—RGO—metal configuration. We have observed that photocurrent, responsivity as well as the external quantum efficiency increase with C/O ratio. The responsivity value in near-infrared region can be as high as 1.34 A · W-1 and the external quantum efficiency is more than 100%. Response times of these devices are in the order of few seconds. Overall, the responsivity of our device is found to be better than many of the already reported values where graphene or reduced graphene oxide is the only active material. The high value of quantum efficiency is due to strong light absorption and the presence of mid-gap states band in RGOs.

  7. Electrodeposition of Polypyrrole/Reduced Graphene Oxide/Iron Oxide Nanocomposite as Supercapacitor Electrode Material

    Directory of Open Access Journals (Sweden)

    Y. C. Eeu

    2013-01-01

    Full Text Available Polypyrrole (PPy was reinforced with reduced graphene oxide (RGO and iron oxide to achieve electrochemical stability and enhancement. The ternary nanocomposite film was prepared using a facile one-pot chronoamperometry approach, which is inexpensive and experimentally friendly. The field emission scanning electron microscopy (FESEM image shows a layered morphology of the ternary nanocomposite film as opposed to the dendritic structure of PPy, suggesting hybridization of the three materials during electrodeposition. X-ray diffraction (XRD profile shows the presence of Fe2O3 in the ternary nanocomposite. Cyclic voltammetry (CV analysis illustrates enhanced current for the nanocomposite by twofold and fourfold compared to its binary (PPy/RGO and individual (PPy counterparts, respectively. The ternary nanocomposite film exhibited excellent specific capacitance retention even after 200 cycles of charge/discharge.

  8. Reduced activation martensitic steels as a structural material for ITER test blanket

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, K. E-mail: shiba@realab01.tokai.jaeri.go.jp; Enoeda, M.; Jitsukawa, S

    2004-08-01

    A Japanese ITER test blanket module (TBM) is planed to use reduced-activation martensitic steel F82H. Feasibility of F82H for ITER test blanket module is discussed in this paper. Several kinds of property data, including physical properties, magnetic properties, mechanical properties and neutron-irradiation data on F82H have been obtained, and these data are complied into a database to be used for the designing of the ITER TBM. Currently obtained data suggests F82H will not have serious problems for ITER TBM. Optimization of F82H improves the induced activity, toughness and HIP resistance. Furthermore, modified F82H is resistant to temperature instability during material production.

  9. Physical Properties Investigation of Reduced Graphene Oxide Thin Films Prepared by Material Inkjet Printing

    Directory of Open Access Journals (Sweden)

    Veronika Schmiedova

    2017-01-01

    Full Text Available The article is focused on the study of the optical properties of inkjet-printed graphene oxide (GO layers by spectroscopic ellipsometry. Due to its unique optical and electrical properties, GO can be used as, for example, a transparent and flexible electrode material in organic and printed electronics. Spectroscopic ellipsometry was used to characterize the optical response of the GO layer and its reduced form (rGO, obtainable, for example, by reduction of prepared layers by either annealing, UV radiation, or chemical reduction in the visible range. The thicknesses of the layers were determined by a mechanical profilometer and used as an input parameter for optical modeling. Ellipsometric spectra were analyzed according to the dispersion model and the influence of the reduction of GO on optical constants is discussed. Thus, detailed analysis of the ellipsometric data provides a unique tool for qualitative and also quantitative description of the optical properties of GO thin films for electronic applications.

  10. Organic microcantilevers based on reduced graphene oxide composite for electrostrictive energy harvesting

    Science.gov (United States)

    Nesser, H.; Debéda, H.; Yuan, J.; Colin, A.; Poulin, P.; Dufour, I.; Ayela, C.

    2016-11-01

    Electrostrictive materials are promising for mechanical energy harvesting applications because of their high power density, low cost and scalability. In this paper, strain sensitive nanocomposite materials based on reduced graphene (rGO) and PDMS are used for energy harvesting; they are characterized by a high electrostrictive coefficient (2.4x10-15 m2/V2) and a giant dielectric constant (ranging from 100 to 1000 at 100 Hz, depending of rGO concentration). Using these nanocomposite materials, electrostrictive MEMS microgenerators are fabricated with an innovative low-cost and environment friendly process in an all-organic approach. The fabricated microcantilevers exhibit excellent mechanoelectrical performances in dynamic mode. With an acceleration of 1 g of the microcantilever base using a shaker, experiment at the first resonant mode (≈ 16 Hz) generates an electrical power density of 8.15 μW/cm3.

  11. High Volumetric Energy Density Hybrid Supercapacitors Based on Reduced Graphene Oxide Scrolls.

    Science.gov (United States)

    Rani, Janardhanan R; Thangavel, Ranjith; Oh, Se-I; Woo, Jeong Min; Chandra Das, Nayan; Kim, So-Yeon; Lee, Yun-Sung; Jang, Jae-Hyung

    2017-07-12

    The low volumetric energy density of reduced graphene oxide (rGO)-based electrodes limits its application in commercial electrochemical energy storage devices that require high-performance energy storage capacities in small volumes. The volumetric energy density of rGO-based electrode materials is very low due to their low packing density. A supercapacitor with enhanced packing density and high volumetric energy density is fabricated using doped rGO scrolls (GFNSs) as the electrode material. The restacking of rGO sheets is successfully controlled through synthesizing the doped scroll structures while increasing the packing density. The fabricated cell exhibits an ultrahigh volumetric energy density of 49.66 Wh/L with excellent cycling stability (>10 000 cycles). This unique design strategy for the electrode material has significant potential for the future supercapacitors with high volumetric energy densities.

  12. Protective coatings based on 2D-materials

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten

    Corrosion has a major impact on the world economy. Barrier coatings is one of the most widely applied strategies to reduce the degradation of materials, however, every coating technology has its drawbacks. Graphene has the potential of creating the ideal coating, being atomically thin and, when...... in perfect condition, impermeable to most molecules. However, it has recently been demonstrated that graphene can promote galvanic corrosion and may actually increase the corrosion rate in the long term. The aim of this thesis is to individuate, develop and demonstrate solutions based on 2Dmaterials......, that can deliver viable coatings technologies circumventing the drawback demonstrated for graphene coatings. The focus is twofold, with a solution that focuses on multi-layer coatings, wherein the drawback of graphene is circumvented by diffusion limitations. Here it will be shown that such solutions...

  13. Spectrophotometric total reducing sugars assay based on cupric reduction.

    Science.gov (United States)

    Başkan, Kevser Sözgen; Tütem, Esma; Akyüz, Esin; Özen, Seda; Apak, Reşat

    2016-01-15

    As the concentration of reducing sugars (RS) is controlled by European legislation for certain specific food and beverages, a simple and sensitive spectrophotometric method for the determination of RS in various food products is proposed. The method is based on the reduction of Cu(II) to Cu(I) with reducing sugars in alkaline medium in the presence of 2,9-dimethyl-1,10-phenanthroline (neocuproine: Nc), followed by the formation of a colored Cu(I)-Nc charge-transfer complex. All simple sugars tested had the linear regression equations with almost equal slope values. The proposed method was successfully applied to fresh apple juice, commercial fruit juices, milk, honey and onion juice. Interference effect of phenolic compounds in plant samples was eliminated by a solid phase extraction (SPE) clean-up process. The method was proven to have higher sensitivity and precision than the widely used dinitrosalicylic acid (DNS) colorimetric method.

  14. Reinforcement of Conducting Silver-based Materials

    Directory of Open Access Journals (Sweden)

    Heike JUNG

    2014-09-01

    Full Text Available Silver is a well-known material in the field of contact materials because of its high electrical and thermal conductivity. However, due to its bad mechanical and switching properties, silver alloys or reinforcements of the ductile silver matrix are required. Different reinforcements, e. g. tungsten, tungsten carbide, nickel, cadmium oxide or tin oxide, are used in different sectors of switches. To reach an optimal distribution of these reinforcements, various manufacturing techniques (e. g. powder blending, preform infiltration, wet-chemical methods, internal oxidation are being used for the production of these contact materials. Each of these manufacturing routes offers different advantages and disadvantages. The mechanical alloying process displays a successful and efficient method to produce particle-reinforced metal-matrix composite powders. This contribution presents the obtained fine disperse microstructure of tungsten-particle-reinforced silver composite powders produced by the mechanical alloying process and displays this technique as possible route to provide feedstock powders for subsequent consolidation processes. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4889

  15. Reinforcement of Conducting Silver-based Materials

    Directory of Open Access Journals (Sweden)

    Heike JUNG

    2014-09-01

    Full Text Available Silver is a well-known material in the field of contact materials because of its high electrical and thermal conductivity. However, due to its bad mechanical and switching properties, silver alloys or reinforcements of the ductile silver matrix are required. Different reinforcements, e. g. tungsten, tungsten carbide, nickel, cadmium oxide or tin oxide, are used in different sectors of switches. To reach an optimal distribution of these reinforcements, various manufacturing techniques (e. g. powder blending, preform infiltration, wet-chemical methods, internal oxidation are being used for the production of these contact materials. Each of these manufacturing routes offers different advantages and disadvantages. The mechanical alloying process displays a successful and efficient method to produce particle-reinforced metal-matrix composite powders. This contribution presents the obtained fine disperse microstructure of tungsten-particle-reinforced silver composite powders produced by the mechanical alloying process and displays this technique as possible route to provide feedstock powders for subsequent consolidation processes. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4889

  16. Enhancement of Saharan groundwater quality by reducing its fluoride concentration using different materials

    KAUST Repository

    Ramdani, Amina

    2014-04-15

    According to the environmental protection regulations, fluoride concentration is considered as a substance of priority for assessment of drinking water quality to determine their impacts on the environment and public health. Saharan groundwater (Algeria) contains an excess of fluoride ions. Regular consumption of this water by the population of the region may cause endemic fluorosis. To solve this problem, we propose to treat this water by adsorption on different materials, such as activated alumina (AA), sodium clay (SC), and hydroxyapatite (HAP) in order to enhance its quality by reducing its fluoride concentration. The maximum adsorption is achieved with an adsorption capacity of the order of 0.9, 0.667, and 0.370 mg/g and with a percentage of 90, 83.4, and 73.95% for AA, HAP, and SC, respectively. Indeed, the acidity and alkalinity of the medium significantly affect the adsorption of fluoride ions. Results deduced from the curves of adsorption isotherms of fluoride ions showed that the retention is predictable from these isotherms in agreement with the Langmuir model. The low removal of fluoride ions was observed in presence of (Formula presented.), (Formula presented.), and (Formula presented.) ions. Finally, AA material proved to be the best adsorbent for fluoride ions removal. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  17. Can bio-based attributes upgrade a brand? How partial and full use of bio-based materials affects the purchase intention of brands

    NARCIS (Netherlands)

    Reinders, Machiel J.; Onwezen, Marleen C.; Meeusen, Marieke J.G.

    2017-01-01

    To reduce human dependency on fossil fuels, increasing attempts are being made to substitute synthetic materials in products with bio-based materials. Global brands attempt to differentiate themselves by adding bio-based materials to their products. However, little is known about consumers'

  18. Li2S-reduced graphene oxide nanocomposites as cathode material for lithium sulfur batteries

    Science.gov (United States)

    Han, Kai; Shen, Jingmei; Hayner, Cary M.; Ye, Hongqi; Kung, Mayfair C.; Kung, Harold H.

    2014-04-01

    A lithium sulfide-reduced graphene oxide nanocomposite (Li2S-rGO) was synthesized and evaluated as the cathode material and Li source for the assembly of Li-S batteries. The composite, with a unique 3-D pocket structure, was synthesized by a combination of facile solution chemistry and thermal treatment. The as-prepared Li2S-rGO nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, which showed 20-40 nm Li2S particles homogeneously dispersed between reduced graphene oxide sheets. Li2S contents as high as ∼66% could be obtained. When used with an electrolyte containing LiNO3 and polysulfide, the Li2S-rGO nanocomposites exhibited a high initial capacity of 982 mAh g-1 Li2S. However, there was noticeable capacity fade in subsequent cycles, probably due to polysulfide dissolution and the shuttle mechanism, but a capacity of 315 mAh g-1 could still be obtained after 100 cycles, with 90-95% coulomb efficiency. The effect of polysulfide additive in the electrolyte on the activation of Li2S in the first delithiation step was discussed.

  19. Reducing Pumping Power in Hydronic Heating and Cooling Systems with Microencapsulated Phase Change Material Slurries

    Science.gov (United States)

    Karas, Kristoffer Jason

    Phase change materials (PCMs) are being used increasingly in a variety of thermal transfer and thermal storage applications. This thesis presents the results of a laboratory study into the feasibility of improving the performance of hydronic heating and cooling systems by adding microcapsules filled with a PCM to the water used as heat transport media in these systems. Microencapsulated PCMs (MPCMs) increase the heat carrying capacity of heat transport liquids by absorbing or releasing heat at a constant temperature through a change of phase. Three sequences of tests and their results are presented: 1) Thermal cycling tests conducted to determine the melting temperatures and extent of supercooling associated with the MPCMs tested. 2) Hydronic performance tests in which MPCM slurries were pumped through a fin-and-tube, air-to-liquid heat exchanger and their thermal transfer performance compared against that of ordinary water. 3) Mechanical stability tests in which MPCM slurries were pumped in a continuous loop in order to gauge the extent of rupture due to pumping. It is shown that slurries consisting of water and MPCMs ˜ 14-24 mum in diameter improve thermal performance and offer the potential for power savings in the form of reduced pumping requirements. In addition, it is shown that while slurries of MPCMs 2-5 mum in diameter appear to exhibit better mechanical stability than slurries of larger diameter MPCMs, the smaller MPCMs appear to reduce the thermal performance of air-to-liquid heat exchangers.

  20. Reduced graphene oxide as a stable and high-capacity cathode material for Na-ion batteries

    Science.gov (United States)

    Ali, Ghulam; Mehmood, Asad; Ha, Heung Yong; Kim, Jaehoon; Chung, Kyung Yoon

    2017-01-01

    We report the feasibility of using reduced graphene oxide (RGO) as a cost-effective and high performance cathode material for sodium-ion batteries (SIBs). Graphene oxide is synthesized by a modified Hummers’ method and reduced using a solid-state microwave irradiation method. The RGO electrode delivers an exceptionally stable discharge capacity of 240 mAh g−1 with a stable long cycling up to 1000 cycles. A discharge capacity of 134 mAh g−1 is obtained at a high current density of 600 mA g−1, and the electrode recovers a capacity of 230 mAh g−1 when the current density is reset to 15 mA g−1 after deep cycling, thus demonstrating the excellent stability of the electrode with sodium de/intercalation. The successful use of the RGO electrode demonstrated in this study is expected to facilitate the emergence of low-cost and sustainable carbon-based materials for SIB cathode applications. PMID:28098231

  1. Reduced graphene oxide as a stable and high-capacity cathode material for Na-ion batteries

    Science.gov (United States)

    Ali, Ghulam; Mehmood, Asad; Ha, Heung Yong; Kim, Jaehoon; Chung, Kyung Yoon

    2017-01-01

    We report the feasibility of using reduced graphene oxide (RGO) as a cost-effective and high performance cathode material for sodium-ion batteries (SIBs). Graphene oxide is synthesized by a modified Hummers’ method and reduced using a solid-state microwave irradiation method. The RGO electrode delivers an exceptionally stable discharge capacity of 240 mAh g-1 with a stable long cycling up to 1000 cycles. A discharge capacity of 134 mAh g-1 is obtained at a high current density of 600 mA g-1, and the electrode recovers a capacity of 230 mAh g-1 when the current density is reset to 15 mA g-1 after deep cycling, thus demonstrating the excellent stability of the electrode with sodium de/intercalation. The successful use of the RGO electrode demonstrated in this study is expected to facilitate the emergence of low-cost and sustainable carbon-based materials for SIB cathode applications.

  2. Biomedical applications of the graphene-based materials.

    Science.gov (United States)

    Zhang, Baomei; Wang, Yang; Zhai, Guangxi

    2016-04-01

    Graphene, a rapidly rising star, has gained extensive research interests lately due to its excellent properties--such as the exceptional optical, electrical, thermal and mechanical features--which are superior to other materials, so it is called "two-dimensional magical materials". This article presents diverse types and various properties of graphene-based materials, and the current methods for the surface modifications of the graphene-based materials are briefly described. In addition, the in vivo and in vitro cytotoxicity of graphene-based materials are comprehensively discussed. What's more, a summary of its biomedical applications such as drug/gene delivery, photothermal therapy, photodynamic therapy and multimodality therapy is also offered. Finally, an outlook of the graphene-based materials and the challenges in this field are briefly discussed.

  3. Quality-Oriented Classification of Aircraft Material Based on SVM

    Directory of Open Access Journals (Sweden)

    Hongxia Cai

    2014-01-01

    Full Text Available The existing material classification is proposed to improve the inventory management. However, different materials have the different quality-related attributes, especially in the aircraft industry. In order to reduce the cost without sacrificing the quality, we propose a quality-oriented material classification system considering the material quality character, Quality cost, and Quality influence. Analytic Hierarchy Process helps to make feature selection and classification decision. We use the improved Kraljic Portfolio Matrix to establish the three-dimensional classification model. The aircraft materials can be divided into eight types, including general type, key type, risk type, and leveraged type. Aiming to improve the classification accuracy of various materials, the algorithm of Support Vector Machine is introduced. Finally, we compare the SVM and BP neural network in the application. The results prove that the SVM algorithm is more efficient and accurate and the quality-oriented material classification is valuable.

  4. Carbon-based electrode materials for DNA electroanalysis.

    Science.gov (United States)

    Kato, Dai; Niwa, Osamu

    2013-01-01

    This review addresses recent studies of newly developed carbon-based electrode materials and their use for DNA electroanalysis. Recently, new carbon materials including carbon nanotubes (CNT), graphene and diamond-based nanocarbon electrodes have been actively developed as sensing platforms for biomolecules, such as DNA and proteins. Electrochemical techniques using these new material-based electrodes can provide very simple and inexpensive sensing platforms, and so are expected to be used as one of the "post-light" DNA analysis methods, which include coulometric detection, amperometric detection with electroactive tags or intercalators, and potentiometric detection. DNA electroanalysis using these new carbon materials is summarized in view of recent advances on electrodes.

  5. Mn based olivine electrode material with high power and energy.

    Science.gov (United States)

    Kim, Jongsoon; Seo, Dong-Hwa; Kim, Sung-Wook; Park, Young-Uk; Kang, Kisuk

    2010-02-28

    We report the Mn based olivine electrode material with high power and energy. Easier and more frequent nucleation by Fe and Co in Mn-based olivines significantly enhanced the rate capability as evidenced by the electrochemical results.

  6. Artificial atoms based on correlated materials

    Science.gov (United States)

    Mannhart, J.; Boschker, H.; Kopp, T.; Valentí, R.

    2016-08-01

    Low-dimensional electron systems fabricated from quantum matter have in recent years become available and are being explored with great intensity. This article gives an overview of the fundamental properties of such systems and summarizes the state of the field. We furthermore present and consider the concept of artificial atoms fabricated from quantum materials, anticipating remarkable scientific advances and possibly important applications of this new field of research. The surprising properties of these artificial atoms and of molecules or even of solids assembled from them are presented and discussed.

  7. Polymerization shrinkage of flowable resin-based restorative materials

    OpenAIRE

    Stavridakis, Minos M; Dietschi, Didier; Krejci, Ivo

    2005-01-01

    This study measured the linear polymerization displacement and polymerization forces induced by polymerization shrinkage of a series of flowable resin-based restorative materials. The materials tested were 22 flowable resin-based restorative materials (Admira Flow, Aelite Flow, Aeliteflow LV, Aria, Crystal Essence, Definite Flow, Dyract Flow, Filtek Flow, FloRestore, Flow-it, Flow-Line, Freedom, Glacier, OmegaFlo, PermaFlo, Photo SC, Revolution 2, Star Flow, Synergy Flow, Tetric Flow, Ultrase...

  8. Densified ultra-light cement-based materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro

    2015-01-01

    be used as a “clean technology” in the production of cement-based materials for structural applications with a low carbon footprint. This paper describes the principles of this concept coupled with experimental results on the basic properties of this enhanced type of cement-based materials with combined...

  9. PLC based Segregation of Scrap Material

    Directory of Open Access Journals (Sweden)

    Mangesh B. Nagapure

    2017-04-01

    Full Text Available This paper describe segregation of scrap materials using automation system. With the growing population rate, the amount of waste being produced is also increasing at a very faster rate. It is also posing a very serious problem at the industrial and domestic level to manage the wastes being dumped everywhere as landfill waste. So, it is very crucial to have some system to manage waste automatically which is currently not there. Prime Minister Modi’s mission of Swaccha Bharat Abhiyan can also be successfully implemented by the proposed system. The paper proposes a novel method where the provision is given to separate out metal and nonmetal waste into respective bins by the sensing of different sensors incorporated along the conveyor belt. Pieces of glass, paper, wood and metallic materials are separated out from proposed work. Using the segregation, most of the metal and nonmetal components like paper, glass, plastic increases the economic value of the waste to its best. For every scrap separation system, a higher level of automation demands more and more accurate programming device. So, we are using programmable logic controller (PLC as main component

  10. Combustion of Han-Based Monopropellant Droplets in Reduced Gravity

    Science.gov (United States)

    Shaw, B. D.

    1999-01-01

    The objective of this research is to study combustion of monopropellant droplets and monopropellant droplet components in reduced-gravity environments so that spherical symmetry is strongly promoted. The experiments will use hydroxylammonium nitrate (HAN, chemical formula NH3OHNO3) based monopropellants. This class of monopropellant is selected for study because of its current relevance and also because it is relatively benign and safe to work with. The experimental studies will allow for accurate determination of fundamental data on deflagration rates, gas-phase temperature profiles, transient gas-phase flame behaviors, the onset of bubbling in droplets at lower pressures, and the low-pressure deflagration limit. The theoretical studies will provide rational models of deflagration mechanisms of HAN-based liquid propellants. Besides advancing fundamental knowledge, the proposed research should aid in applications (e.g., spacecraft thrusters and liquid propellant guns) of this unique class of monopropellants.

  11. Intermetallic-based high-temperature materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-07-01

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminides are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  12. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  13. RDX-based nanocomposite microparticles for significantly reduced shock sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Hongwei, E-mail: hqiu@stevens.edu [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Stepanov, Victor; Di Stasio, Anthony R. [U.S. Army - Armament Research, Development, and Engineering Center, Picatinny, NJ 07806 (United States); Chou, Tsengming; Lee, Woo Y. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2011-01-15

    Cyclotrimethylenetrinitramine (RDX)-based nanocomposite microparticles were produced by a simple, yet novel spray drying method. The microparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and high performance liquid chromatography (HPLC), which shows that they consist of small RDX crystals ({approx}0.1-1 {mu}m) uniformly and discretely dispersed in a binder. The microparticles were subsequently pressed to produce dense energetic materials which exhibited a markedly lower shock sensitivity. The low sensitivity was attributed to small crystal size as well as small void size ({approx}250 nm). The method developed in this work may be suitable for the preparation of a wide range of insensitive explosive compositions.

  14. Oxygen reduction by lithiated graphene and graphene-based materials.

    Science.gov (United States)

    Kataev, Elmar Yu; Itkis, Daniil M; Fedorov, Alexander V; Senkovsky, Boris V; Usachov, Dmitry Yu; Verbitskiy, Nikolay I; Grüneis, Alexander; Barinov, Alexei; Tsukanova, Daria Yu; Volykhov, Andrey A; Mironovich, Kirill V; Krivchenko, Victor A; Rybin, Maksim G; Obraztsova, Elena D; Laubschat, Clemens; Vyalikh, Denis V; Yashina, Lada V

    2015-01-27

    Oxygen reduction reaction (ORR) plays a key role in lithium-air batteries (LABs) that attract great attention thanks to their high theoretical specific energy several times exceeding that of lithium-ion batteries. Because of their high surface area, high electric conductivity, and low specific weight, various carbons are often materials of choice for applications as the LAB cathode. Unfortunately, the possibility of practical application of such batteries is still under question as the sustainable operation of LABs with carbon cathodes is not demonstrated yet and the cyclability is quite poor, which is usually associated with oxygen reduced species side reactions. However, the mechanisms of carbon reactivity toward these species are still unclear. Here, we report a direct in situ X-ray photoelectron spectroscopy study of oxygen reduction by lithiated graphene and graphene-based materials. Although lithium peroxide (Li2O2) and lithium oxide (Li2O) reactions with carbon are thermodynamically favorable, neither of them was found to react even at elevated temperatures. As lithium superoxide is not stable at room temperature, potassium superoxide (KO2) prepared in situ was used instead to test the reactivity of graphene with superoxide species. In contrast to Li2O2 and Li2O, KO2 was demonstrated to be strongly reactive.

  15. Copper ferrites@reduced graphene oxide anode materials for advanced lithium storage applications.

    Science.gov (United States)

    Wang, Junyong; Deng, Qinglin; Li, Mengjiao; Jiang, Kai; Zhang, Jinzhong; Hu, Zhigao; Chu, Junhao

    2017-08-21

    Copper ferrites are emerging transition metal oxides that have potential applications in energy storage devices. However, it still lacks in-depth designing of copper ferrites based anode architectures with enhanced electroactivity for lithium-ion batteries. Here, we report a facile synthesis technology of copper ferrites anchored on reduced graphene oxide (CuFeO2@rGO and Cu/CuFe2O4@rGO) as the high-performance electrodes. In the resulting configuration, reduced graphene offers continuous conductive channels for electron/ion transfer and high specific surface area to accommodate the volume expansion of copper ferrites. Consequently, the sheet-on-sheet CuFeO2@rGO electrode exhibits a high reversible capacity (587 mAh g(-1) after 100 cycles at 200 mA g(-1)). In particular, Cu/CuFe2O4@rGO hybrid, which combines the advantages of nano-copper and reduced graphene, manifests a significant enhancement in lithium storage properties. It reveals superior rate capability (723 mAh g(-1) at 800 mA g(-1); 560 mAh g(-1) at 3200 mA g(-1)) and robust cycling capability (1102 mAh g(-1) after 250 cycles at 800 mA g(-1)). This unique structure design provides a strategy for the development of multivalent metal oxides in lithium storage device applications.

  16. Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials

    Energy Technology Data Exchange (ETDEWEB)

    Byeon, Jeong Hoon, E-mail: postjb@yu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Park, Jae Hong; Peters, Thomas M. [Department of Occupational and Environmental Health, University of Iowa, IA 52242 (United States); Roberts, Jeffrey T., E-mail: jtrob@purdue.edu [Department of Chemistry, Purdue University, IN 47907 (United States)

    2015-07-15

    Highlights: • The cytotoxicity of model welding particles was modulated through in situ passivation. • Model welding particles were incorporated with chitosan nanoparticles for passivation. • In vitro assay revealed that the passivated particles had a lower cytotoxicity. • Passivation with chitosan adhesive or graphite paste could also reduce cytotoxicity. • This method would be suitable for efficient reduction of inhalable toxic components. - Abstract: The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled.

  17. A new method of material resources management based on material flow cost accounting for industrial enterprises

    OpenAIRE

    Khaldin, K. S.

    2016-01-01

    In the article a new method of material resources management for industrial enterprises is introduced. The method is based on the concepts of sustainable development and the elements of environmental management theory, such as life cycle assessment and material flow cost accounting. Steps that have to be completed in order to improve material resources efficiency are outlined and discussed in detail. Two possible optimization routines are also introduced and reviewed, namely: search for a bet...

  18. ARTIFICIAL NEURAL NETWORKS BASED GEARS MATERIAL SELECTION HYBRID INTELLIGENT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    X.C. Li; W.X. Zhu; G. Chen; D.S. Mei; J. Zhang; K.M. Chen

    2003-01-01

    An artificial neural networks(ANNs) based gear material selection hybrid intelligent system is established by analyzing the individual advantages and weakness of expert system (ES) and ANNs and the applications in material select of them. The system mainly consists of tow parts: ES and ANNs. By being trained with much data samples,the back propagation (BP) ANN gets the knowledge of gear materials selection, and is able to inference according to user input. The system realizes the complementing of ANNs and ES. Using this system, engineers without materials selection experience can conveniently deal with gear materials selection.

  19. Diatom-Based Material Production Demonstration

    Science.gov (United States)

    2016-03-14

    diatom cell walls. ............................................................... 19! Fig. 12 Setup for sieving diatom cell walls on the left, metal ...of diatom biomass. .............. 15! Table 4 P1 and P2 step details for cleaning of diatom cell walls at the farm. .................. 19! Table 5...are the most silicified and have the most intricate structures . Diatom valves are used to identify diatoms based on their morphology. Diatom

  20. Facile synthesis of reduced graphene oxide-porous silicon composite as superior anode material for lithium-ion battery anodes

    Science.gov (United States)

    Jiao, Lian-Sheng; Liu, Jin-Yu; Li, Hong-Yan; Wu, Tong-Shun; Li, Fenghua; Wang, Hao-Yu; Niu, Li

    2016-05-01

    We report a new method for synthesizing reduced graphene oxide (rGO)-porous silicon composite for lithium-ion battery anodes. Rice husks were used as a as a raw material source for the synthesis of porous Si through magnesiothermic reduction process. The as-obtained composite exhibits good rate and cycling performance taking advantage of the porous structure of silicon inheriting from rice husks and the outstanding characteristic of graphene. A considerably high delithiation capacity of 907 mA h g-1 can be retained even at a rate of 16 A g-1. A discharge capacity of 830 mA h g-1 at a current density of 1 A g-1 was delivered after 200 cycles. This may contribute to the further advancement of Si-based composite anode design.

  1. Data bases concerning the transportation of radioactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Cashwell, C [Applied Physics, Inc., Albuquerque, NM (United States); McClure, J D [Sandia National Labs., Albuquerque, NM (United States)

    1992-03-01

    This paper will describe two data bases which provide supporting information on radioactive material transport experience in the United States. The Radioactive Material Incident Report (RMIR) documents accident/incident experience from 1971 to the present from data acquired from the US Department of Transportation (DOT) and the Nuclear Regulatory Commission (NRC). The Radioactive Material Postnotification (RAMPOST) data base documents the shipments that have taken place for Highway Route Controlled Quantities (HRCQ) of radioactive material. HRCQ shipments are post notified (that is, after the shipment) to the DOT.

  2. Surface properties of copper based cermet materials

    Energy Technology Data Exchange (ETDEWEB)

    Voinea, M. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)], E-mail: m.voinea@unitbv.ro; Vladuta, C.; Bogatu, C.; Duta, A. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)

    2008-08-25

    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO{sub x} cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO{sub x} was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components.

  3. Reduced content of chloroatranol and atranol in oak moss absolute significantly reduces the elicitation potential of this fragrance material.

    Science.gov (United States)

    Andersen, Flemming; Andersen, Kirsten H; Bernois, Armand; Brault, Christophe; Bruze, Magnus; Eudes, Hervé; Gadras, Catherine; Signoret, Anne-Cécile J; Mose, Kristian F; Müller, Boris P; Toulemonde, Bernard; Andersen, Klaus Ejner

    2015-02-01

    Oak moss absolute, an extract from the lichen Evernia prunastri, is a valued perfume ingredient but contains extreme allergens. To compare the elicitation properties of two preparations of oak moss absolute: 'classic oak moss', the historically used preparation, and 'new oak moss', with reduced contents of the major allergens atranol and chloroatranol. The two preparations were compared in randomized double-blinded repeated open application tests and serial dilution patch tests in 30 oak moss-sensitive volunteers and 30 non-allergic control subjects. In both test models, new oak moss elicited significantly less allergic contact dermatitis in oak moss-sensitive subjects than classic oak moss. The control subjects did not react to either of the preparations. New oak moss is still a fragrance allergen, but elicits less allergic contact dermatitis in previously oak moss-sensitized individuals, suggesting that new oak moss is less allergenic to non-sensitized individuals. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Emerging Ceramic-based Materials for Dentistry

    Science.gov (United States)

    Denry, I.; Kelly, J.R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance. PMID:25274751

  5. An experimental study of low-velocity impacts into granular material in reduced gravity

    Science.gov (United States)

    Murdoch, Naomi; Avila Martinez, Iris; Sunday, Cecily; Zenou, Emmanuel; Cherrier, Olivier; Cadu, Alexandre; Gourinat, Yves

    2017-01-01

    In order to improve our understanding of landing on small bodies and of asteroid evolution, we use our novel drop tower facility (Sunday et al. 2016) to perform low-velocity (2 - 40 cm/s), shallow impact experiments of a 10 cm diameter aluminum sphere into quartz sand in low effective gravities (˜0.2 - 1 m/s2). Using in-situ accelerometers we measure the acceleration profile during the impacts and determine the peak accelerations, collision durations and maximum penetration depth. We find that the penetration depth scales linearly with the collision velocity but is independent of the effective gravity for the experimental range tested, and that the collision duration is independent of both the effective gravity and the collision velocity. No rebounds are observed in any of the experiments. Our low-gravity experimental results indicate that the transition from the quasi-static regime to the inertial regime occurs for impact energies two orders of magnitude smaller than in similar impact experiments under terrestrial gravity. The lower energy regime change may be due to the increased hydrodynamic drag of the surface material in our experiments, but may also support the notion that the quasi-static regime reduces as the effective gravity becomes lower.

  6. Mobile Web Browsing Based On Content Preserving With Reduced Cost

    Directory of Open Access Journals (Sweden)

    Dr.N.Saravanaselvam

    2015-01-01

    Full Text Available Internet has played a drastic change in today’s life. Especially, web browsing has become more exclusive in compact devices. This tempts the people to migrate their innovations & skills into an unimaginable world. With these things in mind, it is necessary for us to concentrate more on the techniques that how the web data’s are accessed and accounted. Developed countries use a widely popular technique called Flat- rate pricing, which is solely independent on data usage. But whereas, developing countries are still behind the concept of “pay as you use”, which leads to high usage bills.With an effort to resolve the problem of high usage bills, we propose a cost effective technique, which reduces the data consumption in web mobile browsing. It reduces the usage bills in the mechanism of usage-based pricing. The key idea of our approach is to leverage the data plan of the user to compute a cost quota for each web request and a network middle-box to automatically adapt any web page to the cost quota. Here we use a simple but effective content adaption technique that highly decides which image or data best fits the mobile display with low cost and high quality resolution. It also emphasis on the trendy technique,” The Data Mining “which mines the requested & required data. The mined data’s are filtered based on the content adaption technique and fit into the display effectively. Interesting and noticeable feature in this concept is that only important web contents requested by the user are exhibited. A feedback process involves in this concept to retrieve the required data alone and also to improve the best fit resolution. With this proposed system web mobile browsing becomes cheaper & contributes an enormous logic for the future project in the field of Mobile browsing.

  7. Propagation law of impact elastic wave based on specific materials

    Directory of Open Access Journals (Sweden)

    Chunmin CHEN

    2017-02-01

    Full Text Available In order to explore the propagation law of the impact elastic wave on the platform, the experimental platform is built by using the specific isotropic materials and anisotropic materials. The glass cloth epoxy laminated plate is used for anisotropic material, and an organic glass plate is used for isotropic material. The PVDF sensors adhered on the specific materials are utilized to collect data, and the elastic wave propagation law of different thick plates and laminated plates under impact conditions is analyzed. The Experimental results show that in anisotropic material, transverse wave propagation speed along the fiber arrangement direction is the fastest, while longitudinal wave propagation speed is the slowest. The longitudinal wave propagation speed in anisotropic laminates is much slower than that in the laminated thick plates. In the test channel arranged along a particular angle away from the central region of the material, transverse wave propagation speed is larger. Based on the experimental results, this paper proposes a material combination mode which is advantageous to elastic wave propagation and diffusion in shock-isolating materials. It is proposed to design a composite material with high acoustic velocity by adding regularly arranged fibrous materials. The overall design of the barrier material is a layered structure and a certain number of 90°zigzag structure.

  8. Life Cycle Assessment of Common Plastic Packaging for Reducing Environmental Impact and Material Consumption

    Directory of Open Access Journals (Sweden)

    Visvaldas Varžinskas

    2009-12-01

    the Faculty of Design and Technologies, Kaunas University of Technology, together with packaging and environmental protection specialists of the University, and in cooperation with the Department of Printed Publications and Packaging of the Ukrainian Print Academy. The present paper analyses certain basic findings of the study on the possibilities of improving the ecological level of packaging within the framework of the project. It is stated that appropriate investigation of packaging, its production and application has to be performed in order to prove that the packaging was produced in compliance with preventive and other principles; this investigation is related to a wide variety of package testing, some of which has not yet got methodology acknowledged at a sufficient level (the EU or groups of countries. Therefore, one of the research directions in the above mentioned project, discussed in the present paper, is related to developing a single system, recognized throughout the EU, which would enable researchers to perform the required tests confirming the packaging quality compliance with the environmental requirements. The paper analyzes the EU prevention regulations for reducing the amount of raw material and the system of checking the realization of the requirements based on identification of critical areas, aimed at reaching the lowest possible package weight and/or volume, consequently, the minimum waste amount, without increasing the amount of faulty products and product waste. The paper presents the findings of the research obtained in assessing the life cycle, when applying the Ecoindicator'99 qualitative analysis, concerning the impact of common plastic packages and processes on the environment during manufacturing, usage and disposal. Compression test results of common type plastic packaging construction are presented, which allow us to assess the impact of the package shape and construction upon the packaging reliability and minimization of its mass.

  9. Lightweight design for servo frame based on lattice material

    Science.gov (United States)

    Jin, Xin; Li, Guoxi; Liu, Encai; Gong, Jingzhong

    2017-06-01

    Lattice material infilling is an important way to achieve lightweight. Focusing on the problems of non-uniform arrangement and the finite element analysis (FEA) of lattice material in the parts, a lightweight design method based on lattice material is proposed with the spacecraft servo frame as the design object. Modal analysis and topology optimization are carried out according to the boundary conditions. The optimized density results are used to guide the design of lattice material parameters and arrangement. The equivalent mechanical properties of lattice material are obtained through the standard specimens experiments. The equivalent material FEA model of the lightweight servo frame is established, and the performance of the lightweight structure is tested by FEA simulation and experiment. The results show that under the impact condition, the lightweight servo frame meets the performance requirements and the simulation method through the equivalent material model is validated.

