WorldWideScience

Sample records for co2 interfacial properties

  1. Molecular Dynamics Simulations of CO2/Water/Quartz Interfacial Properties: Impact of CO2 Dissolution in Water.

    Science.gov (United States)

    Javanbakht, Gina; Sedghi, Mohammad; Welch, William; Goual, Lamia

    2015-06-01

    The safe trapping of carbon dioxide (CO2) in deep saline aquifers is one of the major concerns of CO2 sequestration. The amount of capillary trapping is dominated by the capillary pressure of water and CO2 inside the reservoir, which in turn is controlled by the interfacial tension (IFT) and the contact angle (CA) of CO2/water/rock systems. The measurement of IFT and CA could be very challenging at reservoir conditions, especially in the presence of toxic cocontaminants. Thus, the ability to accurately predict these interfacial properties at reservoir conditions is very advantageous. Although the majority of existing molecular dynamics (MD) studies of CO2/water/mineral systems were able to capture the trends in IFT and CA variations with pressure and temperature, their predictions often deviated from experimental data, possibly due to erroneous models and/or overlooked chemical reactions. The objective of this study was to improve the MD predictions of IFT and CA of CO2/water/quartz systems at various pressure and temperature conditions by (i) considering the chemical reactions between CO2 and water and (ii) using a new molecular model for α-quartz surface. The results showed that the presence of carbonic acid at the CO2/water interface improved the predictions of IFT, especially at low temperature and high pressure where more CO2 dissolution occurs. On the other hand, the effect on CA was minor. The slight decrease in CA observed across the pressure range investigated could be attributed to an increase in the total number of H-bonds between fluid molecules and quartz surface.

  2. Investigation of the interfacial properties for CO2-methanol and CO2-ethanol mixtures%CO2-甲醇和CO2-乙醇体系的界面性质

    Institute of Scientific and Technical Information of China (English)

    付东

    2011-01-01

    An equation of state (EOS) applicable for the interfacial properties of CO2-methanol and CO2-ethanol mixtures was established by combining the cross-association EOS and the density gradient theory (DGT). The correlated surface tensions of CO2-ethanol mixtures agreed well with the experimental data. The results illustrated the temperature and pressure dependence of the cross-association between CO2 and alcohol hydroxyls in the whole vapor-liquid surface, and the influence of the cross-association on the calculation of the surface tensions of binary mixtures.%在交叉缔合的均相状态方程的基础上,结合密度梯度理论(density gradient theory,DGT),建立了适用于CO2-甲醇和CO2-乙醇二元体系界面性质研究的状态方程,对CO2-乙醇体系表面张力的关联结果与实验值吻合良好.阐明了CO2分子与甲醇分子和乙醇分子之间的交叉缔合作用对二元体系表面张力计算结果的影响,以及界面相中CO2与醇羟基之间的交叉缔合与温度和压力之间的关系.

  3. Interfacial, electrical, and spin-injection properties of epitaxial Co2MnGa grown on GaAs(100)

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Hickey, M. C.; Holmes, S. N.

    2009-01-01

    The interfacial, electrical, and magnetic properties of the Heusler alloy Co2MnGa grown epitaxially on GaAs(100) are presented with an emphasis on the use of this metal-semiconductor combination for a device that operates on the principles of spin-injection between the two materials. Through...... systematic growth optimization the stoichiometry in the bulk Co2MnGa can be controlled to better than ±2%, although the interface is disordered and limits the spin-injection efficiency in a practical spintronic device irrespective of the half-metallic nature of the bulk metal. Molecular beam epitaxial growth...

  4. Brine/CO2 Interfacial Properties and Effects on CO2 Storage in Deep Saline Aquifers Propriétés interfaciales saumure/CO2 et effets sur le stockage du CO2 dans des aquifères salins profonds

    Directory of Open Access Journals (Sweden)

    Chalbaud C.

    2010-05-01

    Full Text Available It has been long recognized that interfacial interactions (interfacial tension, wettability, capillarity and interfacial mass transfer govern fluid distribution and behaviour in porous media. Therefore the interfacial interactions between CO2, brine and reservoir oil and/or gas have an important influence on the effectiveness of any CO2 storage operation. There is a lack of experimental data related to interfacial properties for all the geological storage options (oil & gas reservoirs, coalbeds, deep saline aquifers. In the case of deep saline aquifers, there is a gap in data and knowledge of brine-CO2 interfacial properties at storage conditions. More specifically, experimental interfacial tension values and experimental tests in porous media are necessary to better understand the wettability evolution as a function of thermodynamic conditions and it’s effects on fluid flow in the porous media. In this paper, a complete set of experimental values of brine-CO2 Interfaciale Tension (IFT at pressure, temperature and salt concentration conditions representative of those of a CO2 storage operation. A correlation is derived from experimental data published in a companion paper [Chalbaud C., Robin M., Lombard J.-M., Egermann P., Bertin H. (2009 Interfacial Tension Measurements and Wettability Evaluation for Geological CO2 Storage, Adv. Water Resour. 32, 1, 1-109] to model IFT values. This paper pays particular attention to coreflooding experiments showing that the CO2 partially wets the surface in a Intermediate-Wet (IW or Oil-Wet (OW limestone rock. This wetting behavior of CO2 is coherent with observations at the pore scale in glass micromodels and presents a negative impact on the storage capacity of a given site. Il est admis depuis longtemps que les propriétés interfaciales (tension interfaciale, mouillabilité, capillarité et transfert de masse régissent la distribution et le comportement des fluides au sein des milieux poreux. Par cons

  5. The impact of interfacial tension on multiphase flow in the CO2-brine-sandstone system

    Science.gov (United States)

    Reynolds, C. A.; Blunt, M. J.; Krevor, S. C.

    2013-12-01

    Two dominant controls on continuum scale multiphase flow properties are interfacial tension (IFT) and wetting. In hydrocarbon-brine systems, relative permeability is known to increase with decreasing IFT, while residual trapping is controlled by the wetting properties of a permeable rock and the hysteresis between drainage and imbibtion (Amaefule & Handy, 1982; Bardon & Longeron, 1980; Juanes et al., 2006). Fluid properties of the CO2-brine system, such as viscosity, density and interfacial tension, are well characterised and have known dependencies on temperature, pressure and brine salinity. Interest in this particular fluid system is motivated by CO2 storage and enhanced oil recovery. Despite increased interest in CO2 storage, the response of the CO2-brine relative permeability to varying IFT has yet to be comprehensively evaluated. Additionally the wide range of thermophysical properties (density, viscosity etc.) that exist across a relatively small range of pressures and temperatures makes it an ideal system with which to investigate the physics of multiphase flow in general. This is the first systematic study to investigate the impact of IFT on drainage and imbibition relative permeability for the CO2-brine-sandstone system. The experimental design has been adapted from a traditional steady state core flood in two ways. First, while conditions may be easily selected to obtain a range of interfacial tensions, isolating the independent impact of interfacial tension on relative permeability is less simple. Thus experimental conditions are selected so as to vary interfacial tension, while minimising the variation in viscosity ratio between CO2 and brine. Second, in order to attribute the impacts of changing conditions, it is necessary to have precise results such that small shifts in observations can be identified. Multiphase flow theory is used to both design the conditions of the test and interpret the observations, leading to a much higher precision in

  6. Interfacial Tension of CO2 and Organic Liquid under High Pressure and Temperature☆

    Institute of Scientific and Technical Information of China (English)

    Zihao Yang; Mingyuan Li; Bo Peng; Meiqin Lin; Zhaoxia Dong; Yong Ling

    2014-01-01

    In order to investigate the effect of organic liquid molecular structure and the intermolecular force operating with CO2 molecules and organic liquid molecules on interfacial tension (IFT) between CO2 and organic liquid at the first contact, the interfacial tension between CO2 and hexane, octane, ethanol and cyclohexane at different tem-peratures and pressures is measured by using the pendant drop method and the axisymmetric drop shape anal-ysis (ADSA). The results show that the interfacial tension between CO2 and organic liquids is affected by the polarity and the structure of the organic liquid molecule obviously. The intermolecular force operating within CO2 molecules or organic liquid, and that between CO2 and organic liquids molecules play a dominate role on the interfacial tension between CO2 and the organic liquids.

  7. Interfacial phenomena at the compressed co2-water interface

    Directory of Open Access Journals (Sweden)

    B. Bharatwaj

    2006-06-01

    Full Text Available Compressed CO2 is considered to be a viable alternative to toxic volatile organic solvents with potential applications in areas including separation reactions, and materials formation processes. Thus an interest in CO2 stems from the fact that it is very inexpensive, has low toxicity, and is not a regulated. However, compressed CO2 has a zero dipole moment and weak van der Waals forces and thus is a poor solvent for both polar and most high molecular weight solutes, characteristics that severely restrict its applicability. In order to overcome this inherent inability, surfactant-stabilized organic and aqueous dispersions in CO2 have been proposed. This work will discuss fundamentals and recent advances in the design of amphiphiles for the novel CO2-water interface.

  8. Interfacial Evolution of Cement and Steel in CO2 Dissolved Solution Under High Temperature and High Pressure

    Science.gov (United States)

    Ren, Chengqiang; Peng, Ye; Li, Bing; Wang, Shuliang; Shi, Taihe

    2016-09-01

    The experiments were operated for the cylindrical sample (cement/steel) in high temperature and high pressure (HTHP) CO2 environment to simulate surrounding CO2 attack in oil and gas well. The interfacial evolutions between well cement and casing steel were measured, including mechanical property, structure alteration, chemical change and electrochemical character. The interfacial behaviors are attributed to the competition of hydration and degradation of Portland cement. The damage at the interface was faster than the cement bulk deterioration by carbonation. Thus, the interface provided a potential flow leakage pathway for the HTHP gas and fluid in the well, so improving interfacial stability between well cement and casing steel is the key issue to long-term zonal isolation.

  9. Dependence of CO2-Brine Interfacial Tension on Aquifer Pressure, Temperature and Water Salinity

    Science.gov (United States)

    Bachu, S.; Bennion, B.

    2007-12-01

    Carbon dioxide storage in deep saline aquifers is a climate-change mitigation strategy that has significant potential in the short-to-medium term. The displacement of formation water by CO2 (drainage) and of CO2 by invading aquifer brine (imbibition) depend on the interfacial tension (IFT) of the CO2-brine system. To provide needed data, an extensive laboratory program was conducted for the measurement of the interfacial tension between CO2 and water or brine covering the ranges of 2 to 27 MPa pressure, 20°C to 125°C temperature, and 0 to 334,000 mg/l water salinity. The laboratory experiments were conducted using the pendant drop method combined with the Laplace solution for the profile of the brine drop in the CO2-rich environment. The analysis of the resulting set of 294 IFT measurements reveals that: 1) for conditions of constant temperature and water salinity, IFT decreases steeply with increasing pressure in the range PPc, with an asymptotic trend towards a constant value for high pressures; 2) for the same conditions of constant pressure and temperature, IFT increases with increasing water salinity, reflecting decreasing CO2 solubility in brine as salinity increases; 3) the dependence of IFT on temperature is more complex, depending on the CO2 phase. For TTc, with an asymptotic trend towards a constant value for high temperatures. These results indicate that, in the case of CO2 storage in deep saline aquifers, the formation water displacement by injected CO2 during the injection phase of CO2 storage and the CO2 displacement by invading brine during the CO2 migration phase depend on the in-situ conditions of pressure, temperature and water salinity through the effects that these primary variables have on the IFT between CO2 and aquifer brine. Since the IFT of CO2-brine systems affects relative permeability and capillary pressure, it is essential that the in-situ conditions and their effect of secondary variables are properly taken into account when

  10. Effect of Contact Time and Gas Component on Interfacial Tension of CO2/Crude Oil System by Pendant Drop Method

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2015-01-01

    Full Text Available Pendant drop method has been used to measure the equilibrium interfacial tension and dynamic interfacial tension of CO2/crude oil system under the simulated-formation condition, in which the temperature is 355.65 K and pressure ranges from 0 MPa to 30 MPa. The test results indicated that the equilibrium interfacial tension of CO2/crude oil systems decreased with the increase of the systematic pressure. The dynamic interfacial tension of CO2/original oil, CO2/remaining oil, and CO2/produced oil systems is large at the initial contact and decreases gradually after that, and then finally it reaches dynamic balance. In addition, the higher the pressure is, the larger the magnitude of changing of CO2/crude oil interfacial tension with time will reduce. Moreover, by PVT phase experiment, gas-oil ratio, gas composition, and well fluid composition have been got, and different contents of light components in three oil samples under reservoir conditions have also been calculated. The relationship between equilibrium interfacial tensions and pressures of three different components of crude oil and CO2 system was studied, and the higher C1 is, the lower C2–C10 will be, and the equilibrium interfacial tension will get higher. Therefore, the effect of light weight fractions on interfacial tension under formation conditions was studied.

  11. Impact of pressure and temperature on CO2-brine-mica contact angles and CO2-brine interfacial tension: Implications for carbon geo-sequestration.

    Science.gov (United States)

    Arif, Muhammad; Al-Yaseri, Ahmed Z; Barifcani, Ahmed; Lebedev, Maxim; Iglauer, Stefan

    2016-01-15

    Precise characterization of wettability of CO2-brine-rock system and CO2-brine interfacial tension at reservoir conditions is essential as they influence capillary sealing efficiency of caprocks, which in turn, impacts the structural and residual trapping during CO2 geo-sequestration. In this context, we have experimentally measured advancing and receding contact angles for brine-CO2-mica system (surface roughness ∼12nm) at different pressures (0.1MPa, 5MPa, 7MPa, 10MPa, 15MPa, 20MPa), temperatures (308K, 323K, and 343K), and salinities (0wt%, 5wt%, 10wt%, 20wt% and 30wt% NaCl). For the same experimental matrix, CO2-brine interfacial tensions have also been measured using the pendant drop technique. The results indicate that both advancing and receding contact angles increase with pressure and salinity, but decrease with temperature. On the contrary, CO2-brine interfacial tension decrease with pressure and increase with temperature. At 20MPa and 308K, the advancing angle is measured to be ∼110°, indicating CO2-wetting. The results have been compared with various published literature data and probable factors responsible for deviations have been highlighted. Finally we demonstrate the implications of measured data by evaluating CO2 storage heights under various operating conditions. We conclude that for a given storage depth, reservoirs with lower pressures and high temperatures can store larger volumes and thus exhibit better sealing efficiency.

  12. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 STORAGE

    Science.gov (United States)

    The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

  13. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION

    Science.gov (United States)

    The chapter discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of t...

  14. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION (PRESENTATION)

    Science.gov (United States)

    The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

  15. Interfacial contributions to perpendicular magnetic anisotropy in Pd/Co2MnSi/MgO trilayer films

    Science.gov (United States)

    Fu, Huarui; You, Caiyin; Li, Yunlong; Wang, Ke; Tian, Na

    2016-05-01

    Heusler alloy Co2MnSi is widely selected as the ferromagnetic layer to achieve a giant tunneling magnetic resistance (TMR). It is also one of the most promising materials for potential spintronic applications of magnetic random access memory (MRAM) due to the high spin polarization, in which the configuration of perpendicular magnetic anisotropy (PMA) possesses great advantages over the in-plane ones. Therefore, it is highly desirable to investigate the PMA effects of the Co2MnSi layer with a suitable stack structure. In this work, a strong PMA (1.61  ×  106 erg cm-3) is demonstrated in the system of Pd/Co2MnSi/MgO trilayer films. The contributions of the interfaces beside the ferromagnetic Co2MnSi layer were quantitatively clarified. The interfacial anisotropy K s,MgO of 0.79 erg cm-2 at the Co2MnSi/MgO interface is larger than the K s,Pd value of 0.26 erg cm-2 at the Pd/Co2MnSi interface. Due to the dual interfacial effects, the strong PMA can be sustained at the high annealing temperature with a thick Co2MnSi layer of about 4.9 nm, which is favorable to the potential spintronic application. The Mn-O bonding was also found to be enriched at the Co2MnSi/MgO interface for the annealed Pd/Co2MnSi (3.4 nm)/MgO film with the large PMA, showing an experimental evidence for the theoretical results of the Mn-O bonding contribution to PMA.

  16. Crystal structures and dynamical properties of dense CO2.

    Science.gov (United States)

    Yong, Xue; Liu, Hanyu; Wu, Min; Yao, Yansun; Tse, John S; Dias, Ranga; Yoo, Choong-Shik

    2016-10-04

    Structural polymorphism in dense carbon dioxide (CO2) has attracted significant attention in high-pressure physics and chemistry for the past two decades. Here, we have performed high-pressure experiments and first-principles theoretical calculations to investigate the stability, structure, and dynamical properties of dense CO2 We found evidence that CO2-V with the 4-coordinated extended structure can be quenched to ambient pressure below 200 K-the melting temperature of CO2-I. CO2-V is a fully coordinated structure formed from a molecular solid at high pressure and recovered at ambient pressure. Apart from confirming the metastability of CO2-V (I-42d) at ambient pressure at low temperature, results of ab initio molecular dynamics and metadynamics (MD) simulations provided insights into the transformation processes and structural relationship from the molecular to the extended phases. In addition, the simulation also predicted a phase V'(Pna21) in the stability region of CO2-V with a diffraction pattern similar to that previously assigned to the CO2-V (P212121) structure. Both CO2-V and -V' are predicted to be recoverable and hard with a Vicker hardness of ∼20 GPa. Significantly, MD simulations found that the CO2 in phase IV exhibits large-amplitude bending motions at finite temperatures and high pressures. This finding helps to explain the discrepancy between earlier predicted static structures and experiments. MD simulations clearly indicate temperature effects are critical to understanding the high-pressure behaviors of dense CO2 structures-highlighting the significance of chemical kinetics associated with the transformations.

  17. Interfacial Interactions and Wettability Evaluation of Rock Surfaces for CO2 Storage

    NARCIS (Netherlands)

    Shojai Kaveh, N.

    2014-01-01

    To reduce CO2 emissions into the atmosphere, different scenarios are proposed to capture and store carbon dioxide (CO2) in geological formations (CCS). Storage strategies include CO2 injection into deep saline aquifers, depleted gas and oil reservoirs, and unmineable coal seams. To identify a secure

  18. Improved Interfacial Affinity and CO2 Separation Performance of Asymmetric Mixed Matrix Membranes by Incorporating Postmodified MIL-53(Al).

    Science.gov (United States)

    Zhu, Haitao; Wang, Lina; Jie, Xingming; Liu, Dandan; Cao, Yiming

    2016-08-31

    Asymmetric mixed matrix membranes(MMMs) with MOFs hold great application potential for energy-efficient gas separations. However, the particle aggregation and nonselective interfacial microvoids restrict the gas separation performance of asymmetric MMMs. Herein, nanoporous metal-organic framework (MOF) of MIL-53(Al) was modified with aminosilane after solvothermal synthesis. The postfunctionalization by grafting alkyl chains can form hydrogen bonds with polymer chains to enhance the affinity with polymer matrix and facilitate the preferential adsorption of CO2 by dipole-quadrupole interaction with the functional group. Then the postmodified MIL-53(Al) was incorporated as filler into poly(ether imide) Ultem1000 to fabricate high-quality asymmetric MMMs with well dispersed particles in polymer matrix and good adhesion at the MOFs-polymer interface. The Ultem/S-MIL-53(Al) asymmetric MMMs exhibited remarkable combinations of gas permeance and ideal selectivity for CO2/N2 separation at 10 wt % filler loading. The CO2 permeance achieved 24.1 GPU, an increase of 165% compared with pure Ultem membrane. Meanwhile, the ideal CO2/N2 selectivity also increased from 31.0 up to 41.1. The strategy of post covalent modification for MOFs provides an effective way to improve the interfacial affinity and gas separation performance.

  19. Impact of interfacial tension on residual CO2 clusters in porous sandstone

    Science.gov (United States)

    Jiang, Fei; Tsuji, Takeshi

    2015-03-01

    We develop a numerical simulation that uses the lattice Boltzmann method to directly calculate the characteristics of residual nonwetting-phase clusters to quantify capillary trapping mechanisms in real sandstone. For this purpose, a digital-rock-pore model reconstructed from micro-CT-scanned images of Berea sandstone is filtered and segmented into a binary file. The residual-cluster distribution is generated following simulation of the drainage and imbibition processes. The characteristics of the residual cluster in terms of size distribution, major length, interfacial area, and sphericity are investigated under conditions of different interfacial tension (IFT). Our results indicate that high interfacial tension increases the residual saturation and leads to a large size distribution of residual clusters. However, low interfacial tension results in a larger interfacial area, which is beneficial for dissolution and reaction processes during geological carbon storage. Analysis of the force balance acting on the residual clusters demonstrates that trapping stability is higher in high interfacial tension case, and the interfacial tension should be a controlling factor for the trapping stability in addition to the pore geometry and connectivity. The proposed numerical method can handle the complex displacement of multicomponent systems in porous media. By using this method, we can obtain residual-cluster distributions under different conditions for optimizing the storage capacity of carbon-storage projects.

  20. Research on the physical properties of supercritical CO2 and the log evaluation of CO2-bearing volcanic reservoirs

    Science.gov (United States)

    Pan, Baozhi; Lei, Jian; Zhang, Lihua; Guo, Yuhang

    2017-10-01

    CO2-bearing reservoirs are difficult to distinguish from other natural gas reservoirs during gas explorations. Due to the lack of physical parameters for supercritical CO2, particularly neutron porosity, at present a hydrocarbon gas log evaluation method is used to evaluate CO2-bearing reservoirs. The differences in the physical properties of hydrocarbon and CO2 gases have led to serious errors. In this study, the deep volcanic rock of the Songliao Basin was the research area. In accordance with the relationship between the density and acoustic velocity of supercritical CO2 and temperature and pressure, the regularity between the CO2 density and acoustic velocity, and the depth of the area was established. A neutron logging simulation was completed based on a Monte Carlo method. Through the simulation of the wet limestone neutron logging, the relationship between the count rate ratio of short and long space detectors and the neutron porosity was acquired. Then, the nature of the supercritical CO2 neutron moderation was obtained. With consideration given to the complexity of the volcanic rock mineral composition, a volcanic rock volume model was established, and the matrix neutron and density parameters were acquired using the ECS log. The properties of CO2 were applied in the log evaluation of the CO2-bearing volcanic reservoirs in the southern Songliao Basin. The porosity and saturation of CO2 were obtained, and a reasonable application was achieved in the CO2-bearing reservoir.

  1. Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow

    Science.gov (United States)

    Vishwakarma, Niraj K.; Singh, Ajay K.; Hwang, Yoon-Ho; Ko, Dong-Hyeon; Kim, Jin-Oh; Babu, A. Giridhar; Kim, Dong-Pyo

    2017-01-01

    Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas–liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas–liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81–97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps. PMID:28262667

  2. Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow

    Science.gov (United States)

    Vishwakarma, Niraj K.; Singh, Ajay K.; Hwang, Yoon-Ho; Ko, Dong-Hyeon; Kim, Jin-Oh; Babu, A. Giridhar; Kim, Dong-Pyo

    2017-03-01

    Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas-liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas-liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81-97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps.

  3. Interfacial Design of Ternary Mixed Matrix Membranes Containing Pebax 1657/Silver-Nanopowder/[BMIM][BF4] for Improved CO2 Separation Performance.

    Science.gov (United States)

    Ghasemi Estahbanati, Ehsan; Omidkhah, Mohammadreza; Ebadi Amooghin, Abtin

    2017-03-08

    In this research, Pebax1657 as an organic phase and silver nanoparticles as an inorganic phase were used for preparation of binary mixed matrix membranes (MMMs). Silver nanoparticles as a filler could enter the polymer chains and enhance the gas permeability by increasing the fractional free volume of membranes. Afterward, ternary MMMs were fabricated by addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid, in order to have better polymer/filler adhesion and eliminate interfacial defects and nonselective voids. In addition, positively polarized silver nanoparticles in the presence of the IL could interact with PEO segment of the polymer and increase the CO2 affinity of membranes, which results in increasing the CO2/light gases permselectivity of MMMs. Gas permeation properties of MMMs were studied at a temperature of 35 °C and operating pressures from 2 to 10 bar. Moreover, fabricated membranes were characterized by fourier transform infrared-attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The analysis revealed that there is a proper adhesion between positively charged surface of nanoparticles and the polymer, and both filler and IL decrease the crystallinity of the membranes, which could enhance the polar gas transport properties. Gas permeation results showed significant enhancement in CO2 permeability (325 Barrer) for binary membrane (Pebax 1657/1%Ag) at 35 °C and 10 bar. Moreover, ternary MMM (Pebax 1657/0.5%Ag/50%IL) encountered significant increase in both permeability and selectivity in comparison with neat membrane. Indeed, the CO2 permeability increased from 110 Barrer to 180 (about 64%). Moreover, the related CO2/CH4 and CO2/N2 selectivities were increased from 20.8 to 61.0 (more than 193%) and from 78.6 to 187.5 (about 139%), respectively.

  4. Chitosan: Gels and Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.

  5. Interfacial properties of hybrid nanomaterials

    Indian Academy of Sciences (India)

    Itty Binil Ipe; K Yoosaf; K George Thomas

    2005-11-01

    A brief summary of our ongoing efforts to understand the surface properties of nanoparticles using fluorophores, namely pyrene alkanethiols, is presented. Excited state interactions were investigated by varying the length of the spacer group and the concentration of fluorophore. The flexible long alkyl chain tethering pyrene in Au-P2/Au-P3 allows free interaction between fluorophores resulting in excimer formation whereas the intermolecular interactions are limited in the Au-P1 system due to the restriction imposed by the curvature of spherical gold nanoparticle. A gradual increase in the peak intensity ratio of III/I band of the normal fluorescence of pyrene was observed indicating that the surface of nanoparticle is more polar than the bulk solvent (toluene).

  6. Ionic Effects on Supercritical CO2-Brine Interfacial Tensions: Molecular Dynamics Simulations and a Universal Correlation with Ionic Strength, Temperature, and Pressure.

    Science.gov (United States)

    Zhao, Lingling; Ji, Jiayuan; Tao, Lu; Lin, Shangchao

    2016-09-13

    For geological CO2 storage in deep saline aquifers, the interfacial tension (IFT) between supercritical CO2 and brine is critical for the storage security and design of the storage capacitance. However, currently, no predictive model exists to determine the IFT of supercritical CO2 against complex electrolyte solutions involving various mixed salt species at different concentrations and compositions. In this paper, we use molecular dynamics (MD) simulations to investigate the effect of salt ions on the incremental IFT at the supercritical CO2-brine interface with respect to that at the reference supercritical CO2-water interface. Supercritical CO2-NaCl solution, CO2-CaCl2 solution and CO2-(NaCl+CaCl2) mixed solution systems are simulated at 343 K and 20 MPa under different salinities and salt compositions. We find that the valence of the cations is the primary contributor to the variation in IFT, while the Lennard-Jones potentials for the cations pose a smaller impact on the IFT. Interestingly, the incremental IFT exhibits a general linear correlation with the ionic strength in the above three electrolyte systems, and the slopes are almost identical and independent of the solution types. Based on this finding, a universal predictive formula for IFTs of CO2-complex electrolyte solution systems is established, as a function of ionic strength, temperature, and pressure. The predicted IFTs using the established formula agree perfectly (with a high statistical confidence level of ∼96%) with a wide range of experimental data for CO2 interfacing with different electrolyte solutions, such as those involving MgCl2 and Na2SO4. This work provides an efficient and accurate route to directly predict IFTs in supercritical CO2-complex electrolyte solution systems for practical engineering applications, such as geological CO2 sequestration in deep saline aquifers and other interfacial systems involving complex electrolyte solutions.

  7. Spectroscopic properties of five-coordinated Co2+ in phosphates.

    Science.gov (United States)

    Hunault, M; Robert, J-L; Newville, M; Galoisy, L; Calas, G

    2014-01-03

    Co3(PO4)2, SrCo2(PO4)2, Co2P2O7, BaCoP2O7 and SrCoP2O7 present different geometries of five-coordinated Co(2+) (([5])Co(2+)) sites, coexisting with ([6])Co(2+) in Co3(PO4)2 and Co2P2O7, and ([4])Co(2+) in SrCo2(PO4)2. ([5])Co K-edge XANES spectra show that the intensity of the pre-edge and main-edge is intermediate between those of ([6])- and ([4])Co. Diffuse reflectance spectra show the contributions of Co(2+) in (D3h) symmetry for SrCo2(PO4)2, and (C4v) symmetry for BaCoP2O7 and SrCoP2O7. In Co3(PO4)2 and Co2P2O7 the multiple transitions observed arise from energy level splitting and may be labeled in (C2v) symmetry. Spectroscopic data confirm that (D3h) and (C4v) symmetries may be distinguished upon the intensity of the optical absorption bands and crystal field splitting values. We discuss the influence of the geometrical distortion and of the nature of the next nearest neighbors.

  8. Aminosilanes grafted to basic alumina as CO2 adsorbents--role of grafting conditions on CO2 adsorption properties.

    Science.gov (United States)

    Bali, Sumit; Leisen, Johannes; Foo, Guo Shiou; Sievers, Carsten; Jones, Christopher W

    2014-11-01

    Solid oxide-supported amine sorbents for CO2 capture are amongst the most rapidly developing classes of sorbent materials for CO2 capture. Herein, basic γ supports are used as hosts for amine sites through the grafting of 3-aminopropyltrimethoxysilane to the alumina surface under a variety of conditions, yielding the expected surface-grafted alkylamine groups, as demonstrated by FTIR spectroscopy and (29)Si and (13)C cross-polarization magic-angle spinning (CPMAS NMR) spectroscopy. Grafting amine sites on the surface in the presence of water leads to a high density of amine sites on the surface whereas simultaneously creating a unique type of aluminum species on the surface, as demonstrated by both 1D and 2D (27)Al MAS NMR spectroscopy. The thus prepared sorbents result in higher CO2 adsorption capacities and amine efficiencies compared to sorbents prepared in the absence of water or similar amine loading sorbents prepared using silica supports. In situ FTIR spectra of the sorbents exposed to CO2 at various pressures show no distinct difference in the nature of the adsorbed CO2 species on alumina- versus silica-supported amines, whereas water adsorption isotherms show that the improved performance of the amine-grafted alumina support is not a consequence of retained water on the more hydrophobic aminoalumina materials. The findings demonstrate that amine-grafted, basic alumina materials can be tuned to be more efficient than the corresponding silica-supported materials at comparable amine loadings, further demonstrating that the properties of amine sites can be tuned by controlling or adjusting the support surface properties.

  9. Role of interfacial rheological properties in oil field chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos-Szabo, J.; Lakatos, I.; Kosztin, B.

    1996-12-31

    Interfacial rheological properties of different Hungarian crude oil/water systems were determined in wide temperature and shear rate range and in presence of inorganic electrolytes, tensides, alkaline materials and polymers. The detailed laboratory study definitely proved that the interfacial rheological properties are extremely sensitive parameters towards the chemical composition of inmiscible formation liquids. Comparison and interpretation of the interfacial rheological properties may contribute significantly to extension of the weaponry of the reservoir characterization, better understanding of the displacement mechanism, development of the more profitable EOR/IOR methods, intensification of the surface technologies, optimization of the pipeline transportation and improvement of the refinery operations. It was evidenced that the interfacial rheology is an efficient and powerful detection technique, which may enhance the knowledge on formation, structure, properties and behaviour of interfacial layers. 17 refs., 18 figs., 2 tabs.

  10. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Directory of Open Access Journals (Sweden)

    Ana Arenillas

    2013-10-01

    Full Text Available Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar and capacities (>2 mmol·g−1 at 273 K. Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes.

  11. Interfacial properties of stanene-metal contacts

    Science.gov (United States)

    Guo, Ying; Pan, Feng; Ye, Meng; Wang, Yangyang; Pan, Yuanyuan; Zhang, Xiuying; Li, Jingzhen; Zhang, Han; Lu, Jing

    2016-09-01

    Recently, two-dimensional buckled honeycomb stanene has been manufactured by molecular beam epitaxy growth. Free-standing stanene is predicted to have a sizable opened band gap of 100 meV at the Dirac point due to spin-orbit coupling (SOC), resulting in many fascinating properties such as quantum spin Hall effect, quantum anomalous Hall effect, and quantum valley Hall effect. In the first time, we systematically study the interfacial properties of stanene-metal interfaces (metals = Ag, Au, Cu, Al, Pd, Pt, Ir, and Ni) by using ab initio electronic structure calculations considering the SOC effects. The honeycomb structure of stanene is preserved on the metal supports, but the buckling height is changed. The buckling of stanene on the Au, Al, Ag, and Cu metal supports is higher than that of free-standing stanene. By contrast, a planar graphene-like structure is stabilized for stanene on the Ir, Pd, Pt, and Ni metal supports. The band structure of stanene is destroyed on all the metal supports, accompanied by a metallization of stanene because the covalent bonds between stanene and the metal supports are formed and the structure of stanene is distorted. Besides, no tunneling barrier exists between stanene and the metal supports. Therefore, stanene and the eight metals form a good vertical Ohmic contact.

  12. Magnetic properties and interfacial characteristics of all-epitaxial Heusler-compound stacking structures

    Science.gov (United States)

    Yamada, S.; Honda, S.; Hirayama, J.; Kawano, M.; Santo, K.; Tanikawa, K.; Kanashima, T.; Itoh, H.; Hamaya, K.

    2016-09-01

    We study magnetic properties and interfacial characteristics of all-epitaxial D 03-Fe3Si /L 21 - Fe3 -xMnxSi /L 21-Co2FeSi Heusler-compound trilayers grown on Ge(111) by room-temperature molecular beam epitaxy. We find that the magnetization reversal processes can be intentionally designed by changing the chemical composition of the intermediate Fe3 -xMnxSi layers because of their tunable ferromagnetic-paramagnetic phase-transition temperature. From first-principles calculations, interfacial half metallicity in the Co2FeSi layer is nearly expected when the sequence of stacking layers along of the Fe2MnSi /Co2FeSi interface includes the atomic row of L 21 - or B 2 -ordered structures. We believe that Co2FeSi /Fe2MnSi /Co2FeSi trilayer systems stacked along will open a new avenue for high-performance current-perpendicular-to-plane giant magnetoresistive devices with Heusler compounds.

  13. Interfacial properties and emulsification performance of thylakoid membrane fragments

    NARCIS (Netherlands)

    Tamayo Tenorio, A.; Jong, de E.W.M.; Nikiforidis, K.; Boom, R.M.; Goot, van der A.J.

    2017-01-01

    Thylakoids membranes are sophisticated, dynamic structures found in plant leaves, composed of protein complexes in a dynamic lipid matrix. The interfacial absorption dynamics and viscoelasticity of thylakoid membranes fragments were measured to assess the properties of the interfacial layer and to e

  14. CO2 injection effect on physical properties of greensand from the North Sea

    DEFF Research Database (Denmark)

    Hossain, Zakir; Fabricius, Ida Lykke

    2011-01-01

    into brine saturated samples and flush the CO2 saturated samples with brine at reservoir conditions. Helium porosity, Klinkenberg permeability, and specific surface area (SSA) by BET were measured on dry greensand samples before and after the CO2 experiment. NMR T2 distribution and electrical resistivity...... were measured on brine saturated greensand samples before and after the CO2 experiment. Ultrasonic P-and Swave velocities were measured on brine saturated samples as well as on dry samples. Our laboratory results show that CO2 injection has no major effect on porosity, electrical and elastic properties...... of greensand. The Klinkenberg permeability of greensand increased after CO2 injection. An NMR T2 distribution and NMR permeability modeling approach was tested to evaluate the effect on matrix permeability of CO2 injection. It appears that permeability after CO2 injection increased due to the increase of macro...

  15. Interfacial Tension and Contact Angle Determination in Water-sandstone Systems with Injection of Flue Gas and CO2

    NARCIS (Netherlands)

    Shojaikaveh, N.; Rudolph, E.S.J.; Rossen, W.R.; Van Hemert, P.; Wolf, K.H.A.A.

    2013-01-01

    Carbon capture and storage (CCS) has the potential for reducing CO2 emissions to the atmosphere. This option includes storage strategies such as CO2 injection into deep saline aquifers, depleted oil and gas reservoirs, and unmineable coal seams. This process is largely controlled by the interactions

  16. Pore-scaling Modeling of Physical Property Changes During CO2 Injection into Sandstone

    Science.gov (United States)

    Keehm, Y.; Yoo, G.