  10. Resin-based composite as a direct esthetic restorative material.

    Science.gov (United States)

    Malhotra, Neeraj; Mala, Kundabala; Acharya, Shashirashmi

    2011-06-01

    The search for an ideal esthetic material for tooth restoration has resulted in significant improvements in both materials and the techniques for using them. Various resin-based composite (RBC) materials have recently been introduced into the market that offer improved esthetic and physical properties. This article reviews RBCs, including their compositions, advantages, and disadvantages, that are contemporary to today's clinical practice as well as those that are under research consideration and/ or in clinical trial phase.

  11. Biogas Filter Based on Local Natural Zeolite Materials

    OpenAIRE

    Satriyo Krido Wahono; Wahyu Anggo Rizal

    2014-01-01

    UPT BPPTK LIPI has created a biogas filter tool to improve the purity of methane in the biogas. The device shaped cylindrical tube containing absorbent materials which based on local natural zeolite of Indonesia. The absorbent has been activated and modified with other materials. This absorbtion material has multi-adsorption capacity for almost impurities gas of biogas. The biogas  filter increase methane content of biogas for 5-20%. The biogas filter improve the biogas’s performance such as ...

  12. Environmental assessment of biomass based materials

    DEFF Research Database (Denmark)

    Jørgensen, Susanne Vedel

    level. The temporal scope is defined by the impact category considered. The technological scope includes both current environmental performance of biomaterials and a discussion of future perspectives, including potentials for future change in their environmental impacts compared to fossil based...... place in biomaterials, on which there is currently no consensus. Other important environmental aspects related to biomaterials that are currently not generally included in LCAs are land use and land use change (LULUC) related impacts, such as changes in biogenic carbon stocks (especially including soil......Goal and scope The goal of this PhD project is to contribute to a more consistent methodology for life cycle assessment (LCA) of biomaterials and to address the environmental performance and perspectives of biomaterials. In particular, it is the goal to develop an approach for dealing...

  13. Listener: a probe into information based material specification

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Karmon, Ayelet

    2011-01-01

    This paper presents the thinking and making of the architectural research probe Listener. Developed as an interdisciplinary collaboration between textile design and architecture, Listener explores how information based fabrication technologies are challenging the material practices of architecture....... The paper investigates how textile design can be understood as a model for architectural production providing new strategies for material specification and allowing the thinking of material as inherently variegated and performative. The paper traces the two fold information based strategies present...... in the Listener project. Firstly, the paper presents the design strategy leading to the development of bespoke interfaces between parametric design and CNC based textile fabrication. Secondly, by integrating structural and actuated materials the paper presents the making of a new class of materials...

  14. Graphene-Based Carbon Materials for Electrochemical Energy Storage

    Directory of Open Access Journals (Sweden)

    Fei Liu

    2013-01-01

    Full Text Available Because of their unique 2D structure and numerous fascinating properties, graphene-based materials have attracted particular attention for their potential applications in energy storage devices. In this review paper, we focus on the latest work regarding the development of electrode materials for batteries and supercapacitors from graphene and graphene-based carbon materials. To begin, the advantages of graphene as an electrode material and the existing problems facing its use in this application will be discussed. The next several sections deal with three different methods for improving the energy storage performance of graphene: the restacking of the nanosheets, the doping of graphene with other elements, and the creation of defects on graphene planes. State-of-the-art work is reviewed. Finally, the prospects and further developments in the field of graphene-based materials for electrochemical energy storage are discussed.

  15. Wear-reducing Surface Functionalization of Implant Materials Using Ultrashort Laser Pulses

    Science.gov (United States)

    Oldorf, P.; Peters, R.; Reichel, S.; Schulz, A.-P.; Wendlandt, R.

    The aim of the project called "EndoLas" is the development of a reproducible and reliable method for a functionalization of articulating surfaces on hip joint endoprostheses due to a reduction of abrasion and wear by the generation of micro structures using ultrashort laser pulses. On the one hand, the microstructures shall ensure the capture of abraded particles, which cause third-body wear and thereby increase aseptic loosening. On the other hand, the structures shall improve or maintain the tribologically important lubricating film. Thereby, the cavities serve as a reservoir for the body's own synovial fluid. The dry friction, which promotes abrasion and is a part of the mixed friction in the joint, shall therefore be reduced. In experimental setups it was shown, that the abrasive wear can be reduced significantly due to micro-structuring the articulating implant surfaces. To shape the fine and deterministic cavities on the surfaces, an ultra-short pulsed laser, which is integrated in a high-precision, 5-axes micro-machining system, was used. The laser system, based on an Yb:YAG thin-disk regenerative amplifier, has an average output power of 50 W at the fundamental wavelength of 1030 nm, a maximum repetition rate of 400 kHz and a pulse duration of 6 ps. Due to this, a maximum pulse energy of 125 μJ is achievable. Furthermore external second and third harmonic generation enables the usage of wavelengths in the green and violet spectral range.

  16. Reduced Graphene Oxide/Tin-Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries.

    Science.gov (United States)

    Ji, Liwen; Zhou, Weidong; Chabot, Victor; Yu, Aiping; Xiao, Xingcheng

    2015-11-11

    Reduced graphene oxides loaded with tin-antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20-30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g(-1), stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO-based flexible framework and the nanoscale dimension of the SnSb alloy particles (batteries.

  17. Simple Synthesis of Molybdenum Disulfide/Reduced Graphene Oxide Composite Hollow Microspheres as Supercapacitor Electrode Material

    Directory of Open Access Journals (Sweden)

    Wei Xiao

    2016-09-01

    Full Text Available MoS2/RGO composite hollow microspheres were hydrothermally synthesized by using SiO2/GO microspheres as a template, which were obtained via the sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 microspheres. The structure, morphology, phase, and chemical composition of MoS2/RGO hollow microspheres were systematically investigated by a series of techniques such as FE-SEM, TEM, XRD, TGA, BET, and Raman characterizations, meanwhile, their electrochemical properties were carefully evaluated by CV, GCD, and EIS measurements. It was found that MoS2/RGO hollow microspheres possessed unique porous hollow architecture with high-level hierarchy and large specific surface area up to 63.7 m2·g−1. When used as supercapacitor electrode material, MoS2/RGO hollow microspheres delivered a maximum specific capacitance of 218.1 F·g−1 at the current density of 1 A·g−1, which was much higher than that of contrastive bare MoS2 microspheres developed in the present work and most of other reported MoS2-based materials. The enhancement of supercapacitive behaviors of MoS2/RGO hollow microspheres was likely due to the improved conductivity together with their distinct structure and morphology, which not only promoted the charge transport but also facilitated the electrolyte diffusion. Moreover, MoS2/RGO hollow microsphere electrode displayed satisfactory long-term stability with 91.8% retention of the initial capacitance after 1000 charge/discharge cycles at the current density of 3 A·g−1, showing excellent application potential.

  18. Reactor vibration reduction based on giant magnetostrictive materials

    Science.gov (United States)

    Rongge, Yan; Weiying, Liu; Yuechao, Wu; Menghua, Duan; Xiaohong, Zhang; Lihua, Zhu; Ling, Weng; Ying, Sun

    2017-05-01

    The vibration of reactors not only produces noise pollution, but also affects the safe operation of reactors. Giant magnetostrictive materials can generate huge expansion and shrinkage deformation in a magnetic field. With the principle of mutual offset between the giant magnetostrictive force produced by the giant magnetostrictive material and the original vibration force of the reactor, the vibration of the reactor can be reduced. In this paper, magnetization and magnetostriction characteristics in silicon steel and the giant magnetostrictive material are measured, respectively. According to the presented magneto-mechanical coupling model including the electromagnetic force and the magnetostrictive force, reactor vibration is calculated. By comparing the vibration of the reactor with different inserted materials in the air gaps between the reactor cores, the vibration reduction effectiveness of the giant magnetostrictive material is validated.

  19. Polymers Based on Renewable Raw Materials – Part I

    Directory of Open Access Journals (Sweden)

    2013-09-01

    Full Text Available This paper gives an overview of the production and application of polymer materials based on renewable raw materials – biopolymers. It is pointed out that, investment of resources in the study of renewable raw materials in the last twenty years has led to the improvement of old and development of completely new chemical and biochemical processes for using biomass for the production of low molecular weight chemical substances, and especially for the production of biopolymers, which are biodegradable and compostable, and biopolymers which are nonbiodegradable. In the same period, producers of polymers based on fossil raw materials have also developed biopolymers that are biodegradable and some of them compostable and, most important, compatible with biopolymers based on renewable raw materials. The facts considering the state of biopolymers based on renewable raw materials on the market, and prediction of production increase over the next five years are also stated. Additionally, the main renewable raw materials and the biopolymers made from them that are already present in the world market are briefly listed. A short review of biopolymers based on cellulose from wood and annual plants is also given.

  20. Boron-Based (Nano-Materials: Fundamentals and Applications

    Directory of Open Access Journals (Sweden)

    Umit B. Demirci

    2016-09-01

    Full Text Available The boron (Z = 5 element is unique. Boron-based (nano-materials are equally unique. Accordingly, the present special issue is dedicated to crystalline boron-based (nano-materials and gathers a series of nine review and research articles dealing with different boron-based compounds. Boranes, borohydrides, polyhedral boranes and carboranes, boronate anions/ligands, boron nitride (hexagonal structure, and elemental boron are considered. Importantly, large sections are dedicated to fundamentals, with a special focus on crystal structures. The application potentials are widely discussed on the basis of the materials’ physical and chemical properties. It stands out that crystalline boron-based (nano-materials have many technological opportunities in fields such as energy storage, gas sorption (depollution, medicine, and optical and electronic devices. The present special issue is further evidence of the wealth of boron science, especially in terms of crystalline (nano-materials.

  1. Development of Fe-based nanocrystalline materials by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Suñol, J. J.

    2008-06-01

    Full Text Available Two alloys, Fe80NbB10 and Fe70Ni14Zr6B10, were produced by mechanical alloying. The formation of the nanocrystallites (about 7-8 nm at 80h MA was detected by X-ray diffraction. After milling for 80 h, differential scanning calorimetry scans show low-temperature recovery processes and several crystallization processes related with crystal growth and reordering of crystalline phases. The apparent activation energy values are 315 ± 40 kJ mol–1 for alloy A, and 295 ± 20 kJ mol–1 and 320 ± 25 kJ mol–1 for alloy B. Furthermore, a melt-spun Fe-based ribbon was mechanically alloyed to obtain a powdered-like alloy. The increase of the rotation speed and the ball-to-powder weight ratio reduces the necessary time to obtain the powdered form.

    Dos aleaciones, Fe80Nb10B10 (A y Fe70Ni14Zr6B10 (B, han sido producidas por aleado mecánico. Mediante difracción de rayos X se ha detectado la formación de nanocristales (7-8 nm a las 80 h de aleado. Tras molturar 80 h, las curvas calorimétricas muestran procesos exotérmicos asociados a la relajación estructural y al crecimiento cristalino y reordenación de la fase cristalina. Los valores de la energía aparente de activación de las cristalizaciones son 315 ± 40 kJ mol–1 para la aleación A, y 295 ± 20 kJ mol–1 y 320 ± 25 kJ mol–1 para la aleación B. Por otra parte, se ha procedido a la molturación de una cinta de una aleación de base hierro hasta obtener un material en forma de polvo. El incremento de la velocidad de rotación y de la relación en peso bolas polvo reduce el tiempo necesario para obtener este material.

  2. Nanotechnology-based restorative materials for dental caries management.

    Science.gov (United States)

    Melo, Mary A S; Guedes, Sarah F F; Xu, Hockin H K; Rodrigues, Lidiany K A

    2013-08-01

    Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhibit the demineralization process, to be used for remineralizing tooth structure, and to combat caries-related bacteria. These results are encouraging and open the doors to future clinical studies that will allow the therapeutic value of nanotechnology-based restorative materials to be established.

  3. Electrical conduction in solid materials physicochemical bases and possible applications

    CERN Document Server

    Suchet, J P

    2013-01-01

    Electrical Conduction in Solid Materials (Physicochemical Bases and Possible Applications) investigates the physicochemical bases and possible applications of electrical conduction in solid materials, with emphasis on conductors, semiconductors, and insulators. Topics range from the interatomic bonds of conductors to the effective atomic charge in conventional semiconductors and magnetic transitions in switching semiconductors. Comprised of 10 chapters, this volume begins with a description of electrical conduction in conductors and semiconductors, metals and alloys, as well as interatomic bon

  4. Recent Progress on PEDOT-Based Thermoelectric Materials

    OpenAIRE

    Qingshuo Wei; Masakazu Mukaida; Kazuhiro Kirihara; Yasuhisa Naitoh; Takao Ishida

    2015-01-01

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene) (PEDOT)-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the an...

  5. Organic light emitting device architecture for reducing the number of organic materials

    Science.gov (United States)

    D'Andrade, Brian; Esler, James

    2011-10-18

    An organic light emitting device is provided. The device includes an anode and a cathode. A first emissive layer is disposed between the anode and the cathode. The first emissive layer includes a first non-emitting organic material, which is an organometallic material present in the first emissive layer in a concentration of at least 50 wt %. The first emissive layer also includes a first emitting organic material. A second emissive layer is disposed between the first emissive layer and the cathode, preferably, in direct contact with the first emissive layer. The second emissive material includes a second non-emitting organic material and a second emitting organic material. The first and second non-emitting materials, and the first and second emitting materials, are all different materials. A first non-emissive layer is disposed between the first emissive layer and the anode, and in direct contact with the first emissive layer. The first non- emissive layer comprises the first non-emissive organic material.

  6. Silicon oxide based high capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  7. Graphene and graphene-based materials for energy storage applications.

    Science.gov (United States)

    Zhu, Jixin; Yang, Dan; Yin, Zongyou; Yan, Qingyu; Zhang, Hua

    2014-09-10

    With the increased demand in energy resources, great efforts have been devoted to developing advanced energy storage and conversion systems. Graphene and graphene-based materials have attracted great attention owing to their unique properties of high mechanical flexibility, large surface area, chemical stability, superior electric and thermal conductivities that render them great choices as alternative electrode materials for electrochemical energy storage systems. This Review summarizes the recent progress in graphene and graphene-based materials for four energy storage systems, i.e., lithium-ion batteries, supercapacitors, lithium-sulfur batteries and lithium-air batteries.

  8. Reducing the contamination of beef carcasses by specified risk materials during slaughter

    Directory of Open Access Journals (Sweden)

    Elena Bozzetta

    2013-04-01

    Full Text Available According to the European Community Regulation 1139/2003, a sampling plan based on an appropriate tests to detect the presence of central nervous system (CNS tissue on the surface of the head muscles had to be implemented in each member state starting from 2003. In previous studies, we showed a medium CNS contamination in head meat from Italian slaughterhouses of 14,7%. Recently, German authors referred about alarming rates (82% of CNS contamination in para-vertebral muscles after routine carcass splitting and spinal cord removal practices. In that context, the authors intended to assess the percentage of CNS contamination in muscles close to the vertebral column obtained by applying three different removal practices of specific risk material (SRM. Two alternative techniques, by sucking out and by water-jet, were compared to the traditional one; in both situations the removal of spinal cord occurred before the carcass splitting. The percentage of contamination resulted 62% applying the traditional technique, 60% with the sucking out system and 36% using the water-jet. The results show that water-jet ensures the most significant reduction of SRM contamination in para-vertebral meat as it guarantees a rapid and complete extraction of the spinal cord.

  9. Modified cytotoxicity evaluation of elastomeric impression materials while polymerizing with reduced exposure time.

    Science.gov (United States)

    Kwon, Jae-Sung; Lee, Sang-Bae; Kim, Chong-Kwan; Kim, Kyoung-Nam

    2012-12-01

    Cytotoxicity evaluation is an important step in biocompatibility assessment of dental impression materials. Previously, cytotoxicity evaluations were carried out on already set ('set') impression materials for contact time or extraction time of 24 h or longer in duration. However, clinically, dental impression materials are in contact with oral tissue while they are being set ('polymerizing'), for no longer than 10 min. Hence, the aim of this study was to investigate the difference in results between 'polymerizing' and 'set' forms of impression materials as well as the difference in results between longer duration of contact or extraction time (12 or 24 h) and shorter duration of time (15 or 30 min). Seven dental impression materials of different chemical compositions were tested. Two commonly used in vitro tests were used-test on extraction and test by direct contact. Both 'polymerizing' and 'set' forms of impression materials were used with different durations of extraction and contact (15 min, 30 min, 12 h and 24 h). There were significant (p materials. Also, significant (p material for cytotoxicity evaluation, with 15 or 30 min of contact between cell and dental impression materials and an extraction time of 15 or 30 min that is more reflective of clinical situations.

  10. A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

    Directory of Open Access Journals (Sweden)

    Vardan Galstyan

    2016-10-01

    Full Text Available A hybrid nanostructure based on reduced graphene oxide and ZnO has been obtained for the detection of volatile organic compounds. The sensing properties of the hybrid structure have been studied for different concentrations of ethanol and acetone. The response of the hybrid material is significantly higher compared to pristine ZnO nanostructures. The obtained results have shown that the nanohybrid is a promising structure for the monitoring of environmental pollutants and for the application of breath tests in assessment of exposure to volatile organic compounds.

  11. Inventions on reducing keyboard size: A TRIZ based analysis

    OpenAIRE

    Mishra, Umakant

    2013-01-01

    A conventional computer keyboard consists of as many as 101 keys. The keyboard has several sections, such as text entry section, navigation section, and numeric keypad etc. and each having several keys on the keyboard. The size of the keyboard is a major inconvenience for portable computers, as they cannot be carried easily. Thus there are certain circumstances which compels to reduce the size of a keyboard. Reducing the size of a keyboard leads to several problems. A reduced size keyboard ma...

  12. Reading Sŏktok Kugyŏl materials based on Ŏnhae materials

    Directory of Open Access Journals (Sweden)

    Satoshi JOHO

    2014-12-01

    Full Text Available In this paper, we discussed some advantages of and points of attempt to research how to read Hancha (漢字 with Kugyŏl (口訣 markings based on the premise, that the tradition of Hanmun Hundok (漢文訓讀 in Sŏktok Kugyŏl (釋讀口訣 materials has been succeeded to Ŏnhae (諺解 materials since the mid-15th century, the promulgation of Hunmin Chyŏngŭm (訓民正音, and based on Ŏnhae (諺解 system in these Ŏnhae (諺解 materials. As a result, Hundok (訓讀 systems of Sŏktok Kugyŏl (釋讀口訣 materials had much resemblance to the Non-Buddhist (Confucian Ŏnhae (諺解 materials since the end of 15th century. Therefore, Non-Buddhist (Confucian Ŏnhae (諺解 materials occupy an important position to consider the reading methods of Sŏktok Kugyŏl (釋讀口訣 materials.

  13. Mg2(Si,Sn)-based thermoelectric materials and devices

    Science.gov (United States)

    Gao, Peng

    Thermoelectric effects are phenomena found in materials that can achieve direct conversion between heat flow and electricity. One important application of thermoelectric effects is thermoelectric generators, which can generate electricity when a temperature gradient is applied. Thermoelectric generators make use of various sources of heat and it is considered a promising solution for waste heat recovery. The conversion efficiency of thermoelectric generators depends on the materials used in the devices. Significant improvement in the performance of thermoelectric materials has been made in the past few decades. However, most of the good thermoelectric materials being investigated have limitations, such as the high materials cost, high materials density and toxicity of the constituent elements. The Mg2(Si,Sn)-based materials studied in this work are promising candidates for thermoelectric generators in the mid-temperature range and have drawn increasing research interest in recent years because these materials are high performance thermoelectrics that are low cost, low-density and non-toxic. In this work, systematic studies were performed on the Mg2(Si,Sn) thermoelectric materials. Thermal phase stability was studied for different compositions of Mg2Si1-xSnx and Mg2Si0.4Sn 0.6 was used as base material for further optimization. Both n-type and p-type samples were obtained by doping the materials with different elements. Peak ZT ˜ 1.5 for the n-type and ZT ˜ 0.7 for the p-type materials were obtained, both of which are among the best reported results so far. Experimental work was also done to study the techniques to develop the Mg2Si 0.4Sn0.6 materials into working devices. Different electrode materials were tested in bonding experiment for this compound, and copper was found to be the best electrode material for Mg2Si 0.4Sn0.6. Preliminary work was done to demonstrate the possibility of fabricating a Mg2Si0.4Sn0.6-based thermoelectric generator and the result is

  14. Framework for Reducing Teaching Challenges Relating to Improvisation of Science Education Equipment and Materials in Schools

    Science.gov (United States)

    Akuma, Fru Vitalis; Callaghan, Ronel

    2016-01-01

    The science education budget of many secondary schools has decreased, while shortages and environmental concerns linked to conventional Science Education Equipment and Materials (SEEMs) have emerged. Thus, in some schools, resourceful educators produce low-cost equipment from basic materials and use these so-called improvised SEEMs in practical…

  15. Nanoporous materials for reducing the over potential of creating hydrogen by water electrolysis

    Science.gov (United States)

    Anderson, Marc A.; Leonard, Kevin C.

    2016-06-14

    Disclosed is an electrolyzer including an electrode including a nanoporous oxide-coated conducting material. Also disclosed is a method of producing a gas through electrolysis by contacting an aqueous solution with an electrode connected to an electrical power source, wherein the electrode includes a nanoporous oxide-coated conducting material.

  16. Continued Water-Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Hansen, Scott W.; Sheth, Rubik B.; Poynot, Joe; Giglio, Tony; Ungar, Gene K.

    2015-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to meet the full heat rejection demands. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HX's do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research on freeze front propagation to a full-scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Two units, Units A and B, were constructed and differed only in their midplate design. Both units failed multiple times during testing. This report highlights learning outcomes from these tests and are applied to a final sub-scale PCM HX which is slated to be tested on the ISS in early 2017.

  17. Periodic material-based vibration isolation for satellites

    Directory of Open Access Journals (Sweden)

    Xinnan Liu

    2016-01-01

    Full Text Available The vibration environment of a satellite is very severe during launch. Isolating the satellitevibrations during launch will significantly enhance reliability and lifespan, and reduce the weight of satellite structure and manufacturing cost. Guided by the recent advances in solid-state physics research, a new type of satellite vibration isolator is proposed by usingperiodic material that is hence called periodic isolator. The periodic isolator possesses a unique dynamic property, i.e., frequency band gaps. External vibrations with frequencies falling in the frequency band gaps of the periodic isolator are to be isolated. Using the elastodynamics and the Bloch-Floquet theorem, the frequency band gaps of periodic isolators are determined. A parametric study is conducted to provide guidelines for the design of periodic isolators. Based on these analytical results, a finite element model of a micro-satellite with a set of designed periodic isolators is built to show the feasibility of vibration isolation. The periodic isolator is found to be a multi-directional isolator that provides vibration isolation in the three directions.

  18. Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2007-09-30

    This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated

  19. Nanosynthesis of Iron Based Material for Green Energy

    Science.gov (United States)

    Kirkeminde, Alec W.

    In this work, nanosynthesis of multiple iron-based materials are explored to further their use in green renewable-energy applications. First, the nanosynthesis of the abundant, non-toxic semi-conductor Iron Disulfide (Iron Pyrite, Fool's Gold, FeS2) is investigated. Within these studies, it became possible to tune the shape of the FeS2 nanoparticles easily by modifying injection temperatures and iron precursors. From here, the growth mechanisms of the different shapes were elucidated by examining different time points within the synthesis. It was discovered that the FeS2 did not grow by Ostwald Ripening, but instead by Oriented Attachment. Knowing this, it was possible to not only further the shapes of FeS2 nanoparticles, but also manipulate the size and crystallinity. Focus was then shifted to creating larger micron sized FeS2 crystals. Larger crystals where achieved by a unique FeS nanowire precursor followed by sulfurization. The dominant crystal surface of these crystals could be regulated simply by the time and temperature of the sulfurization. Second, synthetic control of magnetic nanoparticles was examined. A novel synthesis of Iron Palladium (FePd) made possible by interdiffusion of iron into palladium nanocores was identified. Furthermore, a shell of Iron oxide (Fe2O3) could facilely be grown on the FePd nanoparticles, generating a FePd/Fe2O3 core/shell nanoparticle. These FePd/Fe2O3 core/shell particles provided an excellent foundation to create an L10- FePd/α-Fe exchange-coupled nanocomposite that exhibited improved magnetic properties compared to its single phase FePd counterpart. However, the stabilizing ligand used within this FePd synthesis doped into the final nanoparticles, degraded the magnetic properties. iii To overcome the dopant ligand problem, a novel nanoalloy synthetic strategy of Metal Redox was developed. The Metal Redox strategy utilized the inherent reducing power of zero-valent metal sources to create a vast sampling of metal

  20. Multiscale experimental mechanics of hierarchical carbon-based materials.

    Science.gov (United States)

    Espinosa, Horacio D; Filleter, Tobin; Naraghi, Mohammad

    2012-06-05

    Investigation of the mechanics of natural materials, such as spider silk, abalone shells, and bone, has provided great insight into the design of materials that can simultaneously achieve high specific strength and toughness. Research has shown that their emergent mechanical properties are owed in part to their specific self-organization in hierarchical molecular structures, from nanoscale to macroscale, as well as their mixing and bonding. To apply these findings to manmade materials, researchers have devoted significant efforts in developing a fundamental understanding of multiscale mechanics of materials and its application to the design of novel materials with superior mechanical performance. These efforts included the utilization of some of the most promising carbon-based nanomaterials, such as carbon nanotubes, carbon nanofibers, and graphene, together with a variety of matrix materials. At the core of these efforts lies the need to characterize material mechanical behavior across multiple length scales starting from nanoscale characterization of constituents and their interactions to emerging micro- and macroscale properties. In this report, progress made in experimental tools and methods currently used for material characterization across multiple length scales is reviewed, as well as a discussion of how they have impacted our current understanding of the mechanics of hierarchical carbon-based materials. In addition, insight is provided into strategies for bridging experiments across length scales, which are essential in establishing a multiscale characterization approach. While the focus of this progress report is in experimental methods, their concerted use with theoretical-computational approaches towards the establishment of a robust material by design methodology is also discussed, which can pave the way for the development of novel materials possessing unprecedented mechanical properties.

  1. Heat and moisture transport in durian fiber based lightweight construction materials

    Energy Technology Data Exchange (ETDEWEB)

    Charoenvai, S.; Khedari, J.; Hirunlabh, J.; Asasutjarit, C. [King Mongkut' s Univ. of Technology, Building Scientific Research Center, Thonburi, Bangkok (Thailand); Zeghmati, B. [Perpignan Univ., Centre d' Etudes Fondamentales, Groupe de Mecanique, Acoustique et Instrumentation, Perpignan, 66 (France); Quenard, D.; Pratintong, N. [Centre Scientifique et Technique du Batiment (CSTB), Grenoble (France)

    2005-04-01

    This paper presents result on heat and moisture transport in durian (Durio zibethinus) fiber based lightweight construction materials composed of cement, sand and waste fiber from durian peel and the performance of the material was simulated with the surface treatment by using a computational tool. The commercial research software (WUFI 2D) was used to calculate heat and moisture transfer through a durian fiber based lightweight construction material. The materials were exposed to a climate condition similar to the one in Bangkok and the hygrothermal characteristics of the materials were investigated. The investigation reveals that the weekly mean water content on the surface of material was quite low. The effect of moisture on the apparent thermal performance of the composite was found to be higher as water absorbed in the pore structure contributed to higher thermal conductivity than the air it replaced. However, the mean value of thermal conductivity in material is still rather low as the mean value of water content in material is low. Coating the surface reduced the flow of moisture to or from the structure considerably. The results of simulation confirmed that the manufactured composite satisfied the requirement of construction materials. It is then reasonable to conclude that the use of such materials in the design and construction of passive solar buildings is promising. Laboratory investigation is undergoing to validate the simulated performance. (Author)

  2. BUILDING MATERIALS AND PRODUCTS BASED ON SILICON MANGANESE SLAGS

    Directory of Open Access Journals (Sweden)

    BOLSHAKOV V. I.

    2016-05-01

    Full Text Available Raising of problem. Currently of particular relevance was given to the matter of introduction in manufacture of building materials and products, resource-saving techniques and technologies; integrated use of raw materials and materials that prevent or significantly reduce their harmful impact on the environment. This allows you to recycle hundreds of thousands of tons of the fiery liquid slags of silicon manganese and to develop effective structural materials that can replace metals, non-metallic building materials of natural origin, concretes, cast stone, plastics and refractories. Purpose. The study of the structure and properties of building materials and products from electric furnace slag of silicon manganese. Conclusion. Slags from the smelting of silicon manganese are classified as acidic. Their lime factor is in the range of 0.47–0.52. The composition of the slag located in the heterogeneous region SiO2 near the line of separation of cristobalite spread to the crystallization of wollastonite, according to the ternary system MnO-CaO-SiO2, which in consideration of their stability, allows the development of technology of building materials (gravel, sand, granulated slag, etc. and products (foundation blocks, road slabs, containers for transportation and storage of hazardous waste, and others.

  3. A Composite Heterostructure Mesh-shaped Patch Antenna Based on Left Handed Material

    Directory of Open Access Journals (Sweden)

    Ji jun Wang

    2014-01-01

    Full Text Available In this paper, a composite heterostructure mesh-shaped patch antenna based on left handed material (LHM is presented. The method of finite difference time domain (FDTD is used. The results show that electromagnetic wave resonance occurs near 4.52 GHz, where the equivalent permittivity and permeability of composite material are both negative. The composite antenna’s gain improves 9.047 dB, its return loss reduces 20.26 dB compared to the conventional antenna’s ones. The results indicate that this composite patch antenna system can reduce return loss of the antenna and increase the gain obviously.

  4. A Task-Based Approach to Materials Development

    Science.gov (United States)

    Nunan, David

    2010-01-01

    The purpose of this chapter is to present a task-based approach to materials development. In the first part of the chapter, I sketch out the evolution of task based language teaching, drawing on a distinction between synthetic and analytical approaches to syllabus design first articulated by Wilkins (1976).

  5. A Task-based Approach to Materials Development

    OpenAIRE

    2010-01-01

    The purpose of this chapter is to present a task-based approach to materials development. In the first part of the chapter, I sketch out the evolution of task based language teaching, drawing on a distinction between synthetic and analytical approaches to syllabus design first articulated by Wilkins (1976).

  6. A Task-based Approach to Materials Development

    Directory of Open Access Journals (Sweden)

    David Nunan

    2010-07-01

    Full Text Available The purpose of this chapter is to present a task-based approach to materials development. In the first part of the chapter, I sketch out the evolution of task based language teaching, drawing on a distinction between synthetic and analytical approaches to syllabus design first articulated by Wilkins (1976.

  7. The spectrochemical behavior of composites based on poly (para-phenylenevinylene), reduced graphene oxide and pyrene

    Science.gov (United States)

    Ilie, Mirela; Baibarac, Mihaela

    2017-10-01

    A new composite material based on poly (para-phenylenevinylene) (PPV), pyrene (Py) and reduced graphene oxide (RGO) is synthesized using thermal conversion route. The properties of this material are investigated by Raman scattering, photoluminescence (PL), infrared (IR) and ultraviolet-visible (UV-Vis) spectroscopy. Adding Py at PPV precursor solution (PPV PS) containing RGO, yields to important modifications in both vibrational and electronic properties of these composites. The presence of Py into PPV matrix determines a blue shift of PPV PL. According to Raman and IR studies, PPV is non-covalently functionalized with Py which interacts forward with RGO through π-π interactions causing an important modification into the polymer chains conjugation length.

  8. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  9. Material measurement method based on femtosecond laser plasma shock wave

    Science.gov (United States)

    Zhong, Dong; Li, Zhongming

    2017-03-01

    The acoustic emission signal of laser plasma shock wave, which comes into being when femtosecond laser ablates pure Cu, Fe, and Al target material, has been detected by using the fiber Fabry-Perot (F-P) acoustic emission sensing probe. The spectrum characters of the acoustic emission signals for three kinds of materials have been analyzed and studied by using Fourier transform. The results show that the frequencies of the acoustic emission signals detected from the three kinds of materials are different. Meanwhile, the frequencies are almost identical for the same materials under different ablation energies and detection ranges. Certainly, the amplitudes of the spectral character of the three materials show a fixed pattern. The experimental results and methods suggest a potential application of the plasma shock wave on-line measurement based on the femtosecond laser ablating target by using the fiber F-P acoustic emission sensor probe.

  10. Lignin Based Carbon Materials for Energy Storage Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sabornie [ORNL; Saito, Tomonori [ORNL; Rios, Orlando [ORNL; Johs, Alexander [ORNL

    2014-01-01

    The implementation of Li-ion battery technology into electric and hybrid electric vehicles and portable electronic devices such as smart phones, laptops and tablets, creates a demand for efficient, economic and sustainable materials for energy storage. However, the high cost and long processing time associated with manufacturing battery-grade anode and cathode materials are two big constraints for lowering the total cost of batteries and environmentally friendly electric vehicles. Lignin, a byproduct of the pulp and paper industry and biorefinery, is one of the most abundant and inexpensive natural biopolymers. It can be efficiently converted to low cost carbon fibers with optimal properties for use as anode materials. Recent developments in the preparation of lignin precursors and conversion to carbon fiber-based anode materials have created a new class of anode materials with excellent electrochemical characteristics suitable for immediate use in existing Li- or Na-ion battery technologies.

  11. Identification of collagen-based materials in cultural heritage.

    Science.gov (United States)

    Kirby, Daniel P; Buckley, Michael; Promise, Ellen; Trauger, Sunia A; Holdcraft, T Rose

    2013-09-07

    All stakeholders in cultural heritage share an interest in fabrication methods and material technology. Until now methods for analysis of organic materials, particularly proteins, have not been widely available to researchers at cultural institutions. This paper will describe an analytical method for the identification of collagen-based materials from soft tissue sources and show examples of its application to diverse museum objects. The method, peptide mass fingerprinting (PMF), uses enzymatic digestion of extracted proteins to produce a mixture of peptides. The mass spectrum of the mixture contains characteristic marker ions-a peptide mass fingerprint-which are compared to species-specific markers from references as the basis of identification. Preliminary results indicate that analysis of materials from aged samples, several different tissue types, and tanned or untanned materials yields comparable PMF results. Significantly, PMF is simple, rapid, sensitive and specific, has been implemented in a museum laboratory, and is being practiced successfully by non-specialists.

  12. An Overview of Composting Based on Variable Feedstock Material

    Directory of Open Access Journals (Sweden)

    Kadir Aeslina Abdul

    2016-01-01

    Full Text Available Composting is a biological treatment method that provides a potential sustainable way to convert food waste into organic compost. In composting, the feedstock material is an important item to ensure the success of the composting process. This paper reviewed the process of composting based on implementation different types of feedstock, namely: 1 animal waste such as cow dung, poultry litter, swine manure and chicken manure; and 2 agricultural waste such as sawdust, rice straw, bran, bagasse, banana waste and pine chip. The result for poultry litter, cow manure, swine manure, sawdust and rice straw has C/N ratio lower than 20 at final composting process which is considered as satisfactory level for compost maturity. As a conclusion, the selection of the feedstock material is based on the characteristics of the material itself and the selection of materials is important for the quality of compost.

  13. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  14. Sustainable Materials Management (SMM) Web Academy Webinar: Reducing Wasted Food: How Packaging Can Help

    Science.gov (United States)

    This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

  15. The Future of Nuclear Archaeology: Reducing Legacy Risks of Weapons Fissile Material

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Thomas W.; Reid, Bruce D.; Toomey, Christopher M.; Krishnaswami, Kannan; Burns, Kimberly A.; Casazza, Larry O.; S. Daly, Don; L. Duckworth, Leesa

    2014-01-01

    This report describes the value proposition for a "nuclear archeological" technical capability and applications program, targeted at resolving uncertainties regarding fissile materials production and use. At its heart, this proposition is that we can never be sure that all fissile material is adequately secure without a clear idea of what "all" means, and that uncertainty in this matter carries risk. We argue that this proposition is as valid today, under emerging state and possible non-state nuclear threats, as it was in an immediate post-Cold-War context, and describe how nuclear archeological methods can be used to verify fissile materials declarations, or estimate and characterize historical fissile materials production independently of declarations.

  16. Nanoscale Magnetic Materials for Energy-Efficient Spin Based Transistors

    Science.gov (United States)

    Incorvia, Jean Anne Currivan

    In this dissertation, I study the physical behavior of nanoscale magnetic materials and build spin-based transistors that encode information in magnetic domain walls. It can be argued that energy dissipation is the most serious problem in modern electronics, and one that has been resistant to a breakthrough. Wasted heat during computing both wastes energy and hinders further technology scaling. This is an opportunity for physicists and engineers to come up with creative solutions for more energy-efficient computing. I present the device we have designed, called domain wall logic (DW-Logic). Information is stored in the position of a magnetic domain wall in a ferromagnetic wire and read out using a magnetic tunnel junction. This hybrid design uses electrical current as the input and output, keeping the device compatible with charge- based transistors. I build an iterative model to predict both the micromagnetic and circuit behavior of DW- Logic, showing a single device can operate as a universal gate. The model shows we can build complex circuits including an 18-gate Full Adder, and allows us to predict the device switching energy compared to complementary metal-oxide semiconductor (CMOS) transistors. Comparing ?15 nm feature nodes, I find DW-Logic made with perpendicular magnetic anisotropy materials, and utilizing both spin torque transfer and the Spin Hall effect, could operate with 1000x reduced switching energy compared to CMOS. I fabricate DW-Logic device prototypes and show in experiment they can act as AND and NAND gates. I demonstrate that one device can drive two subsequent devices, showing gain, which is a necessary requirement for fanout. I also build a clocked ring oscillator circuit to demonstrate successful bit propagation in a DW-Logic circuit and show that properly scaled devices can have improved operation. Through building the devices, I develop a novel fabrication method for patterning sub-25 nm magnetic wires with very low (˜ 2 nm) average edge

  17. Heat-Resistant Composite Materials Based on Polyimide Matrix

    Directory of Open Access Journals (Sweden)

    Vitaly Sergeyevich Ivanov

    2016-12-01

    Full Text Available Heat-resistant composite materials with a polyimide-based binder were obtained in this paper. Composites were prepared with different content of single-wall carbon nanotubes (SWCNT and nanostructured silicon carbide, and polyimides coated carbon fibers woven into the cloth. Composite materials showed high values of thermostability and resistance to thermo-oxidative degradation, as well as good mechanical properties.

  18. Biogas Filter Based on Local Natural Zeolite Materials

    Directory of Open Access Journals (Sweden)

    Satriyo Krido Wahono

    2014-02-01

    Full Text Available UPT BPPTK LIPI has created a biogas filter tool to improve the purity of methane in the biogas. The device shaped cylindrical tube containing absorbent materials which based on local natural zeolite of Indonesia. The absorbent has been activated and modified with other materials. This absorbtion material has multi-adsorption capacity for almost impurities gas of biogas. The biogas  filter increase methane content of biogas for 5-20%. The biogas filter improve the biogas’s performance such as increasing methane contents, increasing heating value, reduction of odors, reduction of corrosion potential, increasing the efficiency and stability of the generator.

  19. SYNTHESIS of MOLECULE/POLYMER-BASED MAGNETIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Joel S. [Univ. of Utah, Salt Lake City, UT (United States)

    2016-02-01

    We have synthesized and characterized several families of organic-based magnets, a new area showing that organic species can exhibit the technologically important property of magnetic ordering. Thin film magnets with ordering temperatures exceeding room temperature have been exceeded. Hence, organic-based magnets represent a new class of materials that exhibit magnetic ordering and do not require energy-intensive metallurgical processing and are based upon Earth-abundant elements.

  20. Automatic Ration Material Distributions Based on GSM and RFID Technology

    Directory of Open Access Journals (Sweden)

    S.Valarmathy

    2013-10-01

    Full Text Available Now a day ration card is very important for every home and used for various field such as family members details, to get gas connection, it act as address proof for various purposes etc. All the people having a ration card to buy the various materials (sugar, rice, oil, kerosene, etc from the ration shops. But in this system having two draw backs, first one is weight of the material may be inaccurate due to human mistakes and secondly, if not buy the materials at the end of the month, they will sale to others without any intimation to the government and customers. In this paper, proposed an Automatic Ration Materials Distribution Based on GSM (Global System for Mobile and RFID (Radio Frequency Identification technology instead of ration cards. To get the materials in ration shops need to show the RFID tag into the RFID reader, then controller check the customer codes and details of amounts in the card. After verification, these systems show the amount details. Then customer need to enter they required materials by using keyboard, after receiving materials controller send the information to government office and customer through GSM technology. In this system provides the materials automatically without help of humans.

  1. Use of New Water Soluble Surface Film—Forming Material to Reduce Ammonia Loss from Water Solution

    Institute of Scientific and Technical Information of China (English)

    YINBIN; SHENRENFANG; 等

    1996-01-01

    A new water soluble surface film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laboratory,Results showed that the new film formed by the material was not only more effective in reducing ammonia loss than any other films tested but also much cheaper.The optimum amount of addition of the new film-forming material was about 10times the theoretical amount to form a monomolecular film.Under the experimental conditions,the new film could effectively depress the ammonia volatilization for at least 6 days.The cumulative ammonia loss rates for different films were fitted to a simple logistic equation ,and some important parameters such as the cumulative loss,and the maximum and average volatilization rates were calculated.The effect of different films could be,therefore,compared quantitatively,indicating the new film was most effective in depressing ammonia volatilization.

  2. A Knowledge-Based Approach for Selection of Material Handling Equipment and Material Handling System Pre-design

    OpenAIRE

    YAMAN, Ramazan

    2001-01-01

    For material handling system design, material handling equipment selection is the first stage. Also the material handling system and facility layout design problems are coupled. Solving these problems needs consideration of these three different problems. Right material handling equipment selection and good design of the material handling system and facility layout can increase productivity and reduce investments and operations' costs. In this study, after describing the m...

  3. A physically-based abrasive wear model for composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  4. Polymers Based on Renewable Raw Materials – Part II

    Directory of Open Access Journals (Sweden)

    Jovanović, S.

    2013-09-01

    Full Text Available A short review of biopolymers based on starch (starch derivatives, thermoplastic starch, lignin and hemicelluloses, chitin (chitosan and products obtained by degradation of starch and other polysaccharides and sugars (poly(lactic acid, poly(hydroxyalkanoates, as well as some of their basic properties and application area, are given in this part. The problem of environmental and economic feasibility of biopolymers based on renewable raw materials and their competitiveness with polymers based on fossil raw materials is discussed. Also pointed out are the problems that appear due to the increasing use of agricultural land for the production of raw materials for the chemical industry and energy, instead for the production of food for humans and animals. The optimistic assessments of experts considering the development perspectives of biopolymers based on renewable raw materials in the next ten years have also been pointed out.At the end of the paper, the success of a team of researchers gathered around the experts from the company Bayer is indicated. They were the first in the world to develop a catalyst by which they managed to effectively activate CO - and incorporate it into polyols, used for the synthesis of polyurethanes in semi-industrial scale. By applying this process, for the first time a pollutant will be used as a basic raw material for the synthesis of organic compounds, which will have significant consequences on the development of the chemical industry, and therefore the production of polymers.

  5. Materials for Powder-Based AC-Electroluminescence

    Directory of Open Access Journals (Sweden)

    Hubert Schulze Dieckhoff

    2010-02-01

    Full Text Available At present, thick film (powder based alternating current electroluminescence (AC-EL is the only technology available for the fabrication of large area, laterally structured and coloured light sources by simple printing techniques. Substrates for printing may be based on flexible polymers or glass, so the final devices can take up a huge variety of shapes. After an introduction of the underlying physics and chemistry, the review highlights the technical progress behind this development, concentrating on luminescent and dielectric materials used. Limitations of the available materials as well as room for further improvement are also discussed.

  6. Recent Progress on PEDOT-Based Thermoelectric Materials

    Directory of Open Access Journals (Sweden)

    Qingshuo Wei

    2015-02-01

    Full Text Available The thermoelectric properties of poly(3,4-ethylenedioxythiophene (PEDOT-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the anisotropic thermoelectric properties. In the last part, we describe our work on improving the power output of thermoelectric modules by using PEDOT, and we outline the potential applications of polymer thermoelectric generators.

  7. Carbon-based nanomaterials: multifunctional materials for biomedical engineering.

    Science.gov (United States)

    Cha, Chaenyung; Shin, Su Ryon; Annabi, Nasim; Dokmeci, Mehmet R; Khademhosseini, Ali

    2013-04-23

    Functional carbon-based nanomaterials (CBNs) have become important due to their unique combinations of chemical and physical properties (i.e., thermal and electrical conductivity, high mechanical strength, and optical properties), and extensive research efforts are being made to utilize these materials for various industrial applications, such as high-strength materials and electronics. These advantageous properties of CBNs are also actively investigated in several areas of biomedical engineering. This Perspective highlights different types of carbon-based nanomaterials currently used in biomedical applications.

  8. Elastoplastic cup model for cement-based materials

    Directory of Open Access Journals (Sweden)

    Yan ZHANG

    2010-03-01

    Full Text Available Based on experimental data obtained from triaxial tests and a hydrostatic test, a cup model was formulated. Two plastic mechanisms, respectively a deviatoric shearing and a pore collapse, are taken into account. This model also considers the influence of confining pressure. In this paper, the calibration of the model is detailed and numerical simulations of the main mechanical behavior of cement paste over a large range of stress are described, showing good agreement with experimental results. The case study shows that this cup model has extensive applicability for cement-based materials and other quasi-brittle and high-porosity materials in a complex stress state.

  9. Recent Progress on PEDOT-Based Thermoelectric Materials.

    Science.gov (United States)

    Wei, Qingshuo; Mukaida, Masakazu; Kirihara, Kazuhiro; Naitoh, Yasuhisa; Ishida, Takao

    2015-02-16

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene) (PEDOT)-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the anisotropic thermoelectric properties. In the last part, we describe our work on improving the power output of thermoelectric modules by using PEDOT, and we outline the potential applications of polymer thermoelectric generators.

  10. Cement-based materials' characterization using ultrasonic attenuation

    Science.gov (United States)

    Punurai, Wonsiri

    The quantitative nondestructive evaluation (NDE) of cement-based materials is a critical area of research that is leading to advances in the health monitoring and condition assessment of the civil infrastructure. Ultrasonic NDE has been implemented with varying levels of success to characterize cement-based materials with complex microstructure and damage. A major issue with the application of ultrasonic techniques to characterize cement-based materials is their inherent inhomogeneity at multiple length scales. Ultrasonic waves propagating in these materials exhibit a high degree of attenuation losses, making quantitative interpretations difficult. Physically, these attenuation losses are a combination of internal friction in a viscoelastic material (ultrasonic absorption), and the scattering losses due to the material heterogeneity. The objective of this research is to use ultrasonic attenuation to characterize the microstructure of heterogeneous cement-based materials. The study considers a real, but simplified cement-based material, cement paste---a common bonding matrix of all cement-based composites. Cement paste consists of Portland cement and water but does not include aggregates. First, this research presents the findings of a theoretical study that uses a set of existing acoustics models to quantify the scattered ultrasonic wavefield from a known distribution of entrained air voids. These attenuation results are then coupled with experimental measurements to develop an inversion procedure that directly predicts the size and volume fraction of entrained air voids in a cement paste specimen. Optical studies verify the accuracy of the proposed inversion scheme. These results demonstrate the effectiveness of using attenuation to measure the average size, volume fraction of entrained air voids and the existence of additional larger entrapped air voids in hardened cement paste. Finally, coherent and diffuse ultrasonic waves are used to develop a direct

  11. Conductive polymer/reduced graphene oxide/Au nano particles as efficient composite materials in electrochemical supercapacitors

    Science.gov (United States)

    Shabani Shayeh, J.; Ehsani, A.; Ganjali, M. R.; Norouzi, P.; Jaleh, B.

    2015-10-01

    Polyaniline/reduced graphene oxide/Au nano particles (PANI/rGO/AuNPs) as a hybrid supercapacitor were deposited on a glassy carbon electrode (GCE) by cyclic voltammetry (CV) method as ternary composites and their electrochemical performance was evaluated in acidic medium. Scanning electron micrographs clearly revealed the formation of nanocomposites on the surface of the working electrode. Scanning electron micrographs (SEM) clearly revealed the formation of nanocomposites on the surface of working electrode. Different electrochemical methods including galvanostatic charge-discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out in order to investigate the applicability of the system as a supercapacitor. Based on the cyclic voltammogram results obtained, PANI/rGO/AuNPs gave higher specific capacitance, power and energy values than PANI at a current density of 1 mA cm-2. Specific capacitance (SC) of PANI and PANI/rGO/AuNPs electrodes calculated using CV method are 190 and 303 F g-1, respectively. The present study introduces new nanocomposite materials for electrochemical redox capacitors with advantages including long life cycle and stability due to synergistic effects of each component.

  12. Conductive polymer/reduced graphene oxide/Au nano particles as efficient composite materials in electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Shabani Shayeh, J. [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ehsani, A., E-mail: a.ehsani@qom.ac.ir [Department of Chemistry, Faculty of Science, University of Qom, P.O. Box 37185-359, Qom (Iran, Islamic Republic of); Ganjali, M.R.; Norouzi, P. [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrinology & Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Jaleh, B. [Physics Department, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of)

    2015-10-30

    Graphical abstract: - Highlights: • PANI/rGO/AuNPs as a ternary composite synthesized by electrodeposition. • Presence of rGO/AuNPs caused increasing the stability of electrodes. • Composite represented high specific capacitance, specific power and specific energy values than PANI. - Abstract: Polyaniline/reduced graphene oxide/Au nano particles (PANI/rGO/AuNPs) as a hybrid supercapacitor were deposited on a glassy carbon electrode (GCE) by cyclic voltammetry (CV) method as ternary composites and their electrochemical performance was evaluated in acidic medium. Scanning electron micrographs clearly revealed the formation of nanocomposites on the surface of the working electrode. Scanning electron micrographs (SEM) clearly revealed the formation of nanocomposites on the surface of working electrode. Different electrochemical methods including galvanostatic charge–discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out in order to investigate the applicability of the system as a supercapacitor. Based on the cyclic voltammogram results obtained, PANI/rGO/AuNPs gave higher specific capacitance, power and energy values than PANI at a current density of 1 mA cm{sup −2}. Specific capacitance (SC) of PANI and PANI/rGO/AuNPs electrodes calculated using CV method are 190 and 303 F g{sup −1}, respectively. The present study introduces new nanocomposite materials for electrochemical redox capacitors with advantages including long life cycle and stability due to synergistic effects of each component.

  13. Water sorption and solubility of polyamide denture base materials.

    Science.gov (United States)

    Nguyen, Long G; Kopperud, Hilde M; Øilo, Marit

    2017-01-01

    Purpose: Some patients experience adverse reactions to poly(methyl methacrylate)-based (PMMA) dentures. Polyamide (PA) as an alternative to PMMA has, however, not been well documented with regard to water sorption and water solubility. The aim of this in vitro study was to measure water sorption and water solubility of two PA materials compared with PMMA, and to evaluate the major components released from the PA materials and the effect on hardness of the materials. Methods: Ten discs (40.0 mm diameter, 2.0 mm thick) of each material (PA: Valplast and Breflex; PMMA: SR Ivocap HIP) were prepared according to manufacturers' recommendations. The specimens were tested for water sorption and water solubility, according to a modification of ISO 20795-1:2008. Released substances were analysed by gas chromatography/mass spectrometry (GC/MS). Results: There were statistically significant differences among the materials regarding water sorption, water solubility and time to water saturation. Breflex had the highest water sorption (30.4 μg/mm(3)), followed by PMMA-material (25.8 μg/mm(3)) and Valplast (13.6 μg/mm(3)). Both PA materials had statistically significant lower water solubility than the PMMA. Both PA had a net increase in weight. Analysis by GC/MS identified release of the compound 12-aminododecanolactam from the material Valplast. No release was found from the Breflex material. Conclusions: The PA denture materials show differences in water sorption and solubility, but within the limits of the standard requirements. The PA showed a net increase in weight after long-term water sorption. The clinical implications of the findings are not elucidated.

  14. A potential base substrate for deformable scintillation materials

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hidehito, E-mail: hidehito@rri.kyoto-u.ac.jp [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Sato, Nobuhiro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Kitamura, Hisashi [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Shirakawa, Yoshiyuki [Waseda University, 513, Waseda-Tsurumaki-cho, Shinjuku-ku, Tokyo 162-0041 (Japan); Takahashi, Sentaro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2016-05-11

    Deformable scintillation materials for radiation detection are an original concept that will impact many applications. Here we reveal the optical characteristics of readily available, transparent grease that consists of adhesive aromatic ring polymers. The aromatic ring polymer is methyl phenyl polysiloxane, commonly used in cosmetics, lubrication, heat conduction, and mechanical damping. It has a 285-nm excitation maximum and emits short wavelength light that peaks at 315 nm. The stopping power for 1 MeV electrons is 1.78 MeV cm{sup 2}/g. The light-yield distribution has distinct peaks at 976 keV from internal conversion electrons and at 5486 keV from alpha particles. In addition, this particular methyl phenyl polysiloxane is safe for use and disposal, which is an excellent advantage. These aromatic ring polymers are potential base substrates for deformable scintillation materials and make an important addition to the categories of scintillation materials. - Highlights: • Adhesive aromatic ring polymers can be deformable base substrates for scintillation materials. • Transparent grease consisting of methyl phenyl polysiloxane was characterised. • Short-wavelength light with a 315-nm emission maximum was emitted. • Distinct peaks induced by internal conversion electrons and alpha particles were observed in light-yield distributions. • Deformable scintillation materials are an original category of materials for radiation detection.

  15. Physical and mechanical properties of composite materials of different compositions based on waste products

    Directory of Open Access Journals (Sweden)

    A.E. Burdonov

    2012-12-01

    Full Text Available This paper presents a study on the effect of mineral filler on the polymer composite material based on waste products of heat and power engineering - fly ash. This type of waste products has never been used for the production of polymer-mineral composites. Depending on the type of ash, its chemical composition and its quantity in the material, we can adjust the properties of the resulting composites. The use of fly ash as a filler will not only make a product less expensive, but it also will reduce development pressure on the environment and improve the physical and mechanical properties of the material. The article shows research results of the ash chemical composition as well as the properties of the resulting materials on its basis. According to the research conclusions there is a prospect for using this material in the construction industry.

  16. Materialized View Selection Approach Using Tree Based Methodology

    Directory of Open Access Journals (Sweden)

    MR. P. P. KARDE

    2010-10-01

    Full Text Available In large databases particularly in distributed database, query response time plays an important role as timely access to information and it is the basic requirement of successful business application. A data warehouse uses multiple materialized views to efficiently process a given set of queries. Quick response time and accuracy areimportant factors in the success of any database. The materialization of all views is not possible because of the space constraint and maintenance cost constraint. Selection of Materialized views is one of the most important decisions in designing a data warehouse for optimal efficiency. Selecting a suitable set of views that minimizesthe total cost associated with the materialized views and is the key component in data warehousing. Materialized views are found to be very useful for fast query processing. This paper gives the results of proposed tree based materialized view selection algorithm for query processing. In distributed environment where database is distributed over the nodes on which query should get executed and also plays an important role. This paper also proposes node selection algorithm for fast materialized view selection in distributed environment. And finally it is found that the proposed methodology performs better for query processing as compared to other materializedview selection strategies.

  17. Greenhouse gas emissions from the treatment of household plastic containers and packaging: replacement with biomass-based materials.

    Science.gov (United States)

    Yano, Junya; Hirai, Yasuhiro; Sakai, Shin-ichi; Tsubota, Jun

    2014-04-01

    The purpose of this study was to quantify the life-cycle greenhouse gas (GHG) emissions reduction that could be achieved by replacement of fossil-derived materials with biodegradable, biomass-based materials for household plastic containers and packaging, considering a variety of their treatment options. The biomass-based materials were 100% polylactide or a combination of polybutylene succinate adipate and polylactide. A scenario analysis was conducted considering alternative recycling methods. Five scenarios were considered: two for existing fossil-derived materials (the current approach in Japan) and the three for biomass-based materials. Production and waste disposal of 1 m(3) of plastic containers and packaging from households was defined as the functional unit. The results showed that replacement of fossil-derived materials with biomass-based materials could reduce life-cycle GHG emissions by 14-20%. Source separation and recycling should be promoted. When the separate collection ratio reached 100%, replacement with biomass-based materials could potentially reduce GHG emissions by 31.9%. Food containers are a priority for replacement, because they alone could reduce GHG emissions by 10%. A recycling system for biomass-based plastics must be carefully designed, considering aspects such as the transition period from fossil-derived plastics to biomass-based plastics.

  18. Dynamic brittle material response based on a continuum damage model

    Energy Technology Data Exchange (ETDEWEB)

    Chen, E.P.

    1994-12-31

    The response of brittle materials to dynamic loads was studied in this investigation based on a continuum damage model. Damage mechanism was selected to be interaction and growth of subscale cracks. Briefly, the cracks are activated by bulk tension and the density of activated cracks are described by a Weibull statistical distribution. The moduli of a cracked solid derived by Budiansky and O`Connell are then used to represent the global material degradation due to subscale cracking. This continuum damage model was originally developed to study rock fragmentation and was modified in the present study to improve on the post-limit structural response. The model was implemented into a transient dynamic explicit finite element code PRONTO 2D and then used for a numerical study involving the sudden stretching of a plate with a centrally located hole. Numerical results characterizing the dynamic responses of the material were presented. The effect of damage on dynamic material behavior was discussed.

  19. Neutron shielding material based on colemanite and epoxy resin.

    Science.gov (United States)

    Okuno, Koichi

    2005-01-01

    In recent years, there has been a need for compact shielding design such as self-shielding of a PET cyclotron or upgradation of radiation machinery in existing facilities. In these cases, high performance shielding materials are needed. Concrete or polyethylene have been used for a neutron shield. However, for compact shielding, they fall short in terms of performance or durability. Therefore, a new type of neutron shielding material based on epoxy resin and colemanite has been developed. Slab attenuation experiments up to 40 cm for the new shielding material were carried out using a 252Cf neutron source. Measurement was carried out using a REM-counter, and compared with calculation. The results show that the shielding performance is better than concrete and polyethylene mixed with 10 wt% boron oxide. From the result, we confirmed that the performance of the new material is suitable for practical use.

  20. Novel synchrotron based techniques for characterization of energy materials

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, H.F.; Nielsen, S.F.; Olsen, U.L.; Schmidt, S. (Risoe DTU, Materials Research Dept., Roskilde (Denmark)); Wright, J. (European Synchrotron Radiation Facility, Grenoble Cedex (France))

    2008-10-15

    Two synchrotron techniques are reviewed, both based on the use of high energy x-rays, and both applicable to in situ studies of bulk materials. Firstly, 3DXRD microscopy, which enables 3D characterization of the position, morphology, phase, elastic strain and crystallographic orientation of the individual embedded grains in polycrystalline specimens. In favourable cases, hundreds of grains can be studied simultaneously during processing. Secondly, plastic strain tomography: a unique method for determining the plastic strain field within materials during processing the potential applications of these techniques for basic and applied studies of four types of energy materials are discussed: polymer composites for wind turbines, solid oxide fuel cells, hydrogen storage materials and superconducting tapes. Furthermore, progress on new detectors aiming at improving the spatial and temporal resolution of such measurements is described. (au)

  1. Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

    Directory of Open Access Journals (Sweden)

    Olaf Mühling

    2010-12-01

    Full Text Available The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field.

  2. MapReduce-based Dimensional ETL Made Easy

    DEFF Research Database (Denmark)

    Xiufeng, Liu; Thomsen, Christian; Pedersen, Torben Bach

    2012-01-01

    This paper demonstrates ETLMR, a novel dimensional Extract–Transform–Load (ETL) programming framework that uses MapReduce to achieve scalability. ETLMR has builtin native support of data warehouse (DW) specific constructs such as star schemas, snowflake schemas, and slowly changing dimensions (SCDs...

  3. Reducing Respiratory Health Risks to Horses and Workers: A Comparison of Two Stall Bedding Materials

    Directory of Open Access Journals (Sweden)

    Markku Saastamoinen

    2015-10-01

    Full Text Available Stable air quality and the choice of bedding material are an important health issue both in horses and people working or visiting horse stables. Risks of impaired respiratory health are those that can especially be avoided by improving air quality in the stable. The choice of bedding material is particularly important in cold climate conditions; where horses are kept most of the day and year indoors throughout their life. This study examined the effect of two bedding materials; wood shavings and peat; on stable air quality and health of horses. Ammonia and dust levels were also measured to assess conditions in the stable. Ammonia was not detected or was at very low levels (<0.25 ppm in the boxes in which peat was used as bedding; but its concentration was clearly higher (1.5–7.0 ppm in stalls with wood shavings as bedding. Personal measurements of workers revealed quite high ammonia exposure (5.9 ppm8h in the boxes in which wood shavings were used; but no exposure was Animals 2015, 5 966 observed in stalls bedded with peat. The respiratory symptoms in horses increased regardless of the bedding material at the beginning of the study. The health status of the horses in the peat bedding group returned to the initial level in the end of the trial but horses bedded with wood shavings continued to be symptomatic. The hooves of the horses with peat bedding had a better moisture content than those of the horses bedded with wood shavings. The results suggest that peat is a better bedding material for horses than wood shavings regarding the health of both horses and stable workers.

  4. Polyazulene based materials for heavy metal ions detection

    Science.gov (United States)

    Oprisanu, A.; Ungureanu, E. M.; Isopescu, R.; Birzan, L.; Mihai, M.; Vasiliu, C.

    2017-06-01

    Azulene is a special monomer used to functionalize electrodes, due to its spontaneous electron drift from the seven-membered ring to the five-membered ring. The seven-membered ring of the molecule may act as electron acceptor, while the five-membered ring - as electron donor. This leads to very attractive properties for the synthesis of functional advanced materials like: materials with nonlinear optical and photorefractive properties, cathode materials for lithium batteries, or light emitting diodes based on organic materials. Azulene derivatives have been used rarely to the metal ions electroanalysis. Our study concerns the synthesis and electrochemical characterization of a new azulene based monomer 4-(azulen-1-yl)-2,6-bis((E)-2-(thiophen-3-yl)vinyl)pyridine (L). L has been used to obtain modified electrodes by electrochemical polymerization. PolyL films modified electrodes have been characterized by cyclic voltammetry in ferrocene solutions. The complexing properties of polyL based functional materials have been investigated towards heavy metals (Pb, Cd Hg, Cu) by preconcentration - anodic stripping technique in order to analyze the content of these cations from water samples.

  5. Effectiveness of Print Education at Reducing Urban Mosquito Infestation through Improved Resident-Based Management.

    Directory of Open Access Journals (Sweden)

    Danielle Bodner

    Full Text Available Improving resident-based management and knowledge of mosquitoes is often an integral component of integrated mosquito management, especially in urban landscapes with considerable mosquito habitat on privately owned lands. This study tested the effectiveness of print education materials at reducing urban mosquito exposure through improving resident knowledge of, and attitudes towards, mosquitoes and mosquito management in Washington DC, USA. There was a specific focus on the removal of water-filled containers that are utilized by the developmental stages of the two most common vector species in the region, Aedes albopictus and Culex pipiens. Households in six neighborhoods that varied in socio-economic status were administered knowledge, attitude, and practice (KAP surveys in 2010 and 2012, and had their yards surveyed for container habitats and immature mosquitoes (larvae and pupae in 2010, 2011, and 2012. Half the households (intervention, n = 120 received education materials in 2011 and 2012 to yield a before-after control-intervention (BACI design. Unexpectedly, residents in intervention households were more likely to show decreased concern for mosquito-borne illnesses than residents in control households, which did not receive materials. Moreover, there was a greater probability that control households reduced containers in 2012 than intervention households, particularly when they had low numbers of baseline (2010 containers. Irrespective of control, reductions in containers were associated with decreased abundances of immature mosquitoes. Overall, our findings suggest that print education materials may have unintended negative effects on resident attitudes and household management of mosquito production. We recommend that mosquito control agencies need to carefully consider their content of print messages and the effectiveness of strategies that passively convey information with little or no engagement with control professionals.

  6. Photochromic ordered mesoporous hybrid materials based on covalently grafted polyoxometalates.

    Science.gov (United States)

    Luo, Xiujuan; Yang, Chun

    2011-05-07

    Novel polyoxometalate (POM)-grafting mesoporous hybrid silicas, XW(11)/MHS (X=P, Si) and TBAPW(11)Si(2)/MHS, have been prepared respectively by co-condensation and post-synthesis routes based on the employment of Keggin-type monovacant XW(11) or a Si-substituted compound TBAPW(11)Si(2) as POM precursors. Upon characterization of the samples by FT-IR, XRD, ICP-AES, TEM and N(2) adsorption-desorption measurement, it was found that Keggin units were retained perfectly in ordered hexagonal mesopore channels with SBA-15 architecture and immobilized by covalent linkages on the mesopore wall. These materials, especially the co-condensed samples, exhibited stable and reversible photochromic properties under UV irradiation although no special organic component was supplied additionally as an electron donor. An investigation of the photochromism revealed that the photochromic response depended on the centre atom of the POM species (i.e., the redox potential of the POM), the content of the POM and the synthetic route of the sample, while the bleaching process was correlated not only to the redox potential but also to the pore size of the sample. The photochromic mechanism was also studied in detail by cyclic voltammetry, ESR, FT-IR and XPS techniques. It was found that the remaining P123 template acted as a reducing agent and was oxidized during the photochromic process accompanied by the reduction of the POM to heteropolyblue. Thus, a close contact between the POM and the remaining P123 chain in the sample is necessary. Low close-contact degree results in poor photochromic behavior of the post-synthesized sample and impregnated samples.

  7. Characterization of electrical and optical properties of silicon based materials

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Guobin

    2009-12-04

    In this work, the electrical and luminescence properties of a series of silicon based materials used for photovoltaics, microelectronics and nanoelectronics have been investigated by means of electron beam induced current (EBIC), cathodoluminescence (CL), photoluminescence (PL) and electroluminescence (EL) methods. Photovoltaic materials produced by block casting have been investigated by EBIC on wafers sliced from different parts of the ingot. Various solar cell processings have been compared in parallel wafers by means of EBIC collection efficiency measurements and contrast-temperature C(T) behaviors of the extended defects, i. e. dislocations and grain boundaries (GBs). It was found that the solar cell processing with phosphorus diffusion gettering (PDG) followed with a SiN firing greatly reduces the recombination activity of extended defects at room temperature, and improves the bulk property simultaneously. A remaining activity of the dislocations indicates the limitation of the PDG at extended defects. Abnormal behavior of the dislocation activity after certain solar cell processes was also observed in the region with high dislocation density, the dislocations are activated after certain solar cell processings. In order to evaluate the properties of a thin polycrystalline silicon layer prepared by Al-induced layer exchange (Alile) technique, epitaxially layer grown on silicon substrate with different orientations was used as a model system to investigate the impact by the process temperature and the substrates. EBIC energy dependent collection efficiency measurements reveal an improvement of the epilayer quality with increasing substrate temperature during the growth from 450 C to 650 C, and a decrease of epilayer quality at 700 C. PL measurements on the epitaxially grown Si layer on silicon substrates revealed no characteristic dislocation-related luminescence (DRL) lines at room temperature and 77 K, while in the samples prepared by Alile process, intense

  8. A novel solid-state thermal rectifier based on reduced graphene oxide.

    Science.gov (United States)

    Tian, He; Xie, Dan; Yang, Yi; Ren, Tian-Ling; Zhang, Gang; Wang, Yu-Feng; Zhou, Chang-Jian; Peng, Ping-Gang; Wang, Li-Gang; Liu, Li-Tian

    2012-01-01

    Recently, manipulating heat transport by phononic devices has received significant attention, in which phonon--a heat pulse through lattice, is used to carry energy. In addition to heat control, the thermal devices might also have broad applications in the renewable energy engineering, such as thermoelectric energy harvesting. Elementary phononic devices such as diode, transistor and logic devices have been theoretically proposed. In this work, we experimentally create a macroscopic scale thermal rectifier based on reduced graphene oxide. Obvious thermal rectification ratio up to 1.21 under 12 K temperature bias has been observed. Moreover, this ratio can be enhanced further by increasing the asymmetric ratio. Collectively, our results raise the exciting prospect that the realization of macroscopic phononic device with large-area graphene based materials is technologically feasible, which may open up important applications in thermal circuits and thermal management.

  9. Gelatin-Based Materials in Ocular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    James B. Rose

    2014-04-01

    Full Text Available Gelatin has been used for many years in pharmaceutical formulation, cell culture and tissue engineering on account of its excellent biocompatibility, ease of processing and availability at low cost. Over the last decade gelatin has been extensively evaluated for numerous ocular applications serving as cell-sheet carriers, bio-adhesives and bio-artificial grafts. These different applications naturally have diverse physical, chemical and biological requirements and this has prompted research into the modification of gelatin and its derivatives. The crosslinking of gelatin alone or in combination with natural or synthetic biopolymers has produced a variety of scaffolds that could be suitable for ocular applications. This review focuses on methods to crosslink gelatin-based materials and how the resulting materials have been applied in ocular tissue engineering. Critical discussion of recent innovations in tissue engineering and regenerative medicine will highlight future opportunities for gelatin-based materials in ophthalmology.

  10. [Evidence-based management of medical disposable materials].

    Science.gov (United States)

    Yang, Hai

    2009-03-01

    Evidence-based management of medical disposable materials pays attention to collect evidence comprehensively and systematically, accumulate and create evidence through its own work and also evaluate evidence strictly. This can be used as a function to guide out job. Medical disposable materials evidence system contains product register qualification, product quality certification, supplier's behavior, internal and external communication evidence. Managers can find different ways in creating and using evidence referring to specific inside and outside condition. Evidence-based management can help accelerating the development of management of medical disposable materials from traditional experience pattern to a systematic and scientific pattern. It also has the very important meaning to improve medical quality, control the unreasonable growth of medical expense and make purchase and supply chain be more efficient.

  11. Novel hybrid materials based on the vanadium oxide nanobelts

    Science.gov (United States)

    Zabrodina, G. S.; Makarov, S. G.; Kremlev, K. V.; Yunin, P. A.; Gusev, S. A.; Kaverin, B. S.; Kaverina, L. B.; Ketkov, S. Yu.

    2016-04-01

    Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V2O5·nH2O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB - cetyltrimethylammonium bromide, TBAB - tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA)0.33V2O5 flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA)0.33V2O5, (TBA)0.16V2O5 nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

  12. Plasma deposition of amorphous silicon-based materials

    CERN Document Server

    Bruno, Giovanni; Madan, Arun

    1995-01-01

    Semiconductors made from amorphous silicon have recently become important for their commercial applications in optical and electronic devices including FAX machines, solar cells, and liquid crystal displays. Plasma Deposition of Amorphous Silicon-Based Materials is a timely, comprehensive reference book written by leading authorities in the field. This volume links the fundamental growth kinetics involving complex plasma chemistry with the resulting semiconductor film properties and the subsequent effect on the performance of the electronic devices produced. Key Features * Focuses on the plasma chemistry of amorphous silicon-based materials * Links fundamental growth kinetics with the resulting semiconductor film properties and performance of electronic devices produced * Features an international group of contributors * Provides the first comprehensive coverage of the subject, from deposition technology to materials characterization to applications and implementation in state-of-the-art devices.

  13. N-Modified Carbon-Based Materials: Nanoscience for Catalysis.

    Science.gov (United States)

    Prati, Laura; Chan-Thaw, Carine E; Campisi, Sebastiano; Villa, Alberto

    2016-10-01

    Carbon-based materials constitute a large family of materials characterized by some peculiarities such as resistance to both acidic and basic environments, flexibility of structure, and surface chemical groups. Moreover, they can be deeply modified by simple organic reactions (acid-base or redox) to acquire different properties. In particular, the introduction of N-containing groups, achieved by post-treatments or during preparation of the material, enhances the basic properties. Moreover, it has been revealed that the position and chemical nature of the N-containing groups is important in determining the interaction with metal nanoparticles, and thus, their reactivity. The modified activity was addressed to a different metal dispersion. Moreover, experiments on catalysts, showing the same metal dispersion, demonstrated that the best results were obtained when N was embedded into the carbon structure and not very close to the metal active site.

  14. Mechanical Testing of Carbon Based Woven Thermal Protection Materials

    Science.gov (United States)

    Pham, John; Agrawal, Parul; Arnold, James O.; Peterson, Keith; Venkatapathy, Ethiraj

    2013-01-01

    Three Dimensional Woven thermal protection system (TPS) materials are one of the enabling technologies for mechanically deployable hypersonic decelerator systems. These materials have been shown capable of serving a dual purpose as TPS and as structural load bearing members during entry and descent operations. In order to ensure successful structural performance, it is important to characterize the mechanical properties of these materials prior to and post exposure to entry-like heating conditions. This research focuses on the changes in load bearing capacity of woven TPS materials after being subjected to arcjet simulations of entry heating. Preliminary testing of arcjet tested materials [1] has shown a mechanical degradation. However, their residual strength is significantly more than the requirements for a mission to Venus [2]. A systematic investigation at the macro and microstructural scales is reported here to explore the potential causes of this degradation. The effects of heating on the sizing (an epoxy resin coating used to reduce friction and wear during fiber handling) are discussed as one of the possible causes for the decrease in mechanical properties. This investigation also provides valuable guidelines for margin policies for future mechanically deployable entry systems.

  15. Phosphorus-based compounds for EUV multilayer optics materials

    NARCIS (Netherlands)

    Medvedev, V.V.; Yakshin, A.E.; Kruijs, van de R.W.E.; Bijkerk, F.

    2015-01-01

    We have evaluated the prospects of phosphorus-based compounds in extreme ultraviolet multilayer optics. Boron phosphide (BP) is suggested to be used as a spacer material in reflective multilayer optics operating just above the L-photoabsorption edge of P (λ ≈9.2 nm). Mo, Ag, Ru, Rh, and Pd were cons

  16. Innovations in bonding to zirconia-based materials: Part I

    NARCIS (Netherlands)

    Abou Shelib, M.N.M.; Matinlinna, J.P.; Salameh, Z.; Ounsi, H.

    2008-01-01

    Abstract Objectives Establishing a reliable bond to zirconia-based materials has proven to be difficult which is the major limitation against fabricating adhesive zirconia restorations. This bond could be improved using novel selective infiltration etching conditioning in combination with engineered

  17. Developing Corpus-Based Materials to Teach Pragmatic Routines

    Science.gov (United States)

    Bardovi-Harlig, Kathleen; Mossman, Sabrina; Vellenga, Heidi E.

    2015-01-01

    This article describes how to develop teaching materials for pragmatics based on authentic language by using a spoken corpus. The authors show how to use the corpus in conjunction with textbooks to identify pragmatic routines for speech acts and how to extract appropriate language samples and adapt them for classroom use. They demonstrate how to…

  18. Developing Corpus-Based Materials to Teach Pragmatic Routines

    Science.gov (United States)

    Bardovi-Harlig, Kathleen; Mossman, Sabrina; Vellenga, Heidi E.

    2015-01-01

    This article describes how to develop teaching materials for pragmatics based on authentic language by using a spoken corpus. The authors show how to use the corpus in conjunction with textbooks to identify pragmatic routines for speech acts and how to extract appropriate language samples and adapt them for classroom use. They demonstrate how to…

  19. Engineering the electronic structure of lanthanide based materials

    NARCIS (Netherlands)

    Rogers, E.G.

    2012-01-01

    Lanthanide based materials are used in everything from phosphors for light bulbs and LEDs, to scintillators for medical imaging purposes to magnets. They also show potential for spintronics and for increasing the efficiency of solar cells. Knowing the energy of the lanthanide 4f and 5d states is im

  20. Energy enhancer for mask based laser materials processing

    DEFF Research Database (Denmark)

    Bastue, Jens; Olsen, Flemmming Ove

    1996-01-01

    A device capable of drastically improving the energy efficiency of present mask based laser materials processing systems is presented. Good accordance between experiments and simulations for a TEA-CO2 laser system designed for laser marking has been demonstrated. The energy efficiency may...

  1. Molecular Design of Benzodithiophene-Based Organic Photovoltaic Materials.

    Science.gov (United States)

    Yao, Huifeng; Ye, Long; Zhang, Hao; Li, Sunsun; Zhang, Shaoqing; Hou, Jianhui

    2016-06-22

    Advances in the design and application of highly efficient conjugated polymers and small molecules over the past years have enabled the rapid progress in the development of organic photovoltaic (OPV) technology as a promising alternative to conventional solar cells. Among the numerous OPV materials, benzodithiophene (BDT)-based polymers and small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking 10% efficiency barrier in the single junction OPV devices. Remarkably, the OPV device featured by BDT-based polymer has recently demonstrated an impressive PCE of 11.21%, indicating the great potential of this class of materials in commercial photovoltaic applications. In this review, we offered an overview of the organic photovoltaic materials based on BDT from the aspects of backbones, functional groups, alkyl chains, and device performance, trying to provide a guideline about the structure-performance relationship. We believe more exciting BDT-based photovoltaic materials and devices will be developed in the near future.