    2009-12-01

    Carbon dioxide is a green-house gas and is believed to be an important factor in global warming and climate change. Many countries around the world are working on reducing and sequestrating CO2 to follow international regulations. One of promising area for CO2 sequestration is the storage in geological formation. To accurately determine the performance of geological injection and storage, quantification and monitoring of the physical property changes are essential. In this paper, we are presenting a new approach for the monitoring of CO2 sequestration in sandstone using pore-scale simulation techniques. The method consists of three steps: 1) acquisition of high-resolution pore microstructures by X-ray micro-tomography; 2) CO2 injection simulation using lattice-Boltzmann (LB) two-phase flow simulation; and 3) FEM property simulations (electrical and elastic) at different CO2 saturations during the injection. We use three different sandstone samples: sand-pack, Berea sandstone, and B2 sandstone from offshore of Korea. The porosity of the sand-pack is 42% and that of two sandstone samples is around 17%. The digital pore structures were obtained by X-ray micro-tomography with a spatial resolution of 2 micron. The LB two-phase flow simulation is then conducted by injecting CO2 into fully water-saturated samples and gives a realistic movement of CO2 in the pore structure. At each CO2 saturation, electrical and elastic properties are determined by pore-scale FEM simulation techniques. The electrical conductivity decreases almost linearly as CO2 saturations increases; however, the P-wave velocity decrease more rapidly at the low CO2 saturation (up to 30%), than at higher saturation. S-wave velocity does not show any significant changes. The higher porosity rock shows more sensitivity to saturation changes. The modeling shows that we can have quantitative relations between physical properties and CO2 saturation, which can be used to determine injection performance and

  17. Cheminformatics Modeling of Amine Solutions for Assessing their CO2 Absorption Properties.

    Science.gov (United States)

    Kuenemann, Melaine A; Fourches, Denis

    2017-03-07

    As stricter regulations on CO2 emissions are adopted worldwide, identifying efficient chemical processes to capture and recycle CO2 is of critical importance for industry. The most common process known as amine scrubbing suffers from the lack of available amine solutions capable of capturing CO2 efficiently. Tertiary amines characterized by low heats of reaction are considered good candidates but their absorption properties can significantly differ from one analogue to another despite high structural similarity. Herein, after collecting and curating experimental data from the literature, we have built a modeling set of 41 amine structures with their absorption properties. Then we analyzed their chemical composition using molecular descriptors and non-supervised clustering. Furthermore, we developed a series of quantitative structure-property relationships (QSPR) to assess amines' CO2 absorption properties from their structural characteristics. These models afforded reasonable prediction performances (e. g., Q(2)LOO =0.63 for CO2 absorption amount) even though they are solely based on 2D chemical descriptors and individual machine learning techniques (random forest and neural network). Overall, we believe the chemical analysis and the series of QSPR models presented in this proof-of-concept study represent new knowledge and innovative tools that could be very useful for screening and prioritizing hypothetical amines to be synthesized and tested experimentally for their CO2 absorption properties.

  18. Interfacial Properties Modification of Carbon Fiber/ Polyarylacetylene Composites

    Institute of Scientific and Technical Information of China (English)

    FU Hong-jun; MA Chong-qi; KUANG Nai-hang; LUAN Shi-lin

    2007-01-01

    This work was dedicated to performing surface oxidation and coating treatments on carbon fibers (CF) and investigating the changes of fiber surface properties after these treatments, including surface composition, relative volume of functional groups, and surface topography with X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) technology. The results show that,after oxidation treatments, interfacial properties between CF and non-polar polyarylacetylene (PAA) resin are remarkably modified by removing weak surface layers and increasing fiber surface roughness. Coating treatment by high char phenolic resin solution after oxidation makes interface of CF/PAA composites to be upgraded and the interfacial properties further bettered.

  19. Experimental Investigation of Mechanical Properties of Black Shales after CO2-Water-Rock Interaction

    Directory of Open Access Journals (Sweden)

    Qiao Lyu

    2016-08-01

    Full Text Available The effects of CO2-water-rock interactions on the mechanical properties of shale are essential for estimating the possibility of sequestrating CO2 in shale reservoirs. In this study, uniaxial compressive strength (UCS tests together with an acoustic emission (AE system and SEM and EDS analysis were performed to investigate the mechanical properties and microstructural changes of black shales with different saturation times (10 days, 20 days and 30 days in water dissoluted with gaseous/super-critical CO2. According to the experimental results, the values of UCS, Young’s modulus and brittleness index decrease gradually with increasing saturation time in water with gaseous/super-critical CO2. Compared to samples without saturation, 30-day saturation causes reductions of 56.43% in UCS and 54.21% in Young’s modulus for gaseous saturated samples, and 66.05% in UCS and 56.32% in Young’s modulus for super-critical saturated samples, respectively. The brittleness index also decreases drastically from 84.3% for samples without saturation to 50.9% for samples saturated in water with gaseous CO2, to 47.9% for samples saturated in water with super-critical carbon dioxide (SC-CO2. SC-CO2 causes a greater reduction of shale’s mechanical properties. The crack propagation results obtained from the AE system show that longer saturation time produces higher peak cumulative AE energy. SEM images show that many pores occur when shale samples are saturated in water with gaseous/super-critical CO2. The EDS results show that CO2-water-rock interactions increase the percentages of C and Fe and decrease the percentages of Al and K on the surface of saturated samples when compared to samples without saturation.

  20. Magnetic properties of PrCo 2 and its ternary hydride PrCo 2H 4

    Science.gov (United States)

    de Jongh, L. J.; Bartolomé, J.; Greidanus, F. J. A. M.; de Groot, H. J. M.; Stipdonk, H. L.; Buschow, K. H. J.

    1981-12-01

    Magnetization and susceptibility data on PrCo 2 and PrCo 2H 4 are presented. The ac susceptibility of PrCo 2 measured in zero dc field displays a sharp and high peak at Tc = (39.9 ± 0.2) K. The magnetization versus temperature curves show ferromagnetic behaviour for B >1 T, but display a maximum at lower values of the applied field. These results, together with the behaviour of the hysteresis loops at different temperatures below Tc, indicate that PrCo 2 orders ferromagnetically, the magnetic hardness increasing strongly for T → 0. The saturation moment at 4.2 K equals 3.9 μ B per formula unit, as found from the magnetization curve measured in a pulsed-field magnet up to B = 30 T. Similar experiments on PrCo 2H 4 provide evidence that the introduction of hydrogen in PrCo 2 not only destroys the long-range atomic order, but also considerably reduces the ferromagnetic interactions. Such an effect of the hydrogen is commonly observed in cobalt intermetallics. Part of the PrCo 2H 4 is found to have decomposed into PrH 2 and free Co. The clusters of free Co atoms give rise to a maximum in the zero-field ac susceptibility versus temperature curves, similar as observed in spin glasses or magnetic glasses. By increasing the ac frequency, the maximum shifts to higher temperatures. The behavior can be explained in terms of the Néel model for superparamagnetic particles with randomly oriented local anisotropy axes.

  1. Separation performance and interfacial properties of nanocomposite reverse osmosis membranes

    KAUST Repository

    Pendergast, MaryTheresa M.

    2013-01-01

    Four different types of nanocomposite reverse osmosis (RO) membranes were formed by interfacial polymerization of either polyamide (PA) or zeolite A-polyamide nanocomposite (ZA-PA) thin films over either pure polysulfone (PSf) or zeolite A-polysulfone nanocomposite (ZA-PSf) support membranes cast by wet phase inversion. All three nanocomposite membranes exhibited superior separation performance and interfacial properties relative to hand-cast TFC analogs including: (1) smoother, more hydrophilic surfaces (2) higher water permeability and salt rejection, and (3) improved resistance to physical compaction. Less compaction occurred for membranes with nanoparticles embedded in interfacially polymerized coating films, which adds further proof that flux decline associated with physical compaction is influenced by coating film properties in addition to support membrane properties. The new classes of nanocomposite membrane materials continue to offer promise of further improved RO membranes for use in desalination and advanced water purification. © 2011 Elsevier B.V.

  2. Roles of interfacial reaction on mechanical properties of solder interfaces

    Science.gov (United States)

    Liu, Pilin

    This study investigated roles of interfacial reaction in fracture and fatigue of solder interconnects. The interfacial reaction phases in the as-reflowed and after aging were examined by cross-sectional transmission electron microscopy (TEM) while interfacial mechanical properties were determined from a flexural peel fracture mechanics technique. Because of their widespread uses in microelectronic packaging, SnPb solder interfaces, and Bi-containing Pb-free solder interfaces were chosen as the subjects of this study. In the interfacial reaction study, we observed a complicated micro structural evolution during solid-state aging of electroless-Ni(P)/SnPb solder interconnects. In as-reflowed condition, the interfacial reaction produced Ni3Sn 4 and P-rich layers. Following overaging, the interfacial microstructure degenerated into a complex multilayer structure consisting of multiple layers of Ni-Sn compounds and transformed Ni-P phases. In SnPb solder interfacial system, fatigue study showed that the overaging of the high P electroless Ni-P/SnPb interconnects resulted in a sharp reduction in the fatigue resistance of the interface in the high crack growth rate regime. Fracture mechanism analysis indicated that the sharp drop in fatigue resistance was triggered by the brittle fracture of the Ni3Sn2 intermetallic phase developed at the overaged interface. The fatigue behavior was strongly dependent on P concentration in electroless Ni. Kirkendall voids were found in the interfacial region after aging, but they did not cause premature fracture of the solder interfaces. In Bi-containing solder interfacial system, we found that Bi segregated to the Cu-intermetallic interface during aging in SnBi/Cu interconnect. This caused serious embrittlement of Sn-Bi/Cu interface. Further aging induced numerous voids along the Cu3Sn/Cu interface. These interfacial voids were different from Kirkendall voids. Their formation was explained on basis of vacancy condensation at the

  3. Effect of Co2+ doping on solubility, crystal growth and properties of ADP crystals

    Science.gov (United States)

    Ganesh, V.; Shkir, Mohd.; AlFaify, S.; Yahia, I. S.

    2016-09-01

    Bulk size crystal growth of ADP with different concentrations doping of cobalt (Co2+) has been done by low cost slow evaporation technique at ambient conditions. The solubility measurement was carried out on pure and doped crystals and found that the solubility is decreasing with doping concentrations. The presence of Co2+ ion in crystalline matrix of ADP has been confirmed by structural, vibrational and elemental analyses. Scanning electron microscopic study reveals that the doping has strong effect on the quality of the crystals. The optical absorbance and transmission confirms the enhancement of quality of ADP crystals due to Co2+ doping and so the optical band gap. Further the dislocation, photoluminescence, dielectric and mechanical studies confirms that the properties of grown crystals with Co2+ doping has been enriched and propose it as a better candidate for optoelectronic applications.

  4. Loss mechanism and microwave absorption properties of hierarchical NiCo2O4 nanomaterial

    Science.gov (United States)

    Zhou, Min; Lu, Fei; Lv, Tianyi; Yang, Xing; Xia, Weiwei; Shen, Xiaoshuang; He, Hui; Zeng, Xianghua

    2015-06-01

    Understanding the loss mechanism of microwave absorption is of great significance for the design and fabrication of low-cost, high-efficient and light-weight microwave absorbing materials. In this study, the microwave absorption of a hierarchical NiCo2O4 nanomaterial synthesized via a hydrothermal method and a subsequent annealing process was investigated in detail. The effects of the annealing temperature on the phase evaluation and microwave absorption properties were also investigated to reveal the microwave loss mechanism of NiCo2O4 nanostructures. The results show that the Debye relaxation and superior electric conductivity of NiCo2O4 are beneficial to its excellent microwave absorption performance. This study will be useful for the fundamental understanding of microwave absorption in NiCo2O4 nanomaterial, and for the design of a novel microwave absorbent.

  5. In situ determination of interfacial energies between heterogeneously nucleated CaCO3 and quartz substrates: thermodynamics of CO2 mineral trapping.

    Science.gov (United States)

    Fernandez-Martinez, Alejandro; Hu, Yandi; Lee, Byeongdu; Jun, Young-Shin; Waychunas, Glenn A

    2013-01-02

    The precipitation of carbonate minerals--mineral trapping--is considered one of the safest sequestration mechanisms ensuring long-term geologic storage of CO(2). However, little is known about the thermodynamic factors controlling the extent of heterogeneous nucleation at mineral surfaces exposed to the fluids in porous reservoirs. The goal of this study is to determine the thermodynamic factors controlling heterogeneous nucleation of carbonate minerals on pristine quartz (100) surfaces, which are assumed representative of sandstone reservoirs. To probe CaCO(3) nucleation on quartz (100) in solution and with nanoscale resolution, an in situ grazing incidence small-angle X-ray scattering technique has been utilized. With this method, a value of α' = 36 ± 5 mJ/m(2) for the effective interfacial free energy governing heterogeneous nucleation of CaCO(3) has been obtained by measuring nucleation rates at different solution supersaturations. This value is lower than the interfacial energy governing calcite homogeneous nucleation (α ≈ 120 mJ/m(2)), suggesting that heterogeneous nucleation of calcium carbonate is favored on quartz (100) at ambient pressure and temperature conditions, with nucleation barriers between 2.5% and 15% lower than those expected for homogeneous nucleation. These observations yield important quantitative parameters readily usable in reactive transport models of nucleation at the reservoir scale.

  6. Spectroscopic and luminescent properties of Co2+ doped tin oxide thin films by spray pyrolysis

    Directory of Open Access Journals (Sweden)

    K. Durga Venkata Prasad

    2016-07-01

    Full Text Available The wide variety of electronic and chemical properties of metal oxides makes them exciting materials for basic research and for technological applications alike. Oxides span a wide range of electrical properties from wide band-gap insulators to metallic and superconducting. Tin oxide belongs to a class of materials called Transparent Conducting Oxides (TCO which constitutes an important component for optoelectronic applications. Co2+ doped tin oxide thin films were prepared by chemical spray pyrolysis synthesis and characterized by powder X-ray diffraction, SEM, TEM, FT-IR, optical, EPR and PL techniques to collect the information about the crystal structure, coordination/local site symmetry of doped Co2+ ions in the host lattice and the luminescent properties of the prepared sample. Powder XRD data revealed that the crystal structure belongs to tetragonal rutile phase and its lattice cell parameters are evaluated. The average crystallite size was estimated to be 26 nm. The morphology of prepared sample was analyzed by using SEM and TEM studies. Functional groups of the prepared sample were observed in the FT-IR spectrum. Optical absorption and EPR studies have shown that on doping, Co2+ ions enter in the host lattice as octahedral site symmetry. PL studies of Co2+ doped SnO2 thin films exhibit blue and yellow emission bands. CIE chromaticity coordinates were also calculated from emission spectrum of Co2+ doped SnO2 thin films.

  7. Interfacial Properties of an Ionic Liquid by Molecular Dynamics

    NARCIS (Netherlands)

    Heggen, B.; Zhao, W.; Leroy, F.; Dammers, A.T.; Müller-Plathe, F.

    2010-01-01

    We studied the influence of a liquid-vapor interface on dynamic properties like reorientation and diffusion as well as the surface tension of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) by molecular dynamics simulations. In the interfacial region, reorientation of

  8. Interfacial Properties of an Ionic Liquid by Molecular Dynamics

    NARCIS (Netherlands)

    Heggen, B.; Zhao, W.; Leroy, F.; Dammers, A.T.; Müller-Plathe, F.

    2010-01-01

    We studied the influence of a liquid-vapor interface on dynamic properties like reorientation and diffusion as well as the surface tension of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) by molecular dynamics simulations. In the interfacial region, reorientation of

  9. Interfacial properties of immiscible Co-Cu alloys

    DEFF Research Database (Denmark)

    Egry, I.; Ratke, L.; Kolbe, M.

    2010-01-01

    Using electromagnetic levitation under microgravity conditions, the interfacial properties of an Cu75Co25 alloy have been investigated in the liquid phase. This alloy exhibits a metastable liquid miscibility gap and can be prepared and levitated in a configuration consisting of a liquid cobalt......-rich core surrounded by a liquid copper-rich shell. Exciting drop oscillations and analysing the frequency spectrum, both surface and (liquid–liquid) interfacial tension can be derived from the observed oscillation frequencies. This paper briefly reviews the theoretical background and reports on a recent...

  10. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

    Directory of Open Access Journals (Sweden)

    Saravana Periaswamy Sivagnanam

    2015-05-01

    Full Text Available The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri was extracted by using environmentally friendly supercritical CO2 (SC-CO2 with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v. The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.

  11. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction.

    Science.gov (United States)

    Sivagnanam, Saravana Periaswamy; Yin, Shipeng; Choi, Jae Hyung; Park, Yong Beom; Woo, Hee Chul; Chun, Byung Soo

    2015-05-29

    The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone-methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.

  12. Thermal stability, swelling behavior and CO 2 absorption properties of Nanoscale Ionic Materials (NIMs)

    KAUST Repository

    Andrew Lin, Kun-Yi

    2014-11-11

    © The Royal Society of Chemistry 2015. Nanoscale Ionic Materials (NIMs) consist of a nanoscale core, a corona of charged brushes tethered on the surface of the core, and a canopy of the oppositely charged species linked to the corona. Unlike conventional polymeric nanocomposites, NIMs can display liquid-like behavior in the absence of solvents, have a negligible vapor pressure and exhibit unique solvation properties. These features enable NIMs to be a promising CO2 capture material. To optimize NIMs for CO2 capture, their structure-property relationships were examined by investigating the roles of the canopy and the core in their thermal stability, and thermally- and CO2-induced swelling behaviors. NIMs with different canopy sizes and core fractions were synthesized and their thermal stability as well as thermally- and CO2-induced swelling behaviors were determined using thermogravimetry, and ATR FT-IR and Raman spectroscopies. It was found that the ionic bonds between the canopy and the corona, as well as covalent bonds between the corona and the core significantly improved the thermal stability compared to pure polymer and polymer/nanofiller mixtures. A smaller canopy size and a larger core fraction led to a greater enhancement in thermal stability. This thermal stability enhancement was responsible for the long-term thermal stability of NIMs over 100 temperature swing cycles. Owing to their ordered structure, NIMs swelled less when heated or when they adsorbed CO2 compared to their corresponding polymers. This journal is

  13. Synthesis and electrochemical properties of polyaniline nanofibers by interfacial polymerization.

    Science.gov (United States)

    Manuel, James; Ahn, Jou-Hyeon; Kim, Dul-Sun; Ahn, Hyo-Jun; Kim, Ki-Won; Kim, Jae-Kwang; Jacobsson, Per

    2012-04-01

    Polyaniline nanofibers were prepared by interfacial polymerization with different organic solvents such as chloroform and carbon tetrachloride. Field emission scanning electron microscopy and transmission electron microscopy were used to study the morphological properties of polyaniline nanofibers. Chemical characterization was carried out using Fourier transform infrared spectroscopy, UV-Vis spectroscopy, and X-ray diffraction spectroscopy and surface area was measured using BET isotherm. Polyaniline nanofibers doped with lithium hexafluorophosphate were prepared and their electrochemical properties were evaluated.

  14. Thermoelectric Properties and Electronic Structure of Ca3Co2O6

    Institute of Scientific and Technical Information of China (English)

    AN Ji-ming; MIN Xin-min; CHEN Sheng-li; NAN Ce-wen

    2004-01-01

    The nanosized Ca3Co2O6 powder was synthesized via sol-gel process. The phase composition was characterized by means of X-ray diffraction. Polycrystalline samples of Ca3Co2O6 were prepared by a sintering procedure of nanosized power. The seebeck coefficient and electrical conductivity of the samples were measured from 450K up to 750K. The results show that the Seebeck coefficient increases with the increasing temperature. The electronic structures were calculated using the self-consistent full-potential linearized augmented plane-wave(LAPW) method within the density functional theory. The relationship between thermoelectric property and electronic structures was discussed.

  15. Magnetic properties and magnetocaloric effect in TbCo2-xFex compounds

    Institute of Scientific and Technical Information of China (English)

    Zou Jun-Ding; Shen Bao-Gen; Sun Ji-Rong

    2007-01-01

    Magnetic properties and magnetocaloric effect in TbCo2-xFex compounds are studied by DC magnetic measurement. With increasing content of Fe, the entropy changes decrease slightly, though the Curie temperature is tuned from 231 K (x = 0) to 303 K (x = 0.1). Magnetic entropies of TbCo2 compound are calculated by using mean field approximation (MFA). Results estimated by using Maxwell relation are consistent with that of MFA calculation. It si shown that the entropy changes are mainly derived from the magnetic entropy change. The lattice has almost no contribution to the entropy change in the vicinity of phase transition.

  16. Interfacial Properties of Electron Beam Cured Composites

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, C.C.

    1999-12-30

    The objectives of the CRADA are to: Confirm that fiber-resin adhesion is responsible for the observed poor shear properties; Determine the mechanism(s) responsible for poor adhesion between carbon fibers and epoxy resins after e-beam curing; Develop and evaluate resin systems and fiber treatments to improve the properties of e-beam cured, carbon-fiber-reinforced composites; and Develop refined methods for processing e-beam cured, carbon-fiber-reinforced composites.

  17. Effects of copper vapour on thermophysical properties of CO2-N2 plasma

    Science.gov (United States)

    Zhong, Linlin; Wang, Xiaohua; Rong, Mingzhe; Cressault, Yann

    2016-10-01

    CO2-N2 mixtures are often used as arc quenching medium (to replace SF6) in circuit breakers and shielding gas in arc welding. In such applications, copper vapour resulting from electrode surfaces can modify characteristics of plasmas. This paper therefore presents an investigation of the effects of copper on thermophysical properties of CO2-N2 plasma. The equilibrium compositions, thermodynamic properties (including mass density, specific enthalpy, and specific heat), transport coefficients (including electrical conductivity, viscosity, and thermal conductivity), and four kinds of combined diffusion coefficients due to composition gradients, applied electric fields, temperature gradients, and pressure gradients respectively, were calculated and discussed for CO2-N2 (mixing ratio 7:3) plasma contaminated by different proportions of copper vapour. The significant influences of copper were observed on all the properties of CO2-N2-Cu mixtures. The better ionization ability and larger molar mass of copper and larger collision integrals related to copper, should be responsible for such influences.

  18. SWCNT Composites, Interfacial Strength and Mechanical Properties

    DEFF Research Database (Denmark)

    Ma, Jing; Larsen, Mikael

    2013-01-01

    Abstract: Single-Walled Carbon Nanotubes (SWCNT) have despite the superior mechanical properties not fully lived up to the promise as reinforcement in SWCNT composites. The strain transfer from matrix to carbon nanotubes (CNT) is poorly understood and is caused by both fewer localized strong bond...... is applied to the composite materials. The effect of polymer matrix, modification and concentration of the CNTs are discussed. The strain transfer i.e. 2D band shift under tension is compared to the mechanical properties of the SWCNT composite material.......Abstract: Single-Walled Carbon Nanotubes (SWCNT) have despite the superior mechanical properties not fully lived up to the promise as reinforcement in SWCNT composites. The strain transfer from matrix to carbon nanotubes (CNT) is poorly understood and is caused by both fewer localized strong...

  19. Lipases at interfaces: unique interfacial properties as globular proteins.

    Science.gov (United States)

    Reis, P; Miller, R; Krägel, J; Leser, M; Fainerman, V B; Watzke, H; Holmberg, K

    2008-06-01

    The adsorption behavior of two globular proteins, lipase from Rhizomucor miehei and beta-lactoglobulin, at inert oil/water and air/water interfaces was studied by the pendant drop technique. The kinetics and adsorption isotherms were interpreted for both proteins in different environments. It was found that the adopted mathematical models well describe the adsorption behavior of the proteins at the studied interfaces. One of the main findings is that unique interfacial properties were observed for lipase as compared to the reference beta-lactoglobulin. A folded drop with a "skinlike" film was formed for the two proteins after aging followed by compression. This behavior is normally associated with protein unfolding and covalent cross-linking at the interface. Despite this, the lipase activity was not suppressed. By highlighting the unique interfacial properties of lipases, we believe that the presented work contributes to a better understanding of lipase interfacial activation and the mechanisms regulating lipolysis. The results indicate that the understanding of the physical properties of lipases can lead to novel approaches to regulate their activity.

  20. Effect of support structure on CO2 adsorption properties of pore-expanded hyperbranched aminosilicas

    KAUST Repository

    Drese, Jeffrey H.

    2012-03-01

    Hyperbranched aminosilica (HAS) CO 2 adsorbents are prepared by the ring-opening polymerization of aziridine from SBA-15 mesoporous silica, as in the original synthesis of HAS materials, as well as over an array of new support materials with substantially larger average pore diameters to elucidate the effect of support porosity on final adsorbent properties. Pore-expanded hyperbranched aminosilica (PEHAS) CO 2 adsorbents are prepared from several different pore-expanded, ordered mesoporous silicas including pore-expanded SBA-15, mesocellular foam, and a large-pore commercial silica. The effect of the nature of the silica support is determined by examining the degree of aziridine polymerization and the CO 2 adsorption kinetics and capacities of the resulting organic/inorganic hybrid materials. Comparisons are made to non-pore-expanded SBA-15 based HAS adsorbents, reported previously, where pores become blocked at higher amine loadings. The PEHAS materials unexpectedly possess lower amine loadings than the previously reported HAS materials and do not exhibit pore blocking. The use of acetic acid as a catalyst during PEHAS synthesis only marginally increases amine loading. The adsorption kinetics of PEHAS adsorbents are similar to HAS adsorbents with low amine loadings and do not show the detrimental effects of pore-blocking. However, the inability to synthesize PEHAS adsorbents with high amine loadings via this approach limits the total amount of CO 2 captured per gram of material, compared to HAS adsorbents with high amine loadings. © 2011 Elsevier Inc. All rights reserved.

  1. Preparation of activated carbons and their adsorption properties for greenhouse gases: CH4 and CO2

    Institute of Scientific and Technical Information of China (English)

    Hao Yang; Maochu Gong; Yaoqiang Chen

    2011-01-01

    Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD,FT-IR and texture property test.The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces.The texture property test reveals that the activated carbons displayed different texture properties,especially the micropore size distribution.The adsorption capacities of the activated carbons were investigated by adsorbing CH4,CO2,N2 and O2 at 25 ℃ in the pressure range of 0-200 kPa.The results reveal that all the activated carbons had high CO2 adsorption capacity,one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa.And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa.In the pressure range of 0-200 kPa,the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.

  2. The effect of selected supercritical CO2 plant extract addition on user properties of shower gels

    Directory of Open Access Journals (Sweden)

    Vogt Otmar

    2014-12-01

    Full Text Available The formulations of washing cosmetics i.e. shower gels, containing extracts obtained during supercritical CO2 extraction process as active ingredient, were developed. The subject of the study was the analysis of the physicochemical and user properties of the obtained products. In the work supercritical CO2 extracts of black currant seeds, strawberry seeds, hop cones and mint leafs were used. The formulation contains a mixture of surfactants (disodium cocoamphodiacetate, disodium laureth sulfosuccinate, cocoamide DEA, cocoamidepropyl betaine, Sodium Laureth Sulfate. Various thickener agents were applied to the obtained desired rheological properties of the cosmetics. Among others, sorbitol acetal derivatives, methylhydroxypropylcellulose and C10-30 alkyl acrylate crosspolymer were used. For stable products, the effect of extracts addition (black currants seeds, strawberries seeds, mint and hops, obtained from supercritical CO2 extraction process on the cosmetics properties, such as pH, viscosity, detergency and foam ability, were determined. The obtained results showed that the extracts could be used as components of shower gels.

  3. Effects of CO2-induced Reaction on the Transport Properties of Debonded Well Cement-Casing Interfaces: Reactive Flow-through Experiments on the Metre Scale

    Science.gov (United States)

    Wolterbeek, T. K. T.; Peach, C. J.; Spiers, C. J.

    2014-12-01

    Debonding between casing and cement may create interfacial leakage pathways, compromising well integrity in CO2 storage systems. Our previous work on such debonding-defects showed that chemical reactions between cement, steel and CO2-fluids provide only limited potential for local reaction-induced sealing, allowing short-range defects to remain open. Changes in temperature and stress state may subsequently cause these defects to grow and connect, potentially forming long-range interfacial leakage pathways. This study investigates how CO2-induced reaction affects the transport properties of such interconnected defects by means of reactive flow-through experiments. Metre scale sections of debonded cement-casing interface were simulated using composite samples, prepared as follows. Cement was cast into steel tube coils (L 1.5-3.0 m, ø 6-8 mm). After curing, the coils were pressurized using water, causing the steel tube to deform permanently and lift off the cement, creating casing-cement samples that contain sections of (partially) debonded cement-steel interface. Reactive flow-through experiments were performed in a permeameter, capable of running at temperatures (80°C ± 0.5 °C) and fluid pressures (10-12 MPa) representative for downhole environments. The coil samples were one-sidedly flooded with CO2-bearing fluid, continuously measuring apparent sample permeability and periodically sampling the downstream fluid. Additionally, post-experiment microstructural analyses were performed. Results show permeability decreases of several orders, indicating reactive-transport phenomena that occur on the metre scale contribute significantly to the sealing-potential. As such, our experiments can be used to understand the long-range behaviour of annuli in wells, beyond the commonly used lab-scale.

  4. Magnetic properties of Y1- xGdxCo2B2C series of borocarbides

    Science.gov (United States)

    Bud'ko, S. L.; Giordanengo, B.; Sulpice, A.; Fontes, M. B.; Baggio-Saitovitch, E. M.

    1995-04-01

    Magnetic properties of Y1- xGdxCo2B2C series of compounds were studied. Two magnetically ordered phases were observed for 0.7 ≤ x ≤ 1. Change of the magnetic ordering temperatures T 1 and T 2 with the Gd concentration is argued to be related to the dilution of magnetic Gd by nonmagnetic Y and to the reduction of the distance between ( Y1- xGdx) C planes. However, significant contribution to the changes in T 1 between pure GdNi2B2C and GdCo2B2C samples is suggested to be due to the different 3 d band filling in these compounds.

  5. Crystallography and Physical Properties of BaCo2As2, Ba0.94K0.06Co2As2, and Ba0.78K0.22Co2As2

    Energy Technology Data Exchange (ETDEWEB)

    Anand, V K [Ames Laboratory; Quirinale, Dante G [Ames Laboratory; Lee, Yongbin [Ames Laboratory; Harmon, Bruce N [Ames Laboratory; Furukawa, Yuji [Ames Laboratory; Ogloblichev, V V [Ural Division of Russian Academy of Science; Huq, A [Oak Ridge National Laboratory; Abernathy, D L [Oak Ridge National Laboratory; Stephens, P W [SUNY of Stony Brook; McQueeney, Robert J [Ames Laboratory; Kreyssig, Aandreas [Ames Laboratory; Goldman, Alan I [Ames Laboratory; Johnston, David C [Ames Laboratory

    2014-08-01

    The crystallographic and physical properties of polycrystalline and single crystal samples of BaCo2As2 and K-doped Ba{1-x}K{x}Co2As2 (x = 0.06, 0.22) are investigated by x-ray and neutron powder diffraction, magnetic susceptibility chi, magnetization, heat capacity Cp, {75}As NMR and electrical resistivity rho measurements versus temperature T. The crystals were grown using both Sn flux and CoAs self-flux, where the Sn-grown crystals contain 1.6-2.0 mol% Sn. All samples crystallize in the tetragonal ThCr2Si2-type structure (space group I4/mmm). For BaCo2As2, powder neutron diffraction data show that the c-axis lattice parameter exhibits anomalous negative thermal expansion from 10 to 300 K, whereas the a-axis lattice parameter and the unit cell volume show normal positive thermal expansion over this T range. No transitions in BaCo2As2 were found in this T range from any of the measurements. Below 40-50 K, we find rho ~ T^2 indicating a Fermi liquid ground state. A large density of states at the Fermi energy D(EF) ~ 18 states/(eV f.u.) for both spin directions is found from low-T Cp(T) measurements, whereas the band structure calculations give D(EF) = 8.23 states/(eV f.u.). The {75}As NMR shift data versus T have the same T dependence as the chi(T) data, demonstrating that the derived chi(T) data are intrinsic. The observed {75}As nuclear spin dynamics are consistent with the presence of ferromagnetic and/or stripe-type antiferromagnetic spin fluctuations. The crystals of Ba{0.78}K{0.22}Co2As2 were grown in Sn flux and show properties very similar to those of undoped BaCo2As2. On the other hand, the crystals from two batches of Ba{0.94}K{0.06}Co2As2 grown in CoAs self-flux show evidence of weak ferromagnetism at T < 10 K with small ordered moments at 1.8 K of 0.007 and 0.03 muB per formula unit, respectively.

  6. Understanding about How Different Foaming Gases Effect the Interfacial Array Behaviors of Surfactants and the Foam Properties.

    Science.gov (United States)

    Sun, Yange; Qi, Xiaoqing; Sun, Haoyang; Zhao, Hui; Li, Ying

    2016-08-02

    In this paper, the detailed behaviors of all the molecules, especially the interfacial array behaviors of surfactants and diffusion behaviors of gas molecules, in foam systems with different gases (N2, O2, and CO2) being used as foaming agents were investigated by combining molecular dynamics simulation and experimental approaches for the purpose of interpreting how the molecular behaviors effect the properties of the foam and find out the key factors which fundamentally determine the foam stability. Sodium dodecyl sulfate SDS was used as the foam stabilizer. The foam decay and the drainage process were determined by Foamscan. A texture analyzer (TA) was utilized to measure the stiffness and viscoelasticity of the foam films. The experimental results agreed very well with the simulation results by which how the different gas components affect the interfacial behaviors of surfactant molecules and thereby bring influence on foam properties was described.

  7. Exploiting interfacial water properties for desalination and purification applications.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongwu (Los Alamos National Laboratory, Los Alamos, NM); Varma, Sameer; Nyman, May Devan; Alam, Todd Michael; Thuermer, Konrad; Holland, Gregory P.; Leung, Kevin; Liu, Nanguo (University of New Mexico Albuquerque, NM); Xomeritakis, George K. (University of New Mexico Albuquerque, NM); Frankamp, Benjamin L.; Siepmann, J. Ilja (University of Minnesota, Minneapolis, MN); Cygan, Randall Timothy; Hartl, Monika A. (Los Alamos National Laboratory, Los Alamos, NM); Travesset, Alex (Iowa State University, Ames, IA); Anderson, Joshua A. (Iowa State University, Ames, IA); Huber, Dale L.; Kissel, David J. (University of New Mexico Albuquerque, NM); Bunker, Bruce Conrad; Lorenz, Christian Douglas; Major, Ryan C. (University of Minnesota, Minneapolis, MN); McGrath, Matthew J. (University of Minnesota, Minneapolis, MN); Farrow, Darcie; Cecchi, Joseph L. (University of New Mexico Albuquerque, NM); van Swol, Frank B.; Singh, Seema; Rempe, Susan B.; Brinker, C. Jeffrey; Clawson, Jacalyn S.; Feibelman, Peter Julian; Houston, Jack E.; Crozier, Paul Stewart; Criscenti, Louise Jacqueline; Chen, Zhu (University of New Mexico Albuquerque, NM); Zhu, Xiaoyang (University of Minnesota, Minneapolis, MN); Dunphy, Darren Robert (University of New Mexico Albuquerque, NM); Orendorff, Christopher J.; Pless, Jason D.; Daemen, Luke L. (Los Alamos National Laboratory, Los Alamos, NM); Gerung, Henry (University of New Mexico Albuquerque, NM); Ockwig, Nathan W.; Nenoff, Tina Maria; Jiang, Ying-Bing; Stevens, Mark Jackson

    2008-09-01

    A molecular-scale interpretation of interfacial processes is often downplayed in the analysis of traditional water treatment methods. However, such an approach is critical for the development of enhanced performance in traditional desalination and water treatments. Water confined between surfaces, within channels, or in pores is ubiquitous in technology and nature. Its physical and chemical properties in such environments are unpredictably different from bulk water. As a result, advances in water desalination and purification methods may be accomplished through an improved analysis of water behavior in these challenging environments using state-of-the-art microscopy, spectroscopy, experimental, and computational methods.

  8. Physical Properties of CO2 Frost Formed by Radiative Cooling in a Mars Simulation Chamber

    Science.gov (United States)

    Wood, Stephen; Bruckner, A.; Hansen, G.; Cornwall, C.; Kimber, N.; Alvarez, F.

    2013-10-01

    We have performed realistic laboratory simulations of the thermal and radiative environment at the surface of Mars to produce the first samples of carbon dioxide ice formed as it does on Mars, by radiative cooling from a near-pure CO2 gas. It is important to determine the physical characteristics of Mars' seasonal CO2 polar ice caps because these determine their radiative properties which, in turn, control the polar energy balance and the seasonal variation in global surface pressure. It is not known whether they form as fluffy fine-grained deposits, dense solid ice, or something in between. Previous simulations have used conductive cooling, condensing CO2 onto a substrate cooled by liquid nitrogen (Kieffer 1968, Ditteon and Kieffer 1979). This technique favors the growth of grains having the best thermal contact with the surface, resulting in large grain sizes and a coarse texture. On Mars, however, the latent heat released by condensation must be lost radiatively to space. For this experiment, we have constructed a Mars simulation chamber containing low thermal conductivity analog regolith and low pressure CO2 gas. To grow radiation frost in the laboratory requires simultaneous containment of the atmosphere/vapor while allowing infrared radiation to escape (to balance the latent heat of condensation). Planets accomplish this using gravity to hold down the atmosphere. The key to our simulation is the use of a thin polypropylene film that is largely transparent in the thermal infrared yet strong enough to maintain the required pressure differential between our Mars-like "atmosphere" and the vacuum-enclosed space simulator (a liquid-nitrogen cooled plate). We use internal and external light sources to briefly illuminate the frost and obtain high resolution images of its physical morphology and texture using an in situ fiberscope with an articulated tip. Initial results will be presented.

  9. Pore-scale Analysis on Physics Property Changes of CO2 Bleached Sandstone, Entrada Fromation, Utah

    Science.gov (United States)

    Han, J.; Keehm, Y.

    2012-12-01

    Since carbon dioxide injected into geological formations can cause a variety of physical and chemical reaction with minerals, it is important to evaluate the characteristics and aspects of these effects in CO2 geological sequestration. For the analog of the phenomena, we conducted pore-scale analysis on porosity and permeability changes and their characteristics for CO2-bleached Entrada formation, Utah due to natural leakage of CO2. From thin section analysis, we observed mineralogical and pore-shape changes: precipitation of carbonate minerals. Then, we estimated porosity and permeability from thin section, using a computational rock physics technique. The estimated porosity of unbleached sample is approximately 13% and that of bleached sample is around 10%, which implies the precipitation of carbonate minerals. The estimated permeability showed a little differences between two samples. This observations seems to imply that the precipitation would occur where permeability is not significantly affected: grain contacts. For more systematic analysis, we obtained 3D pore microstructures by X-ray microtomography technique. The preliminary analysis using the 3D pore microstructures showed similar results to what we found in the thin-section analysis. And a set of simulations for porosity and permeability are now being conducted. The final result will help understand how injected CO2 changes pore structures and physical properties such as porosity and permeability, and will also help accurate monitoring of geological storage sites. Acknowledgement: This work was supported by the Energy Resources R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 2010201020001A).

  10. Thermoplastic starch/wood composites: interfacial interactions and functional properties.

    Science.gov (United States)

    Müller, Péter; Renner, Károly; Móczó, János; Fekete, Erika; Pukánszky, Béla

    2014-02-15

    Thermoplastic starch (TPS)/wood composites were prepared from starch plasticized with 36 wt% glycerol. The components were homogenized by dry-blending, extruded and injection molded to tensile bars. Tensile properties, structure, deformation, water adsorption and shrinkage were determined as a function of wood content, which changed between 0 and 40 vol% in 7 steps. The modification of TPS with wood particles improves several properties considerably. Stiffness and strength increases, and the effect is stronger for fibers with larger aspect ratio. Wood fibers reinforce TPS considerably due to poor matrix properties and strong interfacial interactions, the latter resulting in the decreased mobility of starch molecules and in the fracture of large wood particles during deformation. Strong interfacial adhesion leads to smaller water absorption than predicted from additivity, but water uptake remains relatively large even in the presence of wood particles. The shrinkage of injection molded TPS parts is very large, around 10%, and dimensional changes occur on a very long timescale of several hundred hours. Shrinkage decreases to a low level already at 15-20 vol% wood content rendering the composites good dimensional stability.

  11. Physical Properties and CO2 Reaction Pathway of 1-Ethyl-3-Methylimidazolium Ionic Liquids with Aprotic Heterocyclic Anions

    Energy Technology Data Exchange (ETDEWEB)

    Seo, S; DeSilva, MA; Brennecke, JF

    2014-12-25

    Ionic liquids (ILs) with aprotic heterocyclic anions (AHA) are attractive candidates for CO2 capture technologies. In this study, a series of AHA ILs with 1-ethyl-3-methylimidazolium ([emim](+)) cations were synthesized, and their physical properties (density, viscosity, and ionic conductivity) were measured. In addition, CO2 solubility in each IL was determined at room temperature using a volumetric method at pressures between 0 and 1 bar. The AHAs are basic anions that are capable of reacting stoichiometrically with CO2 to form carbamate species. An interesting CO2 uptake isotherm behavior was observed, and this may be attributed to a parallel, equilibrium proton exchange process between the imidazolium cation and the basic AHA in the presence of CO2, followed by the formation of "transient" carbene species that react rapidly with CO2. The presence of the imidazolium-carboxylate species and carbamate anion species was verified using H-1 and C-13 NMR spectroscopy. While the reaction between CO2 and the proposed transient carbene resulted in cation-CO2 binding that is stronger than the anion-CO2 reaction, the reactions of the imidazolium AHA ILs were fully reversible upon regeneration at 80 degrees C with nitrogen purging. The presence of water decreased the CO2 uptake due to the inhibiting effect of the neutral species (protonated form of AHA) that is formed.

  12. Octa-BODIPY derivative dendrimeric cyclotetraphosphazenes; photophysical properties and fluorescent chemosensor for Co2 + ions

    Science.gov (United States)

    Şenkuytu, Elif; Eçik, Esra Tanrıverdi

    2017-02-01

    We have designed and synthesized the first examples of fluorescent chemosensors based on octa-BODIPY decorated dendrimeric cyclotetraphosphazenes. The structures these synthesized compounds were verified by 1H, 13C, 31P NMR spectroscopies and UV-vis electronic absorption spectra. The photophysical and metal sensing properties in THF solutions of dendrimeric cyclotetraphosphazenes (OBCP 1-3) were investigated by fluorescence spectroscopy. OBCP 1-3 showed strong absorption in the 500-640 nm region with high molar extinction coefficients. Additionally, octa-BODIPY decorated dendrimeric cyclotetraphosphazenes are candidate for fluorescent chemosensor for Co2 + showing high selectivity with a low limit of detection.

  13. Influence of CO2 Laser Radiation on the Mechanical Properties of Portland Cement Pastes

    Directory of Open Access Journals (Sweden)

    González-Mota, R.

    2011-03-01

    Full Text Available This article presents the results of the treatment of fresh cement pastes with CO2 laser radiation (10.6μm, in order to improve its mechanical properties in addition to obtaining lower setting times than those of a natural setting (without radiation . It was observed that the CO2 laser radiation has a positive influence on the mechanical properties of cement paste, not due to the heat produced during irradiation, but due to the effect of electric field propagation on water molecules, whose are arranged around functional groups of the binder and by the effect of ration, causes a micro vibration effect, resulting in a more compact and less porous paste which has better mechanical properties compared to natural setting paste. The internal and surface temperature of the samples, the evolution of setting, Young's modulus (using ultrasonic pulse velocity and compressive strength were registered.En este artículo se presentan los resultados correspondientes al tratamiento de pastas frescas de cemento con radiación láser de CO2 (10.6µm, con el propósito de mejorar sus propiedades mecánicas además de obtener tiempos de fraguado menores a los del fraguado en forma natural (sin radiación. Se demostró que la radiación con láser de CO2 influye positivamente en las propiedades mecánicas de la pasta de cemento, no por el calentamiento producido durante la irradiación, sino por el efecto de la propagación del campo eléctrico sobre las moléculas de agua que están dispuestas alrededor de los grupos funcionales del aglutinante y que al rotar producen un efecto equivalente a micro vibraciones, dando como resultado un material más compacto, con menos poros y mejores propiedades mecánicas respecto al fraguado natural. Se registró la temperatura interna y superficial de las muestras, la evolución del fraguado, el módulo de Young y la resistencia a compresión.

  14. Effect of Co2+ Ions Doping on the Structural and Optical Properties of Magnesium Aluminate

    Science.gov (United States)

    Kanwal, Kiran; Ismail, Bushra; Rajani, K. S.; Kissinger, N. J. Suthan; Zeb, Aurang

    2017-07-01

    Cobalt-doped nanosized magnesium aluminate (Mg1-xCoxAl2O4) samples having different compositions ( x = 0.2, 0.4, 0.6, 0.8, 1.0) were synthesized by a chemical co-precipitation method. All samples were characterized by means of x-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared spectroscopy, ultra violet-visible spectroscopy, photoluminescence and diffused reflectance spectroscopy. The results of XRD revealed that the samples were spinel single phase cubic close packed crystalline materials. The lattice constant and x-ray density were found to be affected by the ionic radii of the doped metal cations. Using the Debye-Scherrer formula, the calculated crystalline size was found to be Co2+ ion concentration-dependent and varied between 32 nm and 40 nm. Nano-dimensions and phase of the Mg1-xCoxAl2O4 samples were analyzed and the replacement of Mg2+ ions with Co2+ ions was confirmed by elemental analysis. Three strong absorption bands at 540 nm, 580 nm and 630 nm were observed for the doped samples which are attributed to the three spin-allowed 4T1g (4F) → 4T2g, 4A2g, 4T1g (4P) electronic transitions of Co2+ at tetrahedral lattice sites. Nanophosphors have optical properties different from bulk because of spatial confinement and non-radiative relaxation. Decreases in particle size can increase the surface area and the defects, which can in turn increase the luminescent efficiency to make it very useful for tunable laser operations, persistent phosphorescence, color centers, photoconductivity and luminescence for display technology. MgAl2O4 was doped with Co2+ ions using a co-precipitation method and the optical absorption studies revealed that there is a decrease of band gap due to the increase of Co2+ content. The emission intensity of this phosphor is observed at 449 nm with a sharp peak attributed to the smaller size of the particles and the homogeneity of the powder.

  15. Interfacial Properties of CZTS Thin Film Solar Cell

    Directory of Open Access Journals (Sweden)

    N. Muhunthan

    2014-01-01

    Full Text Available Cu-deficient CZTS (copper zinc tin sulfide thin films were grown on soda lime as well as molybdenum coated soda lime glass by reactive cosputtering. Polycrystalline CZTS film with kesterite structure was produced by annealing it at 500°C in Ar atmosphere. These films were characterized for compositional, structural, surface morphological, optical, and transport properties using energy dispersive X-ray analysis, glancing incidence X-ray diffraction, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, UV-Vis spectroscopy, and Hall effect measurement. A CZTS solar cell device having conversion efficiency of ~0.11% has been made by depositing CdS, ZnO, ITO, and Al layers over the CZTS thin film deposited on Mo coated soda lime glass. The series resistance of the device was very high. The interfacial properties of device were characterized by cross-sectional SEM and cross-sectional HRTEM.

  16. Study on Phase Equilibrium Properties for CO2+Cosolvent Binary Systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this study, the constant volume, visual method is used to measure thc critical point of CO2toluene, CO2+cyclohexane, CO2+n-butyraldehyde, CO2+i-butyraldchyde, CO2+methanol and CO2+alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.

  17. Evaluating the impacts of caprock and reservoir properties on potential risk of CO2 leakage after injection

    Science.gov (United States)

    Hou, Z.; Murray, C. J.; Rockhold, M. L.

    2010-12-01

    Numerical models are essential tools for CO2 sequestration projects and should be included in the life cycle of a project. Common practice involves modeling the behavior of CO2 during and after injection using site-specific reservoir and caprock properties. Little has been done to systematically evaluate and compare the effects of a realistic range of reservoir and caprock properties on potential CO2 leakage through caprock. Broad-based research addressing the impacts of caprock properties and their heterogeneity on seal permeation is absent. Efforts along this direction require obtaining information about the physically reasonable range of caprock and reservoir properties, effectively sampling the parameter space to fully explore the range of these properties, and performing flow and transport calculations using reliable numerical simulators. In this study, we identify the most important factors affecting CO2 leakage through intact caprock and try to understand the underlying mechanisms. We use caprock and reservoir properties from various field sites and literature data to identify the range of caprock thickness, permeability, and porosity that might occur. We use a quasi Monte Carlo sampling approach to ensure that the full range of caprock and seal properties is evaluated without introducing bias. For each set of sampled properties, the migration of injected CO2 is simulated for up to 200 years using the water-salt-CO2 operational mode of the STOMP simulator, developed by PNNL. Preliminary results show that critical factors determining CO2 leakage rate through intact caprock are, in decreasing order of significance, the caprock thickness, caprock permeability, reservoir permeability, reservoir porosity, and caprock porosity. This study provides a relatively complete “look-up table” for potential CO2 leakage risk due to permeation of intact caprock, and identifies a range of acceptable seal thicknesses and permeability for sequestration projects. This

  18. Interfacial properties of asphaltenes at toluene-water interfaces.

    Science.gov (United States)

    Zarkar, Sharli; Pauchard, Vincent; Farooq, Umer; Couzis, Alexander; Banerjee, Sanjoy

    2015-05-05

    Asphaltenes are "n-alkane insoluble" species in crude oil that stabilize water-in-oil emulsions. To understand asphaltene adsorption mechanisms at oil-water interfaces and coalescence blockage, we first studied the behavior in aliphatic oil-water systems in which asphaltenes are almost insoluble. They adsorbed as monomers, giving a unique master curve relating interfacial tension (IFT) to interfacial coverage through a Langmuir equation of state (EoS). The long-time surface coverage was independent of asphaltene bulk concentration and asymptotically approached the 2-D packing limit for polydisperse disks. On coalescence, the surface coverage exceeded the 2-D limit and the asphaltene film appeared to become solidlike, apparently undergoing a transition to a soft glassy material and blocking further coalescence. However, real systems consist of mixtures of aliphatic and aromatic components in which asphaltenes may be quite soluble. To understand solubility effects, we focus here on how the increased bulk solubility of asphaltenes affects their interfacial properties in comparison to aliphatic oil-water systems. Unlike the "almost irreversible" adsorption of asphaltenes where the asymptotic interfacial coverage was independent of the bulk concentration, an equilibrium surface pressure, dependent on bulk concentration, was obtained for toluene-water systems because of adsorption being balanced by desorption. The equilibrium surface coverage could be obtained from the short- and long-term Ward-Tordai approximations. The behavior of the equilibrium surface pressure with the equilibrium surface coverage was then derived. These data for various asphaltene concentrations were used to determine the EoS, which for toluene-water could also be fitted by the Langmuir EoS with Γ∞ = 3.3 molecule/nm(2), the same value as that found for these asphaltenes in aliphatic media. Asphaltene solubility in the bulk phase only appears to affect the adsorption isotherm but not the Eo

  19. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-07-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  20. Phase equilibria and physical properties of CO2-saturated cocoa butter mixtures at elevated pressures

    NARCIS (Netherlands)

    Venter, M.J.; Willems, P.; Kareth, S.; Weidner, E.; Kuipers, N.J.M.; de Haan, A.B.

    2007-01-01

    The melting point and phase behaviour of cocoa butter under CO2 pressure were observed in a high-pressure view cell. The melting point decreases from 35 to 23 °C at CO2 pressures higher than 5 MPa. A static analytical procedure was used to measure the solubility of CO2 in cocoa butter at 40, 80 and

  1. Phase equilibria and physical properties of CO2-saturated cocoa butter mixtures at elevated pressures

    NARCIS (Netherlands)

    Venter, M.J.; Willems, P.; Kareth, S.; Weidner, E.; Kuipers, N.J.M.; Haan, de A.B.

    2007-01-01

    The melting point and phase behaviour of cocoa butter under CO2 pressure were observed in a high-pressure view cell. The melting point decreases from 35 to 23 °C at CO2 pressures higher than 5 MPa. A static analytical procedure was used to measure the solubility of CO2 in cocoa butter at 40, 80 and

  2. Curvature Dependence of Interfacial Properties for Associating Lennard-Jones Fluids: A Density Functional Study

    Institute of Scientific and Technical Information of China (English)

    SUN Zong-Li; KANG Yan-Shuang

    2011-01-01

    Classical density functional theory is used to study the associating Lennard Jones fluids in contact with spherical hard wall of different curvature radii. The interfacial properties including contact density and fluid-solid interfacial tension are investigated. The influences of associating energy, curvature of hard wall and the bulk density of Huids on these properties are analyzed in detail. The results may provide helpful clues to understand the interfacial properties of other complex fluids.%@@ Classical density functional theory is used to study the associating Lennard Jones fluids in contact with spherical hard wall of different curvature radii.The interfacial properties including contact density and fluid-solid intcrfacial tension are investigated.The influences of associating energy, curvature of hard wall and the hulk density of fluids on these properties are analyzed in detail.The results may provide helpful clues to understand the interfacial properties of other complex fluids.

  3. CO2 injection effect on physical properties of greensand from the North Sea

    DEFF Research Database (Denmark)

    Hossain, Zakir; Fabricius, Ida Lykke

    2011-01-01

    into brine saturated samples and flush the CO2 saturated samples with brine at reservoir conditions. Helium porosity, Klinkenberg permeability, and specific surface area (SSA) by BET were measured on dry greensand samples before and after the CO2 experiment. NMR T2 distribution and electrical resistivity...... of greensand. The Klinkenberg permeability of greensand increased after CO2 injection. An NMR T2 distribution and NMR permeability modeling approach was tested to evaluate the effect on matrix permeability of CO2 injection. It appears that permeability after CO2 injection increased due to the increase of macro...

  4. Study of energy bands and magnetic properties of Co2CrSi Heusler alloy

    Indian Academy of Sciences (India)

    Dibya Prakash Rai; Sandeep; M P Ghimire; R K Thapa

    2011-10-01

    The electronic and magnetic properties of Co2CrSi is calculated by using full-potential linearized augmented plane wave (FP–LAPW) method based on density functional theory (DFT). Density of states (DOS), magnetic moment and band structures of the system are presented. For the exchange and correlation energy, local spin density approximation (LSDA+U) with the inclusion of Hubbard potential U is used. Our calculation shows indirect bandgap of 0.91 eV in the minority channel of DOS. This is supported by band structures and hence favoured the half metallic ferromagnetic (HMF) nature of the system. The effective magnetic moment of 4.006 B also supported our conclusion with a near integral value. The DOS of Co and Cr were found to hybridize and was also responsible for the ferromagnetic nature of the system.

  5. Growth of NiCo2O4@MnMoO4 Nanocolumn Arrays with Superior Pseudocapacitor Properties.

    Science.gov (United States)

    Cui, Chunyu; Xu, Jiantie; Wang, Lei; Guo, Di; Mao, Minglei; Ma, Jianmin; Wang, Taihong

    2016-04-06

    Three-dimensional heterostructured NiCo2O4@MnMoO4 nanocolumn arrays (NCAs) on Ni foam were first fabricated through an improved two-step hydrothermal process associated with a successive annealing treatment. The hybrid NiCo2O4@MnMoO4 electrode exhibited remarkable pseudocapacitor property with high initial mass specific capacitance of 1705.3 F g(-1) at 5 mA cm(-2), and retained 92.6% after 5000 cycles, compared to the bare NiCo2O4 electrode with 839.1 F g(-1) and 90.9%. The excellent capacitive property of the NiCo2O4@MnMoO4 hydrid was attributed to its high-electron/ion-transfer rate, large electrolyte infiltrate area, and more electroactive reaction sites.

  6. Correlating interfacial properties with stress transfer in SMA composites

    Energy Technology Data Exchange (ETDEWEB)

    Kline, G.E.; Jonnalagadda, K.; Sottos, N.R. [Univ. of Illinois, Urbana-Champaign, Urbana, IL (United States)

    1995-12-31

    Shape memory alloy (SMA) wires have been proposed as large strain actuators for use in smart structures. SMA wires can be embedded in a host material to alter the stiffness or modal response and provide vibration control. The interaction between the embedded SMA and the host material is critical to applications requiring transfer of loads or strain from the wire to the host. Paine, Jones and Rogers have asserted the importance of interfacial adhesion between embedded SMA wires and the host material. When the SMA wires are actuated, large shear strains are generated at the SMA/host interface. The stronger the interface, the greater the transfer of strain from the actuator to the host material. Although there has been a significant amount of research dedicated to characterizing and modeling the response of SMA alone, little work has been done to understand the behavior of embedded SMA wires. Maximum displacement, load transfer and repeatability of actuation of the embedded wire are particularly critical in assessing the effects of the host material. This work continues to investigate the interaction between SMA wires and a host polymer matrix. High resolution photoelasticity was utilized to study the internal stresses induced during actuation of an embedded shape memory alloy wire in a polymer matrix. The influence of several wire surface treatments on the resulting stresses and load transfer was investigated. Four different surface treatments were considered: untreated, acid etched, hand sanded and sandblasted. Pull-out data indicated that sandblasting of wires increased the SMA/polymer interfacial bond strength while hand sanding and acid cleaning actually decreased the bond strength. Wires with greater adhesion (sandblasted) resulted in higher stresses induced in the polymer while those with lower adhesion transferred less load. Overall, properties of the SMA/polymer interface were shown to significantly affect the performance of the embedded SMA actuator.

  7. CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

    Science.gov (United States)

    Baran, Paweł; Zarębska, Katarzyna; Czuma, Natalia

    2016-07-01

    Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support.

  8. On the Structure-Property Relationships of Cation-Exchanged ZK-5 Zeolites for CO2 Adsorption.

    Science.gov (United States)

    Pham, Trong D; Hudson, Matthew R; Brown, Craig M; Lobo, Raul F

    2017-03-09

    The CO2 adsorption properties of cation-exchanged Li-, Na-, K-, and Mg-ZK-5 zeolites were correlated to the molecular structures determined by Rietveld refinements of synchrotron powder X-ray diffraction patterns. Li-, K-, and Na-ZK-5 all exhibited high isosteric heats of adsorption (Qst ) at low CO2 coverage, with Na-ZK-5 having the highest Qst (ca. 49 kJ mol(-1) ). Mg(2+) was located at the center of the zeolite hexagonal prism with the cation inaccessible to CO2 , leading to a much lower Qst (ca. 30 kJ mol(-1) ) and lower overall uptake capacity. Multiple CO2 adsorption sites were identified at a given CO2 loading amount for all four cation-exchanged ZK-5 adsorbents. Site A at the flat eight-membered ring windows and site B/B* in the γ-cages were the primary adsorption sites in Li- and Na-ZK-5 zeolites. Relatively strong dual-cation adsorption sites contributed significantly to an enhanced electrostatic interaction for CO2 in all ZK-5 samples. This interaction gives rise to a migration of Li(+) and Mg(2+) cations from their original locations at the center of the hexagonal prisms toward the α-cages, in which they interact more strongly with the adsorbed CO2 .

  9. Fracture healing and transport properties of wellbore cement in the presence of supercritical CO2

    NARCIS (Netherlands)

    Liteanu, E.; Spiers, C.J.

    2011-01-01

    This paper investigates the process and rate of carbonation reaction of Class A wellbore cement exposed to CO2-saturated solution at confined conditions similar to those employed in geological storage of CO2. The main goal was to investigate whether reaction improves or degrades the sealing/healing

  10. Effect of CO2 on the properties and sinking velocity of aggregates of the coccolithophore Emiliania huxleyi

    Directory of Open Access Journals (Sweden)

    A. Engel

    2010-03-01

    Full Text Available Coccolithophores play an important role in organic matter export due to their production of the mineral calcite that can act as ballast. Recent studies indicated that calcification in coccolithophores may be affected by changes in seawater carbonate chemistry. We investigated the influence of CO2 on the aggregation and sinking behaviour of the coccolithophore Emiliania huxleyi (PML B92/11 during a laboratory experiment. The coccolithophores were grown under low (~180 μatm, medium (~380 μatm, and high (~750 μatm CO2 conditions. Aggregation of the cells was promoted using roller tables. Size and settling velocity of aggregates were determined during the incubation using video image analysis. Our results indicate that aggregate properties are sensitive to changes in the degree of ballasting, as evoked by ocean acidification. Average sinking velocity was highest for low CO2 aggregates (~1292 m d−1 that also had the highest particulate inorganic to particulate organic carbon (PIC/POC ratio. Lowest PIC/POC ratios and lowest sinking velocity (~366 m d−1 at comparable sizes were observed for aggregates of the high CO2 treatment. Aggregates of the high CO2 treatment showed a 4-fold lower excess density (~4.2×10−4 g cm−3 when compared to aggregates from the medium and low CO2 treatments (~1.7 g×10−3 cm−3. We also observed that more aggregates formed in the high CO2 treatment, and that those aggregates contained more bacteria than aggregates in the medium and low CO2 treatment. If applicable to the future ocean, our findings suggest that a CO2 induced reduction of the calcite content of aggregates could weaken the deep export of organic matter in the ocean, particularly in areas dominated by coccolithophores.

  11. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

    Science.gov (United States)

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, K. A.; Long, Y.; Pecharsky, V. K.

    2016-05-01

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. However, the relative cooling power (RCP) of DyCo2 and the B doped alloys remains nearly constant.

  12. A liquid CO2-compatible hydrocarbon surfactant: experiment and modelling

    NARCIS (Netherlands)

    Banerjee, S.; Kleijn, J.M.; Cohen Stuart, M.A.; Leermakers, F.A.M.

    2013-01-01

    Surfactants soluble in liquid CO2 are rare and knowledge on interfacial and self-assembly behaviour is fragmented. We found that polyoxyethylene (5) isooctylphenyl ether is interfacially active at the water–liquid CO2 interface. Water–liquid CO2 interfacial tension was measured at various surfactant

  13. Synthesis and properties of collagen-g-poly(sodium acrylate-co-2-hydroxyethylacrylate superabsorbent hydrogels

    Directory of Open Access Journals (Sweden)

    M. Sadeghi

    2013-06-01

    Full Text Available Novel biopolymer-based superabsorbent hydrogels were prepared by grafting crosslinked poly(acrylic acid-co-2-hydroxyethyl acrylate (PAA-co-PHEA chains onto collagen backbones through a free radical polymerization method. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS as initiator and N,N '-methylene bisacrylamide (MBA as crosslinker. A proposed mechanism for collagen-g-(PAA-co-PHEA formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy and TGA thermal analysis. Moreover, the morphology of the samples was examined by scanning electron microscopy (SEM. The effect of concentration of MBA as well as AA/HEA weight ratio on the swelling capacity of the hydrogel was also studied. Furthermore, the water absorbency of hydrogels was measured in solutions with pH ranging 1 to 13. The collagen-based hydrogel exhibited a pH-responsive character, so that a swelling-deswelling pulsatile behavior was recorded at pHs 2 and 8. Preliminary swelling and deswelling behaviors of the hydrogels were also studied. Additionally, the hydrogels exhibited salt-sensitivity and cation exchange properties.

  14. Spatial structure and coherence properties of Brillouin scatter from CO2 laser-target interaction

    Science.gov (United States)

    Mitchel, G. R.; Grek, B.; Johnston, T. W.; Pépin, H.; Church, P.; Martin, F.

    1982-05-01

    The spatial structure and coherence properties of 10.6-μm light scattered from CO2 laser-target interactions in oblique incidence show many unexpected features. It is found that the Brillouin backscatter is neither a phase conjugate nor a ray retrace of the incident beam. Rather, it shows a preference for scattering directions other than those exactly antiparallel to the incident beam, apparently related to the angular distribution of the scattering source and also of the plasma corona that serves as the Brillouin amplifying medium. As well, the backscatter phasefront is strongly perturbed with respect to the incident phasefront. This is an indication of turbulence in the corona and/or memory of the structure in the source that is then amplified. Small-scale structures seen in the reimaged backscatter are due to phase perturbation and cannot be simply interpreted as geometric images of a (filamented) source. The phasefront of light that is scattered obliquely from the plasma is much more coherent.

  15. Ultrasonic Guided Waves in Piezoelectric Layered Composite with Different Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2011-01-01

    Full Text Available Combining the propagation model of guided waves in a multilayered piezoelectric composite with the interfacial model of rigid, slip, and weak interfaces, the generalized dispersion characteristic equations of guided waves propagating in a piezoelectric layered composite with different interfacial properties are derived. The effects of the slip, weak, and delamination interfaces in different depths on the dispersion properties of the lowest-order mode ultrasonic guided wave are analyzed. The theory would be used to characterize the interfacial properties of piezoelectric layered composite nondestructively.

  16. CO2 Laser Glazing Treatment of a Veneering Porcelain: Effects on Porosity, Translucency, and Mechanical Properties.

    Science.gov (United States)

    Sgura, R; dos Reis, M C; Salvadori, M C; Hernandes, A C; Cesar, P F; Medeiros, I S

    2015-01-01

    This work tested CO2 laser as a glazing agent and investigated the effects of irradiation on the porosity, translucency, and mechanical properties of veneering porcelain. Sixty discs (diameter 3.5 × 2.0 mm) of veneering porcelain for Y-TZP frameworks (VM9, VITA Zahnfabrik) were sintered and had one of their faces mirror polished. The specimens were divided into six groups (n=10/group) according to surface treatment, as follows: no treatment-control; auto-glaze in furnace following manufacturer's instructions (G); and CO2 laser (45 or 50 W/cm(2)) applied for four or five minutes (L45/4, L45/5, L50/4, L50/5). Optical microscopy (Shimadzu, 100×) was conducted and the images were analyzed with Image J software for the determination of the following porosity parameters: area fraction, average size, and Feret diameter. The translucency parameter studied was masking ability, determined by color difference (ΔE) over black and white backgrounds (CM3370d, Konica Minolta). Microhardness and fracture toughness (indentation fracture) were measured with a Vickers indenter (HMV, Shimadzu). Contact atomic force microscopy (AFM) (50 × 50 μm(2), Nanoscope IIIA, Veeco) was performed at the center of one sample from each group, except in the case of L45/5. With regard to porosity and translucency parameters, auto-glazed and laser-irradiated specimens presented statistical similarity. The area fraction of the surface pores ranged between 2.4% and 5.4% for irradiated specimens. Group L50/5 presented higher microhardness when compared to the G group. The higher (1.1) and lower (0.8) values for fracture toughness (MPa.m(1/2)) were found in laser-irradiated groups (L50/4 and L45/4, respectively). AFM performed after laser treatment revealed changes in porcelain surface profile at a submicrometric scale, with the presence of elongated peaks and deep valleys.

  17. Field theoretic simulations of the interfacial properties of complex coacervates

    Science.gov (United States)

    Riggleman, Robert; Fredrickson, Glenn

    2011-03-01

    Many biological processes and emerging technologies, such as wet adhesives and biosensors, rely on the association between oppositely charged polyelectrolytes. Such association is driven not only by the electrostatic interactions between the polyelectrolytes, but there is also a substantial entropy gain associated with counterion release upon complexation. In some cases, the association between oppositely charged polymers can lead to a solid precipitate while others can result in a fluid phase rich in polyelectrolytes (coacervate phase) coexisting with a polyelectrolyte-dilute solvent phase. For many of the applications seeking to exploit coacervation, characterization of the interface between the solvent phase and the coacervate is of paramount importance. In this talk, we will present the results of field-theoretic simulations for a coarse-grained polyelectrolyte model that exhibits complex coacervation. Our simulations sample the fully-fluctuating fields in three-dimensions and provide a detailed characterization of the interface between the solvent and the coacervate phase for symmetric polyelectrolytes (where both the polycations and the polyanions carry identical charge densities) as a function of salt concentration and strength of the electrostatic fields. Finally, we characterize the interfacial properties for a select set of asymmetric conditions.

  18. Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive

    Directory of Open Access Journals (Sweden)

    YUAN Jiang

    2017-09-01

    Full Text Available Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La.The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.

  19. Study on Critical Properties for CO2+Cosolvent Binary System and Ternary System

    Institute of Scientific and Technical Information of China (English)

    张敬畅; 吴向阳; 曹维良

    2002-01-01

    The performance of supercritical fluid (SCF) as a solvent can be greatly affected by addition of anentrainer to the system. In this study, a constant volume visual method is used to measure the critical point ofCO2+n-butyraldehyde, CO2+ i-butyraldehyde and CO2+alcohol binary systems and CO2+entrainer+trisodiumsalt of tri-(m-sulfonphenyl)phosphine (TPPTS) ternary systems, which provides us good theoretical basis for super-critical extraction and chemical reaction. The relationship between critical point and concentration of the entrainerare discussed. The phase behavior of binary system and that of ternary system are compared. The relationshipbetween the concentration of TPPTS and critical point of binary systems are also discussed.

  20. Electrochemical and SEM properties of Co2+ ion in hexagonal mesophase of pluronic lyotropic liquid crystal template

    Indian Academy of Sciences (India)

    I S El-Hallag

    2009-10-01

    The electrochemical and SEM properties of Co2+ ion in hexagonal mesophase of the pluronic lyotropic liquid crystal template are reported. The cyclic voltammetric studies evidenced the occurrence of two slow electron transfer reduction processes. Such a reaction presumably related to the reduction of Co2+ ion to Co metal. The hexagonal (H1) lyotropic liquid crystalline phases of P84 surfactant have been used to template the electrochemical deposition of nanostructured cobalt films as well as its uses as background electrolyte. Electrochemical studies show that these films have very high surface areas, which reveals that the deposited film exhibits promising properties. The electrode parameters of Co(II) ion in hexagonal meso phase of the lyotropic liquid crystal ternary system (pluronic P84/cobalt/-xylene) is determined using cyclic voltammetry, deduced convolutive voltammetry and chronoamperometry techniques. The morphology of nanostructured deposited films of Co2+ ion in pluronic lyotropic liquid crystal template was investigated via scanning electron microscopy (SEM) technique.

  1. Study of the synergistic effect in dielectric breakdown property of CO2-O2 mixtures

    Science.gov (United States)

    Zhao, Hu; Deng, Yunkun; Lin, Hui

    2017-09-01

    Sulfur hexafluoride, SF6, is a common dielectric medium for high-voltage electrical equipment, but because it is a potent greenhouse gas, it is important to find less environmentally harmful alternatives. In this paper we explore the use of CO2 and O2 as one alternative. We studied the synergistic effect in a mixture of CO2 and O2 from both macroscopic and microscopic perspectives. The effect leads to a dielectric strength of the mixture being greater than the linear interpolation of the dielectric strengths of the two isolated gases. We analyzed the critical reduced electric field strength, (E/N)cr, the breakdown gas pressure reduced electric field, E/p, and the breakdown electron temperature, Tb, and their synergistic effect coefficients for various CO2 concentrations and various products of the gas pressure times the gap distance (pd). A gas discharge and breakdown mechanism in a homogenous electric field is known to be controlled by the generation and disappearance of free electrons, which strongly depend on the electron temperature. The results indicate that adding a small amount of O2 to CO2 can effectively improve the value of (E/N)cr and bring a clear synergistic effect. In addition, significantly different variation trends of the synergistic effect in the E/p and Tb of CO2-O2 mixtures at various CO2 concentrations and pd values were also observed.

  2. Interfacial properties of statistical copolymer brushes in contact with homopolymer melts.

    Science.gov (United States)

    Trombly, David M; Pryamitsyn, Victor; Ganesan, Venkat

    2011-04-21

    We use polymer self-consistent field theory to quantify the interfacial properties of random copolymer brushes (AB) in contact with a homopolymer melt chemically identical to one of the blocks (A). We calculate the interfacial widths and interfacial energies between the melt and the brush as a function of the relative chain sizes, grafting densities, compositions of the random copolymer in the brush, and degree of chemical incompatibility between the A and B species. Our results indicate that the interfacial energies between the melt and the brush increase (signifying expulsion of the free chains from the brush) with increasing grafting density, chemical incompatibility between A and B components, and size of the free chains relative to the grafted chains. We also compare the interfacial energies of random copolymers of different sequence characteristics and find that, except for the case of very blocky or proteinlike chains, blockiness of the copolymer has only little effect on interfacial properties. Our results for interfacial energies are rationalized based on the concept of an "effective volume fraction" of the brush copolymers, f(eff), which quantifies the chemical composition of the brush segments in the interfacial zone between the brush and melt copolymers. Using this concept, we modify the strong-stretching theory of brush-melt interfaces to arrive at a simple model whose results qualitatively agree with our results from self-consistent field theory. We discuss the ramifications of our results for the design of neutral surfaces.