  2. Emergency Medical Technician. Competency Based Education Curriculum. Student Material.

    Science.gov (United States)

    Spotts, Sue Ann

    Beginning with an introductory handbook, this competency-based curriculum contains 13 modules for an 81-hour secondary- or postsecondary-level course for Emergency Medical Technician (EMT). Introductory materials include module component descriptions and information for administering an EMT training program, such as an instructor's schedule, list…

  3. Developing the science base for reducing tobacco harm

    Science.gov (United States)

    Hatsukami, Dorothy K.; Joseph, Anne M.; LeSage, Mark; Jensen, Joni; Murphy, Sharon E.; Pentel, Paul R.; Kotlyar, Michael; Borgida, Eugene; Le, Chap; Hecht, Stephen S.

    2014-01-01

    The University of Minnesota Transdisciplinary Tobacco Use Research Center has been examining the multiple dimensions and the scientific evidence required to determine the feasibility of tobacco harm reduction as a means to reduce tobacco-related mortality and morbidity. Because of the complexity associated with exploring this area, an interdisciplinary approach is necessary. The research components that have been of particular focus at our center include (a) developing and validating biomarkers of tobacco-related exposure and toxicity, (b) developing animal models and designing studies with humans to assess a variety of smoking reduction approaches and potential reduced exposure products, and (c) determining individual differences in response to these interventions and products. A description of the ongoing activities and challenges in these areas is provided, along with projected directions for the future. PMID:18067031

  4. Reduced Particle size of plant material does not stimulate decomposition but affects the microbivorous microfauna

    DEFF Research Database (Denmark)

    Vestergaard, Peter; Rønn, Regin; Christensen, Søren

    2001-01-01

    in soils amended with the large pieces on nine out of 10 occasions. Microbial biomass measured as SIR was significantly higher in soils with maize than in those amended with barley, but no effect of particle size was observed (three-way ANOVA, P... material, but significantly higher numbers were found in soil with finely-ground maize than in soil with large pieces (two-way ANOVA, P... barley (three-way ANOVA, P

  5. Model-reduced gradient-based history matching

    NARCIS (Netherlands)

    Kaleta, M.P.

    2011-01-01

    Since the world's energy demand increases every year, the oil & gas industry makes a continuous effort to improve fossil fuel recovery. Physics-based petroleum reservoir modeling and closed-loop model-based reservoir management concept can play an important role here. In this concept measured data a

  6. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2011-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns (

  7. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2012-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns (

  8. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2012-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns

  9. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2011-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns

  10. Model-reduced gradient-based history matching

    NARCIS (Netherlands)

    Kaleta, M.P.

    2011-01-01

    Since the world's energy demand increases every year, the oil & gas industry makes a continuous effort to improve fossil fuel recovery. Physics-based petroleum reservoir modeling and closed-loop model-based reservoir management concept can play an important role here. In this concept measured data a

  11. Materials from April 2010 Mexico Workshop on Reducing Air Pollution from Ships

    Science.gov (United States)

    As part of a U.S.-Mexico Fuel Switching Demonstration, EPA and SEMARNAT jointly sponsored a workshop entitled “Reducing Air Pollution from Ships: Fuel Switching Demonstration in the Gulf of Mexico,” Veracruz, Mexico, April 16, 2010.

  12. Graphene-based materials for supercapacitor electrodes – A review

    Directory of Open Access Journals (Sweden)

    Qingqing Ke

    2016-03-01

    Full Text Available The graphene-based materials are promising for applications in supercapacitors and other energy storage devices due to the intriguing properties, i.e., highly tunable surface area, outstanding electrical conductivity, good chemical stability and excellent mechanical behavior. This review summarizes recent development on graphene-based materials for supercapacitor electrodes, based on their macrostructural complexity, i.e., zero-dimensional (0D (e.g. free-standing graphene dots and particles, one-dimensional (1D (e.g. fiber-type and yarn-type structures, two-dimensional (2D (e.g. graphenes and graphene-based nanocomposite films, and three-dimensional (3D (e.g. graphene foam and hydrogel-based nanocomposites. There are extensive and on-going researches on the rationalization of their structures at varying scales and dimensions, development of effective and low cost synthesis techniques, design and architecturing of graphene-based materials, as well as clarification of their electrochemical performance. It is indicated that future studies should focus on the overall device performance in energy storage devices and large-scale process in low costs for the promising applications in portable and wearable electronic, transport, electrical and hybrid vehicles.

  13. Graphene-based Materials for Photoanodes in Dye-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Xiaoru eGuo

    2015-12-01

    Full Text Available This article reviews the research on the use of graphene and related materials in the photoanode of dye-sensitized solar cells (DSSCs. Graphene-based materials, such as pristine graphene, graphene oxide, and reduced graphene oxide, have properties attractive for various components of the DSSC photoanode. We first provide a brief introduction to graphene properties and analyze requirements for making a high-performance photoanode. Then we introduce applications of graphene-based materials in each part of the DSSC photoanode, i.e., the transparent conducting electrode, the sensitizing material, and the semiconducting layer. Particularly, we discuss how the incorporation of graphene-based materials in those components can enhance the photoanode performance. It is clear that the outstanding properties of graphene, such as the fast electron transfer ability, high Young’s modulus, and good transparency, benefit DSSC photoanode research, and doping or surface modifications of graphene nanosheets with other materials can also improve the photoanode and thus the resulting cell performance. Finally, we present an outlook for current issues and further trends for using graphene materials in DSSC photoanodes.

  14. Comparison of in vitro cytotoxicity and genotoxicity of MMA-based polymeric materials and various metallic materials

    OpenAIRE

    İZ, Sultan GÜLÇE; GÜRHAN, Saime İsmet DELİLOĞLU; ŞEN, Bilge Hakan

    2010-01-01

    To determine the in vitro cytotoxicity and genotoxicity of some polymeric and metallic implant materials used as base materials in dentistry, based on ISO (International Organization for Standardization) and OECD (Organization for Economic Co-Operation and Development) test protocols. Materials and methods: Three different acrylate-based polymeric materials were tested for their in vitro cytotoxicity and genotoxicity (polymethylmethacrylate microspheres [PMMA], a solid cement prepared by mi...

  15. Phosphorene and Phosphorene-Based Materials - Prospects for Future Applications.

    Science.gov (United States)

    Batmunkh, Munkhbayar; Bat-Erdene, Munkhjargal; Shapter, Joseph G

    2016-10-01

    Phosphorene, a single- or few-layered semiconductor material obtained from black phosphorus, has recently been introduced as a new member of the family of two-dimensional (2D) layered materials. Since its discovery, phosphorene has attracted significant attention, and due to its unique properties, is a promising material for many applications including transistors, batteries and photovoltaics (PV). However, based on the current progress in phosphorene production, it is clear that a lot remains to be explored before this material can be used for these applications. After providing a comprehensive overview of recent advancements in phosphorene synthesis, advantages and challenges of the currently available methods for phosphorene production are discussed. An overview of the research progress in the use of phosphorene for a wide range of applications is presented, with a focus on enabling important roles that phosphorene would play in next-generation PV cells. Roadmaps that have the potential to address some of the challenges in phosphorene research are examined because it is clear that the unprecedented chemical, physical and electronic properties of phosphorene and phosphorene-based materials are suitable for various applications, including photovoltaics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Strategies Based on Nitride Materials Chemistry to Stabilize Li Metal Anode.

    Science.gov (United States)

    Zhu, Yizhou; He, Xingfeng; Mo, Yifei

    2017-08-01

    Lithium metal battery is a promising candidate for high-energy-density energy storage. Unfortunately, the strongly reducing nature of lithium metal has been an outstanding challenge causing poor stability and low coulombic efficiency in lithium batteries. For decades, there are significant research efforts to stabilize lithium metal anode. However, such efforts are greatly impeded by the lack of knowledge about lithium-stable materials chemistry. So far, only a few materials are known to be stable against Li metal. To resolve this outstanding challenge, lithium-stable materials have been uncovered out of chemistry across the periodic table using first-principles calculations based on large materials database. It is found that most oxides, sulfides, and halides, commonly studied as protection materials, are reduced by lithium metal due to the reduction of metal cations. It is discovered that nitride anion chemistry exhibits unique stability against Li metal, which is either thermodynamically intrinsic or a result of stable passivation. The results here establish essential guidelines for selecting, designing, and discovering materials for lithium metal protection, and propose multiple novel strategies of using nitride materials and high nitrogen doping to form stable solid-electrolyte-interphase for lithium metal anode, paving the way for high-energy rechargeable lithium batteries.

  17. Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite

    Science.gov (United States)

    Phillips, E.J.P.; Landa, E.R.; Kraemer, T.; Zielinski, R.

    2001-01-01

    Scale and sludge deposits formed during oil production can contain elevated levels of Ra, often coprecipitated with barium sulfate (barite). The potential for sulfate-reducing bacteria to release 226 Ra and Ba (a Ra analog) from oil-field barite was evaluated. The concentration of dissolved Ba increased when samples containing pipe scale, tank sludge, or oil-field brine pond sediment were incubated with sulfate-reducing bacteria Desulfovibrio sp., Str LZKI, isolated from an oil-field brine pond. However, Ba release was not stoichiometric with sulfide production in oil-field samples, and material.

  18. Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

    Energy Technology Data Exchange (ETDEWEB)

    Cara, Irina Gabriela, E-mail: coroirina@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Trincă, Lucia Carmen, E-mail: lctrinca@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Trofin, Alina Elena, E-mail: aetrofin@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Cazacu, Ana, E-mail: anagarlea@gmail.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Ţopa, Denis, E-mail: topadennis@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Peptu, Cătălina Anişoara, E-mail: catipeptu@yahoo.co.uk [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 D. Mangeron Street, 700050 Iasi (Romania); Jităreanu, Gerard, E-mail: gerardj@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania)

    2015-12-15

    Highlights: • Surface characteristics of activated straw (wheat, corn, soybean) were assessed. • Modification methods to enhance materials sorption were presented. • Adsorption mechanism of metribuzin was revealed and discussed. - Abstract: Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

  19. Semantics-based pre-fetching for reducing WWW latency

    Institute of Scientific and Technical Information of China (English)

    赵晨; 施鹏飞; 许欢庆

    2004-01-01

    A semantics-based pre-fetching model is presented. This model predicts future requests based on latent intention that the user's current access path implies in semantics, rather than on temporal relationships, which oversomes the limitation of previous pre-fetching approaches. The hidden Markov model (HMM) was employed for mining actual intention from access patterns. Experimental results show that the proposed pre-fetching model has better general performance.

  20. Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Teber, Ahmet, E-mail: aht10003@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States); Unver, Ibrahim, E-mail: iunver@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Kavas, Huseyin, E-mail: huseyin.kavas@medeniyet.edu.tr [Department of Physics, Istanbul Medeniyet University, Istanbul 34000 (Turkey); Aktas, Bekir, E-mail: aktas@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Bansal, Rajeev, E-mail: rajeev@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States)

    2016-05-15

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K{sub u}, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

  1. Reduced model-based decision-making in schizophrenia.

    Science.gov (United States)

    Culbreth, Adam J; Westbrook, Andrew; Daw, Nathaniel D; Botvinick, Matthew; Barch, Deanna M

    2016-08-01

    Individuals with schizophrenia have a diminished ability to use reward history to adaptively guide behavior. However, tasks traditionally used to assess such deficits often rely on multiple cognitive and neural processes, leaving etiology unresolved. In the current study, we adopted recent computational formalisms of reinforcement learning to distinguish between model-based and model-free decision-making in hopes of specifying mechanisms associated with reinforcement-learning dysfunction in schizophrenia. Under this framework, decision-making is model-free to the extent that it relies solely on prior reward history, and model-based if it relies on prospective information such as motivational state, future consequences, and the likelihood of obtaining various outcomes. Model-based and model-free decision-making was assessed in 33 schizophrenia patients and 30 controls using a 2-stage 2-alternative forced choice task previously demonstrated to discern individual differences in reliance on the 2 forms of reinforcement-learning. We show that, compared with controls, schizophrenia patients demonstrate decreased reliance on model-based decision-making. Further, parameter estimates of model-based behavior correlate positively with IQ and working memory measures, suggesting that model-based deficits seen in schizophrenia may be partially explained by higher-order cognitive deficits. These findings demonstrate specific reinforcement-learning and decision-making deficits and thereby provide valuable insights for understanding disordered behavior in schizophrenia. (PsycINFO Database Record

  2. Industry 1.61803: the transition to an industry with reduced material demand fit for a low carbon future

    Science.gov (United States)

    2017-01-01

    Arising from a discussion meeting in September 2016, this editorial introduces a special issue on the transition to a future industrial system with greatly reduced demand for material production and attempts to synthesize the main findings. The motivation for such a transition is to reduce industrial greenhouse gas emissions, but unlike previous industrial transformations, there are no major stakeholders who will pursue the change for their own immediate benefit. The special issue, therefore, explores the means by which such a transition could be brought about. The editorial presents an overview of the opportunities identified in the papers of the volume, presents examples of actions that can be taken today to begin the process of change and concludes with an agenda for research that might support a rapid acceleration in the rate of change. This article is part of the themed issue ‘Material demand reduction’. PMID:28461426

  3. Improvement of material decomposition and image quality in dual-energy radiography by reducing image noise

    Science.gov (United States)

    Lee, D.; Kim, Y.-s.; Choi, S.; Lee, H.; Choi, S.; Jo, B. D.; Jeon, P.-H.; Kim, H.; Kim, D.; Kim, H.; Kim, H.-J.

    2016-08-01

    Although digital radiography has been widely used for screening human anatomical structures in clinical situations, it has several limitations due to anatomical overlapping. To resolve this problem, dual-energy imaging techniques, which provide a method for decomposing overlying anatomical structures, have been suggested as alternative imaging techniques. Previous studies have reported several dual-energy techniques, each resulting in different image qualities. In this study, we compared three dual-energy techniques: simple log subtraction (SLS), simple smoothing of a high-energy image (SSH), and anti-correlated noise reduction (ACNR) with respect to material thickness quantification and image quality. To evaluate dual-energy radiography, we conducted Monte Carlo simulation and experimental phantom studies. The Geant 4 Application for Tomographic Emission (GATE) v 6.0 and tungsten anode spectral model using interpolation polynomials (TASMIP) codes were used for simulation studies and digital radiography, and human chest phantoms were used for experimental studies. The results of the simulation study showed improved image contrast-to-noise ratio (CNR) and coefficient of variation (COV) values and bone thickness estimation accuracy by applying the ACNR and SSH methods. Furthermore, the chest phantom images showed better image quality with the SSH and ACNR methods compared to the SLS method. In particular, the bone texture characteristics were well-described by applying the SSH and ACNR methods. In conclusion, the SSH and ACNR methods improved the accuracy of material quantification and image quality in dual-energy radiography compared to SLS. Our results can contribute to better diagnostic capabilities of dual-energy images and accurate material quantification in various clinical situations.

  4. Expancel Foams: Fabrication and Characterization of a New Reduced Density Cellular Material for Structural Applications

    Energy Technology Data Exchange (ETDEWEB)

    L. Whinnery; S. Goods; B. Even

    2000-08-01

    This study was initiated to produce a low-density centering medium for use in experiments investigating the response of materials to shock-loading. While the main drivers for material selection were homogeneity, dimensional stability, performance and cost, other secondary requirements included fine cell size, the ability to manufacture 5--10 cm-sized parts and an extremely compressed development time. The authors chose a non-traditional methodology using a hollow, expandable, polymeric microballoon material system called Expancel{reg_sign}. These microballoons are made from a copolymer of polyacrylonitrile (PAN) and polymethacrylonitrile (PMAN) and use iso-pentane as the blowing agent. The average diameter (by volume) of the unexpanded powder is approximately 13 {micro}m, while the average of the expanded powder is 35--55 {micro}m, with a few large microballoons approaching 150--200 p.m. A processing method was developed that established a pre-mixed combination of unexpanded and expanded Expancel at a ratio such that the tap (or vibration) density of the mixed powders was the same as that desired of the final part. Upon heating above the tack temperature of the polymer, this zero-rise approach allowed only expansion of the unexpanded powder to fill the interstices between the pre-expanded balloons. The mechanical action of the expanding powder combined with the elevated processing temperature yielded flee-standing and mechanically robust parts. Although mechanical properties of these foams were not a key performance requirement, the data allowed for the determination of the best temperature to heat the samples. Processing the foam at higher temperatures enhanced both modulus and strength. The maximum allowable temperature was limited by dimensional stability and shrinkback considerations. Tomographic analysis of foam billets revealed very flat density profiles. Parts of any density between the low density expanded powder (approximately 0.013 g/cm{sup 3}) and the

  5. EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States)

    2016-12-08

    The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices with efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.

  6. Integrating UNESCO ICT-Based Instructional Materials in Chemistry Lessons

    Directory of Open Access Journals (Sweden)

    CHARLIE P. NACARIO

    2014-08-01

    Full Text Available This study determined the effectiveness of the lessons in Chemistry integrating UNESCO ICT-based instructional material on the achievement of Chemistry students at Central Bicol State University of Agriculture. It aimed to identify lessons that may be developed integrating UNESCO ICT-based instructional materials, determine the effect of the developed lessons using the material on: conceptual understanding; science process skills; and attitude towards chemistry and gather insights from the experiences of the students and teacher. The study used the single group pretest and posttest experimental design. Descriptive, quantitative and qualitative techniques were also utilized. Quantitative data were taken from the pretest-posttest results on the Test on Conceptual Understanding, Science Process Skills and Chemistry Attitudinaire. Qualitative data were drawn from the experts’ assessment of the developed lessons and research instruments, and the insights of students and teacher. The developed lessons integrating UNESCO ICT-based instructional materials were Atomic Model and Structure, Periodic Table of Elements, Chemical Bonding, and Balancing Chemical Equation. These lessons increased the conceptual understanding of the students by topic and skill from very low mastery to average mastery level. The students have slightly improved along the different science process skills. After teaching the lessons, the students’ attitude also improved. The students became more motivated and interested in Chemistry and the lessons were student centered and entailed teacher’s competence and flexibility in computer use.

  7. Materials science of Mg-Ni-based new hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Orimo, S.; Fujii, H. [Hiroshima Univ. (Japan). Faculty of Integrated Arts and Sciences

    2001-02-01

    One of the advantageous functional properties of Mg alloys (or compounds) is to exhibit the reversible hydriding reaction. In this paper, we present our systematic studies regarding the relationship between nanometer- or atomistic-scale structures and the specific hydriding properties of the Mg-Ni binary system, such as(1) nanostructured (n)-Mg{sub 2}Ni, (2) a mixture of n-Mg{sub 2}Ni and amorphous (a)-MgNi,(3) pure a-MgNi, and(4) n-MgNi{sub 2}. Further studies on(5) an a-MgNi-based system for clarifying the effect of the short-range ordering on the structural and hydriding properties and(6) a MgNi{sub 2}-based system for synthesizing the new Laves phase structure are also presented. The materials science of Mg-Ni-based new hydrides will provide indispensable knowledge for practically developing the Mg alloys as hydrogen-storage materials. (orig.)

  8. Verifiable Distribution of Material Goods Based on Cryptology

    Directory of Open Access Journals (Sweden)

    Radomír Palovský

    2015-12-01

    Full Text Available Counterfeiting of material goods is a general problem. In this paper an architecture for verifiable distribution of material goods is presented. This distribution is based on printing such a QR code on goods, which would contain digitally signed serial number of the product, and validity of this digital signature could be verifiable by a customer. Extension consisting of adding digital signatures to revenue stamps used for state-controlled goods is also presented. Discussion on possibilities in making copies leads to conclusion that cryptographic security needs to be completed by technical difficulties of copying.

  9. Knitted radar absorbing materials (RAM) based on nickel-cobalt magnetic materials

    Science.gov (United States)

    Teber, Ahmet; Unver, Ibrahim; Kavas, Huseyin; Aktas, Bekir; Bansal, Rajeev

    2016-05-01

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, Ku, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under -20 dB return loss over a moderate bandwidth).

  10. Reducing industrial use of fossil raw materials:techno-economic assessment of relevant cases in Northern Finland

    OpenAIRE

    Arvola, J. (Jouko)

    2011-01-01

    Abstract Climate change and global warming are currently widely discussed topics, both of which potentially impact all the nations and industries. Carbon dioxide (CO2) and other green house gases (GHG) are seen as a major challenge. This doctoral dissertation aims to conduct techno-economic calculations on the possibilities of reducing the industrial use of fossil raw materials in Northern Finland. This doctoral dissertation analyses industrial CO2 emissions from five complementary pe...

  11. Using bio-based polymers for curing cement-based materials

    NARCIS (Netherlands)

    Zlopasa, J.; Koenders, E.A.B.; Picken, S.J.

    2014-01-01

    Curing is the process of controlling the rate and extent of moisture loss from the surface of cement based materials. It is the final stage in the production of cement-based materials and it is the essential part for achieving continuous hydration of cement, while avoiding cracking due to drying

  12. An Efficacy Trial of Research-Based Curriculum Materials with Curriculum-Based Professional Development

    Science.gov (United States)

    Taylor, Joseph A.; Getty, Stephen R.; Kowalski, Susan M.; Wilson, Christopher D.; Carlson, Janet; Van Scotter, Pamela

    2015-01-01

    This study examined the efficacy of a curriculum-based intervention for high school science students. Specifically, the intervention was two years of research-based, multidisciplinary curriculum materials for science supported by comprehensive professional development for teachers that focused on those materials. A modest positive effect was…

  13. Using bio-based polymers for curing cement-based materials

    NARCIS (Netherlands)

    Zlopasa, J.; Koenders, E.A.B.; Picken, S.J.

    2014-01-01

    Curing is the process of controlling the rate and extent of moisture loss from the surface of cement based materials. It is the final stage in the production of cement-based materials and it is the essential part for achieving continuous hydration of cement, while avoiding cracking due to drying shr

  14. Effect of different housing retaining materials on the flexural strength of an acrylic resin overdenture base.

    Science.gov (United States)

    Ozkir, Serhat Emre; Yilmaz, Burak

    2017-04-03

    An attachment housing inside an overdenture may weaken the acrylic resin base. The type of housing retaining material may affect the strength of the housing retaining material-acrylic resin base assembly. The effect of different housing retaining materials on the strength of acrylic resin base is unknown. The purpose of this in vitro study was to evaluate the effects of different materials used to retain the housing on the flexural strength of a poly(methyl methacrylate) (PMMA) resin base. Sixty PMMA specimens (64×10×4 mm) were prepared with a clearance inside to allow the insertion of overdenture housings. Five different materials were used for housing orientation: an autopolymerizing composite resin, an acrylic resin reline material, a heat-polymerized PMMA, an autopolymerizing PMMA (n=10), and a control group (n=10) were prepared without any preparation or housing. The specimens were thermocycled 5000 times between 5°C and 55°C. The flexural strength data were analyzed by an analysis of variance using the maximum likelihood estimation method to eliminate the needs for normality within the groups and for equality of variances between the groups. If statistically significant, resolution of the significance factor was obtained by pairwise comparisons using the Tukey adjustment (α=.05). The fracture values were statistically significantly higher (Pmaterial (26.78 ±6.72 MPa), the acrylic resin reline material (16.94 ±4.38 MPa), the Ufigel (16.07 ±3.40 MPa), and the autopolymerizing composite resin (19.37 ±3.13 MPa). Heat- and autopolymerizing PMMA groups were significantly different from acrylic resin-based hard reline materials (Pmaterial except for one of the hard reline groups, which separated from the PMMA. The tested retaining materials significantly reduced the flexural strength of PMMA denture base. The flexural strength of the resin base with housing was significantly higher when PMMA-based retaining materials were used than when acrylic resin-based

  15. Electron Charged Graphite-based Hydrogen Storage Material

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Chinbay Q. Fan; D Manager

    2012-03-14

    The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage methods; however, it could be high for the battery mode.

  16. MapReduce-based Dimensional ETL Made Easy

    DEFF Research Database (Denmark)

    Xiufeng, Liu; Thomsen, Christian; Pedersen, Torben Bach

    2012-01-01

    This paper demonstrates ETLMR, a novel dimensional Extract–Transform–Load (ETL) programming framework that uses MapReduce to achieve scalability. ETLMR has builtin native support of data warehouse (DW) specific constructs such as star schemas, snowflake schemas, and slowly changing dimensions (SCDs......). This makes it possible to build MapReducebased dimensional ETL flows very easily. The ETL process can be configured with only few lines of code. We will demonstrate the concrete steps in using ETLMR to load data into a (partly snowflaked) DW schema. This includes configuration of data sources and targets......, dimension processing schemes, fact processing, and employment. In addition, we also present the scalability on large data sets....

  17. Reducing Hospital ICU Noise: A Behavior-Based Approach

    Directory of Open Access Journals (Sweden)

    Avinash Konkani

    2014-01-01

    Full Text Available Noise in Intensive Care Units (ICUs is gaining increasing attention as a significant source of stress and fatigue for nursing staff. Extensive research indicates that hospital noise also has negative impact on patients. The objective of this study was to analyze noise variations as experienced by both nursing staff and patients, to gain a better understanding of noise levels and frequencies observed in ICU settings over extended (week-long durations, and to implement a low cost behavior modification program to reduce noise. The results of our study indicate that behavioral modification alone is not adequate to control excessive noise. There is a need for further research involving the supportive involvement by clinicians, ICU staff, along with effective medical device alarm management, and continuous process improvement methods.

  18. Model-reduced gradient-based history matching

    NARCIS (Netherlands)

    Kaleta, M.P.; Hanea, R.G.; Heemink, A.W.; Jansen, J.D.

    2010-01-01

    Gradient-based history matching algorithms can be used to adapt the uncertain parameters in a reservoir model using production data. They require, however, the implementation of an adjoint model to compute the gradients, which is usually an enormous programming effort. We propose a new approach to g

  19. High Temperature Thermoelectric Properties of ZnO Based Materials

    DEFF Research Database (Denmark)

    Han, Li

    This thesis investigated the high temperature thermoelectric properties of ZnO based materials. The investigation first focused on the doping mechanisms of Al-doped ZnO, and then the influence of spark plasma sintering conditions on the thermoelectric properties of Al, Ga-dually doped ZnO....... Following that, the nanostructuring effect for Al-doped ZnO was systematically investigated using samples with different microstructure morphologies. At last, the newly developed ZnCdO materials with superior thermoelectric properties and thermal stability were introduced as promising substitutions...... for conventional ZnO materials. For Al-doped ZnO, α- and γ-Al2O3 were selectively used as dopants in order to understand the doping mechanism of each phase and their effects on the thermoelectric properties. The samples were prepared by the spark plasma sintering technique from precursors calcined at various...

  20. Optical Fibre Sensors Using Graphene-Based Materials: A Review

    Science.gov (United States)

    Hernaez, Miguel; Zamarreño, Carlos R.; Melendi-Espina, Sonia; Bird, Liam R.; Mayes, Andrew G.; Arregui, Francisco J.

    2017-01-01

    Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted the attention of the scientific community from different research fields, generating high impact not only in scientific journals, but also in general-interest newspapers. Optical fibre sensing is one of the many fields that can benefit from the use of these new materials, combining the amazing morphological, chemical, optical and electrical features of graphene with the advantages that optical fibre offers over other sensing strategies. In this document, a review of the current state of the art for optical fibre sensors based on graphene materials is presented. PMID:28098825

  1. Thermal analysis of charring materials based on pyrolysis interface model

    Directory of Open Access Journals (Sweden)

    Huang Hai-Ming

    2014-01-01

    Full Text Available Charring thermal protection systems have been used to protect hypersonic vehicles from high heat loads. The pyrolysis of charring materials is a complicated physical and chemical phenomenon. Based on the pyrolysis interface model, a simulating approach for charring ablation has been designed in order to obtain one dimensional transient thermal behavior of homogeneous charring materials in reentry capsules. As the numerical results indicate, the pyrolysis rate and the surface temperature under a given heat flux rise abruptly in the beginning, then reach a plateau, but the temperature at the bottom rises very slowly to prevent the structural materials from being heated seriously. Pyrolysis mechanism can play an important role in thermal protection systems subjected to serious aerodynamic heat.

  2. Optical Fibre Sensors Using Graphene-Based Materials: A Review

    Directory of Open Access Journals (Sweden)

    Miguel Hernaez

    2017-01-01

    Full Text Available Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010 achieved its isolation in 2004. The exceptional properties of graphene have attracted the attention of the scientific community from different research fields, generating high impact not only in scientific journals, but also in general-interest newspapers. Optical fibre sensing is one of the many fields that can benefit from the use of these new materials, combining the amazing morphological, chemical, optical and electrical features of graphene with the advantages that optical fibre offers over other sensing strategies. In this document, a review of the current state of the art for optical fibre sensors based on graphene materials is presented.

  3. Basalt fiber reinforced porous aggregates-geopolymer based cellular material

    Science.gov (United States)

    Luo, Xin; Xu, Jin-Yu; Li, Weimin

    2015-09-01

    Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress-strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress-strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering.

  4. Cement-Based Materials for Nuclear Waste Storage

    CERN Document Server

    Cau-di-Coumes, Céline; Frizon, Fabien; Lorente, Sylvie

    2013-01-01

    As the re-emergence of nuclear power as an acceptable energy source on an international basis continues, the need for safe and reliable ways to dispose of radioactive waste becomes ever more critical. The ultimate goal for designing a predisposal waste-management system depends on producing waste containers suitable for storage, transportation and permanent disposal. Cement-Based Materials for Nuclear-Waste Storage provides a roadmap for the use of cementation as an applied technique for the treatment of low- and intermediate-level radioactive wastes.Coverage includes, but is not limited to, a comparison of cementation with other solidification techniques, advantages of calcium-silicate cements over other materials and a discussion of the long-term suitability and safety of waste packages as well as cement barriers. This book also: Discusses the formulation and production of cement waste forms for storing radioactive material Assesses the potential of emerging binders to improve the conditioning of problemati...

  5. Designing Listening Material Based on Visual Multimodality Compositions

    Directory of Open Access Journals (Sweden)

    Jepri Ali Saiful

    2015-06-01

    Full Text Available In recent decades, multimodality has eventually augmented into the realm of language teaching and learning known as Applied Multimodality. This interdisciplinary approach draws on a multiplicity of communication or representation modes, all of which contribute to meaning. Accordingly, images, colors, and sounds within a text are catalysts to increase an audience’s reception of an idea or concept of the text, that is, a message. Thus, the present article intends to make a contribution to the field of material development in English language teaching. The aim of this article is therefore to provide guidelines for ELT teachers on how to design listening materials based on visual multimodal compositions of image and text. The result is that the compositions of image and text in designing listening materials rests upon three main principles: information value, salience and framing. These principles enable students’ L2 acquisition through listening as proved by recent research.

  6. Carbon-Based Materials for Photo-Triggered Theranostic Applications

    Directory of Open Access Journals (Sweden)

    Karunya Albert

    2016-11-01

    Full Text Available Carbon-based nanomaterials serve as a type of smart material for photo-triggered disease theranostics. The inherent physicochemical properties of these nanomaterials facilitate their use for less invasive treatments. This review summarizes the properties and applications of materials including fullerene, nanotubes, nanohorns, nanodots and nanographenes for photodynamic nanomedicine in cancer and antimicrobial therapies. Carbon nanomaterials themselves do not usually act as photodynamic therapy (PDT agents owing to the high hydrophobicity, however, when the surface is passivated or functionalized, these materials become great vehicles for PDT. Moreover, conjugation of carbonaceous nanomaterials with the photosensitizer (PS and relevant targeting ligands enhances properties such as selectivity, stability, and high quantum yield, making them readily available for versatile biomedical applications.

  7. Feedback-Based Resource Allocation in MapReduce-Based Systems

    Directory of Open Access Journals (Sweden)

    Bunjamin Memishi

    2016-01-01

    Full Text Available Containers are considered an optimized fine-grain alternative to virtual machines in cloud-based systems. Some of the approaches which have adopted the use of containers are the MapReduce frameworks. This paper makes an analysis of the use of containers in MapReduce-based systems, concluding that the resource utilization of these systems in terms of containers is suboptimal. In order to solve this, the paper describes AdaptCont, a proposal for optimizing the containers allocation in MapReduce systems. AdaptCont is based on the foundations of feedback systems. Two different selection approaches, Dynamic AdaptCont and Pool AdaptCont, are defined. Whereas Dynamic AdaptCont calculates the exact amount of resources per each container, Pool AdaptCont chooses a predefined container from a pool of available configurations. AdaptCont is evaluated for a particular case, the application master container of Hadoop YARN. As we can see in the evaluation, AdaptCont behaves much better than the default resource allocation mechanism of Hadoop YARN.

  8. Technical Education Outreach in Materials Science and Technology Based on NASA's Materials Research

    Science.gov (United States)

    Jacobs, James A.

    2003-01-01

    The grant NAG-1 -2125, Technical Education Outreach in Materials Science and Technology, based on NASA s Materials Research, involves collaborative effort among the National Aeronautics and Space Administration s Langley Research Center (NASA-LaRC), Norfolk State University (NSU), national research centers, private industry, technical societies, colleges and universities. The collaboration aims to strengthen math, science and technology education by providing outreach related to materials science and technology (MST). The goal of the project is to transfer new developments from LaRC s Center for Excellence for Structures and Materials and other NASA materials research into technical education across the nation to provide educational outreach and strengthen technical education. To achieve this goal we are employing two main strategies: 1) development of the gateway website and 2) using the National Educators Workshop: Update in Engineering Materials, Science and Technology (NEW:Updates). We have also participated in a number of national projects, presented talks at technical meetings and published articles aimed at improving k-12 technical education. Through the three years of this project the NSU team developed the successful MST-Online site and continued to upgrade and update it as our limited resources permitted. Three annual NEW:Updates conducted from 2000 though 2002 overcame the challenges presented first by the September 11,2001 terrorist attacks and the slow U.S. economy and still managed to conduct very effective workshops and expand our outreach efforts. Plans began on NEW:Update 2003 to be hosted by NASA Langley as a part of the celebration of the Centennial of Controlled Flight.

  9. Nanostructured Mo-based electrode materials for electrochemical energy storage.

    Science.gov (United States)

    Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

    2015-04-21

    The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

  10. Laser -Based Joining of Metallic and Non-metallic Materials

    Science.gov (United States)

    Padmanabham, G.; Shanmugarajan, B.

    Laser as a high intensity heat source can be effectively used for joining of materials by fusion welding and brazing in autogenous or in hybrid modes. In autogenous mode, welding is done in conduction , deep penetration , and keyhole mode. However, due to inherently high energy density available from a laser source, autogenous keyhole welding is the most popular laser welding mode. But, it has certain limitations like need for extremely good joint fit-up, formation of very hard welds in steel , keyhole instability, loss of alloying elements, etc. To overcome these limitations, innovative variants such as laser-arc hybrid welding , induction-assisted welding , dual beam welding , etc., have been developed. Using laser heat, brazing can be performed by melting a filler to fill the joints, without melting the base materials. Accomplishing laser-based joining as mentioned above requires appropriate choice of laser source, beam delivery system, processing head with appropriate optics and accessories. Basic principles of various laser-based joining processes, laser system technology, process parameters, metallurgical effects on different base materials, joint performance, and applications are explained in this chapter.

  11. Evidence-based dentistry as it relates to dental materials.

    Science.gov (United States)

    Bayne, Stephen C; Fitzgerald, Mark

    2014-01-01

    Evidence-based dentistry (EBD) is reviewed in depth to underscore the limitations for evidence-based dental materials information that exist at this time. Anecdotal estimates of evidence for dental practice are in the range of 8 percent to 10 percent. While the process of evaluating the literature base for dental evidence began 20 years ago, it was not practical to implement it until high-speed wireless connections, open access to journals, and omnipresent connections via smart phones became a reality. EBD includes five stages of information collection and analysis, starting with a careful definition of a clinical question using the PICO(T) approach. Clinical evidence in randomized control trials is considered the best. Clinical trial perspectives (prospective, cross-sectional, retrospective) and outcome designs (RCTs, SCTs, CCTs, cohort studies, case-control studies) are quite varied. Aggregation techniques (including meta-analyses) allow meaningful combinations of clinical data from trials with similar designs but with fewer rigors. Appraisals attempt to assess the entire evidence base without bias and answer clinical questions. Varying intensities to these approaches, Cochrane Collaboration, ADA-EBD Library, UTHSCSA CATs Library, are used to answer questions. Dental materials evidence from clinical trials is infrequent, short-term, and often not compliant with current guidelines (registration, CONSORT, PRISMA). Reports in current evidence libraries indicate less than 5 percent of evidence is related to restorative dental materials.

  12. An overview of the cosmic dust analogue material production in reduced gravity: the STARDUST experience.

    Science.gov (United States)

    Ferguson, F; Lilleleht, L U; Nuth, J; Stephens, J R; Bussoletti, E; Colangeli, L; Mennella, V; Dell'Aversana, P; Mirra, C

    1993-01-01

    The formation, properties and chemical dynamics of microparticles are important in a wide variety of technical and scientific fields including synthesis of semiconductor crystals from the vapour, heterogeneous chemistry in the stratosphere and the formation of cosmic dust surrounding the stars. Gravitational effects on particle formation from vapors include gas convection and buoyancy and particle sedimentation. These processes can be significantly reduced by studying condensation and agglomeration of particles in microgravity. In addition, to accurately simulate particle formation near stars, which takes place under low gravity conditions, studies in microgravity are desired. We report here the STARDUST experience, a recent collaborative effort that brings together a successful American program of microgravity experiments on particle formation aboard NASA KC-135 Reduced Gravity Research Aircraft and several Italian research groups with expertise in microgravity research and astrophysical dust formation. The program goal is to study the formation and properties of high temperature particles and gases that are of interest in astrophysics and planetary science. To do so we are developing techniques that are generally applicable to study particle formation and properties, taking advantage of the microgravity environment to allow accurate control of system parameters.