  3. Montmorillonite-supported Pd0, Fe0, Cu0 and Ag0 nanoparticles: Properties and affinity towards CO2

    Science.gov (United States)

    Bouazizi, Nabil; Barrimo, Diana; Nousir, Saadia; Ben Slama, Romdhane; Roy, René; Azzouz, Abdelkrim

    2017-04-01

    This study reports the carbon dioxide (CO2) adsorption on montmorillonite (NaMt) incorporating Cu0, Fe0, Pd0 and Ag0 as metallic nanoparticles (MNPs). The changes in structural, textural, morphological and adsorption properties of the resulting materials (NaMt-MNPs) were investigated. Electron microscopy and X-ray diffraction showed that dispersion of fine MNPs occurs mainly within the interlayer space of NaMt, producing a slight structure expansion. This was accompanied by a visible enhancement of the affinity towards CO2, as supported by thermal programmed desorption measurements. NaMt-MNPs displayed high CO2 retention capacity (CRC) of ca. 657 μmol/g for NaMt-Cu as compared to NaMt. This was explained in terms of increased number of available adsorption sites due to enlarged interlayer spaces caused by MNP insertion. The differences in CO2 adsorption capacities clearly demonstrate the key role of MNPs in improving the surface properties and adsorption capacity. The results reported herein open new prospects for clay supported metal nanoparticles as efficient adsorbents for CO2.

  4. Interfacial microstructure and properties of carbon fiber composites modified with graphene oxide.

    Science.gov (United States)

    Zhang, Xiaoqing; Fan, Xinyu; Yan, Chun; Li, Hongzhou; Zhu, Yingdan; Li, Xiaotuo; Yu, Liping

    2012-03-01

    The performance of carbon fiber-reinforced composites is dependent to a great extent on the properties of fiber-matrix interface. To improve the interfacial properties in carbon fiber/epoxy composites, we directly introduced graphene oxide (GO) sheets dispersed in the fiber sizing onto the surface of individual carbon fibers. The applied graphite oxide, which could be exfoliated to single-layer GO sheets, was verified by atomic force microscope (AFM). The surface topography of modified carbon fibers and the distribution of GO sheets in the interfacial region of carbon fibers were detected by scanning electron microscopy (SEM). The interfacial properties between carbon fiber and matrix were investigated by microbond test and three-point short beam shear test. The tensile properties of unidirectional (UD) composites were investigated in accordance with ASTM standards. The results of the tests reveal an improved interfacial and tensile properties in GO-modified carbon fiber composites. Furthermore, significant enhancement of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and tensile properties was achieved in the composites when only 5 wt % of GO sheets introduced in the fiber sizing. This means that an alternative method for improving the interfacial and tensile properties of carbon fiber composites by controlling the fiber-matrix interface was developed. Such multiscale reinforced composites show great potential with their improved mechanical performance to be likely applied in the aerospace and automotive industries. © 2012 American Chemical Society

  5. Sediment properties and CO2 efflux from intact and cleared temperate mangrove forests

    Science.gov (United States)

    Bulmer, R. H.; Lundquist, C. J.; Schwendenmann, L.

    2015-10-01

    Temperate mangrove forests in New Zealand have increased in area over recent decades. Expansion of temperate mangroves in New Zealand is associated with perceived loss of other estuarine habitats, and decreased recreational and amenity values, resulting in clearing of mangrove forests. In the tropics, changes in sediment characteristics and carbon efflux have been reported following mangrove clearance. This is the first study in temperate mangrove (Avicennia marina) forests investigating the impact of clearing on sediment CO2 efflux and associated biotic and abiotic factors. Sediment CO2 efflux rates from intact (168.5 ± 45.8 mmol m-2 d-1) and cleared (133.9 ± 37.2 mmol m-2 d-1) mangrove forests in New Zealand are comparable to rates measured in tropical mangrove forests. We did not find a significant difference in sediment CO2 efflux rates between intact and cleared temperate mangrove forests. Pre-shading the sediment for more than 30 min prior to dark chamber measurements was found to have no significant effect on sediment CO2 efflux. This suggests that the continuation of photosynthetic CO2 uptake by biofilm communities was not occurring after placement of dark chambers. Rather, above-ground mangrove biomass, sediment temperature and chlorophyll a concentration were the main factors explaining the variability in sediment CO2 efflux in intact mangrove forests. The main factors influencing sediment CO2 efflux in cleared mangrove forest sites were sediment organic carbon concentration, nitrogen concentration and sediment grain size. Our results show that greater consideration should be given regarding the rate of carbon released from mangrove forest following clearance and the relative contribution to global carbon emissions.

  6. 超临界CO2对碳纤维环氧树脂的界面性能的改善%Performance Improvements of Supercritical CO2 on Interface Property of the Carbon Fiber/Epoxy Resin

    Institute of Scientific and Technical Information of China (English)

    刘魁; 孟令辉; 曾竟成; 冯学斌

    2012-01-01

    为提高碳纤维/环氧树脂复合材料的界面结合性能,采用超临界CO2对碳纤维表面进行处理.结果表明:在处理后碳纤维的单丝拉伸强度下降2.81%,碳纤维/环氧树脂界面剪切强度和层间剪切强度在处理后分别提高25.19%和17.11%.通过对碳纤维原子力显微镜(AFM)观察,经过处理的碳纤维表面粗糙度增加明显,同时对复合材料层间剪切断口端面用扫描电子显微镜(SEM)观察,经过超临界CO2处理后的碳纤维与环氧树脂的复合性能得到改善.%To improve the carbon fiber/epoxy resin composite' s interfacial bonding performance; treatment of supercritical CO2 was used to the carbon fiber surface.The single strands of carbon fiber tensile strength decreased by 2.81% and interfacial shear strength and interlaminar shear strength of the carbon fiber/ epoxy resin composite improved by 25.19% and 17.Irrespectively.By atomic force microscopy (AFM) investigation on the carbon fiber surface,it showed that surface roughness increased significantly,while through scanning electron microscope(SEM)investigation on the fracture surface of composite after treatment,it showed that the performance of carbon fiber and epoxy composite improved after the treatment of supercritical CO2.

  7. Model of gas composition and plasma properties in sealed cw CO2 lasers

    Science.gov (United States)

    Byron, Stanley R.; Apter, Henri

    1992-02-01

    A comprehensive set of gas-phase reactions is described that accounts for the observed CO2 decomposition in sealed cw CO2 lasers that are free of H2O vapor. The model includes reactions among the species CO2, CO, O, O2, and O3, the electron Boltzmann equation to determine dissociation and ionization rates, and the negative ions O-, O2-, CO3-, and CO4-, which affect the reduced field E/N through their influence on ambipolar diffusion and ion neutralization. The CO2 formation mechanism is O+O2+M→k2O3+M, k2=4.2×10-34 cm6/s at 300 K, e-+O3→k3O-+O2, k3=1×10-8 cm3/s, O-+CO→k4CO2+e-, k4=7×10-10 cm3/s. The value for k3 is about 5 times larger than expected on the basis of electron-beam and drift tube measurements in room-temperature ozone and is attributed to electronic and/or vibrational excitation of ozone.

  8. Relationship between the density of supercritical CO2 +ethanol binary system and its critical properties

    Institute of Scientific and Technical Information of China (English)

    张敬畅; 张建军; 曹维良

    2003-01-01

    The dependent relation between temperature and pressure of supercritical CO2 + ethanol binary system under the pressure range from 5 to 10 MPa with the variety of densities and mole fractions of ethanol that range from 0 to 2% was investigated by the static visual method in a constant volume. The critical temperature and pressure were experimentally determined simultaneously. The PTρ figures at different ethanol contents were described based on the determined pressure and temperature data, from which pressure of supercritical CO2 + ethanol binary system was found to increase linearly with the increasing temperature. P-T lines show certain convergent feature in a specific concentration of ethanol and the convergent points shift to the region of higher temperature and pressure with the increasing ethanol compositions. Furthermore, the effect of density and ethanol concentration on the critical point of CO2 + ethanol binary system was discussed in details. Critical points increase linearly with the increasing mole fraction of ethanol in specific density and critical points change at different densities. The critical compressibility factors Zc of supercritical CO2 + ethanol binary systems at different compositions of ethanol were calculated and Zc-ρ figure was obtained accordingly. It was found from Zc-ρ figure that critical compressibility factors of supercritical CO2 unitary or binary systems decline linearly with the increasing density, by which the critical point can be predicted precisely.

  9. Effect of macrostructural control of an auxiliary layer on the CO2 sensing properties of NASICON-based gas sensors

    OpenAIRE

    Morio, Masataka; Hyodo, Takeo; Shimizu, Yasuhiro; Egashira, Makoto

    2009-01-01

    Macrostructural effects of an auxiliary electrode on the CO2 gas sensing properties of NASICON (Na3Zr2Si2PO12) solid-electrolyte sensors were investigated. The sensor with a porous Li2CO3–BaCO3-based auxiliary layer (mp-Sensor), which was prepared by utilizing constituent metal acetates and polymethylmethacrylate microspheres as a template, showed faster CO2 response and recovery and smaller cross-response against humidity changes than those obtained with a dense auxiliary layer without pores...

  10. The Baltic Basin: structure, properties of reservoir rocks, and capacity for geological storage of CO2

    Directory of Open Access Journals (Sweden)

    Vaher, Rein

    2009-12-01

    Full Text Available Baltic countries are located in the limits of the Baltic sedimentary basin, a 700 km long and 500 km wide synclinal structure. The axis of the syneclise plunges to the southwest. In Poland the Precambrian basement occurs at a depth of 5 km. The Baltic Basin includes the Neoproterozoic Ediacaran (Vendian at the base and all Phanerozoic systems. Two aquifers, the lower Devonian and Cambrian reservoirs, meet the basic requirements for CO2 storage. The porosity and permeability of sandstone decrease with depth. The average porosity of Cambrian sandstone at depths of 80–800, 800–1800, and 1800–2300 m is 18.6, 14.2, and 5.5%, respectively. The average permeability is, respectively, 311, 251, and 12 mD. Devonian sandstone has an average porosity of 26% and permeability in the range of 0.5–2 D. Prospective Cambrian structural traps occur only in Latvia. The 16 largest ones have CO2 storage capacity in the range of 2–74 Mt, with total capacity exceeding 400 Mt. The structural trapping is not an option for Lithuania as the uplifts there are too small. Another option is utilization of CO2 for enhanced oil recovery (EOR. The estimated total EOR net volume of CO2 (part of CO2 remaining in the formation in Lithuania is 5.6 Mt. Solubility and mineral trapping are a long-term option. The calculated total solubility trapping capacity of the Cambrian reservoir is as high as 11 Gt of CO2 within the area of the supercritical state of carbon dioxide.

  11. Linking temperature sensitivity of soil CO2 release to substrate, environmental, and microbial properties across alpine ecosystems

    Science.gov (United States)

    Ding, Jinzhi; Chen, Leiyi; Zhang, Beibei; Liu, Li; Yang, Guibiao; Fang, Kai; Chen, Yongliang; Li, Fei; Kou, Dan; Ji, Chengjun; Luo, Yiqi; Yang, Yuanhe

    2016-09-01

    Our knowledge of fundamental drivers of the temperature sensitivity (Q10) of soil carbon dioxide (CO2) release is crucial for improving the predictability of soil carbon dynamics in Earth System Models. However, patterns and determinants of Q10 over a broad geographic scale are not fully understood, especially in alpine ecosystems. Here we addressed this issue by incubating surface soils (0-10 cm) obtained from 156 sites across Tibetan alpine grasslands. Q10 was estimated from the dynamics of the soil CO2 release rate under varying temperatures of 5-25°C. Structure equation modeling was performed to evaluate the relative importance of substrate, environmental, and microbial properties in regulating the soil CO2 release rate and Q10. Our results indicated that steppe soils had significantly lower CO2 release rates but higher Q10 than meadow soils. The combination of substrate properties and environmental variables could predict 52% of the variation in soil CO2 release rate across all grassland sites and explained 37% and 58% of the variation in Q10 across the steppe and meadow sites, respectively. Of these, precipitation was the best predictor of soil CO2 release rate. Basal microbial respiration rate (B) was the most important predictor of Q10 in steppe soils, whereas soil pH outweighed B as the major regulator in meadow soils. These results demonstrate that carbon quality and environmental variables coregulate Q10 across alpine ecosystems, implying that modelers can rely on the "carbon-quality temperature" hypothesis for estimating apparent temperature sensitivities, but relevant environmental factors, especially soil pH, should be considered in higher-productivity alpine regions.

  12. In-line monitoring of solvent and CO2 properties: preliminary assessment using design of experiment

    NARCIS (Netherlands)

    Ham, L.V. van der; Bakker, D.E.; Geers, L.F.G. van; Eckeveld, A.C. van; Goetheer. E.L.V.

    2013-01-01

    Removing acid gases such as CO2 and H2S from a gas mixture is nowadays often done using an absorption process. Two essential operating variables of such a process are the amount of active absorbent present in the solvent mixture and the amount of absorbed acid gas. Normally, the solvent concentratio

  13. Bifunctional Imidazolium-Based Ionic Liquid Decorated UiO-67 Type MOF for Selective CO2 Adsorption and Catalytic Property for CO2 Cycloaddition with Epoxides.

    Science.gov (United States)

    Ding, Luo-Gang; Yao, Bing-Jian; Jiang, Wei-Ling; Li, Jiang-Tao; Fu, Qi-Juan; Li, Yan-An; Liu, Zhen-Hua; Ma, Jian-Ping; Dong, Yu-Bin

    2017-02-20

    A bifunctional robust and highly porous imidazolium-based ionic liquid decorated UiO-67 type MOF (UiO-67-IL, 1) was successfully constructed via solvothermal assembly of the imidazolium-based ligand and Zr(IV) ions. It exhibits a highly selective adsorption for CO2 over CH4 and N2. Furthermore, 1 herein can be used as a highly active heterogeneous catalyst for CO2 cycloaddition with epoxides under atmospheric pressure with or without cocatalyst TBAB (n-Bu4NBr).

  14. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals.

    Science.gov (United States)

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-09-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals.

  15. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

    Science.gov (United States)

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-01-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals. PMID:27752504

  16. Identifying changes in chemical, interfacial and foam properties of ß-lactoglobulin–sodium dodecyl sulphate mixtures

    NARCIS (Netherlands)

    Lech, F.J.; Steltenpool, P.; Meinders, M.B.J.; Sforza, S.; Gruppen, H.; Wierenga, P.A.

    2014-01-01

    Techno-functional properties of proteins, such as foam stability, can be affected by the presence of low-molecular-weight surfactants. In order to understand and control the foam properties of such protein–surfactant mixtures, a thorough characterization of foam and interfacial properties needs to b

  17. Identifying changes in chemical, interfacial and foam properties of ß-lactoglobulin–sodium dodecyl sulphate mixtures

    NARCIS (Netherlands)

    Lech, F.J.; Steltenpool, P.; Meinders, M.B.J.; Sforza, S.; Gruppen, H.; Wierenga, P.A.

    2014-01-01

    Techno-functional properties of proteins, such as foam stability, can be affected by the presence of low-molecular-weight surfactants. In order to understand and control the foam properties of such protein–surfactant mixtures, a thorough characterization of foam and interfacial properties needs to

  18. MORPHOLOGY,INTERFACIAL INTERACTION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/MODIFIED HALLOYSITE NANOTUBE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    贾德民

    2009-01-01

    A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH) was used as the interfacial modifier.The structure,morphology and mechanical properties of SBR/m-HNT nanocomposites,especially the interfacial interactions,were investigated.SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix ...

  19. Magnetic and anomalous electronic transport properties of the quaternary Heusler alloys Co2Ti1-xFexGe

    Science.gov (United States)

    Venkateswarlu, B.; Midhunlal, P. V.; Babu, P. D.; Kumar, N. Harish

    2016-06-01

    The half-metallic Heusler alloy Co2TiGe has a ferromagnetic ground state with a low magnetic moment (2 μB). It is free of atomic antisite disorder but has low Curie temperature (~390 K). In contrast the other cobalt based Heusler alloy Co2FeGe has high Curie temperature (~980 K) and high magnetic moment (5.6 μB) while exhibiting antisite disorder and lack of half-metallicity. Hence it is of interest to investigate the magnetic and transport properties of solid solutions of these two materials with contrasting characteristics. We report the structural, magnetic and electronic transport properties of quaternary Co2Ti1-x FexGe (x=0.2, 0.4, 0.6, 0.8) Heusler alloys. The alloys crystallize in L21 structure but with antisite disorder. The magnetization measurements revealed that the alloys were of soft ferromagnetic type with high Curie temperatures. Deviation from Slater-Pauling behavior and drastic change in electronic transport properties with some anomalous features were observed.The complex electronic transport properties have been explained using different scattering mechanisms.

  20. Characterization of carbonate reservoir property changes due to dissolution for far-field conditions of CO2 storage

    Science.gov (United States)

    Mangane, P. O.; Gouze, P.; Luquot, L.

    2012-12-01

    Geological storage of CO2 in reservoir pore fluid (e.g. deep saline aquifers), is one of the diverse technologies being explored for deacreasing atmospheric CO2 concentration. After injecting the CO2 as a supercritical fluid at depth, it will slowly dissolve into the pore water producing low pH fluids with a high capacity for dissolving carbonates and consequently changing irreversibly the hydrodynamical properties of the reservoir. Characterizing these changes is essential for modelling flow and CO2 transport during and after the CO2 injection. Here we report experimental results from the injection of the CO2-saturated brine into two distinct limestone cores (a bioclastic carbonate and an oolitic carbonate) of 9 mm diameter, 18 mm length. 3D high-resolution X-ray microtomography (XRMT) of the rock sample have been performed before and after the experiments. The experiments were performed using in-situ sequestration conditions (P = 12MPa and T = 100°C), and notably, under chemical conditions given at the position far away from the well injection site (i.e area where the volume of dissolved CO2 into the brine is low, due to CO2 consumption by the dissolution processes occured during its transport from the well injection site). Permeability k is calculated from the pressure drop across the sample and porosity Φ is deduced from chemical concentration of the outlet fluid. The change of the pore structure is analysed in terms of connectivity, tortuosity and fluid-rock interface from processing the XRMT images. These experiments show that far from the well injection site, dissolution processes are characterized by slow mass tranfer including, in the case of carbonate rock, transport of fine particles, which locally clog the porous space. Then, that leads to the damage of the carbonate reservoir both in terms of connectivity of the porous space and CO2 hydrodynamical storage capacity. In fact, the results of the two experiments show that the porosity decreased locally

  1. Interfacial mechanical property of steel-mushy Al-20Sn bonding

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang; Yunhui Du; Hanwu Liu; Daben Zeng; Jianzhong Cui; Limin Ba

    2004-01-01

    The bonding of a steel plate to A1-20Sn slurry was conducted using the casting rolling technique. The surface of the steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. A1-20Sn slurry was prepared using the electromagnetic mechanical stirring method. The interfacial mechanical property of the bonding plate was researched to determine the relationship between the diffusion time and the interfacial shear strength. In order to identify the mechanism of bonding, the interfacial structure of the bonding plate was studied. The results show that at a preheat temperature of the steel plate of 505℃ and a solid fraction of A1-20Sn slurry of 35%, the relationship between the interfacial shear strength S and the diffusion time t is S=28.8+4.3t-0.134t2 +0.0011t3. When the diffusion time is 22 s, the largest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one which is made up of Fe-A1 compound and Fe-Al solid solution alternatively and in a right proportion.In this interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound can play its role in strong combination adequately.

  2. Spinel CuCo2O4 Nanoparticles: Facile One-Step Synthesis, Optical, and Electrochemical properties

    Science.gov (United States)

    Silambarasan, M.; Padmanathan, N.; Ramesh, P. S.; Geetha, D.

    2016-09-01

    Nanocrystalline CuCo2O4 spinel structure was prepared by a facile one-step route without any surfactant. The materials physio-chemical properties were systematically investigated with different analytical methods. It is observed that the spinel type CuCo2O4 nanoparticles showed interesting multi-functional features for both optical and electrochemical applications.Typical x-ray diffraction pattern indicates the growth of well-crystalline CuCo2O4 nanoparticles with a cubic spinel structure. From the transmission electron microscope images, a uniform particle distribution with an average size of ˜20 nm can be seen. UV-visible spectrum shows the absorption maximum at 264.5 nm and exhibits an optical band gap 4.02 eV. Electrochemical analysis further reveals the pseudo-capacitive behaviour with the specific capacitance of 290 F g-1 at 2 mA cm-2. In addition, the magnetic study of CuCo2O4 substantiates the presence of room temperature weak ferromagnetic ordering at low magnetic field strength.

  3. CORRELATION BETWEEN POLYMER PACKING AND GAS TRANSPORT PROPERTIES FOR CO2/N2 SEPARATION IN GLASSY FLUORINATED POLYIMIDE MEMBRANE

    Directory of Open Access Journals (Sweden)

    P. C. TAN

    2016-07-01

    Full Text Available Gas separation performance of a membrane highly hinges on its physical properties. In this study, the interplay between polymer packing of a membrane and its gas transport behaviours (permeability and selectivity was investigated through a series of 6FDA-DAM:DABA (3:2 polyimide membranes with different polymer compactness. The chemical structure and the polymer packing of the resulting membrane were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR and packing density measurement, respectively. CO2/N2 separation efficiency of the membrane was evaluated at 25oC with feed pressure up to 6 bar. N2 permeability was found to rely on the membrane’s packing density, which signified its greater dependence on molecular sieving. In contrast, sorption showed a more vital role in determining the CO2 permeability. In this work, the membrane with a final thickness of 97±2 µm had successfully surpassed the Robeson’s 2008 upper bound plot with a CO2 permeability of 83 Barrer and CO2/N2 selectivity of 97 at 3 bar permeation.

  4. Influence of the cation substitution on the magnetic properties of LiCo2O4 and Li(Me,Co2O4 spinels

    Directory of Open Access Journals (Sweden)

    Gautier, J. L.

    2004-08-01

    Full Text Available Lithium-based cells LiCo2O4 have been characterized by magnetic techniques, looking at the influence of the partial substitution of cobalt by 3d or 4d transition metal elements (Fe, Ni, Cu, Cr, Mo. The non-substituted compound LiCo2O4 behaves as an antiferromagnet, with a Néel temperature TN of 30 K, although antiferromagnetic interactions are much more important, as suggested by a Weiss parameter Θ of the order of ‑225 K. In the solid solution Li(NixCo2‑xO4 the Weiss parameter Θ changes with x(Ni, reaching large positive values (e.g., Θ ~ +230 K, for x = 0.5. This phenomenon suggests the existence of a canted‑antiferromagnetic or ferrimagnetic structures with large ferromagnetic components. Substitution of cobalt by other 3d or 4d transition metals in the LiMe0.5Co1.5O4 series shows dramatic effects with respect to the non-substituted LiCo2O4 compound : copper completely suppresses the magnetic order, while iron increases TN to almost room temperature. No modifications are observed when molybdenum substitutes cobalt, while chromium transforms the AF order in a ferromagnetic one, with Tc of about 90 K.Se ha caracterizado por técnicas magnéticas, el efecto de la sustitución parcial de Co por elementos de transición 3d o 4d (Fe, Ni, Cu, Cr, Mo en celdas LiCo2O4 a base de litio. El compuesto no sustituído LiCo2O4, se comporta como un antiferromagneto de temperatura de Néel TN de 30 K, aunque existen interacciones antiferromagnéticas mucho más importantes, como lo indica un parámetro de Weiss Θ del orden de -225K. En la solución sólida Li(NixCo2‑xO4, el parámetro de Weiss Θ cambia con x(Ni, alcanzando valores positivos altos (e.g., Θ ~ +230K, para x=0.5. Este fenómeno sugiere la existencia de una estructura antiferromagnética inclinada (“AF-canted” o de una estructura ferrimagnética, donde predominan componentes ferromagnéticas importantes. La sustitución del cobalto por otros elementos de transición 3d o 4d en

  5. Investigation on CO2 Adsorption Properties of a Regenerative Solid Amine Fiber PPAM%可再生固态胺纤维PPAM对CO2的吸附性能

    Institute of Scientific and Technical Information of China (English)

    林日嘉; 许秀竹; 陈思宇; 陈水挟

    2013-01-01

    Objective To synthesize a solid amine fiber PPAM for CO2 capture with polypropylene (PP) fiber as a substrate and evaluate its CO2 adsorption properties.Methods PPAM was prepared by pre-irradiated grafting with acylamide (AM) onto PP fibers.The chemical and physical properties of PPAM were characterized with FT-IR,TG,EA,SEM,and so on.Its CO2 adsorption capacity was evaluated.Results Higher amination degree of PPAM was favorable for CO2 adsorption.Its highest adsorption capacity was 4.72 mmol/g at the optimal temperature of 30 ℃.PPAM could maintain 99% of its adsorption capacity after 5 adsorption-desorption cycles.Conclusion PPAM fiber proves to be an ideal solid CO2 absorbent with excellent thermal stability,high CO2 adsorption capacity and satisfying regeneration property.%目的 以聚丙烯纤维为基体,制备一种对CO2具有良好吸附性能的固态胺纤维PPAM,并探究其吸附性能.方法 通过预辐照接枝制备PPAM,以红外、热重、元素分析及电子显微镜分析等手段表征PPAM的化学与物理结构及其稳定性.从胺化率、吸附温度等方面评价材料对CO2的吸附性能.结果 高胺化率有利于PPAM材料对CO2的吸附.该材料在30℃下能达到最高吸附容量4.72 mmol/g.经过5次循环再生吸附后,吸附容量仍能达到初次吸附量的99%.结论 PPAM具有良好的热稳定性,对CO2具有高吸附容量和优异的循环再生性能,是一种理想的固态胺吸附剂.

  6. Adsorption of CO2 on Fe-doped graphene nano-ribbons: Investigation of transport properties

    Science.gov (United States)

    Othman, W.; Fahed, M.; Hatim, S.; Sherazi, A.; Berdiyorov, G.; Tit, N.

    2017-07-01

    Density functional theory combined with the non-equilibrium Green’s function formalism is used to study the conductance response of Fe-doped graphene nano-ribbons (GNRs) to CO2 gas adsorption. A single Fe atom is either adsorbed on GNR’s surface (aFe-graphene) or it substitutes the carbon atom (sFe-graphene). Metal atom doping reduces the electronic transmission of pristine graphene due to the localization of electronic states near the impurity site. Moreover, the aFe-graphene is found to be less sensitive to the CO2 molecule attachment as compared to the sFe-graphene system. These behaviours are not only consolidated but rather confirmed by calculating the IV characteristics from which both surface resistance and its sensitivity to the gas are estimated. Since the change in the conductivity is one of the main outputs of sensors, our findings will be useful in developing efficient graphene-based solid-state gas sensors.

  7. Dehydration of CO2-α-cyclodextrin complex powder by desiccant adsorption method and its release properties.

    Science.gov (United States)

    Ho, Thao M; Howes, Tony; Bhandari, Bhesh R

    2016-12-01

    Stability and release properties of CO2-α-cyclodextrin complex powder prepared by solid encapsulation (water activity, aw ≈ 0.95) followed by moisture removal using silica gel and CaCl2 desiccants during post-dehydration were investigated. The results showed that CaCl2 reduced aw much faster than silica gel did under the same conditions. After approximately 60 h, aw of complex powders reduced using silica gel was almost constant at 0.247 (±0.012), while those treated with CaCl2, aw was 0.225 (±0.005) and had not yet reached their lowest value. Moisture adsorption by silica gel and CaCl2 also led to a decrease in the CO2 concentration of complex powder (higher decrease for silica gel adsorption) without affecting the structure and morphology of complex powder. The CO2 release properties of CaCl2-aw-reduced complex powder at different relative humidities (32.73, 52.86, 75.32 and 97.30% RH), liquid environments (water and oil) and packaging methods (normal and vacuum) were also studied.

  8. Physical Property Changes During CO2 Injection into Sandstone from Pukpyeong Formation, South Korea: Pore-scale Approach

    Science.gov (United States)

    Han, J.; Keehm, Y.

    2010-12-01

    Carbon dioxide is believed to be responsible for global warming and climate change, and Korea government puts a great effort in CCS (Carbon Capture and Storage). The geological sequestration is regarded as one viable option and we are looking for prospecting formations for carbon storage. In this paper, we present a new approach to determine physical property changes during CO2 injection and preliminary results from applying the method to one of prospective Tertiary formation in South Korea. The so-called computational rock physics method is composed of three steps: 1) acquisition of high-resolution pore microstructures by X-ray micro-tomography; 2) CO2 injection simulation using lattice-Boltzmann (LB) two-phase flow simulation; and 3) FEM property simulations (electrical and elastic) at different CO2 saturations during the injection. We have been shown the viability of the method last year. This year we applied this method to one of CS (carbon storage) target area, Pukpyeong formation located in north-eastern part of South Korea. From thin section analysis, we found that the formation is composed of mudstone, sandstone and conglomerate, and most of them are poorly consolidated. The mudstone and poorly-sorted conglomerate are believed to have very low permeability, and the effect of CO2 injection would be significant. Thus we focus on sandstone units and get pore microstructure of those units. We then performed the computational rock physics analysis, and present the relations of Vp - CO2 saturation, and electrical conductivity - CO2 saturation for a few sand units. We also present the preliminary upscaling results by putting combined sandstone and mudstone units into FEM modeling. The modeling results implies that the new computational approach can be very useful to characterizing the CS sites especially in early stage. Acknowledgement: This work was supported by the Energy R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP

  9. Effects of Graphene Oxide Modified Sizing Agents on Interfacial Properties of Carbon Fibers/Epoxy Composites.

    Science.gov (United States)

    Zhang, Qingbo; Jiang, Dawei; Liu, Li; Huang, Yudong; Long, Jun; Wu, Guangshun; Wu, Zijian; Umar, Ahmad; Guo, Jiang; Zhang, Xi; Guo, Zhanhu

    2015-12-01

    A kind of graphene oxide (GO) modified sizing agent was used to improve the interfacial properties of carbon fibers/epoxy composites. The surface topography of carbon fibers was investigated by scanning electron microscopy (SEM). The surface compositions of carbon fibers were determined by X-ray photoelectron spectroscopy (XPS) and the interfacial properties of composites were studied by interlaminar shear strength (ILSS). The results show that the existence of GO increases the content of reactive functional groups on carbon fiber surface. Thus it enhances the interfacial properties of carbon fibers/epoxy composites. When GO loading in sizing agents is 1 wt%, the ILSS value of composite reaches to 96.2 MPa, which is increased by 27.2% while comparing with unsized carbon fiber composites. Furthermore, the ILSS of composites after aging is also increased significantly with GO modified sizing agents.

  10. High-temperature Thermoelectric Properties of Cu-substituted Bi2Ba2Co2-xCuxOy Oxides

    Institute of Scientific and Technical Information of China (English)

    Haoshan Hao; Huizhi Yan; Yongtao Liu; Xing Hu

    2011-01-01

    Cu-substituted Bi2Ba2Co2-xCuxOy (0.0≤x≤0.4) samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated. The partial substitution of Cu for Co in Bi2Ba2Co2-xCuxOy led to an increase in the electrical conductivity because of an increase in the hole concentration and grain size of sintered bodies. In addition,Cu substitution led to an increase in Seebeck coefficients while kept the thermal conductivity unchanged. The highest thermoelectric figure of merit (ZT value) was obtained in x=0.4 sample and the value was 1.5 times as large as that of Cu-free sample at 873 K.

  11. Effect of the annealing temperature on dynamic and structural properties of Co2FeAl thin films

    Directory of Open Access Journals (Sweden)

    Belmeguenai M.

    2014-07-01

    Full Text Available 10 nm and 50 nm thick Co2FeAl (CFA thin films have been deposited on thermally oxidized Si(001 substrates by magnetron sputtering using a Tantalum cap layer and were then ex-situ annealed at 415°C, 515°C and 615°C during 15 minutes in vacuum. X-rays diffraction indicates that films CFA are polycrystalline and exhibit an in-plane isotropy growth. Ferromagnetic resonance measurements, using a microstrip line (MS-FMR, reveal a huge interfacial perpendicular magnetic anisotropy and small in-plane uniaxial anisotropy both annealing temperature-dependent. The MS-FMR data also allow concluding that the gyromagnetic factor remains constant and that the exchange stiffness constant increases with annealing temperature. Finally, the FMR linewidth decreases with increasing annealing temperature due to the enhancement of the chemical order, and allow deriving a very low intrinsic damping parameter (1.3×10−3 at 615°C.

  12. Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged

    2011-01-01

    Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation...... and Tor Formation chalk of the South Arne field to reveal the changes in petrophysical and rock mechanics properties of chalk due to the injection of CO2 at supercritical state. An increase in porosity and decrease in specific surface was observed due to injection of supercritical CO2. This indicates...... as indicated by NMR T2 relaxation time was observed. Rock mechanics testing indicates that in 30% porosity chalk from the South Arne field, injection of supercritical CO2 has no significant effect on shear strength and compaction properties, while there is probably a slight decrease in stiffness properties...

  13. Investigation of the Phase Equilibria and Interfacial Properties for Non-polar Fluids

    Institute of Scientific and Technical Information of China (English)

    付东; 赵毅

    2005-01-01

    A self-consistent density-functional theory (DFT) was applied to investigate the phase behavior and interfacial properties of non-polar fluids. For the bulk phases, the theory was reduced to the statistical associating fluid theory(SAFF) that provides accurate descriptions of vapor-liquid phase diagrams below the critical region. The phase diagrams in the critical region were corrected by the renormalization group theory (RGT). The density profile in the surface was obtained by minimizing the grand potential. With the same set of molecular parameters, both the phase equilibria and the interfacial properties of non-polar fluids were investigated satisfactorily.

  14. CO2 sequestration in feldspar-rich sandstone: Coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties

    Science.gov (United States)

    Tutolo, Benjamin M.; Luhmann, Andrew J.; Kong, Xiang-Zhao; Saar, Martin O.; Seyfried, William E.

    2015-07-01

    To investigate CO2 Capture, Utilization, and Storage (CCUS) in sandstones, we performed three 150 °C flow-through experiments on K-feldspar-rich cores from the Eau Claire formation. By characterizing fluid and solid samples from these experiments using a suite of analytical techniques, we explored the coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties during CO2 sequestration in feldspar-rich sandstone. Overall, our results confirm predictions that the heightened acidity resulting from supercritical CO2 injection into feldspar-rich sandstone will dissolve primary feldspars and precipitate secondary aluminum minerals. A core through which CO2-rich deionized water was recycled for 52 days decreased in bulk permeability, exhibited generally low porosity associated with high surface area in post-experiment core sub-samples, and produced an Al hydroxide secondary mineral, such as boehmite. However, two samples subjected to ∼3 day single-pass experiments run with CO2-rich, 0.94 mol/kg NaCl brines decreased in bulk permeability, showed generally elevated porosity associated with elevated surface area in post-experiment core sub-samples, and produced a phase with kaolinite-like stoichiometry. CO2-induced metal mobilization during the experiments was relatively minor and likely related to Ca mineral dissolution. Based on the relatively rapid approach to equilibrium, the relatively slow near-equilibrium reaction rates, and the minor magnitudes of permeability changes in these experiments, we conclude that CCUS systems with projected lifetimes of several decades are geochemically feasible in the feldspar-rich sandstone end-member examined here. Additionally, the observation that K-feldspar dissolution rates calculated from our whole-rock experiments are in good agreement with literature parameterizations suggests that the latter can be utilized to model CCUS in K-feldspar-rich sandstone. Finally, by performing a number of reactive

  15. Remarkable Improvement in the Mechanical Properties and CO2 Uptake of MOFs Brought About by Covalent Linking to Graphene.

    Science.gov (United States)

    Kumar, Ram; Raut, Devaraj; Ramamurty, Upadrasta; Rao, C N R

    2016-06-27

    Metal-organic frameworks (MOFs) are exceptional as gas adsorbents but their mechanical properties are poor. We present a successful strategy to improve the mechanical properties along with gas adsorption characteristics, wherein graphene (Gr) is covalently bonded with M/DOBDC (M=Mg(2+) , Ni(2+) , or Co(2+) , DOBDC=2,5-dioxido-1,4-benzene dicarboxylate) MOFs. The surface area of the graphene-MOF composites increases up to 200-300 m(2)  g(-1) whereas the CO2 uptake increases by ca. 3-5 wt % at 0.15 atm and by 6-10 wt % at 1 atm. What is significant is that the composites exhibit improved mechanical properties. In the case of Mg/DOBDC, a three-fold increase in both the elastic modulus and hardness with 5 wt % graphene reinforcement is observed. Improvement in both the mechanical properties and gas adsorption characteristics of porous MOFs on linking them to graphene is a novel observation and suggests a new avenue for the design and synthesis of porous materials.

  16. Effect of erbium substitution on thermoelectric properties of complex oxide Ca3Co2O6 at high temperatures

    Institute of Scientific and Technical Information of China (English)

    LU Dongqing; CHEN Gang; PEI Jian; YANG Xi; XIAN Hengze

    2008-01-01

    Polycrystalline particles of Ca3-xErxCo2O6 (x=0.0, 0.15, 0.3, 0.45 and 0.6) were synthesized using sol-gel method combined with Low Temperature Sintering procedure (LTS) to evaluate the effect of Er substitution on the thermoelectric properties of Ca3Co2O6. The crystal structure and microstructure were investigated using X-ray diffraction, infrared spectroscopy and scanning electron microscope. The electrical conductivity and Seebeck coefficient of the complex oxides were measured from 300 to 1073 K. The results showed that all the samples were p-type semiconductors. The electrical conductivity increased with the increase in temperature. Er substitutions at Ca site affected carrier concentrations and carrier mobility, resulting an increase in Seebeck coefficient and decrease in electrical conductivity. The power factor of Ca2.85Er0.15Co2O6 reached 10.66 μw/mK2 at 1073 K.

  17. Elastic and Transport Properties of Steam-Cured Pozzolanic-Lime Rock Composites Upon CO2 Injection

    Science.gov (United States)

    Emery, Dan; Vanorio, Tiziana

    2016-04-01

    Understanding the effect of pozzolanic ash-lime reactions on the rock physics properties of the resulting rock microstructure is important for monitoring unrest conditions in volcanic-hydrothermal systems as well as for devising concrete with enhanced performance. By mixing pozzolana ash with lime, the ancient Romans unwittingly incorporated these reactions in the production of their famous concrete. Recently, it has been discovered that a fiber-reinforced, concrete-like rock is forming naturally at depth of 1.5 km within the Campi Flegrei volcanic-hydrothermal systems due to upwelling lime-rich fluids permeating a pozzolana rich layer. This study aims to investigate possible physico-chemical conditions contributing to both enhance and undermine the properties of the subsurface rocks of volcanic-hydrothermal systems and, in turn, build upon those processes that the ancient Romans exploited to create their famous concrete. We prepared samples by mixing the pozzolana volcanic ash, slaked lime, aggregates of Neapolitan Yellow tuff, and seawater from Campi Flegrei in the same ratios as the ancient Romans. To mimic the conditions of the caldera, we used alkaline water from a well in the Campi Flegrei region rich in sulfate, bicarbonate, calcium, potassium, and magnesium ions. Yet, the samples were cured for 28 days in steam-rich environment to favor hydration and hence, enhancing the stability of calcium- alumino-silicate hydrates and setting strength of the rock samples. We measured baseline properties of porosity, permeability, P-wave velocity, and S-wave velocity of the samples as well as imaged the fibrous microstructure. P and S-wave velocities were used to derive bulk, shear, and Young's moduli. Subsequently, samples were injected with an aqueous carbon dioxide, CO2 (aq), solution and the changes in their microstructure and physical properties measured. Exposure of the concrete-like rock samples to CO2 -rich fluid lowers pH below 12.5, thus affecting the stability

  18. Surface Characteristics of Rare Earth Treated Carbon Fibers and Interfacial Properties of Composites

    Institute of Scientific and Technical Information of China (English)

    Xu Zhiwei; Huang Yudong; Song Yuanjun; Zhang Chunhua; Liu Li

    2007-01-01

    Effect of rare earth treatment on surface physicochemical properties of carbon fibers and interfacial properties of carbon fiber/epoxy composites was investigated, and the interfacial adhesion mechanism of treated carbon fiber/epoxy composite was analyzed. It was found that rare earth treatment led to an increase of fiber surface roughness, improvement of oxygen-containing groups, and introduction of rare earth element on the carbon fiber surface. As a result, coordination linkages between fibers and rare earth, and between rare earth and resin matrix were formed separately, thereby the interlaminar shear strength (ILSS) of composites increased, which indicated the improvement of the interfacial adhesion between fibers and matrix resin resulting from the increase of carboxyl and carbonyl.

  19. Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

    Science.gov (United States)

    Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

    2013-01-01

    Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

  20. The Effects of Molecular Properties on Ready Biodegradation of Aromatic Compounds in the OECD 301B CO2 Evolution Test.

    Science.gov (United States)

    He, Mei; Mei, Cheng-Fang; Sun, Guo-Ping; Li, Hai-Bei; Liu, Lei; Xu, Mei-Ying

    2016-07-01

    Ready biodegradation is the primary biodegradability of a compound, which is used for discriminating whether a compound could be rapidly and readily biodegraded in the natural ecosystems in a short period and has been applied extensively in the environmental risk assessment of many chemicals. In this study, the effects of 24 molecular properties (including 2 physicochemical parameters, 10 geometrical parameters, 6 topological parameters, and 6 electronic parameters) on the ready biodegradation of 24 kinds of synthetic aromatic compounds were investigated using the OECD 301B CO2 Evolution test. The relationship between molecular properties and ready biodegradation of these aromatic compounds varied with molecular properties. A significant inverse correlation was found for the topological parameter TD, five geometrical parameters (Rad, CAA, CMA, CSEV, and N c), and the physicochemical parameter K ow, and a positive correlation for two topological parameters TC and TVC, whereas no significant correlation was observed for any of the electronic parameters. Based on the correlations between molecular properties and ready biodegradation of these aromatic compounds, the importance of molecular properties was demonstrated as follows: geometrical properties > topological properties > physicochemical properties > electronic properties. Our study first demonstrated the effects of molecular properties on ready biodegradation by a number of experiment data under the same experimental conditions, which should be taken into account to better guide the ready biodegradation tests and understand the mechanisms of the ready biodegradation of aromatic compounds.

  1. Half-metallic properties of the Co 2Ti 1- xFe xGa Heusler alloys and Co 2Ti 0.5Fe 0.5Ga (0 0 1) surface

    Science.gov (United States)

    Ahmadian, F.; Boochani, A.

    2011-07-01

    Electronic and magnetic properties of the bulk Co 2Ti 1- xFe xGa Heusler alloys and Co 2Ti 0.5Fe 0.5Ga (0 0 1) surfaces are studied within the framework of density functional theory using the augmented plane wave plus local orbital (APW+lo) approach. It will be shown that all alloys have the spin polarization of the ideal 100% value except the Co 2FeGa alloy with spin polarization about 98%. Co 2Ti 0.5Fe 0.5Ga is an example that is stable against the effects destroying the half-metallicity due to the position of the Fermi energy ( EF) in the middle of the minority band gap. The phase diagram obtained by ab-initio atomistic thermodynamics shows that in the higher limit of μGa three surfaces of FeGa, TiGa and TiFeGa are accessible in the Co 2Ti 0.5Fe 0.5Ga alloy but on decreasing μGa, the accessible region gradually moves towards FeGa termination. It is discussed that, at the ideal surfaces, half-metallicity of the alloy is lost, although the TiGa surface keeps high spin polarization (about 95%).

  2. CO2-Controllable Foaming and Emulsification Properties of the Stearic Acid Soap Systems.

    Science.gov (United States)

    Xu, Wenlong; Gu, Hongyao; Zhu, Xionglu; Zhong, Yingping; Jiang, Liwen; Xu, Mengxin; Song, Aixin; Hao, Jingcheng

    2015-06-02

    Fatty acids, as a typical example of stearic acid, are a kind of cheap surfactant and have important applications. The challenging problem of industrial applications is their solubility. Herein, three organic amines-ethanolamine (EA), diethanolamine (DEA), and triethanolamine (TEA)-were used as counterions to increase the solubility of stearic acid, and the phase behaviors were investigated systematically. The phase diagrams were delineated at 25 and 50 °C, respectively. The phase-transition temperature was measured by differential scanning calorimetry (DSC) measurements, and the microstructures were vesicles and planar sheets observed by cryogenic transmission electron microscopy (cryo-TEM) observations. The apparent viscosity of the samples was determined by rheological characterizations. The values, rcmc, for the three systems were less than 30 mN·m(-1). Typical samples of bilayers used as foaming agents and emulsifiers were investigated for the foaming and emulsification assays. CO2 was introduced to change the solubility of stearic acid, inducing the transition of their surface activity and further achieving the goal of defoaming and demulsification.

  3. Incision properties and thermal effects of CO2 lasers in soft tissue

    Science.gov (United States)

    Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.; Liaw, Lih-Huei L.; Berns, Michael W.

    1995-05-01

    Thermal and histological events resulting from soft tissue incision using CO2 lasers at 9.3 (mu) or 10.6 (mu) , fitted with a hollow wave guide or an articulated arm delivery system respectively, were investigated. In 9 fresh pigs' mandibles, standardized incisions 3 cm in length were made in the oral mucosa. Incisions were performed in the cw mode at 1 W, 4 W, and 12 W. Thermal events were measured in adjacent soft tissues using thermocouples. Incisions were dissected out, fixed, embedded in paraffin wax, sectioned and stained with Serius Red. The Students' t-test for paired data was used to compare zones of necrosis, zones of collagen damage and thermal events. No significant temperature rise was measured during irradiation at any timepoints or power settings (p < 0.05). Results were very similar for the two lasers with significantly different results obtained only at the 12 W setting (p < 0.05). Vertical incision depths and horizontal incision widths did not differ significantly (p < 0.0001) at 12 W and 4 W. Horizontal and vertical zones of necrosis did not differ significantly (p < 0.0001) either between the two lasers at 12 W and 4 W. Thus the thermal and histological events occurring during soft tissue incision were similar using these two lasers, despite the difference in wavelength and delivery system.

  4. Development And Optical Absorption Properties Of A Laser Induced Plasma During CO2-Laser Processing

    Science.gov (United States)

    Beyer, E.; Bakowsky, L.; Loosen, P.; Poprawe, R.; Herziger, G.

    1984-03-01

    Laser material processing is accompanied by a laser induced plasma in front of the target surface as soon as the laser radiation exceeds a certain critical intensity. For cw CO2-laser machining of metal targets the threshold for plasma onset is about 106 W/cm2. Critical condition for plasma generation at this intensity level is to reach evaporation temperature at the target's surface. At intensity levels exceeding 106 W/cm2 the laser light is interacting with the laser induced plasma and then the plasma in turn interacts with the target. The absorptivity is no longer constant, but increases with increasing intensity of the incident radiation, so that the total amount of power coupled to the target is increasing. This holds up to intensity levels of 2'10 Wicm2. Then the plasma begins to withdraw from the target surface, thus interrupting plasma-target interaction so that the laser power is no longer coupled into the target completely. The results of laser welding (welding depth) in the intensity level of 106 W/cm2 are governed by the product of incident intensity times focus radius, so that welding results are a measure to determine focus radius and laser intensity.

  5. Structural, chemical and electronic properties of the Co2MnSi(001)/MgO interface

    OpenAIRE

    Fetzer, Roman; Wüstenberg, Jan-Peter; Taira, Tomoyuki; Uemura, Tetsuya; Yamamoto, Masafumi; Aeschlimann, Martin; Cinchetti, Mirko

    2012-01-01

    The performance of advanced magnetic tunnel junctions build of ferromagnetic (FM) electrodes and MgO as insulating barrier depends decisively on the properties of the FM/insulator interface. Here, we investigate interface formation between the half-metallic compound Co2MnSi (CMS) and MgO by means of Auger electron spectroscopy, low energy electron diffraction and low energy photoemission. The studies are performed for different annealing temperatures TA and MgO layer coverages (4, 6, 10, 20 a...

  6. Effect of filler wire on the joint properties of AZ31 magnesium alloys using CO2 laser welding

    Institute of Scientific and Technical Information of China (English)

    Wang Hongying; Li Zhijun

    2007-01-01

    Laser welding with filler wire of AZ31 magnesium alloys is investigated using a CO2 laser experimental system. The effect of three different filler wires on the joint properties is researched. The results show that the weld appearance can be effectively improved when using laser welding with filler wire. The microhardness and tensile strength of joints are almost the same as those of the base metal when ER AZ31 or ER AZ61 wire is adopted. However, when the filler wire of ER 5356 aluminum alloy is used, the mechanical properties of joints become worse. For ER AZ31 and ER AZ61 filler wires, the microstructure of weld zone shows small dendrite grains. In comparison, for ER 5356 filler wire, the weld shows a structure of snowy dendrites and many intermetallic compounds and eutectic phases distribute in the dendrites. These intermetallic constituents with low melting point increase the tendency of hot crack and result in fragile joint properties. Therefore, ER AZ31 and ER AZ61 wire are more suitable filler material than ER 5356 for CO2 laser welding of AZ31 magnesium alloys.

  7. Interfacial properties, thin film stability and foam stability of casein micelle dispersions

    NARCIS (Netherlands)

    Chen, Min; Sala, G.; Meinders, M.B.J.; Valenberg, van H.J.F.; Linden, van der E.; Sagis, L.M.C.

    2017-01-01

    Foam stability of casein micelle dispersions (CMDs) strongly depends on aggregate size. To elucidate the underlying mechanism, the role of interfacial and thin film properties was investigated. CMDs were prepared at 4 °C and 20 °C, designated as CMD4 °C and CMD20 °C. At equal protein concentrations,

  8. Interfacial (Fiber-matrix) Properties of High-strength Mortar (150 MPa) from Fiber Pullout

    DEFF Research Database (Denmark)

    Shannag, M.J.; Brincker, Rune; Hansen, Will

    1996-01-01

     The steel fiber-matrix properties of high-strength mortar (150 MPa), such as DSP (densified small particle), are obtained and compared to an ordinary strength mortar (40 MPa) using a specially designed fiber pullout apparatus. A new method for estimating the debonding energy of the interfacial...

  9. Molecular assembly, interfacial rheology and foaming properties of oligofructose fatty acid esters

    NARCIS (Netherlands)

    Kempen, van S.E.H.J.

    2013-01-01

    Aerated food products consist of air bubbles that are surrounded by a matrix that can be either liquid or solid. Due to the large number of air bubbles that are generally present in aerated products, these systems contain a large interfacial area. Therefore, the properties of the interfaces are

  10. Effect of excluded volume interactions on the interfacial properties of colloid-polymer mixtures

    NARCIS (Netherlands)

    Fortini, A.; Bolhuis, P.G.; Dijkstra, M.

    2008-01-01

    We report a numerical study of equilibrium phase diagrams and interfacial properties of bulk and confined colloid-polymer mixtures using grand canonical Monte Carlo simulations. Colloidal particles are treated as hard spheres, while the polymer chains are described as soft repulsive spheres. The

  11. Optimization of interfacial microstructure and mechanical properties of carbon fiber/epoxy composites via carbon nanotube sizing

    Science.gov (United States)

    Yao, Hongwei; Sui, Xianhang; Zhao, Zhongbo; Xu, Zhiwei; Chen, Lei; Deng, Hui; Liu, Ya; Qian, Xiaoming

    2015-08-01

    Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber-matrix interphase structure was developed and showed great commercial application potential.

  12. Combined effect of the transition layer and interfacial coupling on the properties of ferroelectric bilayer film

    Institute of Scientific and Technical Information of China (English)

    Sun Pu-Nan; Cui Lian; Lü Tian-Quan

    2009-01-01

    Within the framework of modified Ginzburg-Landau-Devonshire phenomenological theory,a ferroelectric bilayer film with a transition layer within each constituent film and an interfacial coupling between two materials has been studied.Properties including the Curie temperature and the spontaneous polarization of a bilayer film composed of two equally thick ferroelectric constituent films are discussed.The results show that the combined effect of the transition layer and the interfacial coupling plays an important role in explaining the interesting behaviour of ferroelectric multilayer structures consisting of two ferroelectric materials.

  13. Three-Dimensional Modeling of the Reactive Transport of CO2 and Its Impact on Geomechanical Properties of Reservoir Rocks and Seals

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Hou, Zhangshuan; Bacon, Diana H.; Murray, Christopher J.; White, Mark D.

    2016-01-04

    This article develops a novel multiscale modeling approach to analyze CO2 reservoirs using Pacific Northwest National Laboratory’s STOMP-CO2-R code that is interfaced with the ABAQUS® finite element package. The STOMP-CO2-R/ABAQUS® sequentially coupled simulator accounts for the reactive transport of CO2 causing mineral composition changes that modify the geomechanical properties of reservoir rocks and seals. Formation rocks’ elastic properties that vary during CO2 injection and govern the poroelastic behavior of rocks are modeled by an Eshelby-Mori-Tanka approach (EMTA) implemented in ABAQUS® via user-subroutines. The computational tool incorporates the change in rock permeability due to both geochemistry and geomechanics. A three-dimensional (3D) STOMP-CO2-R model for a model CO2 reservoir containing a vertical fault is built to analyze a formation containing a realistic geochemical reaction network with 5 minerals: albite, anorthite, calcite, kaolinite and quartz. A 3D ABAQUS® model that maps the above STOMP-CO2-R model is built for the analysis using STOMP-CO2-R/ABAQUS®. The results show that the changes in volume fraction of minerals include dissolution of anorthite, precipitation of calcite and kaolinite, with little change in the albite volume fraction. After a long period of CO2 injection the mineralogical and geomechanical changes significantly reduced the permeability and elastic modulus of the reservoir (between the base and caprock) in front of the fault leading to a reduction of the pressure margin to fracture at and beyond the injection location. The impact of reactive transport of CO2 on the geomechanical properties of reservoir rocks and seals are studied in terms of mineral composition changes that directly affect the rock stiffness, stress and strain distributions as well as the pressure margin to fracture.

  14. Elastic and transport properties of steam-cured pozzolanic-lime rock composites upon CO2 injection

    Science.gov (United States)

    Emery, Dan; Vanorio, Tiziana

    2016-04-01

    Understanding the relationship between pozzolanic ash-lime reactions and the rock physics properties of the resulting rock microstructure is important for monitoring unrest conditions in volcanic-hydrothermal systems as well as devising concrete with enhanced performance. By mixing pozzolanic ash with lime, the ancient Romans incorporated these reactions in the production of concrete. Recently, it has been discovered that a fiber-reinforced, concrete-like rock is forming naturally in the depths of the Campi Flegrei volcanic-hydrothermal systems (Vanorio and Kanitpanyacharoen, 2015). We investigate the physico-chemical conditions contributing to undermine or enhance the laboratory measured properties of the subsurface rocks of volcanic-hydrothermal systems and, in turn, build upon those processes that the ancient Romans unwittingly exploited to create their famous concrete. We prepared samples by mixing the pozzolana volcanic ash, slaked lime, aggregates of Neapolitan Yellow tuff, and seawater from Campi Flegrei in the same ratios as the ancient Romans. To mimic the conditions of the caldera, we used mineral seawater from a well in the Campi Flegrei region rich in sulfate, bicarbonate, calcium, potassium, and magnesium ions. The samples were cured by steam. We measured baseline properties of porosity, permeability, P-wave velocity, and S-wave velocity of the samples. P and S-wave velocities were used to derive bulk, shear, and Young's moduli. Subsequently, half of the samples were injected with CO2-rich aqueous solution and the changes in their microstructure and physical properties measured. One sample was subjected to rapid temperature changes to determine how porosity and permeability changed as a function of the number of thermal shocks. Exposure of CO2 to the concrete-like rock samples destabilized fibrous mineral forming and decreased the samples' ability to deform without breaking. We show that steam- and sulfur-alkaline- rich environments affect both

  15. Interfacial Properties of Methylcelluloses: The Influence of Molar Mass

    Directory of Open Access Journals (Sweden)

    Pauline L. Nasatto

    2014-12-01

    Full Text Available The interfacial interactions of four methylcelluloses having the same average degree of substitution and distribution of methyl groups, but different molar masses, are studied at ambient temperature and at very low polymer concentrations. Firstly, the surface tension σ at the water/air interface is determined for the progressive addition of methylcellulose up to 100 mg/L; σ starts to decrease over 1 mg/L up to the critical aggregation concentration (CAC at 10 mg/L. The curves describing the influence of polymer concentration on σ are independent of the molar mass at equilibrium. Secondly, the adsorption of methylcellulose on silica particles is estimated from ζ-potential measurements. The data are interpreted in terms of an increase of the adsorbed layer thickness at the interface when the molar mass of methylcellulose increases. It is concluded that methylcellulose is adsorbed, forming trains and loops at the interface based on the equilibrium between surface free energy and solvent quality.

  16. Effect of non-ionic surfactants on interfacial rheological properties of water/oil systems

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos-Szabo, J.; Lakatos, I. (Magyar Tudomanyos Akademia, Miskolc-Egyetemvaros (Hungary))

    1989-10-01

    The interfacial rheological properties of characteristic Hungarian oil/water systems are discussed. It is shown that there are differences of several orders of magnitude in interfacial viscosities and in majority of cases the boundary layers have non-Newtonian flow behaviour. The study of tenside solutions proved that ethoxylated nonylphenols significantly reduce both the interfacial viscosity and the non-Newtonian character. The shorter the ethoxy chain in the monomer molecule, the greater the effect of nonionic surfactants. The concentration also enhances the effect and the phenomena can be explained by formation of closely packed adsorption layer between the phases. The results may contribute to elucidation of displacement mechanism, spontaneous emulsification, coalescence of dispersed systems etc. in presence of nonionic surfactants. (orig.).

  17. The effect of processing variables on morphological and mechanical properties of supercritical CO2 foamed scaffolds for tissue engineering.

    Science.gov (United States)

    White, Lisa J; Hutter, Victoria; Tai, Hongyun; Howdle, Steven M; Shakesheff, Kevin M

    2012-01-01

    The porous structure of a scaffold determines the ability of bone to regenerate within this environment. In situations where the scaffold is required to provide mechanical function, balance must be achieved between optimizing porosity and maximizing mechanical strength. Supercritical CO(2) foaming can produce open-cell, interconnected structures in a low-temperature, solvent-free process. In this work, we report on foams of varying structural and mechanical properties fabricated from different molecular weights of poly(DL-lactic acid) P(DL)LA (57, 25 and 15 kDa) and by varying the depressurization rate. Rapid depressurization rates produced scaffolds with homogeneous pore distributions and some closed pores. Decreasing the depressurization rate produced scaffolds with wider pore size distributions and larger, more interconnected pores. In compressive testing, scaffolds produced from 57 kDa P(DL)LA exhibited typical stress-strain curves for elastomeric open-cell foams whereas scaffolds fabricated from 25 and 15 kDa P(DL)LA behaved as brittle foams. The structural and mechanical properties of scaffolds produced from 57 kDa P(DL)LA by scCO(2) ensure that these scaffolds are suitable for potential applications in bone tissue engineering.

  18. Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged

    2011-01-01

    Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation...... and Tor Formation chalk of the South Arne field to reveal the changes in petrophysical and rock mechanics properties of chalk due to the injection of CO2 at supercritical state. An increase in porosity and decrease in specific surface was observed due to injection of supercritical CO2. This indicates...... that a reaction between CO2 enriched water and particles takes place which smoothens the particle surface. Accordingly, partial increase in permeability was also noticed. An effect is also observed from the decrease in pore-space stiffness, calculated from sonic velocity. No significant effect on wettability...

  19. Ultrasound-assisted CO2 flooding to improve oil recovery.

    Science.gov (United States)

    Hamidi, Hossein; Sharifi Haddad, Amin; Mohammadian, Erfan; Rafati, Roozbeh; Azdarpour, Amin; Ghahri, Panteha; Ombewa, Peter; Neuert, Tobias; Zink, Aaron

    2017-03-01

    CO2 flooding process as a common enhanced oil recovery method may suffer from interface instability due to fingering and gravity override, therefore, in this study a method to improve the performance of CO2 flooding through an integrated ultraosund-CO2 flooding process is presented. Ultrasonic waves can deliver energy from a generator to oil and affect its properties such as internal energy and viscosity. Thus, a series of CO2 flooding experiments in the presence of ultrasonic waves were performed for controlled and uncontrolled temperature conditions. Results indicate that oil recovery was improved by using ultrasound-assisted CO2 flooding compared to conventional CO2 flooding. However, the changes were more pronounced for uncontrolled temperature conditions of ultrasound-assisted CO2 flooding. It was found that ultrasonic waves create a more stable interface between displacing and displaced fluids that could be due to the reductions in viscosity, capillary pressure and interfacial tension. In addition, higher CO2 injection rates, increases the recovery factor in all the experiments which highlights the importance of injection rate as another factor on reduction of the fingering effects and improvement of the sweep efficiency.

  20. Electronic absorption spectra and nonlinear optical properties of CO2 molecular aggregates: A quantum chemical study

    Indian Academy of Sciences (India)

    Tarun K Mandal; Sudipta Dutta; Swapan K Pati

    2009-09-01

    We have investigated the structural aspects of several carbon dioxide molecular aggregates and their spectroscopic and nonlinear optical properties within the quantum chemical theory framework. We find that, although the single carbon dioxide molecule prefers to be in a linear geometry, the puckering of angles occur in oligomers because of the intermolecular interactions. The resulting dipole moments reflect in the electronic excitation spectra of the molecular assemblies. The observation of significant nonlinear optical properties suggests the potential application of the dense carbon dioxide phases in opto-electronic devices.

  1. Effect of coadsorbed CO 2 on the magnetic properties of O 2 confined in graphitic slit-shaped micropores

    Science.gov (United States)

    Tohdoh, A.; Kaneko, K.

    2001-05-01

    The magnetic susceptibility of coadsorbed O 2 and CO 2 confined in a slit-shaped graphitic micropore was measured over the temperature range 2-300 K. Coadsorbed CO 2 markedly repressed the susceptibility of confined O 2 because CO 2 restricts the O 2 molecular arrangement to form spin clusters. Curie-Weiss plots show that the coadsorbed CO 2 reduced the effective spin concentration while the negative Weiss constant with CO 2 was larger than that of pure O 2. These results also indicate that the coadsorbed CO 2 promotes the formation of smaller clusters of O 2 molecules than for pure O 2.

  2. Electronic and magnetic properties of the Co2-based Heusler compounds under pressure: first-principles and Monte Carlo studies

    Science.gov (United States)

    Zagrebin, M. A.; Sokolovskiy, V. V.; Buchelnikov, V. D.

    2016-09-01

    Structural, magnetic and electronic properties of stoichiometric Co2 YZ Heusler alloys (Y  =  Cr, Fe, Mn and Z  =  Al, Si, Ge) have been studied by means of ab initio calculations and Monte Carlo simulations. The investigations were performed in dependence on different levels of approximations in DFT (FP and ASA modes, as well as GGA and GGA  +  U schemes) and external pressure. It is shown that in the case of the GGA scheme the half-metallic behavior is clearly observed for compounds containing Cr and Mn transition metals, while Co2FeZ alloys demonstrate the pseudo half-metallic behavior. It is demonstrated that an applied pressure and an account of Coulomb repulsion (U) lead to the stabilization of the half-metallic nature for Co2 YZ alloys. The strongest ferromagnetic inter-sublattice (Co-Y) interactions together with intra-sublattice (Co-Co and Y-Y) interactions explain the high values of the Curie temperature obtained by Monte Carlo simulations using the Heisenberg model. It is observed that a decrease in valence electrons of Y atoms (i.e. Fe substitution by Mn and Cr) leads to the weakening of the exchange interactions and to the reduction of the Curie temperature. Besides, in the case of the FP mode Curie temperatures were found in a good agreement with available experimental and theoretical data, where the latter were obtained by applying the empirical relation between the Curie temperature and the total magnetic moment.

  3. Magnetic, magnetooptical, and magnetotransport properties of Ti-substituted Co2FeGa thin films

    Science.gov (United States)

    Khovaylo, Vladimir; Rodionova, Valeria; Lyange, Maria; Chichay, Ksenia; Gan'shina, Elena; Novikov, Andrey; Zykov, Georgy; Bozhko, Alexei; Ohtsuka, Makoto; Umetsu, Rie Y.; Okubo, Akinari; Kainuma, Ryosuke

    2014-08-01

    Magnetic, magnetooptical and magnetotransport properties of Co50.3Fe20.3Ti5.6Ga23.8 thin films were studied for the as prepared as well as annealed samples. Measurements of transverse magnetooptical Kerr effect revealed that the spectral response of the films strongly depends on the structural ordering which can be manipulated by annealing conditions. Peculiarities in the magnetic properties of the films were attributed to the coexisting phases with different degree of structural disorder. Magnetoresistance of Co50.3Fe20.3Ti5.6Ga23.8 thin films was found to be linear in the fields above 1 T which is typical for half-Heusler systems as well as for Heusler-based ferromagnetic shape memory alloys.

  4. Calculation of 2-temperature plasma thermo-physical properties considering condensed phases: application to CO2-CH4 plasma: part 1. Composition and thermodynamic properties

    Science.gov (United States)

    Wu, Yi; Chen, Zhexin; Rong, Mingzhe; Cressault, Yann; Yang, Fei; Niu, Chunping; Sun, Hao

    2016-10-01

    As the first part of this series of papers, a new calculation method for composition and thermodynamic properties of 2-temperature plasma considering condensed species under local chemical equilibrium (LCE) and local phase equilibrium assumption is presented. The 2-T mass action law and chemical potential are used to determine the composition of multiphase system. The thermo-physical properties of CO2-CH4 mixture, which may be a possible substitution for SF6, are calculated by this method as an example. The influence of condensed graphite, non-LTE effect, mixture ratio and pressure on the thermo-physical properties has been discussed. The results will serve as reliable reference data for computational simulation of CO2-CH4 plasmas.

  5. Effect of cw-CO2 laser surface treatment on structure and properties of AZ91 magnesium alloy

    Science.gov (United States)

    Iwaszko, Józef; Strzelecka, Monika

    2016-06-01

    In the study, samples of AZ91 magnesium alloy were subjected to a surface remelting treatment by means of a continuous wave (cw) CO2 laser. The scope of the investigation included both macro- and microstructural examination, hardness measurements, and wear resistance tests. The investigation has shown that remelting treatment leads to a strong refinement of structure in the surface layer and a more even distribution of phases. Fine α-phase dendrites have been observed to dominate in the remelting zone. The dendritic arm spacing in the laser treated surface was in the range of 1-2.5 μm. The structural changes triggered by remelting have contributed to an increase in the hardness and the wear resistance of AZ91 alloy. The microhardness of the remelted zone has increased to 71-93 HV0.05 for single-strip remelting and to 84-107 HV0.05 for multi-strip remelting in comparison with about ~60 HV0.05 for untreated alloy. The friction coefficient has decreased from 0.375 for material w/o treatment to 0.311 for remelted material. SEM investigations of samples after tribological tests have revealed the presence of parallel grooves proving the occurrence of microploughing and micro cutting of the material during the tribological testing. The results of the conducted investigation have indicated a beneficial influence of the cw-CO2 laser remelting treatment on the structure and properties of AZ91 alloy.

  6. Effect of MnO content on the interfacial property of mold flux and steel

    Science.gov (United States)

    Wang, Wanlin; Li, Jingwen; Zhou, Lejun; Yang, Jian

    2016-07-01

    The interfacial property between liquid mold flux and steel has significant impact on the quality of casting slab, and this property is mainly determined by the chemical composition of mold flux and the reaction between the flux and steel. The effect of MnO content on the contact angle and interfacial tension between liquid mold flux and ultra-low carbon steel was investigated by sessile drop method in this article, and the results suggested that both the contact angle and interfacial tension decreased with the increase of MnO content in the mold flux. The increase of Si and Mn and the reduction of Al and Ti in the interaction layer were caused by the chemical reactions occurred in the vicinity of interface between mold flux and steel substrate. Besides, the thickness of the interaction layer increased from 4 μm to 7 μm, then to 9 μm, 11 μm and 15 μm when the MnO content was added from 1 wt% to 3 wt%, then to 5 wt%, 7 wt%, and 9 wt% due to the fact that MnO can simplify the polymerized structure of the melt and improve the penetrability of molten mold flux to make the interfacial reaction easier.

  7. Effect of the surface roughness on interfacial properties of carbon fibers reinforced epoxy resin composites

    Energy Technology Data Exchange (ETDEWEB)

    Song Wei [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Gu Aijuan, E-mail: ajgu@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Liang Guozheng, E-mail: lgzheng@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Yuan Li [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China)

    2011-02-15

    The effect of the surface roughness on interfacial properties of carbon fibers (CFs) reinforced epoxy (EP) resin composite is studied. Aqueous ammonia was applied to modify the surfaces of CFs. The morphologies and chemical compositions of original CFs and treated CFs (a-CFs) were characterized by Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS). Compared with the smooth surface of original CF, the surface of a-CF has bigger roughness; moreover, the roughness increases with the increase of the treating time. On the other hand, no obvious change in chemical composition takes place, indicating that the treating mechanism of CFs by aqueous ammonia is to physically change the morphologies rather than chemical compositions. In order to investigate the effect of surface roughness on the interfacial properties of CF/EP composites, the wettability and Interfacial Shear Strength (IFSS) were measured. Results show that with the increase of the roughness, the wettabilities of CFs against both water and ethylene glycol improves; in addition, the IFSS value of composites also increases. These attractive phenomena prove that the surface roughness of CFs can effectively overcome the poor interfacial adhesions between CFs and organic matrix, and thus make it possible to fabricate advanced composites based on CFs.

  8. The crystal structure and magnetic properties of Ba2-xSrxCo2Fe12O22

    Science.gov (United States)

    Cho, Kwang Lae; Rhee, Chan Hyuk; Kim, Chul Sung

    2014-05-01

    We have synthesized the Ba2-xSrxCo2Fe12O22 samples (x = 0.1, 0.2, 0.3, 0.4, 0.5) by the solid-state reaction method and investigated their crystalline and magnetic properties by X-ray diffractometer (XRD), Mössbauer spectrometer, vibrating sample magnetometer, and network analyzer. XRD patterns show that all samples are rhombohedral with space group R-3m. The lattice constants a0 and c0 decrease with Sr substitution due to smaller ion radius of Sr2+ (1.27 Å) than that of Ba2+ (1.43 Å). The Mössbauer spectroscopy measurements show that the relative area ratios of Fe ion were maintained constant regardless of the Sr concentration. However, average magnetic hyperfine field slightly increased with the Sr concentration. This observation agrees with the fact that the saturation magnetization (Ms) linearly increases due to the increasing super-exchange interaction, originated from the difference in the ionic radius between Ba2+ and Sr2+. To investigate its properties at high frequency range, all samples were sintered at 1100 °C, and complex permeability and permittivity were measured by network analyzer between 100 MHz and 4 GHz. For x below 0.3, the initial permeability at 100 MHz increases, at higher values of x, its value decreases. Our study shows that magnetic properties of Sr2+ substitution for Ba2+ in Y-type hexaferrite as well as low magnetic loss less than 0.1 in 1 GHz band, indicating the potential application of Ba2-xSrxCo2Fe12O22 samples for RF and antenna devices in ultra high frequency band.

  9. Hydroxyapatite-TiO(2)-based nanocomposites synthesized in supercritical CO(2) for bone tissue engineering: physical and mechanical properties.

    Science.gov (United States)

    Salarian, Mehrnaz; Xu, William Z; Wang, Zhiqiang; Sham, Tsun-Kong; Charpentier, Paul A

    2014-10-08

    Calcium phosphate-based nanocomposites offer a unique solution toward producing scaffolds for orthopedic and dental implants. However, despite attractive bioactivity and biocompatibility, hydroxyapatite (HAp) has been limited in heavy load-bearing applications due to its intrinsically low mechanical strength. In this work, to improve the mechanical properties of HAp, we grew HAp nanoplates from the surface of one-dimensional titania nanorod structures by combining a coprecipitation and sol-gel methodology using supercritical fluid processing with carbon dioxide (scCO2). The effects of metal alkoxide concentration (1.1-1.5 mol/L), reaction temperature (60-80 °C), and pressure (6000-8000 psi) on the morphology, crystallinity, and surface area of the resulting nanostructured composites were examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and Brunauer-Emmet-Teller (BET) method. Chemical composition of the products was characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near-edge structure (XANES) analyses. HAp nanoplates and HAp-TiO2 nanocomposites were homogeneously mixed within poly(ε-caprolactone) (PCL) to develop scaffolds with enhanced physical and mechanical properties for bone regeneration. Mechanical behavior analysis demonstrated that the Young's and flexural moduli of the PCL/HAp-TiO2 composites were substantially higher than the PCL/HAp composites. Therefore, this new synthesis methodology in scCO2 holds promise for bone tissue engineering with improved mechanical properties.