  13. TOPOLOGY DESCRIPTION FUNCTION BASED METHOD FOR MATERIAL DESIGN

    Institute of Scientific and Technical Information of China (English)

    Cao Xianfan; Liu Shutian

    2006-01-01

    The purpose of this paper is to investigate the application of topology description function (TDF) in material design. Using TDF to describe the topology of the microstructure,the formulation and the solving technique of the design problem of materials with prescribed mechanical properties are presented. By presenting the TDF as the sum of a series of basis functions determined by parameters, the topology optimization of material microstructure is formulated as a size optimization problem whose design variables are parameters of TDF basis functions and independent of the mesh of the design domain. By this method, high quality topologies for describing the distribution of constituent material in design domain can be obtained and checkerboard problem often met in the variable density method is avoided. Compared with the conventional level set method, the optimization problem can be solved simply by existing optimization techniques without the process to solve the‘Hamilton-Jacobi-type'equation by the difference method.The method proposed is illustrated with two 2D examples. One gives the unit cell with positive Poisson's ratio, the other with negative Poisson's ratio. The examples show the method based on TDF is effective for material design.

  14. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review.

    Science.gov (United States)

    Morón, Carlos; Cabrera, Carolina; Morón, Alberto; García, Alfonso; González, Mercedes

    2015-11-11

    Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a "simple" and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc.

  15. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2015-11-01

    Full Text Available Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a “simple” and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc.

  16. Do Ca2+-adsorbing ceramics reduce the release of calcium ions from gypsum-based biomaterials?

    Science.gov (United States)

    Belcarz, Anna; Zalewska, Justyna; Pałka, Krzysztof; Hajnos, Mieczysław; Ginalska, Grazyna

    2015-02-01

    Bone implantable materials based on calcium sulfate dihydrate dissolve quickly in tissue liquids and release calcium ions at very high levels. This phenomenon induces temporary toxicity for osteoblasts, may cause local inflammation and delay the healing process. Reduction in the calcium ion release rate by gypsum could be therefore beneficial for the healing of gypsum-filled bone defects. The aim of this study concerned the potential use of calcium phosphate ceramics of various porosities for the reduction of high Ca(2+) ion release from gypsum-based materials. Highly porous ceramics failed to reduce the level of Ca(2+) ions released to the medium in a continuous flow system. However, it succeeded to shorten the period of high calcium level. It was not the phase composition but the high porosity of ceramics that was found crucial for both the shortening of the Ca(2+) release-related toxicity period and intensification of apatite deposition on the composite. Nonporous ceramics was completely ineffective for this purpose and did not show any ability to absorb calcium ions at a significant level. Moreover, according to our observations, complex studies imitating in vivo systems, rather than standard tests, are essential for the proper evaluation of implantable biomaterials.

  17. Material-based engineering strategies for cardiac regeneration.

    Science.gov (United States)

    Marion, Mieke H van; Bax, Noortje A M; Spreeuwel, Ariane C C van; van der Schaft, Daisy W J; Bouten, Carlijn V C

    2014-01-01

    Cardiac tissue is composed of muscle and non-muscle cells, surrounded by extracellular matrix (ECM) and spatially organized into a complex three-dimensional (3D) architecture to allow for coordinated contraction and electrical pulse propagation. Despite emerging evidence for cardiomyocyte turnover in mammalian hearts, the regenerative capacity of human cardiac tissue is insufficient to recover from damage, e.g. resulting from myocardial infarction (MI). Instead, the heart 'repairs' lost or injured tissue by ongoing synthesis and remodeling of scar tissue. Conventional therapies and timely (stem) cell delivery to the injured tissue markedly improve short-term function and remodeling, but do not attenuate later stage adverse remodeling, leading to functional deterioration and eventually failure of the heart. Material-based therapies have been successfully used to mechanically support and constrain the post-MI failing heart, preventing it from further remodeling and dilation. When designed to deliver the right microenvironment for endogenous or exogenous cells, as well as the mechanical and topological cues to guide neo-tissue formation, material-based therapies may even reverse remodeling and boost cardiac regeneration. This paper reviews the up-to-date status of material-based cardiac regeneration with special emphasis on 1) the use of bare biomaterials to deliver passive constraints that unload the heart, 2) the use of materials and cells to create engineered cardiac constructs for replacement, support, or regeneration of damaged myocardium, and 3) the development of bio-inspired and bioactive materials that aim to enhance the endogenous regenerative capacity of the heart. As the therapies should function in the infarcted heart, the damaged host environment and engineered in vitro test systems that mimic this environment, are reviewed as well.

  18. Reducing the cost of Ca-based direct air capture of CO2.

    Science.gov (United States)

    Zeman, Frank

    2014-10-07

    Direct air capture, the chemical removal of CO2 directly from the atmosphere, may play a role in mitigating future climate risk or form the basis of a sustainable transportation infrastructure. The current discussion is centered on the estimated cost of the technology and its link to "overshoot" trajectories, where atmospheric CO2 levels are actively reduced later in the century. The American Physical Society (APS) published a report, later updated, estimating the cost of a one million tonne CO2 per year air capture facility constructed today that highlights several fundamental concepts of chemical air capture. These fundamentals are viewed through the lens of a chemical process that cycles between removing CO2 from the air and releasing the absorbed CO2 in concentrated form. This work builds on the APS report to investigate the effect of modifications to the air capture system based on suggestions in the report and subsequent publications. The work shows that reduced carbon electricity and plastic packing materials (for the contactor) may have significant effects on the overall price, reducing the APS estimate from $610 to $309/tCO2 avoided. Such a reduction does not challenge postcombustion capture from point sources, estimated at $80/tCO2, but does make air capture a feasible alternative for the transportation sector and a potential negative emissions technology. Furthermore, air capture represents atmospheric reductions rather than simply avoided emissions.

  19. RIM as the data base management system for a material properties data base

    Science.gov (United States)

    Karr, P. H.; Wilson, D. J.

    1984-01-01

    Relational Information Management (RIM) was selected as the data base management system for a prototype engineering materials data base. The data base provides a central repository for engineering material properties data, which facilitates their control. Numerous RIM capabilities are exploited to satisfy prototype data base requirements. Numerical, text, tabular, and graphical data and references are being stored for five material types. Data retrieval will be accomplished both interactively and through a FORTRAN interface. The experience gained in creating and exercising the prototype will be used in specifying requirements for a production system.

  20. RIM as the data base management system for a material properties data base

    Science.gov (United States)

    Karr, P. H.; Wilson, D. J.

    1984-01-01

    Relational Information Management (RIM) was selected as the data base management system for a prototype engineering materials data base. The data base provides a central repository for engineering material properties data, which facilitates their control. Numerous RIM capabilities are exploited to satisfy prototype data base requirements. Numerical, text, tabular, and graphical data and references are being stored for five material types. Data retrieval will be accomplished both interactively and through a FORTRAN interface. The experience gained in creating and exercising the prototype will be used in specifying requirements for a production system.

  1. Electro-active material (EAM) based bend sensors

    Science.gov (United States)

    LaComb, Ronald; LaComb, Julie

    2010-04-01

    The capability to accurately estimate strain and orientation of cables in an undersea environment is important for a multitude of applications. One way to estimate the positional location of a submersed cable is to utilize a network of distributed bend sensors providing inputs to a curve fitting algorithm. In this work commercially available bend sensors are characterized for small deflections. In addition proto-type devices are presented which can potentially improve device sensitivity. Commercially available bend sensors are based upon electro-active materials and variable resistance materials. Electro-active materials (EAM) are known for their actuator functionality but certain EAMs are capable of sensing as well. New advances in materials such as Ionic Polymer Metal Composites (IPMC) are proving suitable for quasi-static sensor applications. These sensors are low power, conformal and produce directionally dependent output voltages which are linearly proportional to deflection, with voltage polarity representative of the deflection direction. IPMCs are capable of being morphed for increased sensitivity. Variable resistivity sensors are based on smart epoxy polymer and carbon loaded inks. These sensors are inexpensive and conformal and unlike EAMs provide static measurements.

  2. Highly crystalline MOF-based materials grown on electrospun nanofibers

    Science.gov (United States)

    Bechelany, M.; Drobek, M.; Vallicari, C.; Abou Chaaya, A.; Julbe, A.; Miele, P.

    2015-03-01

    Supported Metal Organic Frameworks (MOFs) with a high specific surface area are of great interest for applications in gas storage, separation, sensing, and catalysis. In the present work we report the synthesis of a novel composite architecture of MOF materials supported on a flexible mat of electrospun nanofibers. The system, based on three-dimensional interwoven nanofibers, was designed by using a low-cost and scalable multistep synthesis protocol involving a combination of electrospinning and low-temperature atomic layer deposition of oxide materials, and their subsequent solvothermal conversion under either conventional or microwave-assisted heating. This highly versatile approach allows the production of different types of supported MOF crystals with controlled sizes, morphology, orientation and high accessibility.Supported Metal Organic Frameworks (MOFs) with a high specific surface area are of great interest for applications in gas storage, separation, sensing, and catalysis. In the present work we report the synthesis of a novel composite architecture of MOF materials supported on a flexible mat of electrospun nanofibers. The system, based on three-dimensional interwoven nanofibers, was designed by using a low-cost and scalable multistep synthesis protocol involving a combination of electrospinning and low-temperature atomic layer deposition of oxide materials, and their subsequent solvothermal conversion under either conventional or microwave-assisted heating. This highly versatile approach allows the production of different types of supported MOF crystals with controlled sizes, morphology, orientation and high accessibility. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06640e

  3. Novel hybrid materials based on the vanadium oxide nanobelts

    Energy Technology Data Exchange (ETDEWEB)

    Zabrodina, G.S., E-mail: kudgs@mail.ru [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Makarov, S.G.; Kremlev, K.V. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Yunin, P.A.; Gusev, S.A. [Institute for Physics of Microstructures Russian Academy of Sciences, Nizhny Novgorod 603087 (Russian Federation); Kaverin, B.S.; Kaverina, L.B. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Ketkov, S.Yu. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation)

    2016-04-15

    Graphical abstract: - Highlights: • Flat and curved vanadium oxide nanobelts have been synthesized. • Hybrid material was prepared via decoration of flexible nanobelts with zinc phthalocyanine. • Investigations of the thermal stability, morphologies and structures were carried out. - Abstract: Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V{sub 2}O{sub 5}·nH{sub 2}O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB – cetyltrimethylammonium bromide, TBAB – tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA){sub 0.33}V{sub 2}O{sub 5} flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA){sub 0.33}V{sub 2}O{sub 5}, (TBA){sub 0.16}V{sub 2}O{sub 5} nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

  4. Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

    Science.gov (United States)

    Cara, Irina Gabriela; Trincă, Lucia Carmen; Trofin, Alina Elena; Cazacu, Ana; Ţopa, Denis; Peptu, Cătălina Anişoara; Jităreanu, Gerard

    2015-12-01

    Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

  5. RECYCLING RECOVERED WOOD-BASED MATERIALS. FLATNESS, MOR AND MOE OF PANELS MADE FROM RECOVERED WOODEN BASED MATERIALS

    Directory of Open Access Journals (Sweden)

    Andrea DEÁK

    2015-12-01

    Full Text Available The objective of the research was to study the mechanical properties of recovered solid wood and wood-based materials, to create new panels made of strips of recovered oak and spruce wood, particleboards and blockboards and to study their mechanical properties, feasibility and use. Flatness, MOR and MOE were determined for the solid wood and wood-based materials recovered from construction and demolition sites. Four types of experimental panels (PL1, PL2, PALL1 and PALL2 were manufactured from solid wood strips alternating with either particleboard or blockboard strips glued edge to edge. Some of their physical and mechanical properties were investigated. All new panels made from recovered materials fell within allowable limits specified in European standard requirements for panel flatness. Panels type PL2, PALL1 and PALL2 show better values for MoR and MoE parallel to the grain when compared to the respective values for the recovered wood-based materials of which they are made, but panels type PL1 show no change. Panels type PALL2 are preferable to panels type PALL1 due to better mechanical properties. Panels type PL1 and PL2 show no such differences in their structure. The results also show that these new panels can be used successfully in furniture production, provided panels type PL1, PL2 ad PALL1 do not bear loads perpendicular to the grain or receive reinforcing elements.

  6. Using performance-based regulation to reduce childhood obesity.

    Science.gov (United States)

    Sugarman, Stephen D; Sandman, Nirit

    2008-11-18

    Worldwide, the public health community has recognized the growing problem of childhood obesity. But, unlike tobacco control policy, there is little evidence about what public policies would work to substantially reduce childhood obesity. Public health leaders currently tend to support traditional "command and control" schemes that order private enterprises and governments to stop or start doing specific things that, is it hoped, will yield lower childhood obesity rates. These include measures such as 1) taking sweetened beverages out of schools, 2) posting calorie counts on fast-food menu boards, 3) labeling foods with a "red light" if they contain high levels of fat or sugar, 4) limiting the density of fast food restaurants in any neighborhood, 5) requiring chain restaurants to offer "healthy" alternatives, and 6) eliminating junk food ads on television shows aimed at children. Some advocates propose other regulatory interventions such as 1) influencing the relative prices of healthy and unhealthy foods through taxes and/or subsidies and 2) suing private industry for money damages as a way of blaming childhood obesity on certain practices of the food industry (such as its marketing, product composition, or portion size decisions). The food industry generally seeks to deflect blame for childhood obesity onto others, such as parents and schools.

  7. Greedy Algorithms for Reduced Bases in Banach Spaces

    KAUST Repository

    DeVore, Ronald

    2013-02-26

    Given a Banach space X and one of its compact sets F, we consider the problem of finding a good n-dimensional space X n⊂X which can be used to approximate the elements of F. The best possible error we can achieve for such an approximation is given by the Kolmogorov width dn(F)X. However, finding the space which gives this performance is typically numerically intractable. Recently, a new greedy strategy for obtaining good spaces was given in the context of the reduced basis method for solving a parametric family of PDEs. The performance of this greedy algorithm was initially analyzed in Buffa et al. (Modél. Math. Anal. Numér. 46:595-603, 2012) in the case X=H is a Hilbert space. The results of Buffa et al. (Modél. Math. Anal. Numér. 46:595-603, 2012) were significantly improved upon in Binev et al. (SIAM J. Math. Anal. 43:1457-1472, 2011). The purpose of the present paper is to give a new analysis of the performance of such greedy algorithms. Our analysis not only gives improved results for the Hilbert space case but can also be applied to the same greedy procedure in general Banach spaces. © 2013 Springer Science+Business Media New York.

  8. Vanadium dioxide - Reduced graphene oxide composite as cathode materials for rechargeable Li and Na batteries

    Science.gov (United States)

    Mahadi, Nurulhuda Binti; Park, Jae-Sang; Park, Jae-Ho; Chung, Kyung Yoon; Yi, Su Youl; Sun, Yang-Kook; Myung, Seung-Taek

    2016-09-01

    In this study, a metastable form of vanadium dioxide, denoted as VO2(B), has been successfully synthesized under solvothermal condition. However, the as-received VO2(B) suffers from fast capacity fading and poor high-rate performance. In order to overcome these problems, the as-received VO2(B) is solvothermally treated with reduced graphene oxide (rGO) to produce VO2(B)/rGO composite. As a result, the resulting electric conductivity of the VO2(B)/rGO composite is improved to ∼10-4 cm S-1 (from ∼10-7 S cm-1 for the as-received VO2(B)). Electrochemical data of the VO2(B)/rGO composite, tested in both Li and Na cells, shows markedly enhanced electrochemical performance compared to bare VO2(B). The effect of electro-conducting rGO is more evident at high rates.

  9. Electric Double-layer Capacitor Based on Activated Carbon Material

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this study electric double-layer capacitors (EDLCs) based on activated carbon material and organic electrolyte (tetraethyl ammonium tetrafluoroborate) were explored. The fabrication method for EDLC is presented and the performance of EDLC was examined by using the cyclic voltammetry, constant-current charging and discharging technique, electrochemical impedance spectroscopy measurements. Influence of various components and design parameters on the performance of the capacitors were preliminarily investigated. Up to now, EDLC based on carbon materials can deliver 20.7 W/kg at the discharge rate ofI=0.3 mA, together with the energy density of 8.5 Wh/kg. Equivalent series resistance (ESR) is 0.716 Ω.cm2. The specific power of the capacitor is low and further attempts to raise the power capability of the capacitors are necessary. Some considerations are put forward to further improve the performance of EDLC.

  10. Energy based model for temperature dependent behavior of ferromagnetic materials

    Science.gov (United States)

    Sah, Sanjay; Atulasimha, Jayasimha

    2017-03-01

    An energy based model for temperature dependent anhysteretic magnetization curves of ferromagnetic materials is proposed and benchmarked against experimental data. This is based on the calculation of macroscopic magnetic properties by performing an energy weighted average over all possible orientations of the magnetization vector. Most prior approaches that employ this method are unable to independently account for the effect of both inhomogeneity and temperature in performing the averaging necessary to model experimental data. Here we propose a way to account for both effects simultaneously and benchmark the model against experimental data from 5 K to 300 K for two different materials in both annealed (fewer inhomogeneities) and deformed (more inhomogeneities) samples. This demonstrates that this framework is well suited to simulate temperature dependent experimental magnetic behavior.

  11. High-Pressure Design of Advanced BN-Based Materials

    Directory of Open Access Journals (Sweden)

    Oleksandr O. Kurakevych

    2016-10-01

    Full Text Available The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN with hardness comparable to diamond, and superhard boron subnitride B13N2. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc. are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure–temperature conditions are considered.

  12. High-Pressure Design of Advanced BN-Based Materials.

    Science.gov (United States)

    Kurakevych, Oleksandr O; Solozhenko, Vladimir L

    2016-10-20

    The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN) with hardness comparable to diamond, and superhard boron subnitride B13N₂. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc.) are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure-temperature conditions are considered.

  13. Investigation on the application of steel slag-fly ash-phosphogypsum solidified material as road base material.

    Science.gov (United States)

    Shen, Weiguo; Zhou, Mingkai; Ma, Wei; Hu, Jinqiang; Cai, Zhi

    2009-05-15

    The aim of the present work is to prepare a new type of steel slag-fly ash-phosphogypsum solidified material totally composed with solid wastes to be utilized as road base material. The mix formula of this material was optimized, the solidified material with optimal mix formula (fly ash/steel slag=1:1, phosphogypsum dosage=2.5%) results in highest strength. The strength development, resilience modulus and splitting strength of this material were studied comparing with some typical road base materials, the 28- and 360-day strength of this material can reach 8MPa and 12MPa, respectively, its resilience modulus reaches 1987MPa and splitting strength reaches 0.82MPa, it has higher early strength than lime-fly ash and lime-soil road base material, its long-term strength is much higher than cement stabilized granular materials, the solidified material has best water stability among those road base materials, it can be engineered as road base material with competitive properties. The strength formation mechanism of this solidified material is discussed also.

  14. Properties of silorane-based dental resins and composites containing a stress-reducing monomer.

    Science.gov (United States)

    Eick, J David; Kotha, Shiva P; Chappelow, Cecil C; Kilway, Kathleen V; Giese, Gregory J; Glaros, Alan G; Pinzino, Charles S

    2007-08-01

    To evaluate properties of silorane-based resins and composites containing a stress reducing monomer. Resin mixtures and composites were formulated containing (a) a developmental stress reducing monomer [TOSU; Midwest Research Institute]; (b) Sil-Mix (3M-ESPE); (c) photo cationic initiator system. Standard BISGMA/TEGDMA resin (B/T) and composite (Filtek Z250) were used as controls. Polymerization volume change was measured using a NIST mercury dilatometer and polymerization stress using an Enduratec mechanical testing machine. Three point bend tests determined flexural elastic modulus, work of fracture, and ultimate strength (ADA 27; ISO 4049). Fracture toughness was measured using ASTM E399-90. Four groups of resins and composites were tested: Sil-Mix, methacrylate standard, and Sil-Mix with two addition levels of TOSU. An ANOVA was used and significant differences ranked using Student-Newman-Keuls test (alpha=0.05). Polymerization stress values for resins containing TOSU were significantly less than the other materials. Polymerization shrinkage values for Sil-Mix formulations were significantly less than for B/T, but were not different from each other. TOSU-containing formulations generally had somewhat lower mechanical properties values than Sil-Mix or B/T. Polymerization stress values for Sil-Mix-based composites were significantly less as compared to Z250. The 1wt.% TOSU composite had the lowest stress. No difference between composite groups was noted for fracture toughness or work of fracture. For ultimate strength, the 5wt.% TOSU formulation differed significantly from Z250. All Sil-Mix formulations had elastic modulus values significantly different from Z250. The ability of TOSU to reduce polymerization stress without a proportional reduction in mechanical properties provides a basis for improvement of silorane-based composites.

  15. A team-based approach to reducing cardiac monitor alarms.

    Science.gov (United States)

    Dandoy, Christopher E; Davies, Stella M; Flesch, Laura; Hayward, Melissa; Koons, Connie; Coleman, Kristen; Jacobs, Jodi; McKenna, Lori Ann; Olomajeye, Alero; Olson, Chad; Powers, Jessica; Shoemaker, Kimberly; Jodele, Sonata; Alessandrini, Evaline; Weiss, Brian

    2014-12-01

    Excessive cardiac monitor alarms lead to desensitization and alarm fatigue. We created and implemented a standardized cardiac monitor care process (CMCP) on a 24-bed pediatric bone marrow transplant unit. The aim of this project was to decrease monitor alarms through the use of team-based standardized care and processes. Using small tests of change, we developed and implemented a standardized CMCP that included: (1) a process for initial ordering of monitor parameters based on age-appropriate standards; (2) pain-free daily replacement of electrodes; (3) daily individualized assessment of cardiac monitor parameters; and (4) a reliable method for appropriate discontinuation of monitor. The Model for Improvement was used to design, test, and implement changes. The changes that were implemented after testing and adaptation were: family/patient engagement in the CMCP; creation of a monitor care log to address parameters, lead changes, and discontinuation; development of a pain-free process for electrode removal; and customized monitor delay and customized threshold parameters. From January to November 2013, percent compliance with each of the 4 components of the CMCP increased. Overall compliance with the CMCP increased from a median of 38% to 95%. During this time, the median number of alarms per patient-day decreased from 180 to 40. Implementation of the standardized CMCP resulted in a significant decrease in cardiac monitor alarms per patient day. We recommend a team-based approach to monitor care, including individualized assessment of monitor parameters, daily lead change, and proper discontinuation of the monitors. Copyright © 2014 by the American Academy of Pediatrics.

  16. Modelling Inter-Particle Forces and Resulting Agglomerate Sizes in Cement-Based Materials

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica

    2005-01-01

    The theory of inter-particle forces versus external shear in cement-based materials is reviewed. On this basis, calculations on maximum agglomerate size present after the combined action of superplasticizers and shear are carried out. Qualitative experimental results indicate that external shear...... affects the particle size distribution of Mg(OH)2 (used as model material) as well as silica, whereas the addition of superplasticizers affects only the smallest particles in cement and thus primarily acts as water reducers and not dispersers....

  17. Reducing Inconsistent Rules Based on Irregular Decision Table

    Institute of Scientific and Technical Information of China (English)

    兰轶东; 张霖; 刘连臣

    2004-01-01

    In this paper, we study the problem of rule extraction from data sets using the rough set method. For inconsistent rules due to improper selection of split-points during discretization, and/or to lack of information, we propose two methods to remove their inconsistency based on irregular decision tables.By using these methods, inconsistent rules are eliminated as far as possible, without affecting the remaining consistent rules. Experimental test indicates that use of the new method leads to an improvement in the mean accuracy of the extracted rules.

  18. SPH-based simulation of multi-material asteroid collisions

    CERN Document Server

    Maindl, Thomas I; Speith, Roland; Süli, Áron; Forgács-Dajka, Emese; Dvorak, Rudolf

    2013-01-01

    We give a brief introduction to smoothed particle hydrodynamics methods for continuum mechanics. Specifically, we present our 3D SPH code to simulate and analyze collisions of asteroids consisting of two types of material: basaltic rock and ice. We consider effects like brittle failure, fragmentation, and merging in different impact scenarios. After validating our code against previously published results we present first collision results based on measured values for the Weibull flaw distribution parameters of basalt.

  19. Theory based design and optimization of materials for spintronics applications

    Science.gov (United States)

    Xu, Tianyi

    The Spintronics industry has developed rapidly in the past decade. Finding the right material is very important for Spintronics applications, which requires good understanding of the physics behind specific phenomena. In this dissertation, we will focus on two types of perpendicular transport phenomena, the current-perpendicular-to-plane giant-magneto-resistance (CPP-GMR) phenomenon and the tunneling phenomenon in the magnetic tunnel junctions. The Valet-Fert model is a very useful semi-classical approach for understanding the transport and spin-flip process in CPP-GMR. We will present a finite element based implementation for the Valet-Fert model which enables a practical way to calculate the electron transport in real CPP-GMR spin valves. It is very important to find high spin polarized materials for CPP-GMR spin valves. The half-metal, due to its full spin polarization, is of interest. We will propose a rational way to find half-metals based on the gap theorem. Then we will focus on the high-MR TMR phenomenon. The tunneling theory of electron transport in mesoscopic systems will be covered. Then we will calculate the transport properties of certain junctions with the help of Green's function under the Landauer-Buttiker formalism, also known as the scattering formalism. The damping constant determines the switching rate of a device. We can calculate it using a method based on the Extended Huckel Tight-Binding theory (EHTB). The symmetry filtering effect is very helpful for finding materials for TMR junctions. Based upon which, we find a good candidate material, MnAl, for TMR applications.

  20. Memory devices based on organic electric bistable materials

    Institute of Scientific and Technical Information of China (English)

    CHEN Qi; BAI Hua; SHI GaoQuan

    2007-01-01

    Organic/metallic composites have demonstrated electrical bistability, as well as memory effects. These advanced materials have shown potential applications in digital information storage because of their good stability, flexibility and fast response speed. The electric bistability phenomenon can be explained by electric field-induced electron transfer/storage. This article reviews the recent progress of memory devices based on organic/metallic and polymeric composites with electric bistability.

  1. Initial chemical transport of reducing elements and chemical reactions in oxide cathode base metal

    Energy Technology Data Exchange (ETDEWEB)

    Roquais, J.M.; Poret, F.; Doze, R. le; Dufour, P.; Steinbrunn, A

    2002-11-30

    In the present work, the formation of compounds associated to the diffusion of reducing elements (Mg and Al) to the nickel surface of a one-piece oxide cathode has been studied. Those compounds have been evidenced after the annealing steps at high temperature performed on cathode base metal prior to the emitting ing deposition. Therefore, they form the ''initial'' interface between the nickel and the coating, in other words, the interface existing at the beginning of cathode life. Extensive analysis to characterize the nickel base prior to coating deposition has been performed by means of scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and glow discharge optical emission spectroscopy (GDOES). TEM and AES analysis have allowed to identify for the first time a spinel compound of MgAl{sub 2}O{sub 4}. The preferential distribution of the different compounds on the nickel surface has been studied by EDX mapping. Experimental profiles of diffusion of the reducing elements in the nickel have been obtained over the entire thickness of the material by GDOES. The mechanism of formation of these compounds together with a related diffusion model are proposed.

  2. Flagging clinical adverse experiences: reducing false discoveries without materially compromising power for detecting true signals.

    Science.gov (United States)

    Mehrotra, Devan V; Adewale, Adeniyi J

    2012-08-15

    Comparative analyses of safety/tolerability data from a typical phase III randomized clinical trial generate multiple p-values associated with adverse experiences (AEs) across several body systems. A common approach is to 'flag' any AE with a p-value less than or equal to 0.05, ignoring the multiplicity problem. Despite the fact that this approach can result in excessive false discoveries (false positives), many researchers avoid a multiplicity adjustment to curtail the risk of missing true safety signals. We propose a new flagging mechanism that significantly lowers the false discovery rate (FDR) without materially compromising the power for detecting true signals, relative to the common no-adjustment approach. Our simple two-step procedure is an enhancement of the Mehrotra-Heyse-Tukey approach that leverages the natural grouping of AEs by body systems. We use simulations to show that, on the basis of FDR and power, our procedure is an attractive alternative to the following: (i) the no-adjustment approach; (ii) a one-step FDR approach that ignores the grouping of AEs by body systems; and (iii) a recently proposed two-step FDR approach for much larger-scale settings such as genome-wide association studies. We use three clinical trial examples for illustration.

  3. Propranolol Reduces Cancer Risk: A Population-Based Cohort Study.

    Science.gov (United States)

    Chang, Ping-Ying; Huang, Wen-Yen; Lin, Cheng-Li; Huang, Tzu-Chuan; Wu, Yi-Ying; Chen, Jia-Hong; Kao, Chia-Hung

    2015-07-01

    β-Blockers have been reported to exhibit potential anticancer effects in cancer cell lines and animal models. However, clinical studies have yielded inconsistent results regarding cancer outcomes and cancer risk when β-blockers were used. This study investigated the association between propranolol and cancer risk.Between January 1, 2000 and December 31, 2011, a patient cohort was extracted from the Longitudinal Health Insurance Database 2000, a subset of the Taiwan National Health Insurance Research Database. A propranolol cohort (propranolol usage >6 months) and nonpropranolol cohort were matched using a propensity score. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% confidence intervals (CIs) of cancer associated with propranolol treatment.The study sample comprised 24,238 patients. After a 12-year follow-up period, the cumulative incidence for developing cancer was low in the propranolol cohort (HR: 0.75; 95% CI: 0.67-0.85; P propranolol treatment exhibited significantly lower risks of cancers in head and neck (HR: 0.58; 95% CI: 0.35-0.95), esophagus (HR: 0.35; 95% CI: 0.13-0.96), stomach (HR: 0.54; 95% CI: 0.30-0.98), colon (HR: 0.68; 95% CI: 0.49-0.93), and prostate cancers (HR: 0.52; 95% CI: 0.33-0.83). The protective effect of propranolol for head and neck, stomach, colon, and prostate cancers was most substantial when exposure duration exceeded 1000 days.This study supports the proposition that propranolol can reduce the risk of head and neck, esophagus, stomach, colon, and prostate cancers. Further prospective study is necessary to confirm these findings.

  4. Reducing the temperature sensitivity of SOI waveguide-based biosensors

    Science.gov (United States)

    Gylfason, Kristinn B.; Mola Romero, Albert; Sohlström, Hans

    2012-06-01

    Label-free photonic biosensors fabricated on silicon-on-insulator (SOI) can provide compact size, high evanescent field strength at the silicon waveguide surface, and volume fabrication potential. However, due to the large thermo optic coefficient of water-based biosamples, the sensors are temperature-sensitive. Consequently, active temperature control is usually used. However, for low cost applications, active temperature control is often not feasible. Here, we use the opposite polarity of the thermo-optic coefficients of silicon and water to demonstrate a photonic slot waveguide with a distribution of power between sample and silicon that aims to give athermal operation in water. Based on simulations, we made three waveguide designs close to the athermal point, and asymmetric integrated Mach- Zehnder interferometers for their characterization. The devices were fabricated on SOI with a 220 nm device layer and 2 μm buried oxide, by electron beam lithography of hydrogen silsesquioxane (HSQ) resist, and etching in a Cl2/HBr/O2/He plasma. With Cargile 50350 fused silica matching oil as top cladding, the group index of the three guides varies from 1.9 to 2.8 at 1550 nm. The temperature sensitivity of the devices varied from -70 to -160 pm/K under the same conditions. A temperature sensitivity of -2 pm/K is projected with water as top cladding.

  5. An Analysis Of The Industrial Forging Process Of Flange In Order To Reduce The Weight Of The Input Material

    Directory of Open Access Journals (Sweden)

    Gronostajski Z.

    2015-06-01

    Full Text Available This paper presents an analysis of the industrial process of hot forging a flange. The authors developed several thermomechanical models of the forging process for which they carried out computer simulations using the MSC.Marc 2013 software. In the Jawor Forge flanges with a neck are manufactured by hot forging in crank presses with a maximum load of 25 MN. The input material, in the form of a square bar, is heated up to a temperature of 1150°C and then formed in three operations: upsetting, preliminary die forging and finishing die forging. The main aim of the studies and the numerical analyses, in which the geometry of the tools would be modified, was to maximally reduce the amount of the input material taking into account the capabilities of the Jawor Forge, and consequently to significantly reduce the production costs. Besides the Forge’s equipment resources, the main constraint for modifications was the flange-with-neck forging standard which explicitely defines the tolerances for this element. The studies, which included numerical modelling, infrared measurements and technological tests, consisted in changing the geometry of the tools and that of the forging preform. As a result, the optimum direction for modifications aimed at reducing the mass of the input material was determined. The best of the solutions, making it possible to produce a correct forging in the Jawor Forge operating conditions, were adopted whereby the weight of the preform was reduced by 6.11%. Currently research is underway aimed at the application of the proposed and verified modifications to other flange forgings.

  6. Industrial Preparation of Bauxite-based Mullite Raw Material

    Institute of Scientific and Technical Information of China (English)

    YANG Zhongzheng; DING Baohua

    2008-01-01

    Bauxite-based mullite grogs were prepared with grade II bauxite(≤3mm)and coal gangue(≤3mm)as starting materials with formula of w(Al2O3)=68%~72%.Mill the mixture to particle size≤0.044mm by wet milling to homogenize chemical composition. After shaping by wet extrusion and drying, the materials were fired at 1550℃, 1600℃ and 1700℃ for 6 hours respectively. After cooling apparent porosity and bulk density of fired materials were tested. The results show as follows: the appropriate sintering temperature for bauxite-based mullite with homogeneous and consistent composition and microstructure and properties is 1600℃,at which the mullite has apparent porosity≤1.5%,bulk density≥2.81g·cm-3and refractoriness under load is 1610-1650℃.Compared with the laboratory results, the sintering temperature is lowered about 100℃,bulk density increased 0.06g?cm-3.The industrial feasibility of preparing bauxite-based mullite grogs with the processing is confirmed.

  7. Risk-Based Pricing and Risk-Reducing Effort: Does the Private Insurance Market Reduce Environmental Accidents?

    OpenAIRE

    Haitao Yin; Howard Kunreuther; Matthew White

    2009-01-01

    This paper examines whether risk-based pricing promotes risk-reducing effort. Such mechanisms are common in private insurance markets, but are rarely incorporated in government assurance programs. We analyze accidental underground fuel tank leaks--a source of environmental damage to water supplies--over a fourteen-year period, using disaggregate (facility-level) data and policy variation in financing the cleanup of tank leaks over time. The data suggest that eliminating a state-level governme...

  8. Phase I. Lanthanum-based Start Materials for Hydride Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gschneidner, K. A. [Ames Lab., Ames, IA (United States); Schmidt, F. A. [Ames Lab., Ames, IA (United States); Frerichs, A. E. [Ames Lab., Ames, IA (United States); Ament, K. A. [Ames Lab., Ames, IA (United States)

    2013-08-20

    The purpose of Phase I of this work is to focus on developing a La-based start material for making nickel-metal (lanthanum)-hydride batteries based on our carbothermic-silicon process. The goal is to develop a protocol for the manufacture of (La1-xRx)(Ni1-yMy)(Siz), where R is a rare earth metal and M is a non-rare earth metal, to be utilized as the negative electrode in nickel-metal hydride (NiMH) rechargeable batteries.

  9. Comparison of Candida Albicans Adherence to Conventional Acrylic Denture Base Materials and Injection Molding Acrylic Materials

    Directory of Open Access Journals (Sweden)

    Masoomeh Aslanimehr

    2017-03-01

    Full Text Available Statement of the Problem: Candida species are believed to play an important role in initiation and progression of denture stomatitis. The type of the denture material also influences the adhesion of candida and development of stomatitis. Purpose: The aim of this study was comparing the adherence of candida albicans to the conventional and injection molding acrylic denture base materials. Materials and Method: Twenty injection molding and 20 conventional pressure pack acrylic discs (10×10×2 mm were prepared according to their manufacturer’s instructions. Immediately before the study, samples were placed in sterile water for 3 days to remove residual monomers. The samples were then sterilized using an ultraviolet light unit for 10 minutes. 1×108 Cfu/ml suspension of candida albicans ATCC-10231 was prepared from 48 h cultured organism on sabouraud dextrose agar plates incubated at 37oC. 100 μL of this suspension was placed on the surface of each disk. After being incubated at 37oC for 1 hour, the samples were washed with normal saline to remove non-adherent cells. Attached cells were counted using the colony count method after shaking at 3000 rmp for 20 seconds. Finally, each group was tested for 108 times and the data were statistically analyzed by t-test. Results: Quantitative analysis revealed that differences in colony count average of candida albicans adherence to conventional acrylic materials (8.3×103 comparing to injection molding acrylic resins (6×103 were statistically significant (p<0.001. Conclusion: Significant reduction of candida albicans adherence to the injection acrylic resin materials makes them valuable for patients with high risk of denture stomatitis.