  10. Thermal and mechanical interfacial properties of the DGEBA/PMR-15 blend system.

    Science.gov (United States)

    Park, Soo-Jin; Lee, Hwa-Young; Han, Mijeong; Hong, Sung-Kwon

    2004-02-15

    In this work, the blend system of diglycidyl ether of bisphenol A and PMR-15 polyimide is investigated in terms of thermal and dynamic mechanical interfacial properties of the casting specimens. The thermal stabilities are studied by thermogravimetric and thermomechanical analyses, and the dynamic mechanical properties are carried out by dynamic mechanical analysis. The results show that the thermal stabilities based on the initial decomposition temperature, the integral procedural decomposition temperature, and the glass transition temperature are increased with increasing PMR-15 content. The crosslinking density (rho) of the blend system is increased at 10 phr of PMR-15, compared with that of neat epoxy. Mechanical interfacial properties measured in the context of critical stress intensity factor and critical strain energy release rate show similar behaviors with E(a) and rho, probably due to the increase in intermolecular interactions or hydrogen bondings in polymer chains.

  11. Facile synthesis of urchin-like NiCo2O4 hollow microspheres with enhanced electrochemical properties in energy and environmentally related applications.

    Science.gov (United States)

    Yu, Xin-Yao; Yao, Xian-Zhi; Luo, Tao; Jia, Yong; Liu, Jin-Huai; Huang, Xing-Jiu

    2014-03-12

    A facile synthesis of novel urchin-like NiCo2O4 hierarchical hollow microspheres has been developed based on a template-free solvothermal and subsequent calcination method. The growth process of NiCo2O4 hollow microsphere precursors has been investigated, and a plausible mechanism was proposed. Because of their unique structure and high specific surface area, these NiCo2O4 hollow microspheres displayed enhanced electrochemical properties in methanol electrooxidation and determination of heavy-metal ions compared with solid urchin-like NiCo2O4 microspheres, Co3O4, and NiO microspheres. The good electrochemical performances suggested that these unique hierarchical NiCo2O4 hollow microspheres could be promising materials for energy and environmentally related applications.

  12. Confinement of Ionic Liquids in Nanocages: Tailoring the Molecular Sieving Properties of ZIF-8 for Membrane-Based CO2 Capture.

    Science.gov (United States)

    Ban, Yujie; Li, Zhengjie; Li, Yanshuo; Peng, Yuan; Jin, Hua; Jiao, Wenmei; Guo, Ang; Wang, Po; Yang, Qingyuan; Zhong, Chongli; Yang, Weishen

    2015-12-14

    Fine-tuning of effective pore size of microporous materials is necessary to achieve precise molecular sieving properties. Herein, we demonstrate that room temperature ionic liquids can be used as cavity occupants for modification of the microenvironment of MOF nanocages. Targeting CO2 capture applications, we tailored the effective cage size of ZIF-8 to be between CO2 and N2 by confining an imidazolium-based ionic liquid [bmim][Tf2 N] into ZIF-8's SOD cages by in-situ ionothermal synthesis. Mixed matrix membranes derived from ionic liquid-modified ZIF-8 exhibited remarkable combinations of permeability and selectivity that transcend the upper bound of polymer membranes for CO2 /N2 and CO2 /CH4 separation. We observed an unusual response of the membranes to varying pressure, that is, an increase in the CO2 /CH4 separation factor with pressure, which is highly desirable for practical applications in natural gas upgrading.

  13. Magnetic Properties of Hard Magnetic Alloy Fe - 28% Cr - 13.4% Co - 2% Mo - 0.5% Si

    Science.gov (United States)

    Vompe, T. A.; Milyaev, I. M.; Yusupov, V. S.

    2017-01-01

    The method of regression analysis is used to obtain equations describing the dependences of magnetic hysteresis properties of magnetically hard powder alloy Fe - 28% Cr - 13.4% Co - 2% Mo - 0.5% Si on regimes of thermomagnetic treatment (the temperatures of the start of the treatment and the rates of cooling in magnetic field). The determined treatment modes make it possible to obtain in an alloy with a coercive force H c up to 40 kA/m, a residual induction B r up to 1.2 T, and a maximum energy product ( BH)max up to 25 kJ/m3. The alloy may find application in the production of rotors of synchronous hysteresis-reluctance motors.

  14. Magnetic properties of a Pt/Co2FeAl/MgO structure with perpendicular magnetic anisotropy

    Science.gov (United States)

    Li, Xiao-Qi; Xu, Xiao-Guang; Wang, Sheng; Wu, Yong; Zhang, De-Lin; Miao, Jun; Jiang, Yong

    2012-10-01

    Microstructures and magnetic properties of Ta/Pt/Co2FeAl (CFA)/MgO multilayers are studied to understand perpendicular magnetic anisotropy (PMA) of half-metallic full-Heusler alloy films. PMA is realized in a 2.5-nm CFA film with B2-ordered structure observed by a high resolution transmission electron microscope. It is demonstrated that a high quality interface between the ferromagnetic layer and oxide layer is not essential for PMA. The conversions between in-plane anisotropy and PMA are investigated to study the dependence of magnetic moment on temperature. At the intersection points, the decreasing slope of the saturation magnetization (Ms) changes because of the conversions. The dependence of Ms on the annealing temperature and MgO thickness is also studied.

  15. Magnetic properties of a Pt/Co2FeAl/MgO structure with perpendicular magnetic anisotropy

    Institute of Scientific and Technical Information of China (English)

    Li Xiao-Qi; Xu Xiao-Guang; Wang Sheng; Wu Yong; Zhang De-Lin; Miao Jun; Jiang Yong

    2012-01-01

    Microstructures and magnetic properties of Ta/Pt/Co2FeAl (CFA)/MgO multilayers are studied to understand perpendicular magnetic anisotropy (PMA) of half-metallic full-Heusler alloy films.PMA is realized in a 2.5-nm CFA film with B2-ordered structure observed by a high resolution transmission electron microscope.It is demonstrated that a high quality interface between the ferromagnetic layer and oxide layer is not essential for PMA.The conversions between in-plane anisotropy and PMA are investigated to study the dependence of magnetic moment on temperature.At the intersection points,the decreasing slope of the saturation magnetization (Ms) changes because of the conversions.The dependence of Ms on the annealing temperature and MgO thickness is also studied.

  16. Effect of combined treatment with supercritical CO2 and rosemary on microbiological and physicochemical properties of ground pork stored at 4°C.

    Science.gov (United States)

    Huang, Shirong; Liu, Bin; Ge, Du; Dai, Jiehui

    2017-03-01

    The effect of combined treatment with supercritical CO2 (2000psi, 35°C for 2h) and rosemary powder (2.5% and 5.0% (w/w)) on microbiological and physicochemical properties of ground pork stored at 4°C was investigated. The changes in total viable count, pH, total volatile base nitrogen (TVB-N), lipid oxidation and instrumental color (CIE L(⁎), a(⁎), b(⁎)) were analyzed during a week period of refrigerated storage. It was found that microbial populations were reduced by supercritical CO2 treatment, with the more pronounced effect being achieved by combined treatment with supercritical CO2 and 5.0g rosemary powder/100g meat. Supercritical CO2 treatment for 2h could accelerate lipid oxidation of ground pork during refrigerated storage, whereas combination with rosemary can significantly slow down the increase of oxidation rate. Combined treatment of supercritical CO2 and rosemary significantly increased L(⁎) and b(⁎) values of the ground pork, while the a(⁎), pH and TVB-N value were not affected as compared to the treatment with supercritical CO2 alone. The results of this study indicate that combined treatment of supercritical CO2 and rosemary may be useful in the meat industry to enhance the storage stability of ground pork treated with long time exposure of supercritical CO2 during refrigerated storage.

  17. Reconsidering the importance of interfacial properties in foam stability

    NARCIS (Netherlands)

    Wierenga, P.A.; Norel, van L.; Basheva, E.S.

    2009-01-01

    In food industry, protein isolates are often used to help in the formation and stabilisation of food foams. Subsequently there is great interest in (1) understanding the effect of processing parameters on the functional properties of the isolate, and (2) methods and techniques that can help to predi

  18. Elucidating the role of interfacial materials properties in microfluidic packages.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Thayne L.

    2013-01-01

    The purpose of this work was to discover a method to investigate the properties of interfaces as described by a numerical physical model. The model used was adopted from literature and applied to a commercially available multiphysics software package. By doing this the internal properties of simple structures could be elucidated and then readily applied to more complex structures such as valves and pumps in laminate microfluidic structures. A numerical finite element multi-scale model of a cohesive interface comprised of heterogeneous material properties was used to elucidate irreversible damage from applied strain energy. An unknown internal state variable was applied to characterize the damage process. Using a constrained blister test, this unknown internal state variable could be determined for an adherend/adhesive/adherend body. This is particularly interesting for laminate systems with microfluidic and microstructures contained within the body. A laminate structure was designed and fabricated that could accommodate a variety of binary systems joined using nearly any technique such as adhesive, welding (solvent, laser, ultrasonic, RF, etc.), or thermal. The adhesive method was the most successful and easy to implement but also one of the more difficult to understand, especially over long periods of time. Welding methods are meant to achieve a bond that is similar to bulk properties and so are easier to predict. However, methods of welding often produce defects in the bonds.. Examples of the test structures used to elucidate the internal properties of the model were shown and demonstrated. The real life examples used this research to improve upon current designs and aided in creating complex structures for sensor and other applications.

  19. Anodization of carbon fibers on interfacial mechanical properties of epoxy matrix composites.

    Science.gov (United States)

    Park, Soo-Jin; Chang, Yong-Hwan; Kim, Yeong-Cheol; Rhee, Kyong-Yop

    2010-01-01

    The influence of anodic oxidation on the mechanical interfacial properties of carbon-fiber-reinforced epoxy resin composites was investigated. The surface properties of the anodized carbon fibers were studied through the measurement of contact angles and through SEM, XPS, and FT-IR analyses. The mechanical interfacial properties of the composites were studied through measurements of interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and critical strain energy release rate (G(IC)). It was shown that the surface functional groups containing oxygen on the anodized carbon fibers exert great effects on the surface energetics of fibers and the mechanical interfacial properties, e.g., ILSS, of the resulting composites. Contact angle measurements based on the wicking rate of a test liquid showed that anodic oxidation lead to an increase in the surface free energy of the carbon fibers, mainly in its specific (or polar) component. In terms of surface energetics, it was found that wetting played an important role in increasing the degree of adhesion at interfaces between the fibers and the resin matrices of the composites.

  20. The role of the [CpM(CO)2](-) chromophore in the optical properties of the [Cp2ThMCp(CO)2](+) complexes, where M = Fe, Ru and Os. A theoretical view.

    Science.gov (United States)

    Cantero-López, Plinio; Le Bras, Laura; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro

    2015-12-14

    The chemical bond between actinide and the transition metal unsupported by bridging ligands is not well characterized. In this paper we study the electronic properties, bonding nature and optical spectra in a family of [Cp2ThMCp(CO)2](+) complexes where M = Fe, Ru, Os, based on the relativistic two component density functional theory calculations. The Morokuma-Ziegler energy decomposition analysis shows an important ionic contribution in the Th-M interaction with around 25% of covalent character. Clearly, charge transfer occurs on Th-M bond formation, however the orbital term most likely represents a strong charge rearrangement in the fragments due to the interaction. Finally the spin-orbit-ZORA calculation shows the possible NIR emission induced by the [FeCp(CO)2](-) chromophore accomplishing the antenna effect that justifies the sensitization of the actinide complexes.

  1. Subcritical Water Induced Complexation of Soy Protein and Rutin: Improved Interfacial Properties and Emulsion Stability.

    Science.gov (United States)

    Chen, Xiao-Wei; Wang, Jin-Mei; Yang, Xiao-Quan; Qi, Jun-Ru; Hou, Jun-Jie

    2016-09-01

    Rutin is a common dietary flavonoid with important antioxidant and pharmacological activities. However, its application in the food industry is limited mainly because of its poor water solubility. The subcritical water (SW) treatment provides an efficient technique to solubilize and achieve the enrichment of rutin in soy protein isolate (SPI) by inducing their complexation. The physicochemical, interfacial, and emulsifying properties of the complex were investigated and compared to the mixtures. SW treatment had much enhanced rutin-combined capacity of SPI than that of conventional method, ascribing to the well-contacted for higher water solubility of rutin with stronger collision-induced hydrophobic interactions. Compared to the mixtures of rutin with proteins, the complex exhibited an excellent surface activity and improved the physical and oxidative stability of its stabilized emulsions. This improving effect could be attributed to the targeted accumulation of rutin at the oil-water interface accompanied by the adsorption of SPI resulting in the thicker interfacial layer, as evidenced by higher interfacial protein and rutin concentrations. This study provides a novel strategy for the design and enrichment of nanovehicle providing water-insoluble hydrophobic polyphenols for interfacial delivery in food emulsified systems.

  2. Effect of Alkali on Daqing Crude Oil/Water Interfacial Properties

    Institute of Scientific and Technical Information of China (English)

    Guo Jixiang; Li Mingyuan; Lin Meiqin; Wu Zhaoliang

    2007-01-01

    Alkaline-surfactant-polymer (ASP) flooding using sodium hydroxide as the alkali component to enhance oil recovery in Daqing Oilfield,northeast China has been successful,but there are new problems in the treatment of produced crude. The alkali added forms stable water-in-crude oil emulsion,hence de-emulsification process is necessary to separate oil and water. The problems in enhanced oil recovery with ASP flooding were investigated in laboratory by using fractions of Daqing crude oil. The oil was separated into aliphatics,aromatics,resin and asphaltene fractions. These fractions were then mixed with an additive-free jet fuel to form model oils. The interfacial properties,such as interfacial tension and interfacial pressure of the systems were also measured,which together with the molecular parameters of the fractions were all used to investigate the problems in the enhanced oil recovery. In our work,it was found that sodium hydroxide solution reacts with the acidic hydrogen in the fractions of crude oil and forms soap-like interfacially active components,which accumulate at the crude oil-water interface.

  3. Geometrical Properties Can Predict CO2 and N2 Adsorption Performance of Metal-Organic Frameworks (MOFs) at Low Pressure.

    Science.gov (United States)

    Fernandez, Michael; Barnard, Amanda S

    2016-05-09

    Metal-organic frameworks (MOFs) are nanoporous materials with exceptional host-guest properties poised for groundbreaking innovations in gas separation applications according to high-throughput (HT) screening data. However, MOF structural libraries are nearly infinite in practice and so statistical and information technology will play a fundamental role in implementing and rationalizing MOF virtual screening. In this work, we apply k-means clustering and archetypal analysis (AA) to identify the truly significant nanoporous structures in a large library of ∼82 000 virtual MOFs. Quantitative structure-property relationship (QSPR) models of the theoretical CO2 and N2 uptake capacities were also developed using a calibration set of ∼16 000 hypothetical MOF structures derived from the prototypes and archetype frameworks. Since uptake capacities correlated poorly to the void fraction, surface area and pore size but these properties were used to build binary classifier predictors that successfully identify "high-performing" nanoporous materials in an external test set of ∼65 000 MOFs with accuracy higher than 94%. The accuracy of the classification decreased for MOFs with fluorine substituents. The classification models can serve as efficient filtering tools to detecting promising high-performing candidates at the early stage of virtual high-throughput screening of novel porous materials.

  4. Interfacial Properties of Colloidal Silica Dispersions in Contact with Solutions of Fatty Amines in Hexane

    OpenAIRE

    Whitby, C.P.; Ravera, Francesca; Fornasiero, D.; Ralston, J.; Liggieri, Libero

    2010-01-01

    Many natural phenomena and technologies are concerned with the interactions between micro- or nano-metre sized particles and surfactant molecules at liquid interfaces. Highly stable emulsions are produced by using surfactants to modify the surfaces of nanoparticles. Particle attachment to bubbles is controlled by surfactant adsorption in flotation technologies. So far, however, few experimental studies have explored the properties of these complex interfacial layers.

  5. Interfacial rheological properties and conformational aspects of soy glycinin at the air/water interface

    NARCIS (Netherlands)

    Martin, A.H.; Bos, M.A.; Vliet, T. van

    2002-01-01

    Interfacial (rheological) properties of soy glycinin were studied at different pH. At acidic and high alkaline pH glycinin (11S form, Mw ∼ 350 kDa) dissociates into smaller subunits, the so called 3S form (Mw ∼ 44 kDa) and 7S form (Mw ∼ 175 kDa). This dissociation behaviour is expected to affect the

  6. Electrochemical evaluation of the p-Si/conducting polymer interfacial properties

    Science.gov (United States)

    Nagasubramanian, G.; Distefano, S.; Moacanin, J.

    1988-01-01

    Results are presented from an experimental investigation of the contact resistance and interfacial properties of a p-Si/conducting polymer interface for solar cell applications. The electronic character of the polymer/semiconductor function is determined by studying the electrochemical behavior of both poly(isothianapthene) (PITN) and polypyrrole (PP) in an acetonitrile solution on p-silicon electrodes. The results obtained indicate that while PITN is intrinsically more conductive than PP, neither passivates surface states nor forms ohmic contact.

  7. Effect of interfacial properties on mechanical stability of ash deposit

    Directory of Open Access Journals (Sweden)

    A. Ontiveros-Ortega

    2016-04-01

    Full Text Available The paper presents a study on the cohesion of volcanic ash particles using surface free energy determination and zeta potential analyses. This is a subject of great interest in physical volcanology, as many researches on volcanic particle aggregation are frequently reported. In this case, special attention is paid to the role of structural or hydration forces between hydrophilic surfaces, which are a consequence of the electron-donor/electron-acceptor character of the interface. From this point of view, the results are potentially interesting as they could give valuable insights into this process. The results are presented in terms of the total energy of interaction between dispersed particles, computed from the extended DLVO theory. Contributions to the total free energy of interaction were determined from the zeta potential and surface free energy of ash, measured under different experimental conditions. Two samples of basaltic volcanic ash (black and white with silica contents of 44% and 63% respectively are studied. The surface free energy and zeta potential were analysed for ashes immersed in different electrolytes (NaCl, CaCl2, FeCl3. The presence of electrolytes changes the surface properties of the solid materials. The analysis of total interaction energy between the ash particles in aqueous medium shows that soil cohesion strongly depends on ash surface properties, chemical nature, the adsorbed cation on the surface, and pH value.

  8. Influences of interfacial properties on second-harmonic generation of Lamb waves propagating in layered planar structures

    Energy Technology Data Exchange (ETDEWEB)

    Deng Mingxi [College of Automation, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Wang Ping [College of Automation, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Lv Xiafu [College of Automation, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China)

    2006-07-21

    This paper describes influences of interfacial properties on second-harmonic generation of Lamb waves propagating in layered planar structures. The nonlinearity in the elastic wave propagation is treated as a second-order perturbation of the linear elastic response. Due to the kinematic nonlinearity and the elastic nonlinearity of materials, there are second-order bulk and surface/interface driving sources in layered planar structures through which Lamb waves propagate. These driving sources can be thought of as forcing functions of a series of double frequency lamb waves (DFLWs) in terms of the approach of modal expansion analysis for waveguide excitation. The total second-harmonic fields consist of a summation of DFLWs in the corresponding stress-free layered planar structures. The interfacial properties of layered planar structures can be described by the well-known finite interfacial stiffness technique. The normal and tangential interfacial stiffness constants can be coupled with the equation governing the expansion coefficient of each DFLW component. On the other hand, the normal and tangential interfacial stiffness constants are associated with the degree of dispersion between Lamb waves and DFLWs. Theoretical analyses and numerical simulations indicate that the efficiency of second-harmonic generation by Lamb wave propagation is closely dependent on the interfacial properties of layered structures. The potential of using the effect of second-harmonic generation by Lamb wave propagation to characterize the interfacial properties of layered structures are considered. Some experimental results are presented.

  9. First-Principles Prediction of Electronic, Magnetic, and Optical Properties of Co2MnAs Full-Heusler Half-Metallic Compound

    Science.gov (United States)

    Bakhshayeshi, A.; Sarmazdeh, M. Majidiyan; Mendi, R. Taghavi; Boochani, A.

    2016-12-01

    Electronic, magnetic, and optical properties of Co2MnAs full-Heusler compound have been calculated using a first-principles approach with the full-potential linearized augmented plane-wave (FP-LAPW) method and generalized gradient approximation plus U (GGA + U). The results are compared with various properties of Co2MnZ (Z = Si, Ge, Al, Ga, Sn) full-Heusler compounds. The results of our calculations show that Co2MnAs is a half-metallic ferromagnetic compound with 100% spin polarization at the Fermi level. The total magnetic moment and half-metallic gap of Co2MnAs compound are found to be 6.00μ B and 0.43 eV, respectively. It is also predicted that the spin-wave stiffness constant and Curie temperature of Co2MnAs compound are about 3.99 meV nm2 and 1109 K, respectively. The optical results show that the dominant behavior, at energy below 2 eV, is due to interactions of free electrons in the system. Interband optical transitions have been calculated based on the imaginary part of the dielectric function and analysis of critical points in the second energy derivative of the dielectric function. The results show that there is more than one plasmon energy for Co2MnAs compound, with the highest occurring at 25 eV. Also, the refractive index variations and optical reflectivity for radiation at normal incidence are calculated for Co2MnAs. Because of its high magnetic moment, high Curie temperature, and 100% spin polarization at the Fermi level as well as its optical properties, Co2MnAs is a good candidate for use in spintronic components and magnetooptical devices.

  10. Mechanical Properties of L80 Steel in CO2/H2S Environment%L80钢在CO2/H2S腐蚀环境中的力学特性

    Institute of Scientific and Technical Information of China (English)

    林海; 许杰; 范白涛; 张羽臣; 王桂萍; 霍宏博; 殷启帅

    2016-01-01

    ABSTRACT:Objective To study the mechanical properties of L80 steel in CO2 / H2S environment.Methods Slow strain rate tensile testing machine was used to conduct tensile tests on L80 samples in specific corrosion conditions, and the influence rules of each factor on the mechanical properties of L80 steel were analyzed.Results In CO2/H2S environment, with the increase of water cut, the tensile curve of L80 tubing steel appeared to degrade, the yield strength, tensile strength, and elongation all de-creased; With the increase of tensile stress, the yield strength of L80 steel had no significant change, the tensile strength and elongation decreased, and the corrosion rate significantly changed when the tensile stress exceeded 0.8σs, which showed strong stress corrosion sensitivity; With the increase of H2S partial pressure, the mechanical properties of L80 steel decreased, show-ing relatively strong hydrogen embrittlement sensitivity, but influence of CO2 partial pressure on L80 steel was not obvious; Tensile curve of L80 steel underwent mild degradation with the increase of temperature, the elongation and yield zone width re-duced with a small amplitude, but the tensile strength just changed a little.ConclusionTemperature and CO2had a small effect on the mechanical properties of L80 steel; The increase of water cut and tensile stress reduced the mechanical toughness of L80 steel, accelerated the corrosion rate of L80 steel, and shortened the anticorrosion longevity of L80 steel; Mechanical properties of L80 steel were more sensitive to H2S than CO2, and sample fracture was the result of the combination of machine tensile and stress corrosion.%目的:研究L80钢在CO2/H2S环境中的力学特性。方法利用微机控制慢应变速率拉伸试验机,对特定腐蚀条件下的L80钢试样进行拉伸实验,分析各因素对L80钢力学特性的影响变化规律。结果在CO2/H2S环境中,随着含水率的增加,L80钢的屈服强度、抗拉强

  11. Effects of Cu doping on the electronic structure and magnetic properties of MnCo2O4 nanostructures

    Science.gov (United States)

    Pramanik, Prativa; Thota, Subhash; Singh, Sobhit; Joshi, Deep Chandra; Weise, Bruno; Waske, Anja; Seehra, M. S.

    2017-10-01

    Reported here are the results and their analysis from our detailed investigations of the effects of Cu doping (x ≤slant 0.2 ) on the electronic structure and magnetic properties of the spinel MnCo2 O4. A detailed comparison is given for the x = 0 and x = 0.2 cases for both the bulk-like samples and nanoparticles. The electronic structure determined from x-ray photoelectron spectroscopy and Rietveld analysis of x-ray diffraction patterns shows the structure to be: (Co3+ )A [Mn3+ Co2+(1-x) Cu2+x ]B O4 i.e. Cu2+ substitutes for Co2+ on the octahedral B-sites. For the bulk samples, the ferrimagnetic T_C= 184 K for x = 0 is lowered to TC = 167 K for the x = 0.2 sample, this decrease being due to the effect of Cu doping. For the nanosize x = 0 (x = 0.2 ) sample, the lower TC = 165 K (TC = 155 K) is observed using \\partial (χdcT)/\\partial T analysis, this lowering being due to finite size effects. For T > TC , fits of dc paramagnetic susceptibility data of χ-1 versus T in nanosize samples to the Néel expression are used to determine the exchange interactions between the A and B sites with exchange constants: JAA / kB ∼ 8.4 K (4.1 K), JBB/kB ∼21.2 K (16.3 K) and JAB / kB ∼ 13.9 K (13.8 K) for x = 0 (0.2) . The temperature dependence of ac susceptibilities χ\\prime(T) and χ\\prime\\prime(T) at different frequencies shows that in bulk samples of x = 0 and x=0.2 , the transition at T C is the normal second order transition. But for the nanosize x = 0 and 0.2 samples, analysis of the ac susceptibilities shows that the ferrimagnetic transition at T C is followed by a re-entrant spin-glass transition at lower temperatures T_SG ∼ 162 K (138 K) for x = 0 (x = 0.20 ). Analysis of the ac susceptibilities, χ\\prime(T) and χ\\prime\\prime(T) , versus T data is done in terms of two scaling laws: (i) Vogel–Fulcher law [τ = τo \\exp(Ea/(kB(T-To)))] ; and (ii) power law of critical slowing-down τ / τo = [(TP/TSG)-1]-zν . These fits confirm the existence

  12. 超临界CO2辅助聚合物加工%Supercritical CO2 assisted polymer processing

    Institute of Scientific and Technical Information of China (English)

    赵玲; 刘涛

    2013-01-01

    近年来,以超临界CO2替代聚合物加工过程中大量使用的有机溶剂实现超临界CO2辅助聚合物加工过程已引起人们越来越多的关注.CO2在聚合物中的溶解扩散可导致其结构和形态的变化,能够溶胀增塑聚合物并且将溶解于其中的小分子物质携带输运到聚合物基体中,进而影响聚合物的结晶及晶型转变行为,聚合物/CO2体系界面张力以及聚合物/CO2体系流变行为等基本物性的变化.利用聚合物基本物性的变化可实现CO2辅助聚合物接枝反应,CO2辅助聚合物渗透小分子物质以及CO2辅助聚合物发泡等超临界CO2辅助聚合物加工过程的应用.结合本研究室的实例,探讨了CO2作用下等规聚丙烯和间规聚丙烯的结晶行为以及一种多晶型聚合物——等规聚丁烯-1的晶型转变行为;探讨了利用CO2对等规聚丙烯、聚乳酸和聚酯三种典型的低熔体强度结晶聚合物具有的不同诱导结晶作用,调控聚合物的结晶行为,使其具备发泡所需的熔体强度,制备了具有不同结构特征的发泡聚合物材料.%The use of CO2 for substituting volatile organic compounds in polymer processing, i. e. , supercritical CO2-assisted polymer processing, has attracted increasing attention in recent years. Dissolution of CO2 in polymer could swell, plasticize and deliver small molecules into the polymer matrixes. Consequently, the structure and morphology of the polymer would change, as well as the fundamental properties, including polymer crystallization, interfacial tension between polymer and gas, and rheology of CO2 /polymers melt. CO2 -induced changes in these properties could be used to realize the supercritical CO2-assisted polymer processing, e.g., CO2-assisted polymer grafting, CO2-assisted penetrating of small molecules into polymer and CO2-assisted polymer foaming. Several cases from the authors' laboratory are presented for elucidating how to use the changes to manipulate

  13. Structural dynamics and interfacial properties of filler-reinforced elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsche, J; Klueppel, M, E-mail: Manfred.Klueppel@DIKautschuk.de [Deutsches Institut fuer Kautschuktechnologie e V, Eupener Strasse 33, D-30519 Hannover (Germany)

    2011-01-26

    The combined effect of filler networking and reduced chain mobility close to the filler interface is analyzed based on investigations of the relaxation dynamics of a solution of styrene butadiene rubber filled with different loadings and types of nanostructured carbon blacks. Dynamic-mechanical and dielectric spectra are studied in a wide frequency and temperature range. By referring to a tunneling process of charge carriers over nanoscopic gaps between adjacent carbon black particles the gap distance is evaluated from the dielectric spectra. This distance corresponds to the length of glassy-like polymer bridges forming flexible bonds between adjacent filler particles of the filler network. It is found that the gap distance decreases with increasing filler loading and specific surface area which correlates with an increase of the apparent activation energy of the filler network evaluated from dynamic-mechanical data. Due to the thermal activation of glassy-like polymer bridges the time-temperature superposition principle is not fulfilled for filled elastomers and the introduction of vertical shift factors is necessary to obtain viscoelastic master curves. The change in the low frequency viscoelastic properties by the incorporation of fillers is shown to be related to the superimposed dynamics of the filler network governed by the viscoelastic response of the glassy-like polymer bridges. This effect is distinguished from the reduced chain mobility close to the filler surface which results in a broadening of the glass transition on the high temperature or low frequency side. The microstructure-based interpretation of viscoelastic data is supported by an analysis of the relaxation time spectra.

  14. Structural dynamics and interfacial properties of filler-reinforced elastomers

    Science.gov (United States)

    Fritzsche, J.; Klüppel, M.

    2011-01-01

    The combined effect of filler networking and reduced chain mobility close to the filler interface is analyzed based on investigations of the relaxation dynamics of a solution of styrene butadiene rubber filled with different loadings and types of nanostructured carbon blacks. Dynamic-mechanical and dielectric spectra are studied in a wide frequency and temperature range. By referring to a tunneling process of charge carriers over nanoscopic gaps between adjacent carbon black particles the gap distance is evaluated from the dielectric spectra. This distance corresponds to the length of glassy-like polymer bridges forming flexible bonds between adjacent filler particles of the filler network. It is found that the gap distance decreases with increasing filler loading and specific surface area which correlates with an increase of the apparent activation energy of the filler network evaluated from dynamic-mechanical data. Due to the thermal activation of glassy-like polymer bridges the time-temperature superposition principle is not fulfilled for filled elastomers and the introduction of vertical shift factors is necessary to obtain viscoelastic master curves. The change in the low frequency viscoelastic properties by the incorporation of fillers is shown to be related to the superimposed dynamics of the filler network governed by the viscoelastic response of the glassy-like polymer bridges. This effect is distinguished from the reduced chain mobility close to the filler surface which results in a broadening of the glass transition on the high temperature or low frequency side. The microstructure-based interpretation of viscoelastic data is supported by an analysis of the relaxation time spectra.

  15. Interfacial properties and design of functional energy materials.

    Science.gov (United States)

    Sumpter, Bobby G; Liang, Liangbo; Nicolaï, Adrien; Meunier, Vincent

    2014-11-18

    CONSPECTUS: The vital importance of energy to society continues to demand a relentless pursuit of energy responsive materials that can bridge fundamental chemical structures at the molecular level and achieve improved functionality and performance. This demand can potentially be realized by harnessing the power of self-assembly, a spontaneous process where molecules or much larger entities form ordered aggregates as a consequence of predominately noncovalent (weak) interactions. Self-assembly is the key to bottom-up design of molecular devices, because the nearly atomic-level control is very difficult to realize in a top-down, for example, lithographic, approach. However, while function in simple systems such as single crystals can often be evaluated a priori, predicting the function of the great variety of self-assembled molecular architectures is complicated by the lack of understanding and control over nanoscale interactions, mesoscale architectures, and macroscale order. To establish a foundation toward delivering practical solutions, it is critical to develop an understanding of the chemical and physical mechanisms responsible for the self-assembly of molecular and hybrid materials on various support substrates. Typical molecular self-assembly involves noncovalent intermolecular and substrate-molecule interactions. These interactions remain poorly understood, due to the combination of many-body interactions compounded by local or collective influences from the substrate atomic lattice and electronic structure. Progress toward unraveling the underlying physicochemical processes that control the structure and macroscopic physical, chemical, mechanical, electrical, and transport properties of materials increasingly requires tight integration of theory, modeling, and simulation with precision synthesis, advanced experimental characterization, and device measurements. Theory, modeling, and simulation can accelerate the process of materials understanding and design

  16. Thermal and mechanical interfacial properties of epoxy composites based on functionalized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jin Fanlong [School of Chemical and Materials Engineering, Jilin Institute of Chemical Technology, Jilin City 132022 (China); Ma Changjie [Applied Chemical Engineering Department, Jilin Vocational College of Industry and Technology, Jilin City 132013 (China); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, Nam-Gu, Incheon 402-751 (Korea, Republic of)

    2011-11-15

    Highlights: {yields} CNTs were functionalized by acid and amine treatments. {yields} Epoxy resin/CNT composites were prepared. {yields} T{sub g} of the composites increased by about 10 deg. C compared to neat epoxy resins. {yields} Toughness of the composites was significantly improved by the addition of functionalized CNTs. - Abstract: Carbon nanotubes (CNTs) were treated by a mixture of acid and functionalized subsequently by amine treatment to improve interfacial interactions and dispersion of CNTs in epoxy matrix. The thermal stabilities and mechanical interfacial properties of epoxy/CNT composites were investigated using several techniques. The dispersion state of CNTs in the epoxy matrix was observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). As a result, the glass transition temperature of epoxy/CNT composites increased by about 11 deg. C compared to neat epoxy resins. The mechanical interfacial property of the composites was significantly increased by the addition of amine treated CNTs. The SEM and TEM results showed that the separation and uniform dispersion of CNTs in the epoxy matrix.

  17. Effect of chemical treatment of Kevlar fibers on mechanical interfacial properties of composites.

    Science.gov (United States)

    Park, Soo-Jin; Seo, Min-Kang; Ma, Tae-Jun; Lee, Douk-Rae

    2002-08-01

    In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid-base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system.

  18. Understanding the interfacial properties of nanostructured liquid crystalline materials for surface-specific delivery applications.

    Science.gov (United States)

    Dong, Yao-Da; Larson, Ian; Barnes, Timothy J; Prestidge, Clive A; Allen, Stephanie; Chen, Xinyong; Roberts, Clive J; Boyd, Ben J

    2012-09-18

    Nonlamellar liquid crystalline dispersions such as cubosomes and hexosomes have great potential as novel surface-targeted active delivery systems. In this study, the influence of internal nanostructure, chemical composition, and the presence of Pluronic F127 as a stabilizer, on the surface and interfacial properties of different liquid crystalline particles and surfaces, was investigated. The interfacial properties of the bulk liquid crystalline systems with coexisting excess water were dependent on the internal liquid crystalline nanostructure. In particular, the surfaces of the inverse cubic systems were more hydrophilic than that of the inverse hexagonal phase. The interaction between F127 and the bulk liquid crystalline systems depended on the internal liquid crystalline structure and chemical composition. For example, F127 adsorbed to the surface of the bulk phytantriol cubic phase, while for monoolein cubic phase, F127 was integrated into the liquid crystalline structure. Last, the interfacial adsorption behavior of the dispersed liquid crystalline particles also depended on both the internal nanostructure and the chemical composition, despite the dispersions all being stabilized using F127. The findings highlight the need to understand the specific surface characteristics and the nature of the interaction with colloidal stabilizer for understanding and optimizing the behavior of nonlamellar liquid crystalline systems in surface delivery applications.

  19. Microfluidic study for investigating migration and residual phenomena of supercritical CO2 in porous media

    Science.gov (United States)

    Park, Gyuryeong; Wang, Sookyun; Lee, Minhee; Um, Jeong-Gi; Kim, Seon-Ok

    2017-04-01

    The storage of CO2 in underground geological formation such as deep saline aquifers or depleted oil and gas reservoirs is one of the most promising technologies for reducing the atmospheric CO2 release. The processes in geological CO2 storage involves injection of supercritical CO2 (scCO2) into porous formations saturated with brine and initiates CO2 flooding with immiscible displacement. The CO2 migration and porewater displacement within geological formations, and , consequentially, the storage efficiency are governed by the interaction of fluid and rock properties and are affected by the interfacial tension, capillarity, and wettability in supercritical CO2-brine-mineral systems. This study aims to observe the displacement pattern and estimate storage efficiency by using micromodels. This study aims to conduct scCO2 injection experiments for visualization of distribution of injected scCO2 and residual porewater in transparent pore networks on microfluidic chips under high pressure and high temperature conditions. In order to quantitatively analyze the porewater displacement by scCO2 injection under geological CO2 storage conditions, the images of invasion patterns and distribution of CO2 in the pore network are acquired through a imaging system with a microscope. The results from image analysis were applied in quantitatively investigating the effects of major environmental factors and scCO2 injection methods on porewater displacement process by scCO2 and storage efficiency. The experimental observation results could provide important fundamental information on capillary characteristics of reservoirs and improve our understanding of CO2 sequestration progress.

  20. Optimization of interfacial microstructure and mechanical properties of carbon fiber/epoxy composites via carbon nanotube sizing

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Hongwei; Sui, Xianhang; Zhao, Zhongbo; Xu, Zhiwei; Chen, Lei, E-mail: chenlei@tjpu.edu.cn; Deng, Hui; Liu, Ya; Qian, Xiaoming, E-mail: qianxiaoming@tjpu.edu.cn

    2015-08-30

    Highlights: • Multiple sizing treatments were used to modify the surface of carbon fiber with carbon nanotubes. • The distribution state of carbon nanotubes in interface had a great effect on the performance of carbon fiber composites. • Interfacial microstructure changes brought by sizing treatment were detected by energy dispersive X-ray spectroscopy and atomic force microscope. • Gradient interphase composed of carbon nanotubes and epoxy was favorable to improve the mechanical properties of carbon composites. - Abstract: Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber–matrix interphase structure was developed and showed great commercial application potential.

  1. Biofilm-like properties of the sea surface and predicted effects on air-sea CO2 exchange

    Science.gov (United States)

    Wurl, Oliver; Stolle, Christian; Van Thuoc, Chu; The Thu, Pham; Mari, Xavier

    2016-05-01

    Because the sea surface controls various interactions between the ocean and the atmosphere, it has a profound function for marine biogeochemistry and climate regulation. The sea surface is the gateway for the exchange of climate-relevant gases, heat and particles. Thus, in order to determine how the ocean and the atmosphere interact and respond to environmental changes on a global scale, the characterization and understanding of the sea surface are essential. The uppermost part of the water column is defined as the sea-surface microlayer and experiences strong spatial and temporal dynamics, mainly due to meteorological forcing. Wave-damped areas at the sea surface are caused by the accumulation of surface-active organic material and are defined as slicks. Natural slicks are observed frequently but their biogeochemical properties are poorly understood. In the present study, we found up to 40 times more transparent exopolymer particles (TEP), the foundation of any biofilm, in slicks compared to the underlying bulk water at multiple stations in the North Pacific, South China Sea, and Baltic Sea. We found a significant lower enrichment of TEP (up to 6) in non-slick sea surfaces compared to its underlying bulk water. Moreover, slicks were characterized by a large microbial biomass, another shared feature with conventional biofilms on solid surfaces. Compared to non-slick samples (avg. pairwise similarity of 70%), the community composition of bacteria in slicks was increasingly (avg. pairwise similarity of 45%) different from bulk water communities, indicating that the TEP-matrix creates specific environments for its inhabitants. We, therefore, conclude that slicks can feature biofilm-like properties with the excessive accumulation of particles and microbes. We also assessed the potential distribution and frequency of slick-formation in coastal and oceanic regions, and their effect on air-sea CO2 exchange based on literature data. We estimate that slicks can reduce CO2

  2. Effects of fault-controlled CO2 alteration on mineralogical and geomechanical properties of reservoir and seal rocks, Crystal Geyser, Green River, Utah

    Science.gov (United States)

    Major, J. R.; Eichhubl, P.; Urquhart, A.; Dewers, T. A.

    2012-12-01

    An understanding of the coupled chemical and mechanical properties of reservoir and seal units undergoing CO2 injection is critical for modeling reservoir behavior in response to the introduction of CO2. The implementation of CO2 sequestration as a mitigation strategy for climate change requires extensive risk assessment that relies heavily on computer models of subsurface reservoirs. Numerical models are fundamentally limited by the quality and validity of their input parameters. Existing models generally lack constraints on diagenesis, failing to account for the coupled geochemical or geomechanical processes that affect reservoir and seal unit properties during and after CO2 injection. For example, carbonate dissolution or precipitation after injection of CO2 into subsurface brines may significantly alter the geomechanical properties of reservoir and seal units and thus lead to solution-enhancement or self-sealing of fractures. Acidified brines may erode and breach sealing units. In addition, subcritical fracture growth enhanced by the presence of CO2 could ultimately compromise the integrity of sealing units, or enhance permeability and porosity of the reservoir itself. Such unknown responses to the introduction of CO2 can be addressed by laboratory and field-based observations and measurements. Studies of natural analogs like Crystal Geyser, Utah are thus a critical part of CO2 sequestration research. The Little Grand Wash and Salt Wash fault systems near Green River, Utah, host many fossil and active CO2 seeps, including Crystal Geyser, serving as a faulted anticline CO2 reservoir analog. The site has been extensively studied for sequestration and reservoir applications, but less attention has been paid to the diagenetic and geomechanical aspects of the fault zone. XRD analysis of reservoir and sealing rocks collected along transects across the Little Grand Wash Fault reveal mineralogical trends in the Summerville Fm (a siltstone seal unit) with calcite and

  3. Electronic Structure and Thermoelectric Properties of Na and Ni-doped Ca3Co2O6

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; YANG Wen

    2006-01-01

    The electronic structures of Ca3Co2O6, Na and Ni doped models were studied by the quantum chemical software of Cambride Serial Total Energy Package (CASTEP) that is based on density function theory (DFT) and pseudo-potential. The electronic conductivity, seebeck coefficient, thermal conductivity and figure of merit (Z) were computed. The energy band structure reveals the form of the impurity levels due to the substitutional impurity in semiconductors. Na-doped model shows the character of p-type semiconductor, but Ni-doped model is n-type semiconductor. The calculation results show that the electric conductivity of the doped model is higher than that of the non-doped model, while the Seebeck coefficient and thermal conductivity of the doped model are lower than those of the non-doped one. Because of the great increase of the electric conductivity, Z of Na-doped model is enhanced and thermoelectric properties are improved. On the other hand, as the large decline of Seebeck coefficient, Z of Ni-doped model is less than that of the non-doped model.

  4. Effect of structural disorder on the ground state properties of Co2CrAl Heusler alloy

    Science.gov (United States)

    Zagrebin, Mikhail A.; Sokolovskiy, Vladimir V.; Buchelnikov, Vasiliy D.; Pavlukhina, Oksana O.

    2017-08-01

    In order to discuss the difference between the available theoretical and experimental values of the total magnetic moment of Co2CrAl Heusler alloy, in this paper we studied the effects of a structural disorder on the magnetic and electronic ground state properties of the alloy studied by means of ab initio and Monte Carlo methods. On the one hand, it is shown that a calculated magnetic ground state of the austenite L21 structure is ferromagnetic, and the alloy demonstrates half-metallic behavior. However, the equilibrium lattice parameter and magnetic moment calculated for ferrimagnetic state (where the Cr atoms are ordered antiferromagnetically) are in better agreement with the available experimental data than the ferromagnetic one. On the other hand, an account of a structural disorder results in a decrease in the magnetic moment to a value close to the experimental. However, systems with a structural disorder are energetically unfavorable in comparison with the ordered L21 structure at zero temperature. Using the calculated exchange coupling parameters in the Heisenberg Hamiltonian, the temperature dependences of magnetization, specific heat, magnetic part of internal energy as well as Helmholtz energy are simulated in the framework of Monte Carlo technique for both ordered and disordered cases. Eventually, it is shown that the disordered structure with smaller magnetization is more stable at higher temperatures. This indicates that the experimental compound might be disordered.

  5. Sputtering temperature dependent growth kinetics and CO2 sensing properties of ZnO deposited over porous silicon

    Science.gov (United States)

    Martínez, L.; Holguín-Momaca, J. T.; Karthik, T. V. K.; Olive-Méndez, S. F.; Campos-Alvarez, J.; Agarwal, V.

    2016-10-01

    We report the growth kinetics and sensing properties of ZnO deposited over macro-porous silicon substrates at 400 and 600 °C using magnetron-sputtering technique. Scanning electron microscopy was employed to investigate the morphology and the particle size of the ZnO nanoparticles (NPs). The grain growth kinetics was analyzed with the help of the phenomenological equation rn =k0 texp(- Q / RT) finding an activation energy Q = 13.92 kJ/mol. The grain growth exponent (n = 2.85) for the growth at 400 °C corresponds to an Ostwald ripening process, while the growth at 600 °C is described by n = 1.66 implying a higher growth rate attributed to a high surface diffusion of add-atoms contributing to the formation of larger grains. The sensing response of the complete structure has been tested at different temperatures. The highest sensitivity, S ∼10, was obtained at a sensor temperature of 300 °C on the ZnO NPs sputtered on to the porous silicon substrate at 400 °C. The high response is attributed to the infiltration, uniform and homogenous distribution of the ZnO NPs into the pores. ZnO NPs sputtered at 400 °C are found to be smaller than those grown at 600 °C, exhibiting a larger surface-area/volume ratio and hence increasing the oxygen adsorption resulting in an enhanced CO2 sensitivity.

  6. Structure, magnetic properties and electrical resistivity of Co2FeSi1-xGax Heusler alloy thin films

    Science.gov (United States)

    Ramudu, M.; Raja, M. Manivel; Chelvane, J. Arout; Kamat, S. V.

    2016-11-01

    The influence of Ga on the structural, magnetic and half-metallic properties of Co2FeSi1-xGax (0≤x≤1) thin films grown on Si (100) substrates using ultra high vacuum magnetron sputtering has been systematically investigated. The linear increase in cubic lattice parameter from 5.63 Å to 5.73 Å and the Curie temperature (TC) from 854 K to 941 K with x varying from 0 to 1 indicate the progressive substitution of Ga for Si. The coercivity (Hc) was found to decrease from 26 Oe (x=0) to 3 Oe (x=1) at room temperature and is attributed to the decrease in magnetic anisotropy. The magnetic hysteresis loops measured from 300-873 K revealed that the film where Ga completely replaces Si exhibit better stability in both saturation magnetization (Ms) and Hc with temperature. The increase in coercivity at higher temperatures is attributed to the film to substrate interaction. The measured Ms at 100 K decreases from 5.01 μB/f.u. (x=0) to 4.49 μB/f.u. (x=1) and follows the trend of Slater-Pauling rule. The indirect evidence of half-metallic nature is examined from the temperature dependent electrical resistivity measurements.

  7. A new gas/supercritical fluid (SCF diffusivity measurement method for CO2 saturated polymer systems using a dielectric property

    Directory of Open Access Journals (Sweden)

    S. X. Yao

    2017-08-01

    Full Text Available In this research, theoretical CO2 diffusivity coefficients in amorphous polymers were calculated from dielectric constant changes during CO2 desorption. These values showed agreement with experimental diffusivity coefficients from a gravimetric method. Three amorphous polymer films made from Polystyrene (PS, Polycarbonate (PC, and Cyclic Olefin Polymer (COP resins were saturated with supercritical CO2 at 5.5 MPa and 25 °C for 24 hours in a pressure chamber. The CO2 infused films were removed from the chamber for gas desorption experiments. The capacitance of the samples were recorded with an Inductance, Capacitance and Resistance (LCR meter. These values were used to calculate the change in dielectric constants. CO2 weight percentages measured by a scale was used to calculate experimental diffusivity and solubility coefficients. It was found that the trend of dielectric constant changes was similar to that of the CO2 weight percentage changes during gas desorption. A mathematical model was built to predict the CO2 weight percentages during desorption from the measured dielectric constants. Theoretical diffusivity coefficients from this work agree well with literature data.

  8. Effects of NaNbO3-Co2O3 Co-additive on the Properties of PZN-PZT Ceramics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    NaNbO3-Co2O3 co-added PZN-PZT (PZCNNT) ceramics were prepared using conventional solid state reaction. The piezoelectric and dielectric properties were measured. The experimental results show that the addition of 0.3mo1% Co2O3 leads to low dielectric loss (tg δ) in PZCNNT ceramics and the proper addition of NaNbO3 not only improves piezoelectric properties but also decreases intensively dielectric loss and mechanical loss. The optimal ceramic having d33=310 pC/N, kp=0.59, εr=985, tg δ=0.0034, Qm=1380 was obtained.

  9. Structures and Mechanical and Electronic Properties of the Ti2CO2 MXene Incorporated with Neighboring Elements (Sc, V, B and N)

    Science.gov (United States)

    Feng, Li; Zha, Xian-Hu; Luo, Kan; Huang, Qing; He, Jian; Liu, Yijun; Deng, Wei; Du, Shiyu

    2017-04-01

    Ti2CO2, as the representative MXene with semiconducting characteristics and ultrahigh carrier mobility, has attracted increasing attention in material science. Herein, various Ti2CO2 alloys with Ti displaced by neighboring elements Sc and V, or C by B and N are investigated in this paper based on the first-principles density functional calculations. The structures and mechanical and electronic properties are thoroughly studied for the configurations with varying alloying atom concentrations. The choices of alloying elements play a critical role in determining the lattice parameters and layer thickness. The Sc substitutions generally increase the lattice parameter but decrease the layer thickness. In contrast, the introduction of N presents slight influence on the structural parameters. The mechanical strength shows remarkable variations by introducing the alloying elements. The maximum elastic constant c 11 is determined to be 425 GPa in (Ti0.25V0.75)2CO2, and the corresponding minimum value is only 104 GPa found in (Ti0.125Sc0.875)2CO2. With respect to the electronic properties, although B and Sc both present one less valance electron compared to their replaced elements C and Ti, it is easier to realize the p-type semiconductor in the configurations containing Sc. Both the V and N substitutions are capable of generating n-type semiconductors, but their optimal stoichiometric compositions are quite different. Among all the configurations investigated, only (Ti0.5V0.5)2CO2 and (Ti0.375V0.625)2CO2 are magnetic, with their magnetism determined to be 2.61 uB/cell and 1.52 uB/cell, respectively. Thus, the method of alloying neighboring elements provides an effective approach in manipulating the physical properties of the Ti2CO2, which might widen the possible applications of MXene materials.

  10. Spinel NiCo2O4 for use as a high-performance supercapacitor electrode material: Understanding of its electrochemical properties

    Science.gov (United States)

    Zhu, Yirong; Ji, Xiaobo; Wu, Zhengping; Song, Weixin; Hou, Hongshuai; Wu, Zhibin; He, Xiao; Chen, Qiyuan; Banks, Craig E.

    2014-12-01

    In this work, spinel NiCo2O4 is prepared by a facile sol-gel method with the effect of three different chelating agents including citric acid (CA), oxalic acid (OA) and ethylenediamine tetraacetic acid (EDTA) explored upon the fabrication methodology and resulting electrochemical and supercapacitor properties. The electrochemical measurements reveal that NiCo2O4 prepared using OA exhibits ultrahigh specific capacitance of 1254 F g-1 at 2 A g-1 due to the resultant high specific surface area, while NiCo2O4 prepared by EDTA exhibits the best rate capability and cycling stability owing to the subsequent large pore size. The obvious differences can be primarily ascribed to the use of the differing chelating agents which are shown, for the first time, to greatly affect the particle size, pore structure and specific surface area of the fabricated NiCo2O4. Such work is of fundamental importance and demonstrates that the tailoring of these different properties can be readily obtained through the use of differing chelating and is responsible for the observed differing electrochemical properties. Additionally, first-principles calculations were employed to investigate the electronic structure of NiCo2O4, which can help to further understand its excellent electrochemical behaviors. These results above provide a facile, cost-effective and high-performance strategy for supercapacitor electrode applications.

  11. Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuwei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Liquan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Ma, Lichun; Qi, Meiwei; Yu, Jiali [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-10-15

    Highlights: • Carbon fibers are grafted with phenyl amine group via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 73%. • Tensile strength of the carbon fibers does not decrease distinctly. • Using water as the reaction medium can avoid pollution from organic solvents. • Grafting via aryl diazonium reaction in one step can improve modification efficiency. - Abstract: Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction “on water” to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction “on water” could be a facile green platform to functionalize carbon fibers for many interesting applications.

  12. Optimization of interfacial properties of carbon fiber/epoxy composites via a modified polyacrylate emulsion sizing

    Science.gov (United States)

    Yuan, Xiaomin; Zhu, Bo; Cai, Xun; Liu, Jianjun; Qiao, Kun; Yu, Junwei

    2017-04-01

    The adhesion behavior of epoxy resin to carbon fibers has always been a challenge, on account of the inertness of carbon fibers and the lack of reactive functional groups. In this work, a modified polyacrylate sizing agent was prepared to modify the interface between the carbon fiber and the epoxy matrix. The surface characteristics of carbon fibers were investigated to determine chemical composition, morphology, wettability, interfacial phase analysis and interfacial adhesion. Sized carbon fibers featured improved wettability and a slightly decreased surface roughness due to the coverage of a smooth sizing layer, compared with the unsized ones. Moreover, the content of surface activated carbon atoms increased from 12.65% to 24.70% and the interlaminar shear strength (ILSS) of carbon fiber/epoxy composites raised by 14.2%, indicating a significant improvement of chemical activity and mechanical property. SEM images of the fractured surface of composites further proved that a gradient interfacial structure with increased thicknesses was formed due to the transition role of the sizing. Based on these results, a sizing mechanism consisting of chemical interaction bonding and physical force absorption was proposed, which provides an efficient and feasible method to solve the poor adhesion between carbon fiber and epoxy matrix.

  13. Influence of oligomeric silsesquioxane coating treatment on interfacial properties of CF/PAA composites

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuezhong; HUANG Yudong; WANG Tianyu; HU Lijiang

    2007-01-01

    Carbon fibres (CF) were modified with different oligomeric silsesquioxane (SSO) coatings to improve the interfacial property of carbon fibres/polyarylacetylene (CF/PAA).The interlaminar shear strength (ILSS) of CF/PAA was tested to determine the effect of the treatment.Atomic force microscopy (AFM) in force modulation mode was adopted to study the cross-section surface of unidirectional CF/PAA composites and the relative stiffness of various phases, including CF,interphase and resin.The probability histogram and line distribution of CF/PAA cross-section surface relative stiffness,obtained from the statistical analysis of relative stiffness image,were used to compare and study the interface characterizations of composites.The results show that the ILSS increases effectively and the effects on interfacial characterizations are distinguished from each other in accor-dance with the CF surface modified with different SSO coatings owing to the various structures.Cage oligomeric silsesquioxane,including large organic groups (methacryl isobutyl-POSS),has better treatment result.AFM observa-tions lead to the conclusion that an interfacial transition layer with different morphology and stiffness appears in CF/PAA composites after being treated by the SSO coatings of different structures.It can be inferred that the appearance of the transition layer may contribute to the improvement of fibre/matrix adhesion.

  14. Pure- and mixed-gas CO2/CH4 separation properties of PIM-1 and an amidoxime-functionalized PIM-1

    KAUST Repository

    Swaidan, Raja

    2014-05-01

    The prototypical solution-processable polymer of intrinsic microporosity, PIM-1, and derivatives thereof offer combinations of permeability and selectivity that make them potential candidate materials for membrane-based gas separations. Paramount to the design and evaluation of PIMs for economical natural gas sweetening is a high and stable CO2/CH4 selectivity under realistic, mixed-gas conditions. Here, amidoxime-functionalized PIM-1 (AO-PIM-1) was prepared and examined for fundamental structure/property relationships. Qualitative NLDFT pore-size distribution analyses of physisorption isotherms (N2 at -196 oC; CO2 at 0 oC) reveal a tightened microstructure indicating size-sieving ultra-microporosity (<7Å). AO-PIM-1 demonstrated a three-fold increase in αD(CO2/CH4) over PIM-1, surpassing the 2008 upper bound with P(CO2)=1153Barrer and ideal α(CO2/CH4)=34. Under a 50:50 CO2:CH4 mixed-gas feed, AO-PIM-1 showed less selectivity loss than PIM-1, maintaining a mixed-gas α(CO2/CH4) ~21 across a 20bar pressure range. Conversely, PIM-1 endured up to 60% increases in mixed-gas CH4 permeability over pure-gas values concurrent with a selectivity of only ~8 at 20bar. A pervasive intermolecular hydrogen bonding network in AO-PIM-1 predominantly yields a rigidified microstructure that mitigates CO2-induced matrix dilations, reducing detrimental mixed-gas CH4 copermeation. © 2014 Elsevier B.V.

  15. The effect of lanthanide impurities on the physical properties of half-metallic ferromagnet Co 2MnSi

    Science.gov (United States)

    Tetean, R.; Chioncel, L.; Burzo, E.; Bucur, N.; Bezergheanu, A.; Deac, I. G.

    2008-11-01

    The paper reports some preliminary results on possible incorporation of Ho in Co 2MnSi lattice. In addition, the effect of holmium substitution on Mn sites is analyzed on the basis of self-consistent electronic structure calculations.

  16. Properties of Co2FeAl Heusler Alloy Nano-particles Synthesized by Coprecipitation and Thermal Deoxidization Method

    Institute of Scientific and Technical Information of China (English)

    J.H.Du; Y.L.Zuo; Z.Wang; J.H.Ma; L.Xi

    2013-01-01

    Co2FeAl nanoparticles were synthesized by reducing the coprecipitated precursor of CoCl2·6H2O,Fe(NO3)3·9H2O and Al2(SO4)3·18H2O under H2 atmosphere with various annealing temperatures and durations.X-ray diffraction and transmission electron microscopy were used to characterize the crystal structure and microstructure of Co2FeAl particles,respectively.The investigation indicates that the crystal structure of Co2FeAl particles tends to be B2 structure,in which atoms are partially ordered.The saturation magnetization and hyperfine field of Co2FeAl particles,which were measured under a vibrating sample magnetometer and a 57Fe M(o)ssbauer spectroscope,are consistent with those of the bulk sample and thin films.Furthermore,the higher annealing temperature and the longer annealing time,the better crystallinity of Co2FeAl and more ordered arrangement of atoms will be.It turned out that the coprecipitation thermal deoxidization method could be an easy and high efficient way to obtain the half-metallic Co2FeAl nanoparticles.

  17. Simultaneous description of bulk and interfacial properties of fluids by the Mie potential

    CERN Document Server

    Werth, Stephan; Horsch, Martin; Hasse, Hans

    2016-01-01

    The vapor-liquid equilibrium (VLE) of the Mie potential, where the dispersive exponent is constant (m = 6) while the repulsive exponent n is varied between 9 and 48, is systematically investigated by molecular simulation. For systems with planar vapor-liquid interfaces, long-range correction expressions are derived, so that interfacial and bulk properties can be computed accurately. The present simulation results are found to be consistent with the available body of literature on the Mie fluid which is substantially extended. On the basis of correlations for the considered thermodynamic properties, a multicriteria optimization becomes viable. Thereby, users can adjust the three parameters of the Mie potential to the properties of real fluids, weighting different thermodynamic properties according to their importance for a particular application scenario. In the present work, this is demonstrated for carbon dioxide for which different competing objective functions are studied which describe the accuracy of the...

  18. CO2 as a refrigerant

    CERN Document Server

    2014-01-01

    A first edition, the IIR guide “CO2 as a Refrigerant” highlights the application of carbon dioxide in supermarkets, industrial freezers, refrigerated transport, and cold stores as well as ice rinks, chillers, air conditioning systems, data centers and heat pumps. This guide is for design and development engineers needing instruction and inspiration as well as non-technical experts seeking background information on a specific topic. Written by Dr A.B. Pearson, a well-known expert in the field who has considerable experience in the use of CO2 as a refrigerant. Main topics: Thermophysical properties of CO2 – Exposure to CO2, safety precautions – CO2 Plant Design – CO2 applications – Future prospects – Standards and regulations – Bibliography.

  19. Interfacial properties, thin film stability and foam stability of casein micelle dispersions.

    Science.gov (United States)

    Chen, Min; Sala, Guido; Meinders, Marcel B J; van Valenberg, Hein J F; van der Linden, Erik; Sagis, Leonard M C

    2017-01-01

    Foam stability of casein micelle dispersions (CMDs) strongly depends on aggregate size. To elucidate the underlying mechanism, the role of interfacial and thin film properties was investigated. CMDs were prepared at 4°C and 20°C, designated as CMD4°C and CMD20°C. At equal protein concentrations, foam stability of CMD4°C (with casein micelle aggregates) was markedly higher than CMD20°C (without aggregates). Although the elastic modulus of CMD4°C was twice as that of CMD20°C at 0.005Hz, the protein adsorbed amount was slightly higher for CMD20°C than for CMD4°C, which indicated a slight difference in interfacial composition of the air/water interface. Non-linear surface dilatational rheology showed minor differences between mechanical properties of air/water interfaces stabilized by two CMDs. These differences in interfacial properties could not explain the large difference in foam stability between two CMDs. Thin film analysis showed that films made with CMD20°C drained to a more homogeneous film compared to films stabilized by CMD4°C. Large casein micelle aggregates trapped in the thin film of CMD4°C made the film more heterogeneous. The rupture time of thin films was significantly longer for CMD4°C (>1h) than for CMD20°C (foam stability decreased significantly. In conclusion, the increased stability of foam prepared with CMD4°C appears to be the result of entrapment of casein micelle aggregates in the liquid films of the foam.

  20. Effect of Interfacial Polarization and Water Absorption on the Dielectric Properties of Epoxy-Nanocomposites

    Directory of Open Access Journals (Sweden)

    Philipp Marx

    2017-05-01

    Full Text Available Five types of nanofillers, namely, silica, surface-silylated silica, alumina, surface-silylated alumina, and boron nitride, were tested in this study. Nanocomposites composed of an epoxy/amine resin and one of the five types of nanoparticles were tested as dielectrics with a focus on (i the surface functionalization of the nanoparticles and (ii the water absorption by the materials. The dispersability of the nanoparticles in the resin correlated with the composition (OH content of their surfaces. The interfacial polarization of the thoroughly dried samples was found to increase at lowered frequencies and increased temperatures. The β relaxation, unlike the interfacial polarization, was not significantly increased at elevated temperatures (below the glass-transition temperature. Upon the absorption of water under ambient conditions, the interfacial polarization increased significantly, and the insulating properties decreased or even deteriorated. This effect was most pronounced in the nanocomposite containing silica, and occurred as well in the nanocomposites containing silylated silica or non-functionalized alumina. The alternating current (AC breakdown strength of all specimens was in the range of 30 to 35 kV·mm−1. In direct current (DC breakdown tests, the epoxy resin exhibited the lowest strength of 110 kV·mm−1; the nanocomposite containing surface-silylated alumina had a strength of 170 kV·mm−1. In summary, water absorption had the most relevant impact on the dielectric properties of nanocomposites containing nanoparticles, the surfaces of which interacted with the water molecules. Nanocomposites containing silylated alumina particles or boron nitride showed the best dielectric properties in this study.

  1. Ab Initio Thermodynamic Study of the CO2 Capture Properties of Potassium Carbonate Sesquihydrate, K2CO3·1.5H2O

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Luebkes,David R.; Pennline, Henry W; Li, Bingyun Li; Janik, Michael J.; Halley, Woods

    2012-01-01

    By combining density functional theory and lattice phonon dynamics, the thermodynamic properties of CO2 absorption/desorption reactions with dehydrated potassium carbonates through K2CO3·1.5H2O + CO2 = 2KHCO3 + 0.5H2O(g) are analyzed. The energy change and the chemical potential of this reaction have been calculated and used to evaluate its thermodynamic properties and phase transitions. The results indicate that the K2CO3·1.5H2O can only be applied for postcombustion CO2 capture technology at temperatures lower than its phase transition temperature, which depends on the CO2 pressure and the steam pressure with the best range being PH2O ≤ 1.0 bar. Above the phase transition temperature, the sorbent will be regenerated into anhydrous K2CO3. If the steam pressure PH2O is much greater than 1.0 bar, it is possible to use the K2CO3·1.5H2O sorbent for precombustion CO2 capture technology. Compared to anhydrous K2CO3, K2CO3·1.5H2O requires less energy for regeneration.

  2. Microwave synthesis and effect of CTAB on ferromagnetic properties of NiO, Co3O4 and NiCo2O4 nanostructures

    Science.gov (United States)

    Anandha Babu, G.; Ravi, G.; Hayakawa, Y.

    2015-04-01

    Cubic-structured NiO, Co3O4 and spinel-structured NiCo2O4 were synthesized via microwave route. The structural properties of NiO, Co3O4 and NiCo2O4 nanostructures were investigated by X-ray diffraction analysis, and it showed smaller crystallite size for NiO than Co3O4 and NiCo2O4 by using Williamson-Hall method. Flake-like and hexagonal plate-like morphologies were ascertained from HRSEM and TEM analyses. Optical properties of these materials were investigated by photoluminescence study, and it presents the band edge emission for all materials with supplementary emissions in visible region due to the presence of defects such as vacancy and interstitial. Raman and FTIR spectra provide the functional characteristics of NiO, Co3O4 and NiCo2O4 nanostructures. XPS measurement revealed the purity and composition of these nanostructures. Room temperature magnetic measurements were investigated using vibrating sample magnetometer. The low coercivity and remanent magnetization for NiO, Co3O4 and NiCo2O4 nanostructures confirmed that these nanoparticles exhibit a weak ferromagnetic behaviour.

  3. Annealing temperature and thickness dependencies of structural and magnetic properties of Co2FeAl thin films

    Science.gov (United States)

    Belmeguenai, M.; Gabor, M. S.; Zighem, F.; Roussigné, Y.; Faurie, D.; Tiusan, C.

    2016-09-01

    Co2FeAl (CFA) thin films, of various thicknesses (3 nm≤t ≤50 nm ), have been grown by sputtering on (001) MgO single-crystal substrates and annealed at different temperatures (RT≤Ta≤600 ∘C , where RT is the room temperature). The influence of the CFA thickness (t ), as well as ex situ annealing temperature (Ta), on the magnetic and structural properties has been investigated by x-ray diffraction (XRD), vibrating sample magnetometry, and broadband microstrip ferromagnetic resonance (MS-FMR). The XRD revealed an epitaxial growth of the films with the cubic [001] CFA axis normal to the substrate plane and that the chemical order varies from the B 2 phase to the A 2 phase when decreasing t or Ta. The deduced lattice parameters showed an in-plane tetragonal distortion and in-plane and out-plane strains that increase with Ta and 1 /t . For all Ta values, the variation of the effective magnetization, deduced from the fit of MS-FMR measurements, shows two different regimes separated by a critical thickness, which is Ta dependent. It decreases (increases) linearly with the inverse thickness (1 /t ) in the first (second) regime due to the contribution of the magnetoelastic anisotropy to surface (to volume) anisotropy. The observed behavior has been analyzed through a model allowing for the separation of the magnetocrystalline, magnetoelastic, and Néel-type interface anisotropy constants to the surface and the volume anisotropies. Similar behavior has been observed for the effective fourfold anisotropy field which governs the in-plane anisotropy present in all the samples. Finally, the MS-FMR data also allow one to conclude that the gyromagnetic factor remains constant and that the exchange stiffness constant increases with Ta.

  4. MORPHOLOGY, INTERFACIAL INTERACTION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/MODIFIED HALLOYSITE NANOTUBE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Zhi-xin Jia; Yuan-fang Luo; Shu-yan Yang; Bao-chun Guo; Ming-liang Du; De-min Jia

    2009-01-01

    A natural nanotubular material, halloysite nanotubes (HNTs), was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube (SBR/m-HNT) nanocomposites. Complex of resorcinol and hexamethylenetetramine (RH) was used as the interracial modifier. The structure, morphology and mechanical properties of SBR/m-HNT nanocomposites, especially the interfacial interactions, were investigated. SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix at nanometer scale, but also enhance the interracial combination between HNTs and rubber matrix. FTIR and XPS investigations confirmed that a number of hydrogen bonds were formed between the phenol hydroxyl groups in resorcinol-formaldehyde resin derived from RH and the oxygen atoms in Si-O bonds or hydroxyl groups on HNTs surfaces. The m-HNTs modified with RH have significant reinforcing effect on SBR vulcanizates. RH as a good interfacial modifier can remarkably improve mechanical properties of SBR/HNT composites. The substantial improvement of comprehensive properties for SBR/m-HNT nanocomposites can be attributed to good dispersion and orientation of HNTs in SBR matrix at nanometer scale and the enhanced interracial interaction between HNTs and rubber matrix.

  5. CO2 Capture and Separation Properties in the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Nonafluorobutylsulfonate

    Directory of Open Access Journals (Sweden)

    Lingyun Zhou

    2014-05-01

    Full Text Available Recently, the use of ionic liquids (ILs for carbon capture and separation processes has gained great interest by many researchers due to the high solubility of CO2 in ILs. In the present work, solubility measurements of CO2 in the novel IL 1-n-butyl-3-methylimidazolium nonafluorobutylsulfonate [C4mim][CF3CF2CF2CF2SO3] were performed with a high-pressure view-cell technique in the temperature range from 293.15 to 343.15 K and pressures up to about 4.2 MPa. For comparison, solubilities of H2, N2, and O2 in the IL were also measured at 323.15 K via the same procedure. The Krichevsky-Kasarnovsky equation was employed to correlate the measured solubility data. Henry’s law constants, enthalpies, and entropies of absorption for CO2 in the IL were also determined and presented. The CO2 solubility in this IL was compared with other ILs sharing the same cation. It was shown that the solubility of CO2 in these ILs follows the sequence: [C4mim][CF3CF2CF2CF2SO3] ≈ [C4mim][Tf2N] > [C4mim][CF3CF2CF2COO] > [C4mim][BF4], and the solubility selectivity of CO2 relative to O2, N2, and H2 in [C4mim][CF3CF2CF2CF2SO3] was 8, 16, and 22, respectively. Furthermore, this IL is regenerable and exhibits good stability. Therefore, the IL reported here would be a promising sorbent for CO2.

  6. Porous organic polymers with anchored aldehydes: A new platform for post-synthetic amine functionalization en route for enhanced CO2 adsorption properties

    KAUST Repository

    Guillerm, Vincent

    2014-01-01

    A novel porous organic polymer has been synthesized using the molecular building block approach to deliberately encompass aldehyde functionalities amenable to post functionalization. The resultant porous framework allows a facile, one-step quantitative and post-synthetic functionalization by amines, permitting enhanced CO2 sorption properties. © 2014 The Royal Society of Chemistry.

  7. Thermoelectric properties of TbFe2 and TbCo2 in C15- laves phase: Spin-polarized DFT+U approach

    Science.gov (United States)

    Reshak, A. H.

    2017-01-01

    Thermoelectric properties of materials are intimately related to their electronic band structure. Combining first- and second-principles calculations, we have obtained the transport properties for the spin-up and spin-down electrons of the laves phase TbFe2 and TbCo2 compounds. The unique band structure feature and the density of states at Fermi level (EF) promote the EF to a point where carriers are in energetic proximity to these features. The non-zero density of states at EF for the spin-up (↑) and spin-down (↓) electrons leads to unusual transport properties because both the (↑) and (↓) densities contributes to the states at EF. The parabolic bands in the vicinity of EF enhance the carriers mobility and hence the transport properties of TbFe2 and TbCo2. Calculations show that the spin-up/down transport coefficients are temperature-dependent. It has been found that TbCo2 possess larger Seebeck coefficient than that of TbFe2 and hence the power factor. The calculated Seebeck coefficient of TbCo2 agree well with the available experimental data.

  8. Intermolecular network analysis of the liquid and vapor interfaces of pentane and water: microsolvation does not trend with interfacial properties.