  10. Comparison of Candida Albicans Adherence to Conventional Acrylic Denture Base Materials and Injection Molding Acrylic Materials

    Science.gov (United States)

    Aslanimehr, Masoomeh; Rezvani, Shirin; Mahmoudi, Ali; Moosavi, Najmeh

    2017-01-01

    Statement of the Problem: Candida species are believed to play an important role in initiation and progression of denture stomatitis. The type of the denture material also influences the adhesion of candida and development of stomatitis. Purpose: The aim of this study was comparing the adherence of candida albicans to the conventional and injection molding acrylic denture base materials. Materials and Method: Twenty injection molding and 20 conventional pressure pack acrylic discs (10×10×2 mm) were prepared according to their manufacturer’s instructions. Immediately before the study, samples were placed in sterile water for 3 days to remove residual monomers. The samples were then sterilized using an ultraviolet light unit for 10 minutes. 1×108 Cfu/ml suspension of candida albicans ATCC-10231 was prepared from 48 h cultured organism on sabouraud dextrose agar plates incubated at 37oC. 100 μL of this suspension was placed on the surface of each disk. After being incubated at 37oC for 1 hour, the samples were washed with normal saline to remove non-adherent cells. Attached cells were counted using the colony count method after shaking at 3000 rmp for 20 seconds. Finally, each group was tested for 108 times and the data were statistically analyzed by t-test. Results: Quantitative analysis revealed that differences in colony count average of candida albicans adherence to conventional acrylic materials (8.3×103) comparing to injection molding acrylic resins (6×103) were statistically significant (pcandida albicans adherence to the injection acrylic resin materials makes them valuable for patients with high risk of denture stomatitis. PMID:28280761

  11. Potential contribution of materials investigations in reducing the risks of unavailability of nuclear civil engineering infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Goy, R.; Gaine, C.; Cornish-Bowden, I.; Auge, L.; Thillard, G.; Capra, B. [Oxand (France)

    2011-07-01

    Many consulting assignments undertaken by Oxand within the framework of life-cycle management of existing nuclear civil engineering structures, relied on taking into account the structure's level of deterioration, the quantitative estimate of its residual strength capacity and the future progression of this capacity over time. The developments of structure assessment techniques allow more and more the integration of the real state of the existing structure by enhancing the value of measures and investigations carried out on structures. On one hand, this information allows to take into account the structure's ageing and therefore estimate the residual resistance and reliability. On the other hand, by investigating the real properties of the structure and of its operation, refined calculations can sometimes highlight a resistance margin of the structure 'such as built' higher than the one considered during design. The precision on the 'real' reliability of the structure allows to refine its management and thus to optimize the infrastructure's performance. Developments of assessment methods are increasingly oriented toward probabilistic approaches. Although they go out of the 'classical regulatory' framework, they bring precision on the 'real' reliability of the structure. Using higher assessment levels needs to have more important and precise input data, what can lead to the need to carry out more detailed investigations. However, these methods offer interesting ways, which can provide, in certain cases, useful additional information for the decision-making of actions to be engaged. The methodology is illustrated with the case of a network of reinforced concrete beams, which are subjected to a rapid increase in their mechanical stresses. In particular this example shows that investigations on the real performances of materials can provided a significant contribution in managing the risks of unavailability

  12. Third-Party Cooperation: How Reducing Material Involvement Enhances Contributions to the Public Good.

    Science.gov (United States)

    Losecaat Vermeer, Annabel B; Heerema, Roeland L; Sanfey, Alan G

    2016-03-01

    Decisions to cooperate are often delegated to a third party. We examined whether cooperation differs when decisions are made for a third party compared with ourselves and specified which motives are important for third-party cooperation. Participants played multiple rounds of a public goods game (PGG). In Study 1, we varied personal involvement from high to low; participants played for themselves (Self), for themselves and a third party (Shared), and solely for a third party (Third Party). Participants contributed most when personal involvement was lowest (i.e., Third Party) and least when personal involvement was high (i.e., Self). Study 2 explored if social motives underlie third-party cooperation by comparing cooperation with social (human) and non-social (computer) group members. Reducing personal involvement in the PGG (i.e., Third Party) increased cooperation in social contexts compared with non-social contexts, indicating enhanced collective interest. Increased cooperation for a third party may result from taking the other's perspective, thereby increasing social norm preferences. © 2016 by the Society for Personality and Social Psychology, Inc.

  13. Hydrophilic Dogwood Extracts as Materials for Reducing the Skin Irritation Potential of Body Wash Cosmetics.

    Science.gov (United States)

    Nizioł-Łukaszewska, Zofia; Osika, Paweł; Wasilewski, Tomasz; Bujak, Tomasz

    2017-02-19

    A significant problem related to the use of surfactants in body wash cosmetics is their propensity to trigger skin irritations. Only scarce literature exists on the effect of plant extracts on the skin irritation potential. The present study is an attempt to determine the effect of hydrophilic dogwood extracts on the irritant potential of body wash gels. Extractants used in the study were water and mixtures of water with glycerine, water with trimethylglycine (betaine), and water with plant-derived glycol (propanediol). The basic biochemical properties, i.e., the ability to neutralize free radicals, and the content of polyphenols, anthocyanins and flavonoids, were determined. An attempt was undertaken to analyze the impact of the extract added to natural body wash gel formulations on product properties. The skin irritation potential was assessed by determining the zein number and the increase in the pH level of the bovine serum albumin (BSA) solution. The viscosity and foaming ability of the resulting products were evaluated. The studies revealed that an addition of dogwood extract contributes to an improvement in the properties of body wash gels and significantly increases the safety of product use through reducing the skin irritation effect.

  14. Hydrophilic Dogwood Extracts as Materials for Reducing the Skin Irritation Potential of Body Wash Cosmetics

    Directory of Open Access Journals (Sweden)

    Zofia Nizioł-Łukaszewska

    2017-02-01

    Full Text Available A significant problem related to the use of surfactants in body wash cosmetics is their propensity to trigger skin irritations. Only scarce literature exists on the effect of plant extracts on the skin irritation potential. The present study is an attempt to determine the effect of hydrophilic dogwood extracts on the irritant potential of body wash gels. Extractants used in the study were water and mixtures of water with glycerine, water with trimethylglycine (betaine, and water with plant-derived glycol (propanediol. The basic biochemical properties, i.e., the ability to neutralize free radicals, and the content of polyphenols, anthocyanins and flavonoids, were determined. An attempt was undertaken to analyze the impact of the extract added to natural body wash gel formulations on product properties. The skin irritation potential was assessed by determining the zein number and the increase in the pH level of the bovine serum albumin (BSA solution. The viscosity and foaming ability of the resulting products were evaluated. The studies revealed that an addition of dogwood extract contributes to an improvement in the properties of body wash gels and significantly increases the safety of product use through reducing the skin irritation effect.

  15. A new silver based composite material for SPA water disinfection.

    Science.gov (United States)

    Tartanson, M A; Soussan, L; Rivallin, M; Chis, C; Penaranda, D; Lapergue, R; Calmels, P; Faur, C

    2014-10-15

    A new composite material based on alumina (Al2O3) modified by two surface nanocoatings - titanium dioxide (TiO2) and silver (Ag) - was studied for spa water disinfection. Regarding the most common microorganisms in bathing waters, two non-pathogenic bacteria Escherichia coli (Gram-negative) and Staphylococcus epidermidis (Gram positive) were selected as surrogates for bacterial contamination. The bactericidal properties of the Al2O3-TiO2-Ag material were demonstrated under various operating conditions encountered in spa water (temperature: 22-37 °C, presence of salt: CaCO3 or CaCl2, high oxygen content, etc.). Total removal of 10(8) CFU mL(-1) of bacteria was obtained in less than 10 min with 16 g L(-1) of material. Best results were observed for both conditions: a temperature of 37 °C and under aerobic condition; this latest favouring Reactive Oxygen Species (ROS) generation. The CaCO3 salt had no impact on the bactericidal activity of the composite material and CaCl2 considerably stabilized the silver desorption from the material surface thanks to the formation of AgCl precipitate. Preliminary tests of the Al2O3-TiO2-Ag bactericidal behaviour in a continuous water flow confirmed that 2 g L(-1) of material eliminated more than 90% of a 2.0 × 10(8) CFU mL(-1) bacterial mixture after one water treatment recycle and reached the disinfection standard recommended by EPA (coliform removal = 6 log) within 22 h.

  16. Nanoporous Carbide-Derived Carbon Material-Based Linear Actuators

    Directory of Open Access Journals (Sweden)

    Janno Torop

    2009-12-01

    Full Text Available Devices using electroactive polymer-supported carbon material can be exploited as alternatives to conventional electromechanical actuators in applications where electromechanical actuators have some serious deficiencies. One of the numerous examples is precise microactuators. In this paper, we show for first time the dilatometric effect in nanocomposite material actuators containing carbide-derived carbon (CDC and polytetrafluoroetylene polymer (PTFE. Transducers based on high surface area carbide-derived carbon electrode materials are suitable for short range displacement applications, because of the proportional actuation response to the charge inserted, and high Coulombic efficiency due to the EDL capacitance. The material is capable of developing stresses in the range of tens of N cm-2. The area of an actuator can be dozens of cm2, which means that forces above 100 N are achievable. The actuation mechanism is based on the interactions between the high-surface carbon and the ions of the electrolyte. Electrochemical evaluations of the four different actuators with linear (longitudinal action response are described. The actuator electrodes were made from two types of nanoporous TiC-derived carbons with surface area (SA of 1150 m2 g-1 and 1470 m2 g-1, respectively. Two kinds of electrolytes were used in actuators: 1.0 M tetraethylammonium tetrafluoroborate (TEABF4 solution in propylene carbonate and pure ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf. It was found that CDC based actuators exhibit a linear movement of about 1% in the voltage range of 0.8 V to 3.0 V at DC. The actuators with EMITf electrolyte had about 70% larger movement compared to the specimen with TEABF4 electrolyte.

  17. Modification of clay-based waste containment materials

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K. [DuPont Central Research and Development, Newark, DE (United States); Whang, J.M. [DuPont Specialty Chemicals, Deepwater, NJ (United States); McDevitt, M.F. [DuPont Central Research and Development, Wilmington, DE (United States)

    1997-12-31

    Bentonite clays are used extensively for waste containment barriers to help impede the flow of water in the subsurface because of their low permeability characteristics. However, they do little to prevent diffusion of contaminants, which is the major transport mechanism at low water flows. A more effective way of minimizing contaminant migration in the subsurface is to modify the bentonite clay with highly sorptive materials. Batch sorption studies were conducted to evaluate the sorptive capabilities of organo-clays and humic- and iron-based materials. These materials proved to be effective sorbents for the organic contaminants 1,2,4-trichlorobenzene, nitrobenzene, and aniline in water, humic acid, and methanol solution media. The sorption capacities were several orders of magnitude greater than that of unmodified bentonite clay. Modeling results indicate that with small amounts of these materials used as additives in clay barriers, contaminant flux through walls could be kept very small for 100 years or more. The cost of such levels of additives can be small compared to overall construction costs.

  18. Cathodoluminescence Emission Studies for Selected Phosphor-Based Sensor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Goedeke, Shawn [ORNL; Hollerman, William Andrew [ORNL; Allison, Stephen W [ORNL; Gray, P A [Integrated Concepts and Research Corporation - Huntsville, AL; Lewis, Linda A [ORNL; Smithwick III, Robert W [ORNL; Boatner, Lynn A [ORNL; Glasgow, David C [ORNL; Ivanov, Ilia N [ORNL; Wise, H. [Integrated Concepts and Research Corporation - Huntsville, AL

    2005-01-01

    The current interest in returning to the Moon and Mars by 2030 makes cost effective and low mass health monitoring sensors essential for spacecraft development. In space, there are many surface measurements that are required to monitor the condition of the spacecraft including: surface temperature, radiation dose, and impact. Through the use of phosphors, these conditions can be monitored. Practical space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and the ability to anneal or self-heal from damage caused by ionizing radiation. The cathodoluminescence (CL) testing was performed using the low energy electron system located at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. For the materials tested, several interesting results were observed. For most materials, increases in both beam energy and current density improved the CL fluorescence yield. It was also noted that YAG:Nd,Ce has the greatest near infrared intensity for any of the tested materials. The evaluation of dopant concentration in YPO{sub 4}:Nd showed minimal differences in spectral shape and intensity. While the total electron dose was small, the intention was to maximize the number of irradiated materials.

  19. Advanced Materials Based on Polymers and Ionic Liquids.

    Science.gov (United States)

    Kitazawa, Yuzo; Ueno, Kazuhide; Watanabe, Masayoshi

    2017-09-19

    Ionic liquids (ILs) are ambient temperature molten salts, which have attracted considerable attention owing to their unique properties. In this contribution, we review advanced materials composed of ILs and polymers for the basis of a new design protocol to fabricate novel materials. As electrolytes for electrochemical devices, cross-linked polymers containing ILs (ion gels) are endowed with functional properties inherited from ILs and mechanical consistency derived from polymers. To create such materials, micro-phase separation of block copolymers and colloidal arrays in the ILs are utilized. Based on the molecular design of task-specific ILs, the resultant ion gels are applicable as electrolytes for actuator, fuel cell, and secondary battery applications. Thermo- and photo-responsive polymers in ILs are also highlighted, whereby such stimuli elicit changes in the solubility of the self-assembly of block copolymers and colloidal arrays in the ILs. Further, thermo- and photo-reversible changes in the self-assembled structure can be exploited to demonstrate sol-gel transitions and fabricate photo-healable materials. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Degradation of chitosan-based materials after different sterilization treatments

    Science.gov (United States)

    San Juan, A.; Montembault, A.; Gillet, D.; Say, J. P.; Rouif, S.; Bouet, T.; Royaud, I.; David, L.

    2012-02-01

    Biopolymers have received in recent years an increasing interest for their potential applications in the field of biomedical engineering. Among the natural polymers that have been experimented, chitosan is probably the most promising in view of its exceptional biological properties. Several techniques may be employed to sterilize chitosan-based materials. The aim of our study was to compare the effect of common sterilization treatments on the degradation of chitosan-based materials in various physical states: solutions, hydrogels and solid flakes. Four sterilization methods were compared: gamma irradiation, beta irradiation, exposure to ethylene oxide and saturated water steam sterilization (autoclaving). Exposure to gamma or beta irradiation was shown to induce an important degradation of chitosan, regardless of its physical state. The chemical structure of chitosan flakes was preserved after ethylene oxide sterilization, but this technique has a limited use for materials in the dry state. Saturated water steam sterilization of chitosan solutions led to an important depolymerization. Nevertheless, steam sterilization of chitosan flakes bagged or dispersed in water was found to preserve better the molecular weight of the polymer. Hence, the sterilization of chitosan flakes dispersed in water would represent an alternative step for the preparation of sterilized chitosan solutions. Alternatively, autoclaving chitosan physical hydrogels did not significantly modify the macromolecular structure of the polymer. Thus, this method is one of the most convenient procedures for the sterilization of physical chitosan hydrogels after their preparation.

  1. DEVELOPING ISLAMIC ENGLISH INSTRUCTIONAL MATERIALS BASED ON SCHOOL-BASED CURRICULUM

    Directory of Open Access Journals (Sweden)

    Zaitun Qamariah

    2015-09-01

    Full Text Available This study was a research and development (R&D which is basically aimed at developing English instructional materials based on School-based Curriculum for the first-year students of MAN Model Palangka Raya. This study involved: need analysis, reference study, material development, expert validation, try out (empirical validation, and revision. The data were gathered through observation, questionnaires, interview, and validation technique.  The result of the need analysis shows that the students are in need of English instructional materials relevant to their major content needs and school characteristics. However, the existing English instructional materials used by the teachers and the first-grade students of MAN Model Palangka Raya as a senior high school with Islamic feature still served from available published course books which are too general and still do not reflect the need of the students and particular characteristics of the school. English instructional materials developed in this study is intended to develop English instructional materials which could provide a set of instructional materials to accomodate the Islamic characteristics and the needs of the first-year students of MAN Model Palangka Raya. For the purpose, the materials were adopted and adapted from some Islamic textbooks and Islamic reading websites. Keywords: research and development, Islamic English instructional material, school-based curriculum

  2. Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

    Directory of Open Access Journals (Sweden)

    Emmanuel Joao Nogueira Leal SILVA

    2014-01-01

    Full Text Available A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications. Objectives: The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA. Material and Methods: Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212, Staphylococcus aureus. (ATCC 25923 and Candida albicans (ATCC 10556 was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey`s test with a significance level of 5%. Results: EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>.05. All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (P.05. Conclusion: Under these experimental conditions, we concluded that the calcium aluminate-based endodontic material EndoBinder demonstrated suitable biological and physicochemical properties, so it can be suggested as a material of choice in root resorption, perforations and root-end filling.

  3. Safety issues of tooth whitening using peroxide-based materials.

    Science.gov (United States)

    Li, Y; Greenwall, L

    2013-07-01

    In-office tooth whitening using hydrogen peroxide (H₂O₂) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H₂O₂, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

  4. Recent Advances in Conjugated Polymer-Based Microwave Absorbing Materials

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2017-01-01

    Full Text Available Microwave absorbing materials (MAMs are paving the way for exciting applications in electromagnetic (EM pollution precaution and national defense security, as they offer an advanced alternative to conventional reflection principles to fundamentally eliminate the EM waves. Conjugated polymer (CP-based composites appear as a promising kind of MAM with the desirable features of low density and high performance. In this review, we introduce the theory of microwave absorption and summarize recent advances in the fabrication of CP-based MAMs, including rational design of the microstructure of pure conjugated polymers and tunable chemical integration with magnetic ferrites, magnetic metals, transition metal oxides, and carbon materials. The key point of enhancing microwave absorption in CP-based MAMs is to regulate their EM properties, improve matching of characteristic impedance, and create diversified loss mechanisms. The examples presented in this review will provide new insights into the design and preparation of CP-based composites that can satisfy the high demands of the oncoming generation of MAMs.

  5. Development of foamed Inorganic Polymeric Materials based on Perlite

    Science.gov (United States)

    Tsaousi, G.-M.; Douni, I.; Taxiarchou, M.; Panias, D.; Paspaliaris, I.

    2016-04-01

    This work deals with the development of lightweight geopolymeric boards for use in construction sector utilizing a solid perlitic waste as the main raw material. Hydrogen peroxide (H2O2) was used for the foaming of geopolymeric pastes and the production of porous and lightweight inorganic polymeric materials. The effect of geopolymeric synthesis parameters, such as the composition of activator and the curing conditions, on paste's properties that affect the foaming process, such as setting time and viscosity, were studied in detailed. Finally, the effects of H2O2 concentration on the properties (apparent density and % cell volume) and the microstructure of foamed boards were also studied. The produced porous boards have effective densities in-between 540 - 900 Kg/m3 and the thermal conductivity of the optimum product is 0.08 W/mK. Based on their properties, the developed lightweight geopolymeric boards have high potential to be used as building elements in construction industry.

  6. Design of biomimetic camouflage materials based on angiosperm leaf organs

    Institute of Scientific and Technical Information of China (English)

    LIU ZhiMing; WU WenJian; HU BiRu

    2008-01-01

    The micro structures and reflectance spectra of angiosperm leaves were compared with those of angiosperm petals. The study indicated that angiosperm leaf organs had identical micro structures and reflectance characteristics in the wave band of near infrared. Micro structures and compositions of leaf organs were the crucial factors influencing their reflectance spectra. The model of biomimetic materials based on angiosperm leaf organs was introduced and verified. From 300 to 2600 nm, the similarity coefficients of reflectance spectra of the foam containing water and Platanus Orientalis Linn. leaves were all above 0.969. The biomimetic camou-flage material exhibited almost the same reflectance spectra with those of green leaves in ultraviolet, visible and near infrared wave bands, And its "concolor and conspectrum" effect might take on reconnaissance of hyperspectral and ultra hyperspectral imaging.

  7. Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators.

    Science.gov (United States)

    Reichmann, Klaus; Feteira, Antonio; Li, Ming

    2015-12-04

    The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.

  8. Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Klaus Reichmann

    2015-12-01

    Full Text Available The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.

  9. Nanocelluloses: a new family of nature-based materials.

    Science.gov (United States)

    Klemm, Dieter; Kramer, Friederike; Moritz, Sebastian; Lindström, Tom; Ankerfors, Mikael; Gray, Derek; Dorris, Annie

    2011-06-06

    Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Design of biomimetic camouflage materials based on angiosperm leaf organs

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The micro structures and reflectance spectra of angiosperm leaves were compared with those of angiosperm petals. The study indicated that angiosperm leaf organs had identical micro structures and reflectance characteristics in the wave band of near infrared. Micro structures and compositions of leaf organs were the crucial factors influencing their reflectance spectra. The model of biomimetic materials based on angiosperm leaf organs was introduced and verified. From 300 to 2600 nm, the similarity coefficients of reflectance spectra of the foam containing water and Platanus Orientalis Linn. leaves were all above 0.969. The biomimetic camou- flage material exhibited almost the same reflectance spectra with those of green leaves in ultraviolet, visible and near infrared wave bands. And its "concolor and conspectrum" effect might take on reconnaissance of hyperspectral and ultra hy- perspectral imaging.

  11. Towards Flexible Transparent Electrodes Based on Carbon and Metallic Materials

    Directory of Open Access Journals (Sweden)

    Minghui Luo

    2017-01-01

    Full Text Available Flexible transparent electrodes (FTEs with high stability and scalability are in high demand for the extremely widespread applications in flexible optoelectronic devices. Traditionally, thin films of indium thin oxide (ITO served the role of FTEs, but film brittleness and scarcity of materials limit its further application. This review provides a summary of recent advances in emerging transparent electrodes and related flexible devices (e.g., touch panels, organic light-emitting diodes, sensors, supercapacitors, and solar cells. Mainly focusing on the FTEs based on carbon nanomaterials (e.g., carbon nanotubes and graphene and metal materials (e.g., metal grid and metal nanowires, we discuss the fabrication techniques, the performance improvement, and the representative applications of these highly transparent and flexible electrodes. Finally, the challenges and prospects of flexible transparent electrodes will be summarized.

  12. Mesoporous Carbon-based Materials for Alternative Energy Applications

    Science.gov (United States)

    Cross, Kimberly Michelle

    Increasing concerns for the escalating issues activated by the effect of carbon dioxide emissions on the global climate from extensive use of fossil fuels and the limited amount of fossil resources has led to an in-depth search for alternative energy systems, primarily based on nuclear or renewable energy sources. Recent innovations in the production of more efficient devices for energy harvesting, storage, and conversion are based on the incorporation of nanostructured materials into electrochemical systems. The aforementioned nano-electrochemical energy systems hold particular promise for alternative energy transportation related technologies including fuel cells, hydrogen storage, and electrochemical supercapacitors. In each of these devices, nanostructured materials can be used to increase the surface area where the critical chemical reactions occur within the same volume and mass, thereby increasing the energy density, power density, electrical efficiency, and physical robustness of the system. Durable corrosion resistant carbon support materials for fuel cells have been designed by adding conductive low cost carbon materials with chemically robust ceramic materials. Since a strict control of the pore size is mandatory to optimize properties for improved performance, chemical activation agents have been utilized as porogens to tune surface areas, pore size distributions, and composition of carbon-based mesoporous materials. Through the use of evaporative self-assembly methods, both randomly disordered and surfactant-templated, ordered carbon-silica nanocomposites have been synthesized with controlled surface area, pore volume, and pore size ranging from 50-800 m2/g, 0.025-0.75 cm3/g, and 2-10 nm, respectively. Multi-walled carbon nanotubes (MWNTs) ranging from 0.05-1.0 wt. % were added to the aforementioned carbon-silica nanocomposites, which provided an additional increase in surface area and improved conductivity. Initially, a conductivity value of 0.0667 S

  13. Factors affecting the bond strength of denture base and reline acrylic resins to base metal materials

    Directory of Open Access Journals (Sweden)

    Naomi Tanoue

    2013-07-01

    Full Text Available OBJECTIVE: The shear bond strengths of two hard chairside reline resin materials and an auto-polymerizing denture base resin material to cast Ti and a Co-Cr alloy treated using four conditioning methods were investigated. MATERIAL AND METHODS: Disk specimens (diameter 10 mm and thickness 2.5 mm were cast from pure Ti and Co-Cr alloy. The specimens were wet-ground to a final surface finish of 600 grit, air-dried, and treated with the following bonding systems: 1 air-abraded with 50-70-µm grain alumina (CON; 2 1 + conditioned with a primer, including an acidic phosphonoacetate monomer (MHPA; 3 1 + conditioned with a primer including a diphosphate monomer (MDP; 4 treated with a tribochemical system. Three resin materials were applied to each metal specimen. Shear bond strengths were determined before and after 10,000 thermocycles. RESULTS: The strengths decreased after thermocycling for all combinations. Among the resin materials assessed, the denture base material showed significantly (p<0.05 greater shear bond strengths than the two reline materials, except for the CON condition. After 10,000 thermocycles, the bond strengths of two reline materials decreased to less than 10 MPa for both metals. The bond strengths of the denture base material with MDP were sufficient: 34.56 MPa for cast Ti and 38.30 for Co-Cr alloy. CONCLUSION: Bonding of reline resin materials to metals assessed was clinically insufficient, regardless of metal type, surface treatment, and resin composition. For the relining of metal denture frameworks, a denture base material should be used.

  14. New absorbent material acoustic based on kenaf’s fibre

    Directory of Open Access Journals (Sweden)

    Ramis, J.

    2010-09-01

    Full Text Available Acoustic Standards in the building are responsible for, companies and individuals, propose new acoustic materials for the sound isolation. This paper presents a new sound-absorbent material, it is based on natural fibres, particularly fibres of kenaf. It also proposes an empirical model for this material, this models depends on the frequency. There are accepted models from the scientific community about mineral wool, glass wool, rock wool, foam or polyester fibre. Several of these models are empirical. They are obtained from the equation adjustments about the acoustic impedance and propagation constant behaviour, depending upon the flow resistivity, fibre’s diameter and density. There are even standards like UNE-EN 12354-6 where these models are accepted under certain limitations like the fundamental basis as in the materials’ acoustics behaviour prediction. From the various tests conducted in the laboratory, empirical equations are proposed for this new acoustic material. In addition, there has been a first approach to validate this model in combination with a micro-structural model, based on the steps taken by Bies-Hansen (1, which allows us to obtain the value of the resistance to flow.

    El carácter marcadamente prestacional de las normativas acústicas en la edificación abre el camino a la propuesta, por parte de empresas y particulares, de nuevos materiales acústicos susceptibles de ser utilizados en el ámbito de la acústica de la edificación. Éste es el caso que nos ocupa en el presente trabajo en el que se presenta un nuevo material acústico absorbente basado en fibras vegetales, concretamente el kenaf. Además se propone un modelo empírico de modelización del comportamiento absorbente de varias composiciones de este material en función de la frecuencia. Existen modelos de diferentes lanas minerales, lanas de roca, lanas de vidrio, espumas o lanas de poliéster. Algunos de estos modelos —llamados empíricos— se

  15. Progress of Si-based nanocrystalline luminescent materials

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Si-based nanomaterials are some new photoelctronic and informational materials developed rapidly in recent years, and they have potential applications in the light emitting devices, e. g. Si light emitting diode, Si laser and integrated Si-based photoelectronics. Among them are nanoscale porous silicon (ps), Si nanocrystalline embedded SiO2 (SiOx, x < 2.0) matrices, Si nanoquantum dot and Si/SiO2 superlattice, etc. At present, there are various indications that if these materials can achieve efficient and stable luminescence, which are photoluminescence (PL) and electroluminescence (EL), it is possible for them to lead to a new informational revolution in the early days of the 21st century. In this article, we will mainly review the progress of study on Si-based nanomaterials in the past ten years. The involved contents are the fabricated methods, structural characterizations and light emitting properties. Finally, we predicate the developed tendency of this field in the following ten years.

  16. New gadolinium based glasses for gamma-rays shielding materials

    Energy Technology Data Exchange (ETDEWEB)

    Kaewjang, S.; Maghanemi, U.; Kothan, S. [Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chang Mai University, Chang Mai 50200 (Thailand); Kim, H.J. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Limkitjaroenporn, P. [Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom Rajabhat University, Nakhon Pathom 73000 (Thailand); Kaewkhao, J., E-mail: mink110@hotmail.com [Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom Rajabhat University, Nakhon Pathom 73000 (Thailand)

    2014-12-15

    Highlights: • Gd{sub 2}O{sub 3} based glasses have been fabricated and investigated radiation shielding properties between 223 and 662 keV. • Density of the glass increases with increasing of Gd{sub 2}O{sub 3.} • All the glasses of Gd{sub 2}O{sub 3} compositions studied had been shown lower HVL than X-rays shielding window. • Prepared glasses to be utilized as radiation shielding material with Pb-free advantage. • This work is the first to reports on radiation shielding properties of Gd{sub 2}O{sub 3} based glass matrices. - Abstract: In this work, Gd{sub 2}O{sub 3} based glasses in compositions (80−x)B{sub 2}O{sub 3}-10SiO{sub 2}-10CaO-xGd{sub 2}O{sub 3} (where x = 15, 20, 25, 30 and 35 mol%) have been fabricated and investigated for their radiation shielding, physical and optical properties. The density of the glass was found to increase with the increasing of Gd{sub 2}O{sub 3} concentration. The experimental values of mass attenuation coefficients (μ{sub m}), effective atomic number (Z{sub eff}) and effective electron densities (N{sub e}) of the glasses were found to increase with the increasing of Gd{sub 2}O{sub 3} concentration and also with the decreasing of photon energy from 223 to 662 keV. The glasses of all Gd{sub 2}O{sub 3} compositions studied have been shown with lower HVL values in comparison to an X-rays shielding window, ordinary concrete and commercial window; indicating their potential as radiation shielding materials with Pb-free advantage. Optical spectra of the glasses in the present study had been shown with light transparency; an advantage when used as radiation shielding materials.

  17. Dissolution performance of plutonium nitride based fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Aneheim, E.; Hedberg, M. [Nuclear Chemistry, Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivaegen 4, Gothenburg, SE41296 (Sweden)

    2016-07-01

    Nitride fuels have been regarded as one viable fuel option for Generation IV reactors due to their positive features compared to oxides. To be able to close the fuel cycle and follow the Generation IV concept, nitrides must, however, demonstrate their ability to be reprocessed. This means that the dissolution performance of actinide based nitrides has to be thoroughly investigated and assessed. As the zirconium stabilized nitrides show even better potential as fuel material than does the pure actinide containing nitrides, investigations on the dissolution behavior of both PuN and (Pu,Zr)N has been undertaken. If possible it is desirable to perform the fuel dissolutions using nitric acid. This, as most reprocessing strategies using solvent-solvent extraction are based on a nitride containing aqueous matrix. (Pu,Zr)N/C microspheres were produced using internal gelation. The spheres dissolution performance was investigated using nitric acid with and without additions of HF and Ag(II). In addition PuN fuel pellets were produced from powder and their dissolution performance were also assessed in a nitric acid based setting. It appears that both PuN and (Pu,Zr)N/C fuel material can be completely dissolved in nitric acid of high concentration with the use of catalytic amounts of HF. The amount of HF added strongly affects dissolution kinetics of (Pu, Zr)N and the presence of HF affects the 2 solutes differently, possibly due to inhomogeneity o the initial material. Large additions of Ag(II) can also be used to facilitate the dissolution of (Pu,Zr)N in nitric acid. PuN can be dissolved by pure nitric acid of high concentration at room temperature while (Pu, Zr)N is unaffected under similar conditions. At elevated temperature (reflux), (Pu,Zr)N can, however, also be dissolved by concentrated pure nitric acid.

  18. Thin absorber EUV photomask based on mixed Ni and TaN material

    Science.gov (United States)

    Hay, Derrick; Bagge, Patrick; Khaw, Ian; Sun, Lei; Wood, Obert; Chen, Yulu; Kim, Ryoung-han; Qi, Zhengqing John; Shi, Zhimin

    2016-05-01

    Lithographic patterning at the 7 and 5 nm nodes will likely require EUV (λ=13.5 nm) lithography for many of the critical levels. All optical elements in an EUV scanner are reflective which requires the EUV photomask to be illuminated at an angle to its normal. Current scanners have an incidence of 6 degree, but future designs will be properties of the Ni-Ta nano-composite material. Finite integral method and effective medium theory-based transfer matrix method have been independently developed to analyze the performance of the nano-composite absorption layer. We show that inserting 15% volume fraction Ni nanoparticles into 40-nm of TaN absorber material can reduce the reflection below 2% over the EUV range. Numerical simulations confirm that the reduced reflectivity is due to the increased absorption of Ni, while scattering only contributes to approximately 0.2% of the reduction in reflectivity.

  19. Porphyrin Based Near Infrared-Absorbing Materials for Organic Photovoltaics

    Science.gov (United States)

    Zhong, Qiwen

    The conservation and transformation of energy is essential to the survival of mankind, and thus concerns every modern society. Solar energy, as an everlasting source of energy, holds one of the key solutions to some of the most urgent problems the world now faces, such as global warming and the oil crisis. Advances in technologies utilizing clean, abundant solar energy, could be the steering wheel of our societies. Solar cells, one of the major advances in converting solar energy into electricity, are now capturing people's interest all over the globe. While solar cells have been commercially available for many years, the manufacturing of solar cells is quite expensive, limiting their broad based implementation. The cost of solar cell based electricity is 15-50 cents per kilowatt hour (¢/kwh), depending on the type of solar cell, compared to 0.7 ¢/kwh for fossil fuel based electricity. Clearly, decreasing the cost of electricity from solar cells is critical for their wide spread deployment. This will require a decrease in the cost of light absorbing materials and material processing used in fabricating the cells. Organic photovoltaics (OPVs) utilize organic materials such as polymers and small molecules. These devices have the advantage of being flexible and lower cost than conventional solar cells built from inorganic semiconductors (e.g. silicon). The low cost of OPVs is tied to lower materials and fabrication costs of organic cells. However, the current power conversion efficiencies of OPVs are still below 15%, while convention crystalline Si cells have efficiencies of 20-25%. A key limitation in OPVs today is their inability to utilize the near infrared (NIR) portion of the solar spectrum. This part of the spectrum comprises nearly half of the energy in sunlight that could be used to make electricity. The first and foremost step in conversion solar energy conversion is the absorption of light, which nature has provided us optimal model of, which is

  20. Terahertz detection using mechanical resonators based on 2D materials

    Directory of Open Access Journals (Sweden)

    Juha Hassel

    2017-06-01

    Full Text Available We have investigated a THz detection scheme based on mixing of electrical signals in a voltage-dependent capacitance made out of suspended graphene. We have analyzed both coherent and incoherent detection regimes and compared their performance with the state of the art. Using a high-amplitude local oscillator, we anticipate potential for quantum limited detection in the coherent mode. The sensitivity stems from the extraordinary mechanical and electrical properties of atomically thin graphene or graphene-related 2D materials.

  1. Behavior of W-based materials in hot helium gas

    Directory of Open Access Journals (Sweden)

    J. Matějíček

    2016-12-01

    A number of W-based materials (pure tungsten and some of its alloys prepared by powder metallurgy techniques was exposed to He atmosphere at 720ºC and 500kPa for 500h. Morphological surface changes were observed by SEM, chemical and phase composition was analyzed by EDS and XRD, respectively. The internal microstructure was observed by a combination of SEM, FIB and TEM techniques. Mechanical properties were determined by instrumented indentation. Some alloys developed a thin oxide layer, in some cases new morphological features were observed, while some samples remained mostly intact. The observed changes are correlated with specific compositions and microstructures.

  2. Charge transport in metal oxide nanocrystal-based materials

    Science.gov (United States)

    Runnerstrom, Evan Lars

    There is probably no class of materials more varied, more widely used, or more ubiquitous than metal oxides. Depending on their composition, metal oxides can exhibit almost any number of properties. Of particular interest are the ways in which charge is transported in metal oxides: devices such as displays, touch screens, and smart windows rely on the ability of certain metal oxides to conduct electricity while maintaining visible transparency. Smart windows, fuel cells, and other electrochemical devices additionally rely on efficient transport of ionic charge in and around metal oxides. Colloidal synthesis has enabled metal oxide nanocrystals to emerge as a relatively new but highly tunable class of materials. Certain metal oxide nanocrystals, particularly highly doped metal oxides, have been enjoying rapid development in the last decade. As in myriad other materials systems, structure dictates the properties of metal oxide nanocrystals, but a full understanding of how nanocrystal synthesis, the processing of nanocrystal-based materials, and the structure of nanocrystals relate to the resulting properties of nanocrystal-based materials is still nascent. Gaining a fundamental understanding of and control over these structure-property relationships is crucial to developing a holistic understanding of metal oxide nanocrystals. The unique ability to tune metal oxide nanocrystals by changing composition through the introduction of dopants or by changing size and shape affords a way to study the interplay between structure, processing, and properties. This overall goal of this work is to chemically synthesize colloidal metal oxide nanocrystals, process them into useful materials, characterize charge transport in materials based on colloidal metal oxide nanocrystals, and develop ways to manipulate charge transport. In particular, this dissertation characterizes how the charge transport properties of metal oxide nanocrystal-based materials depend on their processing and

  3. Water Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Hansen, Scott W.; Sheth, Ribik B.; Atwell, Matt; Cheek, Ann; Agarwal, Muskan; Hong, Steven; Patel, Aashini,; Nguyen, Lisa; Posada, Luciano

    2014-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft’s radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a “topper” to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. Studies conducted in this paper investigate utilizing water’s high latent heat of formation as a PCM, as opposed to traditional waxes, and corresponding complications surrounding freezing water in an enclosed volume. Work highlighted in this study is primarily visual and includes understanding ice formation, freeze front propagation, and the solidification process of water/ice. Various test coupons were constructed of copper to emulate the interstitial pin configuration (to aid in conduction) of the proposed water PCM HX design. Construction of a prototypic HX was also completed in which a flexible bladder material and interstitial pin configurations were tested. Additionally, a microgravity flight was conducted where three copper test articles were frozen continuously during microgravity and 2-g periods and individual water droplets were frozen during microgravity.

  4. Recent advances in biopolymers and biopolymer-based nanocomposites for food packaging materials.

    Science.gov (United States)

    Tang, X Z; Kumar, P; Alavi, S; Sandeep, K P

    2012-01-01

    Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.

  5. Material flow-based economic assessment of landfill mining processes.

    Science.gov (United States)

    Kieckhäfer, Karsten; Breitenstein, Anna; Spengler, Thomas S

    2017-02-01

    This paper provides an economic assessment of alternative processes for landfill mining compared to landfill aftercare with the goal of assisting landfill operators with the decision to choose between the two alternatives. A material flow-based assessment approach is developed and applied to a landfill in Germany. In addition to landfill aftercare, six alternative landfill mining processes are considered. These range from simple approaches where most of the material is incinerated or landfilled again to sophisticated technology combinations that allow for recovering highly differentiated products such as metals, plastics, glass, recycling sand, and gravel. For the alternatives, the net present value of all relevant cash flows associated with plant installation and operation, supply, recycling, and disposal of material flows, recovery of land and landfill airspace, as well as landfill closure and aftercare is computed with an extensive sensitivity analyses. The economic performance of landfill mining processes is found to be significantly influenced by the prices of thermal treatment (waste incineration as well as refuse-derived fuels incineration plant) and recovered land or airspace. The results indicate that the simple process alternatives have the highest economic potential, which contradicts the aim of recovering most of the resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Compatibility studies of metallic materials with lithium-based oxides

    Science.gov (United States)

    Hofmann, P.; Dienst, W.

    1988-07-01

    The compatibility of Li 2O, Li 4SiO 4 and Li 2SiO 3 with the cladding materials AISI 316, 1.4914, Hastelloy X and Inconel 625 was investigated at 800-1000°C for annealing times up to 1000 h. A controlled oxygen reactivity was established by adding 1 mol% NiO per mole Li 2O to the Li-based oxides. In addition, some compatibility tests were performed at 600-900°C on Be, which is of interest as a neutron multiplier material, with Li 2SiO 3 as well as AISI 316. Li 2O accounted for the strongest cladding attack, followed by Li 4SiO 4 and Li 2SiO 3. In the absence of NiO, Li 2SiO 3 caused no chemical interactions at all. With respect to the cladding materials, there was no considerable difference in the reaction rates of AISI 316, Hastelloy X and Inconel 625. However, the steel 1.4914 was clearly more heavily attacked at and above 800°C. The compatibility of Be with Li 2SiO 3 or AISI 316 seems to be tolerable up to about 650°C. At higher temperatures a liquid Li suicide phase is formed which results in strong local attack and penetration into Li 2SiO 3.

  7. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Tatiana S. Koltsova

    2015-09-01

    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7355

  8. Graphene: A Versatile Carbon-Based Material for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Nileshkumar Dubey

    2015-01-01

    Full Text Available The development of materials and strategies that can influence stem cell attachment, proliferation, and differentiation towards osteoblasts is of high interest to promote faster healing and reconstructions of large bone defects. Graphene and its derivatives (graphene oxide and reduced graphene oxide have received increasing attention for biomedical applications as they present remarkable properties such as high surface area, high mechanical strength, and ease of functionalization. These biocompatible carbon-based materials can induce and sustain stem cell growth and differentiation into various lineages. Furthermore, graphene has the ability to promote and enhance osteogenic differentiation making it an interesting material for bone regeneration research. This paper will review the important advances in the ability of graphene and its related forms to induce stem cells differentiation into osteogenic lineages.

  9. Multiscale Lattice Boltzmann-Finite Element Modelling of Transport Properties in Cement-based Materials

    NARCIS (Netherlands)

    Zhang, M.

    2013-01-01

    Cement-based materials are the most widely used man-made materials in the world. The durability of cement-based materials has been a major concern due to the premature failure and serviceability issues of many reinforced concrete structures. Durability of cement-based materials is to a large content

  10. Multiscale Lattice Boltzmann-Finite Element Modelling of Transport Properties in Cement-based Materials

    NARCIS (Netherlands)

    Zhang, M.

    2013-01-01

    Cement-based materials are the most widely used man-made materials in the world. The durability of cement-based materials has been a major concern due to the premature failure and serviceability issues of many reinforced concrete structures. Durability of cement-based materials is to a large content

  11. Selecting the Best Materials Compositions of Resin Based Bioasphalt

    Science.gov (United States)

    Setyawan, Ary; Widiharjo, Budi; Djumari

    2017-07-01

    Damar asphalt is one type of bioaspal which is a mixture with the main ingredient is a resin as a binder and cooking oil as a solvent. One major drawback of this damar asphalt is the low ductility. To improve the ductility values, then use the added material Filler. Filler serves as a divider between the impurities with damar asphalt, increases ductility and increase the ability of cohesion or bonding between the particles of material damar asphalt. The purpose of this study was to determine damar asphalt modifications to the properties in accordance with the properties of damar asphalt test specifications based on the value of penetration. This method uses some variant on material such as powder bricks and fly ash as a binder. Solvent in constituent used oil and used cooking oil. It also added the polymer latex up to 10% at intervals of 2%. The best composition of damar asphalt materials were obtained with gum rosin, Fly Ash, Oil and Latex. Damar asphalt modification damar asphalt optimum mix of resin (100g pure resin or resin chunk + 350g powder), Fly Ash powder (150g), cooking oil (205g), and latex 4%, ductility increased from 63.5 cm to 119.5 cm, the value of the flash point was originally at temperature of 240 °C to 260 °C, damar asphalt penetration of 68.2 dmm to 43 dmm, and the value of density decreases from 1.01 g / cm3 to 0.99 g / cm3. Damar asphalt at these modifications meet the specifications in terms of solubility in trichlore ethylene is equal to 99.5%, and also meet the affinity of damar asphalt at 99%. With the optimum value, damar asphalt could be categorized as bitumen 40/60 penetration.

  12. Technical issues related to the development of reduced-activation ferritic/martensitic steels as structural materials for a fusion blanket system

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, Hiroyasu, E-mail: tanigawa.hiroyasu@jaea.go.jp [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Shiba, Kiyoyuki; Sakasegawa, Hideo; Hirose, Takanori; Jitsukawa, Shiro [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan)

    2011-10-15

    Reduced activation ferritic/martensitic (RAFM) steels are recognized as the primary candidate structural materials for fusion blanket systems. Because of the possibility of creating sound engineering bases, such as a suitable fabrication technology and a materials database, RAFM steels can be used as structural materials for pressure equipment. Further, the development of an irradiation database in addition to design methodologies for fusion-centered applications is critical when evaluating the applicability of RAFM steels as structural materials for fusion-neutron-irradiated pressure equipment. In the International Fusion Energy Research Centre (IFERC) project in the Broader Approach (BA) activities between the EU and Japan, R and D is underway to optimize RAFM steel fabrication and processing technologies, develop a method for estimating fusion-neutron-irradiation effects, and study the deformation behaviors of irradiated structures. The results of these research activities are expected to form the basis for the DEMO power plant design criteria and licensing. The objective of this paper is to review the BA R and D status of RAFM steel development in Japan, especially F82H (Fe-8Cr-2W-V, Ta). The key technical issues relevant to the design and fabrication of the DEMO blanket and the recent achievements in Japan are introduced.

  13. Teaching-Material Design Center: An Ontology-Based System for Customizing Reusable e-Materials

    Science.gov (United States)

    Wang, Hei-Chia; Hsu, Chien-Wei

    2006-01-01

    Use of electronic teaching materials (e-material) to support teaching is a trend. e-Material design is therefore an important issue. Currently, most e-material providers offer a package of solutions for different purposes. However, not all teachers and learners need everything from a single package. A preferable alternative is to find useful…

  14. N,O-Type Carborane-Based Materials

    Directory of Open Access Journals (Sweden)

    José Giner Planas

    2016-05-01

    Full Text Available This review summarizes the synthesis and coordination chemistry of a series of carboranyl ligands containing N,O donors. Such carborane-based ligands are scarcely reported in the literature when compared to other heteroatom-containing donors. The synthetic routes for metal complexes of these N,O-type carborane ligands are summarized and the properties of such complexes are described in detail. Particular attention is paid to the effect that the incorporation of carboranes has into the coordination chemistry of the otherwise carbon-based ligands and the properties of such materials. The reported complexes show a variety of properties such as those used in magnetic, chiroptical, nonlinear optical, catalytic and biomedical applications.

  15. Negative Index Materials and Plasmonic Antennas Based Nanocouplers

    DEFF Research Database (Denmark)

    Andryieuski, Andrei

    an optical fiber and future optical integrated circuit. Multiple nanocoupler possibilities are analyzed. Two realizations are investigated: negative index metamaterial and plasmonic nanoantenna based. The cubic symmetric negative index metamaterial Split cube in Cage and Split cube in Carcass designs...... for the telecom frequencies are proposed. It is shown that despite the exceptional bulkness (effective properties do not depend on the number of layers) and cubic symmetry the abovementioned designs exhibit strong spatial dispersion in the frequency range of interest. That prevents treating them as an isotropic...... negative index material. The wave propagation retrieval method for metamaterials with linear and circular eigenpolarizations and the field averaging of the restored Bloch mode method are proposed for metamaterials effective properties characterization. The methods are based on observation of the wave...

  16. Smart Material-actuated Flexible Tendon-based Snake Robot

    Directory of Open Access Journals (Sweden)

    Mohiuddin Ahmed

    2016-05-01

    Full Text Available A flexible snake robot has better navigation ability compare with the existing electrical motor-based rigid snake robot, due to its excellent bending capability during navigation inside a narrow maze. This paper discusses the modelling, simulation and experiment of a flexible snake robot. The modelling consists of the kinematic analysis and the dynamic analysis of the snake robot. A platform based on the Incompletely Restrained Positioning Mechanism (IRPM is proposed, which uses the external force provided by a compliant flexible beam in each of the actuators. The compliant central column allows the configuration to achieve three degrees of freedom (3DOFs with three tendons. The proposed flexible snake robot has been built using smart material, such as electroactive polymers (EAPs, which can be activated by applying power to it. Finally, the physical prototype of the snake robot has been built. An experiment has been performed in order to justify the proposed model.

  17. Stem cell homing-based tissue engineering using bioactive materials

    Science.gov (United States)

    Yu, Yinxian; Sun, Binbin; Yi, Chengqing; Mo, Xiumei

    2017-06-01

    Tissue engineering focuses on repairing tissue and restoring tissue functions by employing three elements: scaffolds, cells and biochemical signals. In tissue engineering, bioactive material scaffolds have been used to cure tissue and organ defects with stem cell-based therapies being one of the best documented approaches. In the review, different biomaterials which are used in several methods to fabricate tissue engineering scaffolds were explained and show good properties (biocompatibility, biodegradability, and mechanical properties etc.) for cell migration and infiltration. Stem cell homing is a recruitment process for inducing the migration of the systemically transplanted cells, or host cells, to defect sites. The mechanisms and modes of stem cell homing-based tissue engineering can be divided into two types depending on the source of the stem cells: endogenous and exogenous. Exogenous stem cell-based bioactive scaffolds have the challenge of long-term culturing in vitro and for endogenous stem cells the biochemical signal homing recruitment mechanism is not clear yet. Although the stem cell homing-based bioactive scaffolds are attractive candidates for tissue defect therapies, based on in vitro studies and animal tests, there is still a long way before clinical application.

  18. Two-dimensional materials based transparent flexible electronics

    Science.gov (United States)

    Yu, Lili; Ha, Sungjae; El-Damak, Dina; McVay, Elaine; Ling, Xi; Chandrakasan, Anantha; Kong, Jing; Palacios, Tomas

    2015-03-01

    Two-dimensional (2D) materials have generated great interest recently as a set of tools for electronics, as these materials can push electronics beyond traditional boundaries. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. These thin, lightweight, bendable, highly rugged and low-power devices may bring dramatic changes in information processing, communications and human-electronic interaction. In this report, for the first time, we demonstrate two complex transparent flexible systems based on molybdenum disulfide (MoS2) grown by chemical vapor method: a transparent active-matrix organic light-emitting diode (AMOLED) display and a MoS2 wireless link for sensor nodes. The 1/2 x 1/2 square inch, 4 x 5 pixels AMOLED structures are built on transparent substrates, containing MoS2 back plane circuit and OLEDs integrated on top of it. The back plane circuit turns on and off the individual pixel with two MoS2 transistors and a capacitor. The device is designed and fabricated based on SPICE simulation to achieve desired DC and transient performance. We have also demonstrated a MoS2 wireless self-powered sensor node. The system consists of as energy harvester, rectifier, sensor node and logic units. AC signals from the environment, such as near-field wireless power transfer, piezoelectric film and RF signal, are harvested, then rectified into DC signal by a MoS2 diode. CIQM, CICS, SRC.

  19. Dynamic Oxygen Storage Capacity Measurements on Ceria-Based Material

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Dynamic oxygen storage and release capability (OSC) measurement apparatus was designed to evaluate the OSC performance of ceria-based oxygen storage material. The optimum measurement condition was at a frequency of 0.1 Hz with the inlet gas-flow sequence CO (5S)→O2 (5S)→CO→O2 and a flow rate of 300 ml·min-1. Under this condition, similar regular square wave in the inlet and outlet of the reactor was obtained to guarantee the reliability of the dynamic OSC results. The dynamic OSC performance of the CeO2 and Ce0.67Zr0.33O2 mixed oxide prepared using the citric sol-gel method was studied at the optimum measurement condition with focus on both quantitative and qualitative analyses. The results reveal distinctly that Ce0.67Zr0.33O2 had better dynamic OSC performance because of its higher oxygen migration rate than CeO2. Under dynamic conditions, two CO2 production peaks occurred corresponding to the CO pulse and the O2 pulse, respectively, during the entire cycle. The intensity and ratio between the two CO2 productions were highly influenced by temperature and frequency indicating complex surface phenomena during the oxygen storage/release process. As a result, this set-up can be applied to the evaluation of ceria-based material on the OSC performance.

  20. Effect of silicate solutions on metakaolinite based cementitious material

    Institute of Scientific and Technical Information of China (English)

    XIAO Xue-jun; LI Hua-jian; SUN Heng-hu

    2006-01-01

    High performance metakaolinite based cementitious materials were prepared with metakaolinite as main component, and the different modules of Na and Na-K silicate solutions as diagenetic agent. The results show that the mechanical properties are affected by different silicate solutions, compressive strengths of pastes hydrated for 3 d and 28 d with Na-K silicate solution (The modulus is 1) are about 43.68 and 78.52 MPa respectively. By analyzing the mechanical properties of Metakaolinite based cementitious materials, the diagenetic effect of lower module is better than higher module, and Na-K silicate solution is better than Na silicate solution. The structure of the Na and Na-K silicate solutions is studied with IR and 29Si NMR, the reason of the lower module and Na-K silicate solution improving the mechanical properties is that the low module silicate solution has lower polymeric degree of silicon dioxide, and the higher polymeric degree of silicon oxide tetrahedron(Q4) in Na-K silicate solution is less than Na silicate solution.

  1. Graphene-Based Materials for Stem Cell Applications

    Directory of Open Access Journals (Sweden)

    Tae-Hyung Kim

    2015-12-01

    Full Text Available Although graphene and its derivatives have been proven to be suitable for several biomedical applications such as for cancer therapy and biosensing, the use of graphene for stem cell research is a relatively new area that has only recently started to be investigated. For stem cell applications, graphene has been utilized by itself or in combination with other types of materials such as nanoparticles, nanofibers, and polymer scaffolds to take advantage of the several unique properties of graphene, such as the flexibility in size, shape, hydrophilicity, as well as its excellent biocompatibility. In this review, we will highlight a number of previous studies that have investigated the potential of graphene or its derivatives for stem cell applications, with a particular focus on guiding stem cell differentiation into specific lineages (e.g., osteogenesis, neurogenesis, and oligodendrogenesis, promoting stem cell growth, stem cell delivery/transplantation, and effective monitoring of their differentiation. We hope that this review promotes and accelerates the use of graphene-based materials for regenerative therapies, especially for stem cell-based approaches to cure various incurable diseases/disorders such as neurological diseases (e.g., Alzheimer’s disease and Parkinson’s disease, stroke, spinal cord injuries, bone/cartilage defects, and cardiovascular diseases.

  2. Scene-based nonuniformity correction based on bilateral filter with reduced ghosting

    Science.gov (United States)

    Li, Zhaolong; Shen, Tongsheng; Lou, Shuli

    2016-07-01

    In order to correct the nonuniformity noise of the IR imaging system, a nonuniformity correction deghosting algorithm based on high-brightness region detection was proposed. Firstly, the bilateral filter was used to filter the image. The high-brightness regions in the result image were detected, and the correction factors corresponding to the regions were reduced. And then, the positions were detected which are high-brightness pixels in former frame but are not in current frame, and the correction factors corresponding to the regions were enlarged. Thus, the wrong update of the correction factor caused by high-brightness region of both the current frame and the previous frame was reduced. The correction method was validated using a real image sequence. The experimental results showed that the suppression effect of the proposed algorithm on the 'ghost' effect caused by the high-brightness region is better than the other two algorithms named SLTH-NUC and BFTH-NUC, respectively. Moreover, the proposed algorithm can also suppress the 'ghost' effect caused by the sharp edge of the scene.

  3. Investigation of high-temperature materials for uranium-fluoride-based gas core reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Collins, C.; Wang, S.C.P.; Anghaie, S.

    1988-01-01

    The development of the uranium-fluoride-based gas core reactor (GCR) systems will depend on the availability of wall materials that can survive the severe thermal, chemical, and nuclear environments of these systems. In the GCR system, the fuel/working fluid chemical constituents include enriched uranium fluorides UF{sub n} (n = 1 to 4) and fluorides operating at gas pressures of {approx}1 to 100 atm. The peak temperature of the fissioning gas/working fluid in the system can be 4000 K or higher, and the temperatures of the inner surface of the construction wall may exceed 1500 K. Wall materials that can be compatible in this environment must possess high melting points, good resistance to creep and thermal shock, and high resistance to fluorination. Compatible materials that feature high fluorination resistance are those that either do not react with fluorine/fluoride gases or those that can form a protective fluoride scale, which prevents or reduces further attack by the corrosive gas. Because fluorine and fluoride gases are strong oxidizing agents, formation of high melting point protective scales on substrate materials is more likely to be expected. This paper summarizes results of corrosion testing for evaluation of materials compatibility with uranium fluoride. These tests have been carried out by exposing different materials to UF{sub 6} gas in a closed capsule at temperatures up to 1500 K. Past exposure examinations were conducted to determine the morphology and composition of scales that were formed.

  4. Speed of sound in rubber-based materials for ultrasonic phantoms.

    Science.gov (United States)

    Cafarelli, A; Miloro, P; Verbeni, A; Carbone, M; Menciassi, A

    2016-12-01

    In this work we provide measurements of speed of sound (SoS) and acoustic impedance (Z) of some doped/non-doped rubber-based materials dedicated to the development of ultrasound phantoms. These data are expected to be useful for speeding-up the preparation of multi-organ phantoms which show similar echogenicity to real tissues. Different silicones (Ecoflex, Dragon-Skin Medium) and polyurethane rubbers with different liquid (glycerol, commercial detergent, N-propanol) and solid (aluminum oxide, graphene, steel, silicon powder) inclusions were prepared. SoS of materials under investigation was measured in an experimental setup and Z was obtained by multiplying the density and the SoS of each material. Finally, an anatomically realistic liver phantom has been fabricated selecting some of the tested materials. SoS and Z evaluation for different rubber materials and formulations are reported. The presence of liquid additives appears to increase the SoS, while solid inclusions generally reduce the SoS. The ultrasound images of realized custom fabricated heterogeneous liver phantom and a real liver show remarkable similarities. The development of new materials' formulations and the knowledge of acoustic properties, such as speed of sound and acoustic impedance, could improve and speed-up the development of phantoms for simulations of ultrasound medical procedures.

  5. Sensitive detection of rutin based on {beta}-cyclodextrin-chemically reduced graphene/Nafion composite film

    Energy Technology Data Exchange (ETDEWEB)

    Liu Kunping; Wei Jinping [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang Chunming, E-mail: wangcm@lzu.edu.cn [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2011-05-30

    Highlights: > {beta}-CD-graphene composite obtained via a simple sonication-induced assembly. > Accelerating electron transfer on electrode to amplify the electrochemical signal. > A highly sensitive electrochemical sensor for rutin detection. > Good selectivity and reproducibility for the detection of rutin in real samples. - Abstract: An electrochemical sensor based on chemically reduced graphene (CRG) was developed for the sensitive detection of rutin. To construct the base of the sensor, a novel composite was initially fabricated and used as the substrate material by combining CRG and {beta}-cyclodextrin ({beta}-CD) via a simple sonication-induced assembly. Due to the high rutin-loading capacity on the electrode surface and the upstanding electric conductivity of graphene, the electrochemical response of the fabricated sensor was greatly enhanced and displayed excellent analytical performance for rutin detection from 6.0 x 10{sup -9} to 1.0 x 10{sup -5} mol L{sup -1} with a low detection limit of 2.0 x 10{sup -9} mol L{sup -1} at 3{sigma}. Moreover, the proposed electrochemical sensor also exhibited good selectivity and acceptable reproducibility and could be used for the detection of rutin in real samples. Therefore, the present work offers a new way to broaden the analytical applications of graphene in pharmaceutical analysis.

  6. A Reduced Graphene Oxide Based Radio Frequency Glucose Sensing Device Using Multi-Dimensional Parameters

    Directory of Open Access Journals (Sweden)

    Byeongho Park

    2016-08-01

    Full Text Available A reduced graphene oxide (RGO based glucose sensor using a radio frequency (RF signal is demonstrated. An RGO with outstanding electrical property was employed as the interconnector material between signal electrodes in an RF electric circuit, and it was functionalized with phenylbutyric acid (PBA as a linker molecule to bind glucoses. By adding glucose solution, the fabricated sensor with RGO and PBA showed detecting characteristics in RF signal transmission and reflection. Frequency dependent electrical parameters such as resistance, inductance, shunt conductance and shunt capacitance were extracted from the RF results under the equivalent circuit model. These parameters also provided sensing characteristics of glucose with different concentrations. Using these multi-dimensional parameters, the RF sensor device detected glucose levels in the range of 1–4 mM, which ordinarily covers the testing range for diabetes or medical examination. The RGO based RF sensor, which fits well to a linear curve with fine stability, holds considerable promise for biomaterials detection, including glucose.

  7. A systems-based approach for integrated design of materials, products and design process chains

    Science.gov (United States)

    Panchal, Jitesh H.; Choi, Hae-Jin; Allen, Janet K.; McDowell, David L.; Mistree, Farrokh

    2007-12-01

    The concurrent design of materials and products provides designers with flexibility to achieve design objectives that were not previously accessible. However, the improved flexibility comes at a cost of increased complexity of the design process chains and the materials simulation models used for executing the design chains. Efforts to reduce the complexity generally result in increased uncertainty. We contend that a systems based approach is essential for managing both the complexity and the uncertainty in design process chains and simulation models in concurrent material and product design. Our approach is based on simplifying the design process chains systematically such that the resulting uncertainty does not significantly affect the overall system performance. Similarly, instead of striving for accurate models for multiscale systems (that are inherently complex), we rely on making design decisions that are robust to uncertainties in the models. Accordingly, we pursue hierarchical modeling in the context of design of multiscale systems. In this paper our focus is on design process chains. We present a systems based approach, premised on the assumption that complex systems can be designed efficiently by managing the complexity of design process chains. The approach relies on (a) the use of reusable interaction patterns to model design process chains, and (b) consideration of design process decisions using value-of-information based metrics. The approach is illustrated using a Multifunctional Energetic Structural Material (MESM) design example. Energetic materials store considerable energy which can be released through shock-induced detonation; conventionally, they are not engineered for strength properties. The design objectives for the MESM in this paper include both sufficient strength and energy release characteristics. The design is carried out by using models at different length and time scales that simulate different aspects of the system. Finally, by

  8. Laser (cooling) refrigeration in erbium based solid state materials

    Science.gov (United States)

    Lynch, Jonathan W.

    The objective of this study was to investigate the potential of erbium based solid state materials for laser refrigeration in bulk material. A great deal of work in the field has been focused on the use of ytterbium based ZBLAN glass. Some experiments have also reported cooling in thulium based solid state materials but with considerably less success. We proposed that erbium had many attractive features compared to ytterbium and therefore should be tried for cooling. The low lying energy level structure of erbium provides energy levels that could bring obtainable temperatures two orders of magnitude lower. Erbium transitions of interest for cooling fall in the near IR region (0.87 microns and 1.5 microns). Lasers for one of these transitions, in the 1.5 micron region, are well developed for communication and are in the eye-safe and water and atmosphere transparent region. Theoretical calculations are also presented so as to identify energy levels of the eleven 4f electrons in Er3+ in Cs2NaYCl 6:Er3+ and the transitions between them. The strengths of the optical transitions between them have been calculated. Knowledge of such energy levels and the strength of the laser induced transitions between them is crucial for understanding the refrigeration mechanisms and different energy transfer pathways following the laser irradiation. The crystal host for erbium was a hexa-chloro-elpasolite crystal, Cs 2NaYCl6:Er3+ with an 80% (stoichiometric) concentration of erbium. The best cooling results were obtained using the 0.87 micron transition. We have demonstrated bulk cooling in this crystal with a temperature difference of ~6.2 K below the surrounding temperature. The temperatures of the crystal and its immediate surrounding environment were measured using differential thermometry. Refrigeration experiments using the 1.5 micron transition were performed and the results are presented. The demonstrated temperature difference was orders of magnitude smaller. Only a temperature

  9. Developing V-Xanes Oxybarometry for Probing Materials Formed in Reducing Environments in the Early Solar Disk

    Science.gov (United States)

    Butterworth, A. L.; Gainsforth, Z.; Jilly-Rehak, C. E.; Righter, K.; Westphal, A. J.

    2017-01-01

    Vanadium exhibits four oxidation states (V(sup 2+), V(sup 3+), V(sup 4+) and V(sup 5+)) that have been shown to preferentially partition between melt phases dependent on redox conditions, spanning oxygen fugacity across more than 10 log units. We are developing synchrotron-based x-ray absorption spectroscopy of low-fugacity standards for the determination of V oxidation state in highly reducing conditions relevant to the early solar nebula.

  10. Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hui Zhang; Raman P. Singh

    2008-11-30

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These include refractory alloys base on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as those based on silicon carbide (SiCf-SiC); carbon-carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor componets is necessary for improved efficiency. Improving thermal conductivity of the materials used in nuclear fuels and other temperature critical components can lower the center-line fuel temperature and thereby enhance durability and reduce the risk of premature failure.

  11. Acid-base properties of Ni-MgO-Al2O3 materials

    Science.gov (United States)

    Gac, Wojciech

    2011-01-01

    Ni-MgO-Al2O3 materials of different Ni/Mg ratios were prepared by the co-precipitation method. Acid-base properties of the samples after calcination and reduction were examined by the temperature programmed desorption of ammonia and carbon dioxide. Thermal treatment of the materials in air at 400 °C led to the formation of hydrotalcite-like phases. The increase of Ni/Mg ratio decreased the stability of the hydrotalcite structure. The number and the strength of acid and base sites were related to the Ni/Mg ratio and thermal treatment conditions of materials. It was found that the replacement of Ni with Mg decreased the acidity and increased basicity of the surface of oxide materials. Thermal treatment of the samples in hydrogen led to the structural changes. The presence of magnesia improved thermal stability. The ratio of the number of acid to base sites in the reduced samples gradually increased with the increase of magnesia content.

  12. Eco-friendly wood-based solid-state flexible supercapacitors from wood transverse section slice and reduced graphene oxide

    Science.gov (United States)

    Lv, Shaoyi; Fu, Feng; Wang, Siqun; Huang, Jingda; Hu, La

    2015-07-01

    An interesting wood-based all-solid-state supercapacitor is produced using reduced graphene oxide (RGO) coated on wood transverse section slice (WTSS) as electrode material by means of a low-cost, eco-friendly, and simple method for the first time. The RGO-coated WTSS electrode has a porous 3D honeycomb framework due to the hierarchical cellular structure of the WTSS substrate and can function as an electrolyte reservoir. This special construction endows this novel electrode with good areal capacitance (102 mF cm-2) and excellent cyclic stability (capacitance retention of 98.9% after 5000 cycles). In addition, the supercapacitors exhibit good mechanical flexibility and preserve almost constant capacitive behavior under different bending conditions. Our study introduces a new and eco-friendly material design for electrodes in future flexible energy storage devices that closely resemble natural materials. [Figure not available: see fulltext.

  13. Research progress of Si-based germanium materials and devices

    Science.gov (United States)

    Buwen, Cheng; Cheng, Li; Zhi, Liu; Chunlai, Xue

    2016-08-01

    Si-based germanium is considered to be a promising platform for the integration of electronic and photonic devices due to its high carrier mobility, good optical properties, and compatibility with Si CMOS technology. However, some great challenges have to be confronted, such as: (1) the nature of indirect band gap of Ge; (2) the epitaxy of dislocation-free Ge layers on Si substrate; and (3) the immature technology for Ge devices. The aim of this paper is to give a review of the recent progress made in the field of epitaxy and optical properties of Ge heterostructures on Si substrate, as well as some key technologies on Ge devices. High crystal quality Ge epilayers, as well as Ge/SiGe multiple quantum wells with high Ge content, were successfully grown on Si substrate with a low-temperature Ge buffer layer. A local Ge condensation technique was proposed to prepare germanium-on-insulator (GOI) materials with high tensile strain for enhanced Ge direct band photoluminescence. The advances in formation of Ge n+p shallow junctions and the modulation of Schottky barrier height of metal/Ge contacts were a significant progress in Ge technology. Finally, the progress of Si-based Ge light emitters, photodetectors, and MOSFETs was briefly introduced. These results show that Si-based Ge heterostructure materials are promising for use in the next-generation of integrated circuits and optoelectronic circuits. Project supported in part by the National Natural Science Foundation (Nos. 61036003, 61435013) and the Major State Basic Research Development Program of China (No. 2013CB632103).

  14. Deactivation Mechanisms of Base Metal/Zeolite Urea Selective Catalytic Reduction Materials, and Development of Zeolite-Based Hydrocarbon Adsorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ja Hun; Lee, Jong H.; Kim, Do Heui; Li, Xiaohong S.; Tran, Diana N.; Peden, Charles HF

    2011-12-22

    This annual report describes recent progress on a collaborative project between scientists and engineers in the Institute for Integrated Catalysis at PNNL and at Ford Motor Company, involving investigations of laboratory- and engine-aged SCR catalysts, containing mainly base metal zeolites. These studies are leading to a better understanding of various aging factors that impact the long-term performance of SCR catalysts and improve the correlation between laboratory and engine aging, saving experimental time and cost. We are investigating SCR catalysts with reduced ammonia slip, increased low temperature activity, and increased product selectivity to N2. More recent recognition that high temperature performance, under regimes that sometimes cause deactivation, also needs to be improved is driving current work focused on catalyst materials modifications needed to achieve this enhanced performance. We are also studying materials effective for the temporary storage of HC species during the cold-start period. In particular, we examine the adsorption and desorption of various HC species produced during the combustion with different fuels (e.g., gasoline, E85, diesel) over potential HC adsorber materials, and measure the kinetic parameters to update Ford’s HC adsorption model.

  15. Sorption of radionuclides by cement-based barrier materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kefei, E-mail: likefei@tsinghua.edu.cn; Pang, Xiaoyun

    2014-11-15

    This paper investigates the sorption of radionuclide ions, {sup 137}Cs{sup +} and {sup 90}Sr{sup 2+}, by cement-based barrier materials for radioactive waste disposal. A mortar with ternary binder is prepared and powder samples are ground from the hardened material following a predetermined granulometry. After pre-equilibrium with an artificial pore solution, the sorption behaviors of powder samples are investigated through single sorption and blended sorption. The results show that: (1) no systematic difference is observed for single and blended sorptions thus the interaction between {sup 137}Cs{sup +} and {sup 90}Sr{sup 2+} sorptions must be weak; (2) the sorption kinetics is rapid and all characteristic times are less than 1d; (3) the sorption capacity is enhanced by C–A–S–H hydrates and the measured K{sub d} values can be predicted from C–S–H sorption data with Ca/Si ratio equal to Ca/(Si + Al) ratio.

  16. Solar cells based on organic materials; Solceller av organisk materiale

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsen, Emil J.; Breiby, Dag W.

    2009-07-01

    Organic Solar cells are still in the early research phase, and the efficiency so far is merely 5 - 6 %. But since this field of technology is recognised to be highly promising and potentially important, the research and development effort is formidable, and one foresees an improvement in efficiency of 10 -15%. Introduction: Today's commercial solar cells are based on the semiconductive material silicium with an energy efficiency close to 15% , i e this share of the solar energy which hit the cell will be transformed into electric energy. Research versions of silicium cells have efficiencies up towards 25% and certain combined cells from other inorganic materials may attain 30 - 40%. For so called third generation solar cells one even expects figures up to 60%. Organic solar cells are not developed in order to compete with Si cells, but to complement them. They will be cheap, light, pliable and rugged, well suited for use under special conditions, as cruises and expeditions in mountains and wilderness, and the cells may be integrated in equipment and textiles. (EW)

  17. Hydrophilic behavior of graphene and graphene-based materials.

    Science.gov (United States)

    Accordino, Sebastián R; Montes de Oca, Joan Manuel; Rodriguez Fris, J Ariel; Appignanesi, Gustavo A

    2015-10-21

    Graphene and the graphene-based materials like graphite, carbon nanotubes, and fullerenes are not only usually regarded as hydrophobic but also have been widely employed as paradigms for the investigation of the behavior of water under nonpolar confinement, a question of major concern for fields ranging from biology to materials design. However, some experimental and theoretical insights seem to contradict, at least partially, such a picture. In this work, we will provide firm evidence for a neat hydrophilic nature of graphene surfaces. Our molecular dynamics studies will demonstrate that parallel graphene sheets present a strong tendency to remain fully hydrated for moderately long times (even when the equilibrium state is indeed the collapse of the plates), and thus, they are less prone to self-assembly than model hydrophobic surfaces we shall employ as control which readily undergo a hydrophobic collapse. Potential of mean force calculations will indeed make evident that the solvent exerts a repulsive contribution on the self-assembly of graphene surfaces. Moreover, we shall also quantify graphene hydrophilicity by means of the calculation of water density at two pressures and water density fluctuations. This latter study has never been performed on graphene and represents a means both to confirm and to quantify its neat hydrophilic behavior. We shall also make evident the relevance of the mildly attractive water-carbon interactions, since their artificial weakening will be shown to revert from typically hydrophilic to typically hydrophobic behavior.

  18. A Statistics-Based Material Property Analysis to Support TPS Characterization

    Science.gov (United States)

    Copeland, Sean R.; Cozmuta, Ioana; Alonso, Juan J.

    2012-01-01

    Accurate characterization of entry capsule heat shield material properties is a critical component in modeling and simulating Thermal Protection System (TPS) response in a prescribed aerothermal environment. The thermal decomposition of the TPS material during the pyrolysis and charring processes is poorly characterized and typically results in large uncertainties in material properties as inputs for ablation models. These material property uncertainties contribute to large design margins on flight systems and cloud re- construction efforts for data collected during flight and ground testing, making revision to existing models for entry systems more challenging. The analysis presented in this work quantifies how material property uncertainties propagate through an ablation model and guides an experimental test regimen aimed at reducing these uncertainties and characterizing the dependencies between properties in the virgin and charred states for a Phenolic Impregnated Carbon Ablator (PICA) based TPS. A sensitivity analysis identifies how the high-fidelity model behaves in the expected flight environment, while a Monte Carlo based uncertainty propagation strategy is used to quantify the expected spread in the in-depth temperature response of the TPS. An examination of how perturbations to the input probability density functions affect output temperature statistics is accomplished using a Kriging response surface of the high-fidelity model. Simulations are based on capsule configuration and aerothermal environments expected during the Mars Science Laboratory (MSL) entry sequence. We identify and rank primary sources of uncertainty from material properties in a flight-relevant environment, show the dependence on spatial orientation and in-depth location on those uncertainty contributors, and quantify how sensitive the expected results are.

  19. Spintronic materials and devices based on antiferromagnetic metals

    Directory of Open Access Journals (Sweden)

    Y.Y. Wang

    2017-04-01

    Full Text Available In this paper, we review our recent experimental developments on antiferromagnet (AFM spintronics mainly comprising Mn-based noncollinear AFM metals. IrMn-based tunnel junctions and Hall devices have been investigated to explore the manipulation of AFM moments by magnetic fields, ferromagnetic materials and electric fields. Room-temperature tunneling anisotropic magnetoresistance based on IrMn as well as FeMn has been successfully achieved, and electrical control of the AFM exchange spring is realized by adopting ionic liquid. In addition, promising spin-orbit effects in AFM as well as spin transfer via AFM spin waves reported by different groups have also been reviewed, indicating that the AFM can serve as an efficient spin current source. To explore the crucial role of AFM acting as efficient generators, transmitters, and detectors of spin currents is an emerging topic in the field of magnetism today. AFM metals are now ready to join the rapidly developing fields of basic and applied spintronics, enriching this area of solid-state physics and microelectronics.

  20. A study on compression paddle materials to reduce radiation exposure dose during mammography: PC and PMMA and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Dong Hee [Dept. of Radiological Science, Far east University, Eumsung (Korea, Republic of); Jung, Hong Ryang [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2015-06-15

    This study was designed the band material in order to reduce the exposure pressure of the breast and the material was measured of Radiolucent and radiation properties with a radiation materials of PC, PMMA, Carbon. Also the image quality by image analysis to obtain the following results are below: Unfors Xi dosimetry using radiation transmittance when the results of 8.353 mGy is measured after removal of the cuff, the PC 6.308 mGy, PMMA 6.223 mGy, Carbon 7.218 mGy were measured respectively. Semi-layer PC 0.375 mmAl, PMMA 0.370 mmAl, with Carbon 0.360 mmAl Carbon, PC, PMMA was higher radiation properties and transparency in order. InLight / OSL NanoDotTM dosimeter was used in the cuff and then removed by placing the dosimeter measured results center on 1.143 mGy, at the edge 12.56 mGy, on the central PC 8.990 mGy, at the edge 10.291 mGy, PMMA center on 8.391 mGy , the edge 9.654 mGy, on Carbon center 9.581 mGy, 11.313 mGy were measured at the edge of Carbon, PC, PMMA showed a high permeability in order. Image Pixel average J is then removed from the cuff 976.655, PC 831.032, PMMA 819.069, Carbon 897.118 Carbon, PC, PMMA was measured by high order.

  1. Graphene based 2D-materials for supercapacitors

    Science.gov (United States)

    Palaniselvam, Thangavelu; Baek, Jong-Beom

    2015-09-01

    Ever-increasing energy demands and the depletion of fossil fuels are compelling humanity toward the development of suitable electrochemical energy conversion and storage devices to attain a more sustainable society with adequate renewable energy and zero environmental pollution. In this regard, supercapacitors are being contemplated as potential energy storage devices to afford cleaner, environmentally friendly energy. Recently, a great deal of attention has been paid to two-dimensional (2D) nanomaterials, including 2D graphene and its inorganic analogues (transition metal double layer hydroxides, chalcogenides, etc), as potential electrodes for the development of supercapacitors with high electrochemical performance. This review provides an overview of the recent progress in using these graphene-based 2D materials as potential electrodes for supercapacitors. In addition, future research trends including notable challenges and opportunities are also discussed.

  2. Recent advances in "bioartificial polymeric materials" based nanovectors

    Science.gov (United States)

    Conte, Raffaele; De Luca, Ilenia; Valentino, Anna; Di Salle, Anna; Calarco, Anna; Riccitiello, Francesco; Peluso, Gianfranco

    2017-04-01

    This chapter analyzes the advantages of the use of bioartificial polymers as carriers and the main strategies used for their design. Despite the enormous progresses in this field, more studies are required for the fully evaluation of these nanovectors in complex organisms and for the characterization of the pharmacodynamic and pharmacokinetic of the loaded drugs. Moreover, progresses in polymer chemistry are introducing a wide range of functionalities in the bioartificial polymeric material (BPM) nanostructures leading to a second generation of bioartificial polymer therapeutics based on novel and heterogeneous architectures with higher molecular weight and predictable structures, in order to achieve greater multivalency and increased loading capacity. Therefore, research on bioartificial polymeric nanovectors is an "on-going" field capable of attracting medical interest.

  3. 3D CHARACTERIZATION OF WOOD BASED FIBROUS MATERIALS: AN APPLICATION

    Directory of Open Access Journals (Sweden)

    Jérôme Lux

    2011-05-01

    Full Text Available Morphological characterization of wood based fibrous materials is carried out using X-ray tomography. This technique allows the non destructive observation at the scales of a fibre (microscopic scale and of a network of fibres (mesoscopic scale. The 3D images are processed using classical tools of mathematical morphology. Measures of porosities and estimations of the size distributions of fibres and pores are carried out and compared to other results. An alternative method for the calculation of the local orientation of the fibres is also described to quantify the anisotropy of the fibres network. Finally, the individualization of the fibres is obtained from the representation of the fibrous network as a 3D skeleton, making possible further measurements on the isolated fibres.

  4. Colloidal quantum dot based solar cells: from materials to devices

    Science.gov (United States)

    Song, Jung Hoon; Jeong, Sohee

    2017-08-01

    Colloidal quantum dots (CQDs) have attracted attention as a next-generation of photovoltaics (PVs) capable of a tunable band gap and low-cost solution process. Understanding and controlling the surface of CQDs lead to the significant development in the performance of CQD PVs. Here we review recent progress in the realization of low-cost, efficient lead chalcogenide CQD PVs based on the surface investigation of CQDs. We focus on improving the electrical properties and air stability of the CQD achieved by material approaches and growing the power conversion efficiency (PCE) of the CQD PV obtained by structural approaches. Finally, we summarize the manners to improve the PCE of CQD PVs through optical design. The various issues mentioned in this review may provide insight into the commercialization of CQD PVs in the near future.

  5. The digital divide in Internet-based patient education materials.

    Science.gov (United States)

    Sun, Gordon H

    2012-11-01

    The ubiquity of the Internet has led to the widespread availability of health-related information to the public, and the subsequent empowerment of patients has fundamentally altered the patient-physician relationship. Among several concerns of physicians is the possibility that patients may be misinformed by information obtained from the Internet. One opportunity for health care providers to address this problem exists within Internet-based patient education materials (IPEMs). According to recent research in Otolaryngology-Head and Neck Surgery, IPEMs found within professional otolaryngology websites are written at the 8th- to 18th-grade reading comprehension level, essentially unchanged over the past 3 years. This greatly exceeds the fourth- to sixth-grade reading level recommended by the National Institutes of Health. Benefits, strategies, and challenges to improving the readability of IPEMs are discussed.

  6. Disaster mitigation based on smart structures/materials

    Science.gov (United States)

    Asanuma, H.; Su, J.; Shahinpoor, M.; Felli, F.; Paolozzi, A.; Nejhad, M.; Hihara, L.; Aimmanee, S.; Furuya, Y.; Adachi, K.; Yanaseko, T.

    2016-04-01

    The concept "Disaster Mitigation and Sustainable Engineering" is introduced comprehensively and several examples are shown in this paper. It is emphasized that it can be effectively realized in the field "smart materials and structural systems." As serious disasters may not occur for a long period of time, and the structures for disaster mitigation suffer from vast amount of maintenance cost etc., they are better to be used daily. Their compactness and deploying function are also very useful. In order to demonstrate the concept, two examples having been experimentally tried are introduced, that is, artificial forests and deployable structure based on honeycomb to be used against flooding. Other examples and products in the world are also introduced and future directions are discussed.

  7. Enhanced Materials Based on Submonolayer Type-II Quantum Dots

    Energy Technology Data Exchange (ETDEWEB)

    Tamargo, Maria C [City College of New York, NY (United States); Kuskovsky, Igor L. [City Univ. (CUNY), NY (United States) Queens College; Meriles, Carlos [City College of New York, NY (United States); Noyan, Ismail C. [Columbia Univ., New York, NY (United States)

    2017-04-15

    We have investigated a nanostructured material known as sub-monolayer type-II QDs, made from wide bandgap II-VI semiconductors. Our goal is to understand and exploit their tunable optical and electrical properties by taking advantage of the type-II band alignment and quantum confinement effects. Type-II ZnTe quantum dots (QDs) in a ZnSe host are particularly interesting because of their relatively large valence band and conduction band offsets. In the current award we have developed new materials based on sub-monolayer type-II QDs that may be advantageous for photovoltaic and spintronics applications. We have also expanded the structural characterization of these materials by refining the X-ray diffraction methodologies needed to investigate them. In particular, we have 1) demonstrated ZnCdTe/ZnCdSe type-II QDs materials that have ideal properties for the development of novel high efficiency “intermediate band solar cells”, 2) we developed a comprehensive approach to describe and model the growth of these ultra-small type-II QDs, 3) analysis of the evolution of the photoluminescence (PL) emission, combined with other characterization probes allowed us to predict the size and density of the QDs as a function of the growth conditions, 4) we developed and implemented novel sophisticated X-ray diffraction techniques from which accurate size and shape of the buried type-II QDs could be extracted, 5) a correlation of the shape anisotropy with polarization dependent PL was observed, confirming the QDs detailed shape and providing insight about the effects of this shape anisotropy on the physical properties of the type-II QD systems, and 6) a detailed “time-resolved Kerr rotation” investigation has led to the demonstration of enhanced electron spin lifetimes for the samples with large densities of type-II QDs and an understanding of the interplay between the QDs and Te-isoelectroic centers, a defect that forms in the spacer layers that separate the QDs.

  8. Sensitivity and performance of azole-based energetic materials.

    Science.gov (United States)

    Yu, Zijun; Bernstein, Elliot R

    2013-10-24

    Imidazole, pyrazole, 1,2,3-triazole-, 1,2,4-triazole-, and tetrazole-based energetic materials are theoretically investigated by employing density functional theory (DFT). Heats of formation (ΔfH(0)'s) for the studied compounds (298 K) in the gas phase are determined at the B3P86/6-311G (d, p) theory level through isodesmic reactions. The bond dissociation energies (BDEs) corresponding to NO2, NH2, CH3, and Cl removal from carbon or nitrogen positions of the azole ring are also calculated at the B3P86/6-311G (d, p) theory level. The substituent effect of electron-withdrawing (NO2, Cl) and electron-donating (NH2, CH3) groups on the ΔfH(0)s and BDEs is discussed. Both electron-withdrawing groups and electron-donating groups (except the CH3 group) dramatically increase the ΔfH(0)s of these energetic materials when the substituent is at an N position on the azole ring. For substitution at a C atom on the azole ring, electron-withdrawing and electron-donating groups have different effects on the ΔfH(0)s for different azole compounds. A correlation is developed for this series of energetics between impact sensitivity h50% and the defined sensitivity index (SI): based on this empirical relationship and its extrapolation, the impact sensitivities of compounds for which experiments are not available are provided. The promising energetic compounds in each groups, which have potentially good energetic performance and low sensitivity, are 1-amino-2,4,5-trinitroimidazole, 1-amino-3,4,5-trinitropyrazole, 1,4-dinitro-1,2,3-triazole, 1,3-dinitro-1,2,4-triazole, and 1-nitrotetrazole.

  9. Return of target material ions leads to a reduced hysteresis in reactive high power impulse magnetron sputtering: Model

    Science.gov (United States)

    Kadlec, Stanislav; Čapek, Jiří

    2017-05-01

    A tendency to disappearing hysteresis in reactive High Power Impulse Magnetron Sputtering (HiPIMS) has been reported previously without full physical explanation. An analytical model of reactive pulsed sputtering including HiPIMS is presented. The model combines a Berg-type model of reactive sputtering with the global HiPIMS model of Christie-Vlček. Both time and area averaging is used to describe the macroscopic steady state, especially the reactive gas balance in the reactor. The most important effect in the presented model is covering of reacted parts of target by the returning ionized metal, effectively lowering the target coverage by reaction product at a given partial pressure. The return probability of ionized sputtered metal has been selected as a parameter to quantify the degree of HiPIMS effects. The model explains the reasons for reduced hysteresis in HiPIMS. The critical pumping speed was up to a factor of 7 lower in reactive HiPIMS compared to the mid-frequency magnetron sputtering. The model predicts reduced hysteresis in HiPIMS due to less negative slope of metal flux to substrates and of reactive gas sorption as functions of reactive gas partial pressure. Higher deposition rate of reactive HiPIMS compared to standard reactive sputtering is predicted for some parameter combinations. Comparison of the model with experiment exhibits good qualitative and quantitative agreement for three material combinations, namely, Ti-O2, Al-O2, and Ti-N2.

  10. Polylactide-based bionanocomposites: a promising class of hybrid materials.

    Science.gov (United States)

    Sinha Ray, Suprakas

    2012-10-16

    Polylactide (PLA) is the oldest and potentially one of the most interesting and useful biodegradable man-made polymers because of its renewable origin, controlled synthesis, good mechanical properties, and inherent biocompatibility. The blending of PLA with functional nanoparticles can yield a new class of hybrid materials, commonly known as bionanocomposites, where 1-5% nanoparticles by volume are molecularly dispersed within the PLA matrix. The dispersed nanoparticles with their large surface areas and low percolation thresholds both can improve the properties significantly in comparison with neat PLA and can introduce new value-added properties. Recently, researchers have made extraordinary progress in the practical processing and development of products from PLA bionanocomposites. The variation of the nanofillers with different functionalities can lead to many bionanocomposite applications including environmentally friendly packaging, materials for construction, automobiles, and tissue regeneration, and load-bearing scaffolds for bone reconstruction. This Account focuses on these recent research efforts, processing techniques, and key research challenges in the development of PLA-based bionanocomposites for use in applications from green plastics to biomedical applications. Growing concerns over environmental issues and high demand for advanced polymeric materials with balanced properties have led to the development of bionanocomposites of PLA and natural origin fillers, such as nanoclays. The combination of nanoclays with the PLA matrix allows us to develop green nanocomposites that possess several superior properties. For example, adding ∼5 vol % clay to PLA improved the storage modulus, tensile strength, break elongation, crystallization rate, and other mechanical properties. More importantly, the addition of clay decreases the gas and water vapor permeation, increases the heat distortion temperature and scratch resistance, and controls the biodegradation

  11. Nanostructured reduced graphene oxide/Fe2O3 composite as a high-performance anode material for lithium ion batteries.

    Science.gov (United States)

    Zhu, Xianjun; Zhu, Yanwu; Murali, Shanthi; Stoller, Meryl D; Ruoff, Rodney S

    2011-04-26

    Reduced graphene oxide/Fe(2)O(3) composite was prepared using a facile two-step synthesis by homogeneous precipitation and subsequent reduction of the G-O with hydrazine under microwave irradiation to yield reduced graphene oxide (RG-O) platelets decorated with Fe(2)O(3) nanoparticles. As an anode material for Li-ion batteries, the RG-O/Fe(2)O(3) composite exhibited discharge and charge capacities of 1693 and 1227 mAh/g, respectively, normalized to the mass of Fe(2)O(3) in the composite (and ∼1355 and 982 mAh/g, respectively, based on the total mass of the composite), with good cycling performance and rate capability. Characterization shows that the Fe(2)O(3) nanoparticles are uniformly distributed on the surface of the RG-O platelets in the composite. The total specific capacity of RG-O/Fe(2)O(3) is higher than the sum of pure RG-O and nanoparticle Fe(2)O(3), indicating a positive synergistic effect of RG-O and Fe(2)O(3) on the improvement of electrochemical performance. The synthesis approach presents a promising route for a large-scale production of RG-O platelet/metal oxide nanoparticle composites as electrode materials for Li-ion batteries.

  12. Predictive Multiscale Modeling of Nanocellulose Based Materials and Systems

    Science.gov (United States)

    Kovalenko, Andriy

    2014-08-01

    Cellulose Nanocrysals (CNC) is a renewable biodegradable biopolymer with outstanding mechanical properties made from highly abundant natural source, and therefore is very attractive as reinforcing additive to replace petroleum-based plastics in biocomposite materials, foams, and gels. Large-scale applications of CNC are currently limited due to its low solubility in non-polar organic solvents used in existing polymerization technologies. The solvation properties of CNC can be improved by chemical modification of its surface. Development of effective surface modifications has been rather slow because extensive chemical modifications destabilize the hydrogen bonding network of cellulose and deteriorate the mechanical properties of CNC. We employ predictive multiscale theory, modeling, and simulation to gain a fundamental insight into the effect of CNC surface modifications on hydrogen bonding, CNC crystallinity, solvation thermodynamics, and CNC compatibilization with the existing polymerization technologies, so as to rationally design green nanomaterials with improved solubility in non-polar solvents, controlled liquid crystal ordering and optimized extrusion properties. An essential part of this multiscale modeling approach is the statistical- mechanical 3D-RISM-KH molecular theory of solvation, coupled with quantum mechanics, molecular mechanics, and multistep molecular dynamics simulation. The 3D-RISM-KH theory provides predictive modeling of both polar and non-polar solvents, solvent mixtures, and electrolyte solutions in a wide range of concentrations and thermodynamic states. It properly accounts for effective interactions in solution such as steric effects, hydrophobicity and hydrophilicity, hydrogen bonding, salt bridges, buffer, co-solvent, and successfully predicts solvation effects and processes in bulk liquids, solvation layers at solid surface, and in pockets and other inner spaces of macromolecules and supramolecular assemblies. This methodology

  13. A REDUCED MFE FORMULATION BASED ON POD FOR THE NON-STATIONARY CONDUCTION-CONVECTION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Luo Zhendong; Xie Zhenghui; Chen Jing

    2011-01-01

    In this article,a reduced mixed finite element (MFE) formulation based on proper orthogonal decomposition (POD) for the non-stationary conduction-convection problems is presented.Also the error estimates between the reduced MFE solutions based on POD and usual MFE solutions are derived.It is shown by numerical examples that the results of numerical computation are consistent with theoretical conclusions.Moreover,it is shown that the reduced MFE formulation based on POD is feasible and efficient in finding numerical solutions for the non-stationary conduction-convection problems.

  14. Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Basiruddin, SK; Swain, Sarat K., E-mail: swainsk2@yahoo.co.in

    2016-01-01

    Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO–PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV–visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH 7.4. - Highlights: • Easy and simple synthesis of PBA functionalized reduced GO based nano probe. • PBA functionalized reduced GO graphene based nano-probes are characterized. • PBA functionalized reduced GO nano probe is used to detect glucose molecules. • It is very cost-effective and enzyme-free detection of glucose in solution.

  15. Developing Novel Protein-based Materials using Ultrabithorax: Production, Characterization, and Functionalization

    Science.gov (United States)

    Huang, Zhao

    2011-12-01

    Compared to 'conventional' materials made from metal, glass, or ceramics, protein-based materials have unique mechanical properties. Furthermore, the morphology, mechanical properties, and functionality of protein-based materials may be optimized via sequence engineering for use in a variety of applications, including textile materials, biosensors, and tissue engineering scaffolds. The development of recombinant DNA technology has enabled the production and engineering of protein-based materials ex vivo. However, harsh production conditions can compromise the mechanical properties of protein-based materials and diminish their ability to incorporate functional proteins. Developing a new generation of protein-based materials is crucial to (i) improve materials assembly conditions, (ii) create novel mechanical properties, and (iii) expand the capacity to carry functional protein/peptide sequences. This thesis describes development of novel protein-based materials using Ultrabithorax, a member of the Hox family of proteins that regulate developmental pathways in Drosophila melanogaster. The experiments presented (i) establish the conditions required for the assembly of Ubx-based materials, (ii) generate a wide range of Ubx morphologies, (iii) examine the mechanical properties of Ubx fibers, (iv) incorporate protein functions to Ubx-based materials via gene fusion, (v) pattern protein functions within the Ubx materials, and (vi) examine the biocompatibility of Ubx materials in vitro. Ubx-based materials assemble at mild conditions compatible with protein folding and activity, which enables Ubx chimeric materials to retain the function of appended proteins in spatial patterns determined by materials assembly. Ubx-based materials also display mechanical properties comparable to existing protein-based materials and demonstrate good biocompatibility with living cells in vitro. Taken together, this research demonstrates the unique features and future potential of novel Ubx-based

  16. Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

    Directory of Open Access Journals (Sweden)

    Kaczmar J.W.

    2013-06-01

    Full Text Available Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu - 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300oC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

  17. A binder-free sulfur/reduced graphene oxide aerogel as high performance electrode materials for lithium sulfur batteries

    Science.gov (United States)

    Nitze, Florian; Agostini, Marco; Lundin, Filippa; Palmqvist, Anders E. C.; Matic, Aleksandar

    2016-12-01

    Societies’ increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3-5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of “no battery without binder” and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm2 after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications.

  18. Reduced rule base self-tuning fuzzy PI controller for TCSC

    Energy Technology Data Exchange (ETDEWEB)

    Hameed, Salman; Das, Biswarup; Pant, Vinay [Department of Electrical Engineering, Indian Institute of Technology, Roorkee, Roorkee - 247 667, Uttarakhand (India)

    2010-11-15

    In this paper, a reduced rule base self-tuning fuzzy PI controller (STFPIC) for thyristor controlled series capacitor (TCSC) is proposed. Essentially, a STFPIC consists of two fuzzy logic controllers (FLC). In this work, for each FLC, 49 rules have been used and as a result, the overall complexity of the STFPIC increases substantially. To reduce this complexity, application of singular value decomposition (SVD) based rule reduction technique is also proposed in this paper. By applying this methodology, the number of rules in each FLC has been reduced from 49 to 9. Therefore, the proposed rule base reduction technique reduces the total number of rules in the STFPIC by almost 80% (from 49 x 2 = 98 to 9 x 2 = 18), thereby reducing the complexity of the STFPIC significantly. The feasibility of the proposed algorithm has been tested on 2-area 4-machine power system and 10-machine 39-bus system through detailed digital simulation using MATLAB/SIMULINK. (author)

  19. PLC BASED RATIO CONTROLLER AND MATERIAL DISTRIBUTION SYSTEM

    Directory of Open Access Journals (Sweden)

    V. M. Badwaik Prof. V. M. Umale

    2012-04-01

    Full Text Available Automation in an industry using programmable logic controller (PLC can be enumerated by optimizing the use of process control equipment, decreases the response time for process and equipment contingencies, provides information about process status, manages process logic at the plant floor level and increases overall productivity and plant efficiency. The primary reason for designing such a system is to eliminate large cost involved in replacing complicated relay based machine control system & to reduce process time. Ratio control system is feed forward system where one variable is controlled in ratio to another to satisfy some higher level objectives. Two difference chemicals are supplied from different tanks in proper ratio by maintaining the flow of quantity. Then desired mixture is obtained &checks the ratio of composition if any unbalanced, controlled by controlled values of supply tanks. Then this mixture is distributed as per requirements. In Industries for ten machines, total cycle time with existing PLC based system is 75 sec. But our modified PLC based system total cycle time is improved as 45 sec. Hence total reach time of distribution system is improved.

  20. Novel materials process for alcohol based fuel cells. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, K.; Smith, R.

    2005-07-01

    At present, the unit cost of producing alcohol fuel cells, in particular the cost of the ion-exchange membrane and the platinum catalyst, is limiting the sales. Since the cost of platinum cannot be reduced, an effective means of making the cells more attractive would be to increase the power output per unit area of membrane other than by operating at elevated temperatures. To replace the expensive Nafion, ITM and Cranfield University have developed a new membrane based on ionic hydrophilic polymers. Both acidic and alkaline-based membranes have been produced, the latter may well avoid the use of platinum thus gaining a further cost bonus. Conductivity of the new styrene-sulphonic acid graft membranes is more than double that of Nafion. Similarly, in cross-over tests, the new cells outperformed the Nafion cells. Palladium was investigated as a cheaper alternative to platinum. Based on this study, ITM have applied for five new patents. The study was conducted by ITM Power Plc under contract to the DTI.

  1. The effects of material property assumptions on predicted meltpool shape for laser powder bed fusion based additive manufacturing

    Science.gov (United States)

    Teng, Chong; Ashby, Kathryn; Phan, Nam; Pal, Deepankar; Stucker, Brent

    2016-08-01

    The objective of this study was to provide guidance on material specifications for powders used in laser powder bed fusion based additive manufacturing (AM) processes. The methodology was to investigate how different material property assumptions in a simulation affect meltpool prediction and by corrolary how different material properties affect meltpool formation in AM processes. The sensitvity of meltpool variations to each material property can be used as a guide to help drive future research and to help prioritize material specifications in requirements documents. By identifying which material properties have the greatest affect on outcomes, metrology can be tailored to focus on those properties which matter most; thus reducing costs by eliminating unnecessary testing and property charaterizations. Futhermore, this sensitivity study provides insight into which properties require more accurate measurements, thus motivating development of new metrology methods to measure those properties accurately.

  2. A new photopolymerizable holographic recording material based on acrylamide and N-hydroxymethyl acrylamide

    Institute of Scientific and Technical Information of China (English)

    Gong Qiao-Xia; Wang Su-Lian; Huang Ming-Ju; Gan Fu-Xi

    2005-01-01

    A new polyvinylalcohol-based photopolymeric holographic recording material has been developed. The recording is obtained by the copolymerization of acrylamide and N-hydroxymethyl acrylamide. Diffraction efficiencies near 50% are obtained with energetic exposure of 80m J/cm2. N-hydroxymethyl acrylamide can improve the optical quality of the film. With the increase of the concentration of N-hydroxymethyl acrylamide, the flatness of the film increases, scattering reduces and the straight image is clearer with a small distortion. The postexposure effect on the grating is also studied.The diffraction efficiency of grating increases further during postexposure, gradient of monomer exists after exposure.

  3. Ultra High p-doping Material Research for GaN Based Light Emitters

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir Dmitriev

    2007-06-30

    The main goal of the Project is to investigate doping mechanisms in p-type GaN and AlGaN and controllably fabricate ultra high doped p-GaN materials and epitaxial structures. Highly doped p-type GaN-based materials with low electrical resistivity and abrupt doping profiles are of great importance for efficient light emitters for solid state lighting (SSL) applications. Cost-effective hydride vapor phase epitaxial (HVPE) technology was proposed to investigate and develop p-GaN materials for SSL. High p-type doping is required to improve (i) carrier injection efficiency in light emitting p-n junctions that will result in increasing of light emitting efficiency, (ii) current spreading in light emitting structures that will improve external quantum efficiency, and (iii) parameters of Ohmic contacts to reduce operating voltage and tolerate higher forward currents needed for the high output power operation of light emitters. Highly doped p-type GaN layers and AlGaN/GaN heterostructures with low electrical resistivity will lead to novel device and contact metallization designs for high-power high efficiency GaN-based light emitters. Overall, highly doped p-GaN is a key element to develop light emitting devices for the DOE SSL program. The project was focused on material research for highly doped p-type GaN materials and device structures for applications in high performance light emitters for general illumination P-GaN and p-AlGaN layers and multi-layer structures were grown by HVPE and investigated in terms of surface morphology and structure, doping concentrations and profiles, optical, electrical, and structural properties. Tasks of the project were successfully accomplished. Highly doped GaN materials with p-type conductivity were fabricated. As-grown GaN layers had concentration N{sub a}-N{sub d} as high as 3 x 10{sup 19} cm{sup -3}. Mechanisms of doping were investigated and results of material studies were reported at several International conferences providing

  4. Synthesis of designed materials by laser-based direct metal deposition technique: Experimental and theoretical approaches

    Science.gov (United States)

    Qi, Huan

    Direct metal deposition (DMD), a laser-cladding based solid freeform fabrication technique, is capable of depositing multiple materials at desired composition which makes this technique a flexible method to fabricate heterogeneous components or functionally-graded structures. The inherently rapid cooling rate associated with the laser cladding process enables extended solid solubility in nonequilibrium phases, offering the possibility of tailoring new materials with advanced properties. This technical advantage opens the area of synthesizing a new class of materials designed by topology optimization method which have performance-based material properties. For better understanding of the fundamental phenomena occurring in multi-material laser cladding with coaxial powder injection, a self-consistent 3-D transient model was developed. Physical phenomena including laser-powder interaction, heat transfer, melting, solidification, mass addition, liquid metal flow, and species transportation were modeled and solved with a controlled-volume finite difference method. Level-set method was used to track the evolution of liquid free surface. The distribution of species concentration in cladding layer was obtained using a nonequilibrium partition coefficient model. Simulation results were compared with experimental observations and found to be reasonably matched. Multi-phase material microstructures which have negative coefficients of thermal expansion were studied for their DMD manufacturability. The pixel-based topology-optimal designs are boundary-smoothed by Bezier functions to facilitate toolpath design. It is found that the inevitable diffusion interface between different material-phases degrades the negative thermal expansion property of the whole microstructure. A new design method is proposed for DMD manufacturing. Experimental approaches include identification of laser beam characteristics during different laser-powder-substrate interaction conditions, an

  5. Applying distance-to-target weighing methodology to evaluate the environmental performance of bio-based energy, fuels, and materials

    NARCIS (Netherlands)

    Weiss, M.; Patel, M.K.; Heilmeier, H.; Bringezu, S.

    2007-01-01

    The enhanced use of biomass for the production of energy, fuels, and materials is one of the key strategies towards sustainable production and consumption. Various life cycle assessment (LCA) studies demonstrate the great potential of bio-based products to reduce both the consumption of non-renewabl

  6. Applying distance-to-target weighing methodology to evaluate the environmental performance of bio-based energy, fuels, and materials

    NARCIS (Netherlands)

    Weiss, M.|info:eu-repo/dai/nl/156419912; Patel, M.K.|info:eu-repo/dai/nl/18988097X; Heilmeier, H.; Bringezu, S.

    2007-01-01

    The enhanced use of biomass for the production of energy, fuels, and materials is one of the key strategies towards sustainable production and consumption. Various life cycle assessment (LCA) studies demonstrate the great potential of bio-based products to reduce both the consumption of

  7. Photonic devices based on black phosphorus and related hybrid materials

    Science.gov (United States)

    Vitiello, M. S.; Viti, L.

    2016-08-01

    Artificial semiconductor heterostructures played a pivotal role in modern electronic and photonic technologies, providing a highly effective means for the manipulation and control of carriers, from the visible to the far-infrared, leading to the development of highly efficient devices like sources, detectors and modulators. The discovery of graphene and the related fascinating capabilities have triggered an unprecedented interest in devices based on inorganic two-dimensional (2D) materials. Amongst them, black phosphorus (BP) recently showed an extraordinary potential in a variety of applications across micro-electronics and photonics. With an energy gap between the gapless graphene and the larger gap transition metal dichalcogenides, BP can form the basis for a new generation of high-performance photonic devices that could be specifically engineered to comply with different applications, like transparent saturable absorbers, fast photocounductive switches and low noise photodetectors, exploiting its peculiar electrical, thermal and optical anisotropy. This paper will review the latest achievements in black-phosphorus-based THz photonics and discuss future perspectives of this rapidly developing research field.

  8. Characterization techniques for graphene-based materials in catalysis

    Directory of Open Access Journals (Sweden)

    Maocong Hu

    2017-06-01

    Full Text Available Graphene-based materials have been studied in a wide range of applications including catalysis due to the outstanding electronic, thermal, and mechanical properties. The unprecedented features of graphene-based catalysts, which are believed to be responsible for their superior performance, have been characterized by many techniques. In this article, we comprehensively summarized the characterization methods covering bulk and surface structure analysis, chemisorption ability determination, and reaction mechanism investigation. We reviewed the advantages/disadvantages of different techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR and Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS, X-Ray diffraction (XRD, X-ray absorption near edge structure (XANES and X-ray absorption fine structure (XAFS, atomic force microscopy (AFM, scanning electron microscopy (SEM, transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM, ultraviolet-visible spectroscopy (UV-vis, X-ray fluorescence (XRF, inductively coupled plasma mass spectrometry (ICP, thermogravimetric analysis (TGA, Brunauer–Emmett–Teller (BET, and scanning tunneling microscopy (STM. The application of temperature-programmed reduction (TPR, CO chemisorption, and NH3/CO2-temperature-programmed desorption (TPD was also briefly introduced. Finally, we discussed the challenges and provided possible suggestions on choosing characterization techniques. This review provides key information to catalysis community to adopt suitable characterization techniques for their research.

  9. Hierarchically organized soft-materials based on fullerenes

    Science.gov (United States)

    Nakanishi, Takashi

    2009-04-01

    Simple chemical modifications of fullerene (C60) with long aliphatic chains provide novel type amphiphilic molecules playing in organic solvents due to the two different intermolecular interactions, namely π-π on C60 and van der Waals interactions on aliphatic chain moieties, respectively, and open a door developing supramolecular soft-materials having hierarchically organized architectures, various morphologies and functions based on fullerenes. By tuning the length and number of aliphatic chains on the derivatives as well as experimental conditions such as solvents, temperature, substrates for preparation of the assemblies, the assembled fullerenes showed various faces such as creating of many unique-shaped objects with controlled their dimensionality. For instance, nanowires and thin disks with single bilayer thickness in nanometer size, globular, fibrous, conical objects in mesoscopic (sub-micrometer) scale and flower-shaped and direction-controlled spiral objects in micrometer scale are obtained. As bulk states, thermotropic liquid crystals and room temperature (isotropic) liquid fullerenes are interestingly prepared from this molecular designs and showed not only their fluid natures and comparably high carrier mobility as fullerene-based organic-semiconductor phenomena. In addition, nano-carbon superhydrophobic surface with fractal morphology of the two-tier roughness on a nano- and microscopic scale was created from one of the supramolecular objects. The all of hierarchical supramolecular assemblies describing in this review is derived from fine-tuning intermolecular interactions of fullerene derivatives bearing long aliphatic chains.

  10. Subscale Water Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Sheth, Rubik; Hansen, Scott

    2016-01-01

    Supplemental heat rejection devices are required in many spacecraft as the radiators are not sized to meet the full heat rejection demand. One means of obtaining additional heat rejection is through the use of phase change material heat exchangers (PCM HX's). PCM HX's utilize phase change to store energy in unfavorable thermal environments (melting) and reject the energy in favorable environments (freezing). Traditionally, wax has been used as a PCM on spacecraft. However, water is an attractive alternative because it is capable of storing about 40% more energy per unit mass due to its higher latent heat of fusion. The significant problem in using water as a PCM is its expansion while freezing, leading to structural integrity concerns when housed in an enclosed heat exchanger volume. Significant investigation and development has taken place over the past five years to understand and overcome the problems associated with water PCM HX's. This paper reports on the final efforts by Johnson Space Center's Thermal Systems Branch to develop a water based PCM HX. The test article developed and reported on is a subscale version of the full-scale water-based PCM HX's constructed by Mezzo Technologies. The subscale unit was designed by applying prior research on freeze front propagation and previous full-scale water PCM HX development. Design modifications to the subscale unit included use of urethane bladder, decreased aspect ratio, perforated protection sheet, and use of additional mid-plates. Testing of the subscale unit was successful and 150 cycles were completed without fail.

  11. Suitable Friction Sliding Materials for Base Isolation of Masonry Buildings

    Directory of Open Access Journals (Sweden)

    Radhikesh P. Nanda

    2012-01-01

    Full Text Available A feasibility study of friction base isolation system for seismic protection has been performed. Four different sliding interfaces, namely, green marble/High Density Poly Ethylene (HDPE, green marble/green marble, green marble/geosynthetic, and green marble/ rubber layers have been studied through experimental and analytical investigations. The experimental investigations show that the coefficient of friction values of these interfaces lies in the desirable range for seismic protection, i.e., 0.05 to 0.15. The analytical investigation reveals that most of these sliding interfaces are effective in reducing spectral accelerations up to 50% and the sliding displacement is restricted within plinth projection of 75 mm (3 in. Green marble and geosynthetic are found to be better alternatives for use in friction isolation system with equal effectiveness of energy dissipation and limiting the earthquake energy transmission to super structure during strong earthquake leading to a low cost, durable solution for earthquake protection of masonry buildings.

  12. Copper base materials prepared by gel-casting process

    Institute of Scientific and Technical Information of China (English)

    LIU Weihua; JIA Chengchang; SHI Yantao; HAN Yuepeng

    2008-01-01

    Gel-casting process was developed as a new molding process in the field of copper base powder metallurgy to manufacture metal parts with excellent performance and complex shapes.Through changing the parameters of gel-casting process,such as dispersant and solid loading,the corresponding effects on the rheology of Cu slurries,molding and sintering behaviors were studied.The results show that the viscosity of Cu slurries was significantly reduced with an increase in dispersant.The most appropriate solid loading was found to be 61% and the sintering temperature was 910℃ in these experiments.After the optimization of parameters of gel-casting process,copper composite parts with relatively high density and better properties were obtained.

  13. Reduction study of oxidized two-dimensional graphene-based materials by chemical and thermal reduction methods

    Science.gov (United States)

    Douglas, Amber M.

    Graphene is a two-dimensional (2D) sp2-hybridized carbon-based material possessing properties which include high electrical conductivity, ballistic thermal conductivity, tensile strength exceeding that of steel, high flexural strength, optical transparency, and the ability to adsorb and desorb atoms and molecules. Due to the characteristics of said material, graphene is a candidate for applications in integrated circuits, electrochromic devices, transparent conducting electrodes, desalination, solar cells, thermal management materials, polymer nanocomposites, and biosensors. Despite the above mentioned properties and possible applications, very few technologies have been commercialized utilizing graphene due to the high cost associated with the production of graphene. Therefore, a great deal of effort and research has been performed to produce a material that provides similar properties, reduced graphene oxide due (RGO) to the ease of commercial scaling of the production processes. This material is typically prepared through the oxidation of graphite in an aqueous media to graphene oxide (GO) followed by reduction to yield RGO. Although this material has been extensively studied, there is a lack of consistency in the scientific community regarding the analysis of the resulting RGO material. In this dissertation, a study of the reduction methods for GO and an alternate 2D carbon-based material, humic acid (HA), followed by analysis of the materials using Raman spectroscopy and Energy Dispersive X-ray Spectroscopy (EDS). Means of reduction will include chemical and thermal methods. Characterization of the material has been carried out on both before and after reduction.

  14. Model Stirrer Based on a Multi-Material Turntable for Microwave Processing Materials

    Science.gov (United States)

    Ye, Jinghua; Hong, Tao; Wu, Yuanyuan; Wu, Li; Liao, Yinhong; Zhu, Huacheng; Yang, Yang; Huang, Kama

    2017-01-01

    Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE) and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation. During the heating process, the processed material is placed on a fixed Teflon bracket which covers the constantly rotating turntable. Experiments are conducted to measure the surface and point temperatures using an infrared thermal imaging camera and optical fibers. Simulated results are compared qualitatively with the measured ones, which verifies the simulated models. Compared with the turntables consisting of a single material, a 26%–47% increase in temperature uniformity from adapting the multi-material turntable can be observed for the microwave-processed materials. PMID:28772457

  15. Transparent Façade Panel Typologies Based on Recyclable Polymer Materials

    Directory of Open Access Journals (Sweden)

    Harry Giles

    2012-11-01

    Full Text Available Buildings are large consumers of energy. In the United States of America; they constitute over 33% of the total annual energy consumption, produce 35% of the total carbon dioxide emissions and attribute 40% of landfill wastes. The building industry is also a large consumer of non-renewable materials and this trend has escalated dramatically over the past century. It is essential that we find ways to save on energy consumption through the use of solar energy, improved thermal insulation, and alternative efficient glazed façade systems. In this paper, we demonstrate how alternative typologies of transparent and translucent load-bearing façade systems based on biocomposite and recyclable materials, are structurally and thermally efficient at the same time they contribute towards reduced pollutant emissions and non-renewable material uses.Composite insulated panel systems are used extensively in the engineering and building industry, owing to their structural and thermal efficiency. However, these systems are generally opaque and offer little flexibility in building applications. As an alternative, we demonstrate how building products comprised of hybrid material typologie scan be made to perform efficiently as load-bearing façade systems that substitute for current glazing systems with adequate thermal and structural performance, which also possess good light transmission characteristics and integral shading capability. The materials are configured to work as composite panel systems made from a combination of biocomposite and recyclable polymer materials. These materials are environmentally sustainable, because they either originate from naturally grown renewable resources or are recyclable. Our research program includes the design and development of prototype panel systems; the evaluation of structural and thermal performance, together with their role in reducing energy consumption and pollution emission through life cycle analysis. The paper

  16. Reducing self-objectification: are dissonance-based methods a possible approach?

    National Research Council Canada - National Science Library

    Becker, Carolyn Black; Hill, Kaitlin; Greif, Rebecca; Han, Hongmei; Stewart, Tiffany

    2013-01-01

    ...) pathology, and negative affect. This exploratory open study investigated whether or not an evidence-based body image improvement program that targets thin-ideal internalization in university women also reduces self-objectification...

  17. Reducing School Violence: School-Based Curricular Programs and School Climate

    Science.gov (United States)

    Greene, Michael B.

    2008-01-01

    This article examines two different, but interrelated approaches to reduce school violence: school-based curricular programs and efforts to change school climate. The state of the research for each is reviewed and the relationship between them is explored.

  18. Silk fibroin based antibacterial bionanotextiles as wound dressing materials

    Energy Technology Data Exchange (ETDEWEB)

    Çalamak, Semih [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey); Erdoğdu, Ceren; Özalp, Meral [Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Microbiology, 06100 Ankara (Turkey); Ulubayram, Kezban, E-mail: ukezban@hacettepe.edu.tr [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey)

    2014-10-01

    New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa. - Highlights: • Bionanotextiles are combination of nanotechnology and biotextile technology. • Bionanotextiles have good antibacterial activity against both of S. aureus and P. aeruginosa. • Antibacterial bionanotextiles are applicable to most of the infected wounds. • No cytotoxicity was observed on L929 cell line.

  19. Method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material

    NARCIS (Netherlands)

    Kattenberg, H.R.; Willemsen, J.H.A.; Starmans, D.A.J.; Hoving, H.D.; Winters, M.G.M.

    2002-01-01

    Described is a method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material, such as coffee or tea, and in particular cocoa, at least comprising the steps of: introducing the food base material into an aqueous extractant and incubating the food base material

  20. Recent Advances in the Sound Insulation Properties of Bio-based Materials

    Directory of Open Access Journals (Sweden)

    Xiaodong Zhu

    2013-12-01

    Full Text Available Many bio-based materials, which have lower environmental impact than traditional synthetic materials, show good sound absorbing and sound insulation performances. This review highlights progress in sound transmission properties of bio-based materials and provides a comprehensive account of various multiporous bio-based materials and multilayered structures used in sound absorption and insulation products. Furthermore, principal models of sound transmission are discussed in order to aid in an understanding of sound transmission properties of bio-based materials. In addition, the review presents discussions on the composite structure optimization and future research in using co-extruded wood plastic composite for sound insulation control. This review contributes to the body of knowledge on the sound transmission properties of bio-based materials, provides a better understanding of the models of some multiporous bio-based materials and multilayered structures, and contributes to the wider adoption of bio-based materials as sound absorbers.