    Science.gov (United States)

    Ghadar, Yasaman; Clark, Aurora E

    2014-06-28

    Liquid:vapor and liquid:liquid interfaces exhibit complex organizational structure and dynamics at the molecular level. In the case of water and organic solvents, the hydrophobicity of the organic, its conformational flexibility, and compressibility, all influence interfacial properties. This work compares the interfacial tension, width, molecular conformations and orientations at the vapor and aqueous liquid interfaces of two solvents, n-pentane and neopentane, whose varying molecular shapes can lead to significantly different interfacial behavior. Particular emphasis has been dedicated toward understanding how the hydrogen bond network of water responds to the pentane relative to the vapor interface and the sensitivity of the network to the individual pentane isomer and system temperature. Interfacial microsolvation of the immiscible solvents has been examined using graph theoretical methods that quantify the structure and dynamics of microsolvated species (both H2O in C5H12 and C5H12 in H2O). At room temperature, interfacial water at the pentane phase boundary is found to have markedly different organization and dynamics than at the vapor interface (as indicated by the hydrogen bond distributions and hydrogen bond persistence in solution). While the mesoscale interfacial properties (e.g. interfacial tension) are sensitive to the specific pentane isomer, the distribution and persistence of microsolvated species at the interface is nearly identical for both systems, irrespective of temperature (between 273 K and 298 K). This has important implications for understanding how properties defined by the interfacial organization are related to the underlying solvation reactions that drive formation of the phase boundary.

  9. EFFECT OF INTERFACIAL ADHESION ON CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE)/GLASS BEAD COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    OU Yuchun; YU Zhongzhen; ZHU Jin; LI Ge; ZHU Shanguang

    1996-01-01

    The interfacial adhesion between poly (ethylene terephthalate) (PET) and glass bead was investigated by scanning electron microscope and parallel-plate rheometer. Effect of interfacial adhesion on the crystallization and mechanical properties of PET/glass bead composites was also studied by differential scanning calorimeter and mechanical testers.The results obtained indicate that the glass bead has a heterogeneous nucleation effect on the PET crystallization. Although better interfacial adhesion is advantageous to the increase of the tensile strength of the composite, yet it is unfavorable to the crystallization of PET. It should be pointed out that the crystallization rate of filled PET is always higher than that of pure PET, regardless of the state of interfacial adhesion.

  10. Effect of Ba Filling Fraction on Thermoelectric Properties of p-type BayFe1.6Co2.4Sb12

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Effects of Ba filling fraction on the thermoelectric properties of p-type filled skutterudite compounds BayFe1.6Co2.4Sb12(y=0-0.63) were investigated.BayFe1.6Co2.4Sb12 showed p-type conduction.The hall coefficient (RH) and seebeck coefficient(α) increased with increasing Ba filling fraction.But hole concentration (p) and electrical conductivity (σ) decreased.While Ba filling fraction was about 0.4,the lattice thermal conductivity (κL) reached the minimum value.The results show that effect of Ba rattling on phonon scattering is the strongest as Sb-icosahedron partial voids are filled by Ba.A maximum dimensionless thermoelectric figure of merit (ZT) value of 0.7 was obtained for Ba0.38Fe1.6Co2.4 Sb12 at 750K.

  11. Properties and Developments of Combustion and Gasification of Coal and Char in a CO2-Rich and Recycled Flue Gases Atmosphere by Rapid Heating

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    2012-01-01

    Full Text Available Combustion and gasification properties of pulverized coal and char have been investigated experimentally under the conditions of high temperature gradient of order 200°C·s−1 by a CO2 gas laser beam and CO2-rich atmospheres with 5% and 10% O2. The laser heating makes a more ideal experimental condition compared with previous studies with a TG-DTA, because it is able to minimize effects of coal oxidation and combustion by rapid heating process like radiative heat transfer condition. The experimental results indicated that coal weight reduction ratio to gases followed the Arrhenius equation with increasing coal temperature; further which were increased around 5% with adding H2O in CO2-rich atmosphere. In addition, coal-water mixtures with different water/coal mass ratio were used in order to investigate roles of water vapor in the process of coal gasification and combustion. Furthermore, char-water mixtures with different water/char mass ratio were also measured in order to discuss the generation ratio of CO/CO2, and specified that the source of Hydrocarbons is volatile matter from coal. Moreover, it was confirmed that generations of CO and Hydrocarbons gases are mainly dependent on coal temperature and O2 concentration, and they are stimulated at temperature over 1000°C in the CO2-rich atmosphere.

  12. Thermogravimetric Study on Oxygen Adsorption/Desorption Properties of Double Perovskite Structure Oxides REBaCo2O5+δ (RE= Pr, Gd, Y)

    Institute of Scientific and Technical Information of China (English)

    Hao Haoshan; Zheng Lu; Wang Yingfang; Liu Shijiang; Hu Xing

    2007-01-01

    The oxygen adsorption/desorption properties of double perovskite structure oxides PrBaCo2O5+δ, GdBaCo2O5+δ, and YBaCo2O5+δ were investigated by the thermogravimetry (TG) method in the temperature range of 400~900 ℃. The calculated oxygen adsorption/desorption surface reaction rate constants ka and kd of these double perovskite structure oxides were larger than the commonly used cubic perovskite oxides, such as Ba0.95Ca0.05Co0.8Fe0.2O3-δ and Ba0.5Sr0.5Co0.8Fe0.2O3-δ, whereas, the oxygen permeation flux was comparable to that of the latter, which was attributed to the smaller difference of oxygen vacancy in oxygen and nitrogen atmosphere (Δδ/Vmol) in these double perovskite structure oxides. The large oxygen adsorption/desorption rate constants of GdBaCo2O5+δ and PrBaCo2O5+δ made them nice catalyst coating materials, on other membrane surfaces, to improve the oxygen permeability.

  13. Interfacial and emulsifying properties of soybean peptides with different degrees of hydrolysis.

    Science.gov (United States)

    Imura, Tomohiro; Nakayama, Mio; Taira, Toshiaki; Sakai, Hideki; Abe, Masahiko; Kitamoto, Dai

    2015-01-01

    In this study, the effects of the degree of hydrolysis on the interfacial and emulsifying properties of soybean peptides were evaluated based on surface and interfacial tension, dynamic light scattering (DLS), and freeze-fracture transmission electron microscopy (FF-TEM) analyses. Of the five evaluated soybean peptides (SP95, SP87, SP75, SP49, and SP23), those with higher degrees of hydrolysis (SP95 and SP87) did not exhibit noticeable surface-active properties in water, whereas those with relatively low degrees of hydrolysis (SP75, SP49, and SP23) exhibited remarkable surface tension-lowering activity. The latter set (SP75, SP49, and SP23) also formed giant associates with average sizes ranging from 64.5 nm to 82.6 nm above their critical association concentration (CAC). Moreover, SP23 with the lowest degree of hydrolysis exhibited excellent emulsifying activity for soybean oil, and FF-TEM analysis demonstrated that the emulsions were stabilized by a lamella-like multilayer peptide structure on the oil droplets that prevented coagulation. The peptide with the lowest degree of hydrolysis (SP23) was effective not only for soybean oil emulsification, but also for the emulsification of liquid paraffin and silicon oil that are generally difficult to emulsify.

  14. P- V- T properties of fluids in the system H 2O ± CO 2 ± NaCl: New graphical presentations and implications for fluid inclusion studies

    Science.gov (United States)

    Brown, Philip E.; Lamb, William M.

    1989-06-01

    Understanding the role of fluids in geologic processes requires a knowledge of the P- V- T properties of fluids over a wide range of conditions. Comparisons of several published equations of state with available experimental data for fluids composed of H 2O and CO 2 lead to the conclusion that the hard-sphere modified Redlich-Kwong equation of state of Kerrick and Jacobs (1981) most accurately predicts the P- V- T properties in this binary system. To model the volumetric properties in the H 2OCO 2NaCl system a formulation is presented involving a linear (ideal) interpolation between a pure-CO 2 isochore predicted by the equation of state of Kerrick. and Jacobs (1981) and an H 2O-NaCl isochore predicted by an empirical equation derived from the regression of available P- V- T data for the H 2O-NaCl system. This formulation is applicable over a wide range of temperatures (>350°C) and pressures (2-10 kbars) and is especially suitable for high pressures and low-to-moderate temperatures (fluid densities ≥ 1.0 cm 3). Determination of the appropriate isochore for an H 2OCO 2NaCl fluid inclusion requires (1) the relative salinity (NaCl/H 2O + NaCl), (2) bulk density of the combined gas and liquid CO 2 phases, and (3) volume percent estimate of the aqueous p the total homogenization temperature. The commonly encountered problem of estimating the volume percents of phases in inclusions may be avoided in some applications, and several new P- X(CO 2) diagrams have been constructed and contoured with (a) the solvi in the mixed volatile system and (b) the measured density of the CO 2 phase. The effects of H 2OCO 2 clathrates during microthermometric observations in the laboratory are evaluated and in most instances can be minimized or avoided. Application of these results to fluid inclusion studies have led to improved determinations of (1) pressures and temperatures of fluid entrapment in a variety of geologic settings and (2) pressures and temperatures of

  15. Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Ruiz, F. J.; Blas, F. J., E-mail: felipe@uhu.es [Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Física Aplicada, Universidad de Huelva, 21007 Huelva (Spain); Moreno-Ventas Bravo, A. I. [Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Geología, Universidad de Huelva, 21007 Huelva (Spain)

    2015-09-14

    We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ{sub 11} = σ{sub 22}, with the same dispersive energy between like species, ϵ{sub 11} = ϵ{sub 22}, but different dispersive energies between unlike species low enough to induce phase separation. We use the extensions of the improved version of the inhomogeneous long-range corrections of Janecek [J. Phys. Chem. B 110, 6264 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] and Martínez-Ruiz et al. [J. Chem. Phys. 141, 184701 (2014)], to deal with the interaction energy and microscopic components of the pressure tensor. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of the symmetrical mixture with different cut-off distances r{sub c} and in combination with the inhomogeneous long-range corrections. The pressure tensor is obtained using the mechanical (virial) and thermodynamic route. The liquid-liquid interfacial tension is also evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the test-area methodology. This allows to check the validity of the recent extensions presented to deal with the contributions due to long-range corrections for intermolecular energy and pressure tensor in the case of binary mixtures that exhibit liquid-liquid immiscibility. In addition to the pressure tensor and the surface tension, we also obtain density profiles and coexistence densities and compositions as functions of pressure, at a given temperature. According to our results, the main effect of increasing the cut-off distance r{sub c} is to sharpen the liquid-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative minimum in the total density profiles of the symmetrical mixture. This minimum is related

  16. A novel microbond bundle pullout technique to evaluate the interfacial properties of fibre-reinforced plastic composites

    Indian Academy of Sciences (India)

    PADMANABHAN KRISHNAN

    2017-08-01

    The interfacial properties of the fibre composite systems decide the overall usability of a composite in simpleand complex shapes, as they are the deciding factors in determination of the mechanical properties, structural propertiesand above all a complete understanding of the reliability of composite systems. In the present investigation, the interfacialproperties of carbon fibre/epoxy composites viz., matrix shrinkage pressure, interfacial frictional stress, interfacial shear stress and coefficient of friction were evaluated through a novel microbond bundle pullout test. This test is different from the single fibre pull out, fibre fragmentation or the fibre push in test. Based on some of the physical principles involving the single fibre microbond pullout test, like the contact angle of the microbond matrix drop with the fibre surface, the surface tension/energy of the two surfaces before and after adhesion and the interfacial fibre/matrix chemistry, this is simple to perform and statistically averaged mesomechanical test is also easy to evaluate and is shown to be a test method thatenables a conservative prediction of the laminate level or macromechanical shear properties of fibre composite systems.This test demonstrates the validity of the mesomechanical tests that are more relevant to the macromechanical tests thanthe micromechanical tests. Fractography carried out to corroborate the observed mechanical properties with the fracturefeatures is also reported. The general advantages of the mesomechanical interfacial tests over those based on micromechanical assumptions is also discussed along with some common limitations.

  17. Synthesis, crystal structure and properties of a new organic-inorganic hybrid Dawson-like polyoxotungstate [Co(2,2'-bpy)3]2[Co(2,2'-bpy)2Cl][Co(2,2'-bpy)2]H2-[SbW18O60]·4H2O

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new organic-inorganic hybrid polyoxometalate based on Dawson-like polyoxotungstate anion [SbW18O60]9-, formulated [Co(2,2'-bpy)3]2[Co(2,2'-bpy)2Cl][Co(2,2'-bpy)2]H2[SbW18O60]·4H2O (2,2'-bpy= 2,2(-bipyridine) has been synthesized from Sb2O3, Na2WO4, CoCl2, and 2,2'-bipyridine materials by hydrothermal method, and which was characterized by elemental analyses, IR, XPS, EPR, TG, and X-ray single crystal diffraction. Structure analysis shows that the polyoxoanion self-assembled under hydrothermal conditions consists of a Dawson-like polyoxotungstate cluster anion [SbW18O60]9- encapsulating a pyramidal {SbO3} group within the {W18} cluster cage. EPR spectra show that the high-spin octahedral CoⅡ and low-spin CoⅡ ions coexist in the title compound. Magnetic properties indicate that the compound is antiferromagnetic.

  18. Enhanced Microwave Absorption Properties of Flexible Polymer Composite Based on Hexagonal NiCo2O4 Microplates and PVDF

    Science.gov (United States)

    Luo, Hui; Wang, Xian; Song, Kai; Yang, Jing; Gong, Rongzhou

    2016-08-01

    Hexagonal NiCo2O4 microplates were synthesized via a facile one-pot hydrothermal method and followed by a subsequent annealing process. The complex permittivity and permeability of a NiCo2O4 and polyvinylidene fluoride (PVDF) composite were investigated over 2-18 GHz. The experiment indicated that the good microwave absorption performance of NiCo2O4@PVDF depends on dielectric loss and quarter-wavelength cancellation. Our results show that the absorption frequency bandwidth of reflection loss (RL) less than -20 dB for the NiCo2O4@PVDF composite can be measured over the frequency range of 3-15.5 GHz with an absorbing thickness that varies in the range of 1.25-5 mm. Furthermore, an optimal RL of -44.8 dB was observed at 10.7 GHz with a thickness of 1.75 mm. The loss mechanism is also discussed.

  19. Effect of Pressure on Wetting Properties of Crude Oil, Sandstone Rock, Water, CO2 and (or) Flue Gas System

    NARCIS (Netherlands)

    Shojaikaveh, N.; Amerighasrodashti, A.; Rossen, W.R.; Bruining, J.; Wolf, K-H.A.A.

    2014-01-01

    Carbon dioxide injection, either miscible or immiscible, has been known as an efficient strategy to enhance oil recovery as well as reduce CO2 emission. Wettability has a significant effect on the performance of enhanced oil recovery techniques because of its effect on fluid saturation distribution

  20. Optical and Structural Properties of ZnO Nanoparticles Synthesized by CO2 Microwave Plasma at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Se Min Chun

    2014-01-01

    Full Text Available The results of carbon-doped zinc oxide nanoparticles synthesized by CO2 microwave plasma at atmospheric pressure are presented. The 2.45-GHz microwave plasma torch and feeder for injecting Zn granules are used in the synthesis of zinc oxide nanoparticles. The Zn granules (13.5 g/min were introduced into the microwave plasma by CO2 (5 l/min swirl gas. The microwave power delivered to the CO2 microwave plasma was 1 kW. The synthesis of carbon-doped zinc oxide nanoparticles was carried out in accordance with CO2 + Zn → carbon-doped ZnO + CO. The synthesized carbon-doped zinc oxide nanoparticles have a high purity hexagonal phase. The absorption edge of carbon-doped zinc oxide nanoparticles exhibited a red shift from a high-energy wavelength to lower in the UV-visible spectrum, due to band gap narrowing. A UV-NIR spectrometer, X-ray diffraction, emission scanning electron-microscopy, energy dispersive X-ray microanalysis, Fourier transform infrared spectroscopy, and a UV-Vis-NIR spectrophotometer were used for the characterization of the as-produced products.

  1. Stabilized density gradient theory algorithm for modeling interfacial properties of pure and mixed systems

    CERN Document Server

    Mu, Xiaoqun; Alpak, Faruk O; Chapman, Walter G

    2016-01-01

    Density gradient theory (DGT) allows fast and accurate determination of surface tension and density profile through a phase interface. Several algorithms have been developed to apply this theory in practical calculations. While the conventional algorithm requires a reference substance of the system, a modified "stabilized density gradient theory" (SDGT) algorithm is introduced in our work to solve DGT equations for multiphase pure and mixed systems. This algorithm makes it possible to calculate interfacial properties accurately at any domain size larger than the interface thickness without choosing a reference substance or assuming the functional form of the density profile. As part of DGT inputs, the perturbed chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) was employed for the first time with the SDGT algorithm. PC-SAFT has excellent performance in predicting liquid phase properties as well as phase behaviors. The SDGT algorithm with the PC-SAFT EoS was tested and compared with ...

  2. Study on magnetic properties of (Nd0.8Ce0.2)2-xFe12Co2B (x = 0-0.6) alloys

    Science.gov (United States)

    Tan, G. S.; Xu, H.; Yu, L. Y.; Tan, X. H.; Zhang, Q.; Gu, Y.; Hou, X. L.

    2017-09-01

    In the present work, (Nd0.8Ce0.2)2-xFe12Co2B (x = 0-0.6) permanent alloys are prepared by melt-spinning method. The hard magnetic properties of (Nd0.8Ce0.2)2-xFe12Co2B (x = 0-0.6) alloys annealed at optimum temperatures have been investigated systematically. Depending on the Nd, Ce concentration, the maximum energy product ((BH)max) and remanence (Br) increase gradually with x in the range of 0 ≤ x ≤ 0.4, whereas decrease gradually in the alloys with 0.4 Ce0.2)1.6Fe12Co2B (x = 0.4) annealed ribbons. The magnetic properties Br, (BH)max and squareness are all enhanced after the magnetic field heat treatment. The (BH)max shows a substantial increase from 13.7 MGOe to 16.0 MGOe after the heat treatment at 623 K with a magnetic field of 1 T, which gets 17% improvement compared with that of the sample without a magnetic field heat treatment. We demonstrate that the magnetic field heat treatment plays a certain role in the magnetization reversal behavior and can improve the microstructure of (Nd0.8Ce0.2)1.6Fe12Co2B alloy.

  3. Equilibrium and dynamic interfacial properties of protein/ionic-liquid-type surfactant solutions at the decane/water interface.

    Science.gov (United States)

    Cao, Chong; Lei, Jinmei; Zhang, Lu; Du, Feng-Pei

    2014-11-25

    The interfacial behavior of β-casein and lysozyme solutions has been investigated in the presence of an ionic liquid-type imidazolium surfactant ([C16mim]Br) at the decane/water interface. The dynamic dilational properties of the protein/surfactant solutions are investigated by the oscillating drop method and interfacial tension relaxation method. The interfacial tension isotherms for the mixed adsorption layers indicate that the increased addition of [C16mim]Br to a pure protein changes the properties of the complex formed at the decane/water interface. Whereas the interfacial tension data of the protein/surfactant mixed layers do not clearly show differences with changing bulk composition, the dilational rheology provides undoubted evidence that the structure and, in particular, the dynamics of the adsorbed layers depend on the bulk surfactant concentration. The experiment data for β-casein/[C16mim]Br solutions indicate that at higher bulk [C16mim]Br concentrations, β-casein in the interfacial layer is subject to conformational changes, where it gives space to [C16mim]Br molecules in the form of coadsorb rather than replacement; in contrast, in lysozyme/[C16mim]Br solutions some lysozyme molecules desorb from the interface due to the competitive adsorption of free [C16mim]Br molecules. Experimental results related to the interfacial dilational properties of the protein/surfactant solutions show that the dilational modulus turns out to be more sensitive to the conformation of protein/surfactant mixture at the liquid interface than the interfacial tension.

  4. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim......The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  5. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  6. CO2-Neutral Fuels

    Science.gov (United States)

    Goede, Adelbert; van de Sanden, Richard

    2016-06-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy efficiency.

  7. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  8. Effect of Interfacial Modifying on Thermo-physical Properties of SiCp/Cu Composites

    Directory of Open Access Journals (Sweden)

    LIU Meng

    2016-08-01

    Full Text Available SiCp/Cu composites were successfully fabricated by vacuum hot-pressing method. Molybdenum coating was deposited on the surface of silicon carbide by sol-gel method. The effects of the interfacial design on thermo-physical properties of SiCp/Cu composites were studied. The results indicate that:continuous and uniform MoO3 coating can be deposited on the surface of silicon carbide by peroxomolybdic acid sol-gel system, and the best processing parameters are as follows:SiC:MoO3=5:1(mass ratio, H2O2:C2H5OH=1:1(volume ratio, and surface pretreatment with acetone and hydrofluoric acid is good to the deposition and growth of MoO3 coating. After hydrogen reduction at 540℃ for 90min the MoO3 is changed into MoO2, and then hydrogen reduction at 940℃ for 90min the MoO2 is changed into Mo absolutely, and the Mo coating is continuous and uniform. SiCp/Cu composites prepared by vacuum hot-pressing method show a compact and uniform microstructure, and the thermal conductivity of the composites is increased obviously after the Mo coating interfacial modification, which can reach 214.16W·m-1·K-1 when the volume of silicon carbide is about 50%.

  9. Surfactant induced complex formation and their effects on the interfacial properties of seawater.

    Science.gov (United States)

    Guzmán, Eduardo; Santini, Eva; Benedetti, Alessandro; Ravera, Francesca; Ferrari, Michele; Liggieri, Libero

    2014-11-01

    The effect of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), on the interfacial properties of seawater has been studied by dynamic and equilibrium surface tension and by dilational rheology essays. Important modifications of the surface tension and dilational rheology response have been observed already at the very low CTAB concentrations, where the effects due to the high ionic strength are negligible. The comparison with the effects of CTAB in different seawater models, or in natural seawater fractions, points out the establishment of strong interactions between the surfactant molecules and the lipophilic fraction of organic material dispersed/dissolved in seawater, affecting the interfacial activity of the molecules. Considering the biochemical richness of seawater, these results can be explained assuming interaction mechanisms and adsorption schemes similar to those speculated for protein and other macromolecules in the presence of surfactants, which in fact show similar features. Thus already at the low concentrations the surfactant molecules form highly surface-active complexes with part of the organic fraction of seawater. At the larger surfactant concentrations these complexes compete for adsorption with an excess of free CTAB molecules which, according to the thermodynamic conditions, are most favoured to occupy the liquid interface. The results of this study underline the important role of the sea organic content in enhancing the surface-activity of surfactants, which is relevant for a deeper understand of the direct and indirect effects of these types of pollutants on the physico-chemical environment in the sea coastal areas and develop mitigation strategies.

  10. Impact of hydrogeological and geomechanical properties on surface uplift at a CO2 injection site: Parameter estimation and uncertainty quantification

    Science.gov (United States)

    Newell, P.; Yoon, H.; Martinez, M. J.; Bishop, J. E.; Arnold, B. W.; Bryant, S.

    2013-12-01

    It is essential to couple multiphase flow and geomechanical response in order to predict a consequence of geological storage of CO2. In this study, we estimate key hydrogeologic features to govern the geomechanical response (i.e., surface uplift) at a large-scale CO2 injection project at In Salah, Algeria using the Sierra Toolkit - a multi-physics simulation code developed at Sandia National Laboratories. Importantly, a jointed rock model is used to study the effect of postulated fractures in the injection zone on the surface uplift. The In Salah Gas Project includes an industrial-scale demonstration of CO2 storage in an active gas field where CO2 from natural gas production is being re-injected into a brine-filled portion of the structure downdip of the gas accumulation. The observed data include millimeter scale surface deformations (e.g., uplift) reported in the literature and injection well locations and rate histories provided by the operators. Our preliminary results show that the intrinsic permeability and Biot coefficient of the injection zone are important. Moreover pre-existing fractures within the injection zone affect the uplift significantly. Estimation of additional (i.e., anisotropy ratio) and coupled parameters will help us to develop models, which account for the complex relationship between mechanical integrity and CO2 injection-induced pressure changes. Uncertainty quantification of model predictions will be also performed using various algorithms including null-space Monte Carlo and polynomial-chaos expansion methods. This work will highlight that our coupled reservoir and geomechanical simulations associated with parameter estimation can provide a practical solution for designing operating conditions and understanding subsurface processes associated with the CO2 injection. This work is supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office

  11. A novel method to control oxygen stoichiometry and thermoelectric properties in (RE)BaCo2O5+

    Indian Academy of Sciences (India)

    T Dasgupta; S Sumithra; A M Umarji

    2008-11-01

    Rare earth cobaltites of the type (RE)BaCo2O5+ (RE = Y, Gd, Eu and Nd) were synthesized by solid state technique. A novel, fast quenching technique was used to tune the oxygen content in these compounds. Room temperature Seebeck and electrical resistivity measurements were used to infer the oxygen content. A maximum in the and ρ was observed for all the compositions when value was close to 0.5.

  12. CO2 capture properties of lithium silicates with different ratios of Li2O/SiO2: an ab initio thermodynamic and experimental approach.

    Science.gov (United States)

    Duan, Yuhua; Pfeiffer, Heriberto; Li, Bingyun; Romero-Ibarra, Issis C; Sorescu, Dan C; Luebke, David R; Halley, J Woods

    2013-08-28

    The lithium silicates have attracted scientific interest due to their potential use as high-temperature sorbents for CO2 capture. The electronic properties and thermodynamic stabilities of lithium silicates with different Li2O/SiO2 ratios (Li2O, Li8SiO6, Li4SiO4, Li6Si2O7, Li2SiO3, Li2Si2O5, Li2Si3O7, and α-SiO2) have been investigated by combining first-principles density functional theory with lattice phonon dynamics. All these lithium silicates examined are insulators with band-gaps larger than 4.5 eV. By decreasing the Li2O/SiO2 ratio, the first valence bandwidth of the corresponding lithium silicate increases. Additionally, by decreasing the Li2O/SiO2 ratio, the vibrational frequencies of the corresponding lithium silicates shift to higher frequencies. Based on the calculated energetic information, their CO2 absorption capabilities were extensively analyzed through thermodynamic investigations on these absorption reactions. We found that by increasing the Li2O/SiO2 ratio when going from Li2Si3O7 to Li8SiO6, the corresponding lithium silicates have higher CO2 capture capacity, higher turnover temperatures and heats of reaction, and require higher energy inputs for regeneration. Based on our experimentally measured isotherms of the CO2 chemisorption by lithium silicates, we found that the CO2 capture reactions are two-stage processes: (1) a superficial reaction to form the external shell composed of Li2CO3 and a metal oxide or lithium silicate secondary phase and (2) lithium diffusion from bulk to the surface with a simultaneous diffusion of CO2 into the shell to continue the CO2 chemisorption process. The second stage is the rate determining step for the capture process. By changing the mixing ratio of Li2O and SiO2, we can obtain different lithium silicate solids which exhibit different thermodynamic behaviors. Based on our results, three mixing scenarios are discussed to provide general guidelines for designing new CO2 sorbents to fit practical needs.

  13. Effect of microstructure on the thermoelectric properties of CSD-grown Bi2Sr2Co2Oy thin films

    Institute of Scientific and Technical Information of China (English)

    Wang Shu-Fang; Yan Guo-Ying; Chen Shan-Shan; Bai Zi-Long; Wang Jiang-Long; Yu Wei; Fu Guang-Sheng

    2013-01-01

    Three Bi2Sr2Co2Oy thin films with different microstructures have been prepared by chemical solution deposition on LaAIO3(001) through varying the annealing temperature.With the decrease in the annealing temperature,both the size and c-axis alignment degree of grains in the film decrease as well,leading to an increase in the film resistivity.In addition,the decrease in the annealing temperature also results in a slight increase in the Seebeck coefficient due to the enhanced energy filtering effect of the small-grain film.The nanostructured Bi2Sr2Co2Oy film with an average grain size of about 100 nm shows a power factor comparable to that of films with larger grains.Since the thermal conductivity of the nanostructured films can be depressed due to the enhanced phonon scattering by grain boundary,a higher figure of merit is expected in Bi2Sr2Co2Oy thin film with grains in nanometer size.

  14. Crystal structure and high temperature transport properties of Yb-filled p-type skutterudites YbxCo2.5Fe1.5Sb12

    KAUST Repository

    Dong, Yongkwan

    2014-01-01

    Partially Yb-filled Fe substituted polycrystalline p-type skutterudites with nominal compositions YbxCo2.5Fe1.5Sb 12, with varying filler concentrations x, were synthesized by reacting the constituent elements and subsequent solid state annealing, followed by densification by hot-pressing. The compositions and filling fractions were confirmed with a combination of Rietveld refinement and elemental analysis. Their thermoelectric properties were evaluated from 300 to 800 K. The Seebeck coefficients for the specimens increase with increasing temperature and plateau at around 750 K. The thermal conductivity decreases with increasing Yb filling fraction, and bipolar conduction becomes evident and increases at elevated temperatures. A maximum ZT value of 0.8 was obtained at 750 K for Yb 0.47Co2.6Fe1.4Sb12. The thermoelectric properties and potential for further optimization are discussed in light of our results. © 2013 Elsevier Inc.

  15. Effect of extra nonmagnetic Ga atoms on lattice ordering and magnetic properties of Fe2CoGa and Co2FeGa Heusler compounds

    Directory of Open Access Journals (Sweden)

    Hakimi

    2014-04-01

    Full Text Available Arc-melting with ball milling was used for preparing Fe2CoGa1+x and Co2FeGa1+x (x=0,0.2 Heusler samples. Effect of extra nonmagnetic Ga atoms on lattice ordering and magnetic properties of Fe2CoGa and Co2FeGa Heusler compounds was studied. Rietveld refinement showed that lattice parameter of the samples increases in the presence of extra Ga atoms. Results showed that Co2FeGa1.2 has a partial lattice disordering. Saturation magnetization of Co2FeGa sample was lower than Slater – Paulig prediction due to the crystallite size on a scale of nanometer. Reduction of saturation magnetization by increasing Ga atoms was explained through the change of lattice parameter, lattice ordering, and crystallite size. Saturation magnetization of Fe2CoGa sample was greater than Slater – Paulig value. Change of lattice parameter by increasing Ga atoms resulted a decrease of saturation magnetization in Fe2CoGa1.2

  16. Adjustable structure transition and improved gases (H2, CO2) adsorption property of metal-organic framework MIL-53 by encapsulation of BNHx.

    Science.gov (United States)

    Si, Xiaoliang; Zhang, Jian; Li, Fen; Jiao, Chengli; Wang, Shuang; Liu, Shuang; Li, Zhibao; Zhou, Huaiying; Sun, Lixian; Xu, Fen

    2012-03-21

    The structure transition of flexible MOF (MIL-53) can be adjusted by confinement of BNH(x) into MIL-53 channels. Hydrogen and carbon dioxide adsorption properties are also improved by incorporating BNH(x). At 77 K and 1 atm pressure hydrogen storage capacity can reach 2.0 wt% and CO(2) adsorption capacity is 4.5 mmol g(-1) at 273 K 1 atm.

  17. Impact of Interfacial Defects on the Properties of Monolayer Transition Metal Dichalcogenide Lateral Heterojunctions

    KAUST Repository

    Cao, Zhen

    2017-03-25

    We explored the impact of interfacial defects on the stability and optoelectronic properties of monolayer transition metal dichalcogenide lateral heterojunctions using a density functional theory approach. As a prototype, we focused on the MoS2-WSe2 system and found that even a random alloy-like interface with a width of less than 1 nm has only a minimal impact on the band gap and alignment compared to the defect-less interface. The largest impact is on the evolution of the electrostatic potential across the monolayer. Similar to defect-less interfaces, a small number of defects results in an electrostatic potential profile with a sharp change at the interface, which facilitates exciton dissociation. Differently, a large number of defects results in an electrostatic potential profile switching smoothly across the interface, which is expected to reduce the capability of the heterojunction to promote exciton dissociation. These results are generalizable to other transition metal dichalcogenide lateral heterojunctions.

  18. Optical properties of a conjugated-polymer-sensitised solar cell: the effect of interfacial structure.

    Science.gov (United States)

    Drumm, Daniel W; Bilic, A; Tachibana, Y; Miller, A; Russo, S P

    2015-06-14

    Dye-sensitised solar cells (DSSCs) have sparked considerable interest over two decades. Recently, a method of polymer-wire sensitisation was demonstrated; the polymer is suggested to form a hole transport pathway (wire) following initial charge separation. We predict the optical properties of this polymer in various interfacial configurations, including the effects of chain length and attachment to {100} or {101} TiO2 facets. Contrary to most DSSCs, the {100} facet model best describes the experimental spectrum, predicting a relative thickness of 5.7 ± 0.2 μm, although {101} attachment, if implemented, may improve collection efficiency. Long chains are optimal, and stable attachment sites show minimal differences to absorbance in the major solar emission (visible) band. Combinations of {100}, {101}, and pseudo-bulk TiO2 models in three-parameter fits to experiment confirm the relative importance of the {100} facet.

  19. Interfacial properties of nonionic micellar agregates as a function of temperatures and concentrations

    CERN Document Server

    Falconi, L; Briganti, G; D'Arrigo, G; Falconi, Luca; Maccarini, Marco; Briganti, Giuseppe; Arrigo, Giovanni D'

    1998-01-01

    By means of density, dielectric spectroscopy and sound velocity measurements we perform a systematic study on the polyoxyethylene $C_{12}E_{6}$ nonionic surfactant solutions as a function of temperature and concentration. Both density and sound velocity data, at about $34^{\\circ}C$, coincide with the value obtained for pure water. Above this temperature the density is lower than the water density whereas below it is greater, the opposite happens for the compressibility. Combining results from these different techniques we tempt a very detailed description of the evolution of the micellar interfacial properties with temperature. It is well known that nonionic surfactant solutions dehydrate, growing temperature. Our results indicate that this process is associated with a continuous change in the polymer conformation and in the local density of the micellar interface.

  20. Properties and interfacial microstructure of cement-based materials with composite micro-grains

    Institute of Scientific and Technical Information of China (English)

    FENG Qi; BA Heng-jing; LIU Jun-zhe

    2005-01-01

    Silica fume, fly ash and nano-fiber mineral materials (NR powder) are employed to incorporate into cement-based materials. According to the grain grading mathematical model of cement-based materials, two packing systems, namely, spherical grading system and nano-fiber reinforced system were designed. Properties and interfacial microstructure of the two systems were studied according to secondary interface theory. It was shown that nano-fiber mineral materials can improve the grain grading of the admixture, increase the density of the system, improve the microstructure of the interface and the hardened paste, and enhance the uniformity of cement-based materials mixed with composite micro-grains and greatly increase their wearable rigidity and flexure strength. In this paper, two kinds of interface models, including spherical grain model and nano-fiber reinforced interface model of the cement-based materials mixed with composite micro-grains, were brought forward.

  1. The Precise Measurement of Vapor-Liquid Equilibrium Properties of the CO2/Isopentane Binary Mixture, and Fitted Parameters for a Helmholtz Energy Mixture Model

    Science.gov (United States)

    Miyamoto, H.; Shoji, Y.; Akasaka, R.; Lemmon, E. W.

    2017-10-01

    Natural working fluid mixtures, including combinations of CO2, hydrocarbons, water, and ammonia, are expected to have applications in energy conversion processes such as heat pumps and organic Rankine cycles. However, the available literature data, much of which were published between 1975 and 1992, do not incorporate the recommendations of the Guide to the Expression of Uncertainty in Measurement. Therefore, new and more reliable thermodynamic property measurements obtained with state-of-the-art technology are required. The goal of the present study was to obtain accurate vapor-liquid equilibrium (VLE) properties for complex mixtures based on two different gases with significant variations in their boiling points. Precise VLE data were measured with a recirculation-type apparatus with a 380 cm3 equilibration cell and two windows allowing observation of the phase behavior. This cell was equipped with recirculating and expansion loops that were immersed in temperature-controlled liquid and air baths, respectively. Following equilibration, the composition of the sample in each loop was ascertained by gas chromatography. VLE data were acquired for CO2/ethanol and CO2/isopentane binary mixtures within the temperature range from 300 K to 330 K and at pressures up to 7 MPa. These data were used to fit interaction parameters in a Helmholtz energy mixture model. Comparisons were made with the available literature data and values calculated by thermodynamic property models.

  2. Removing adsorbed heavy metal ions from sand surfaces via applying interfacial properties of rhamnolipid.

    Science.gov (United States)

    Haryanto, Bode; Chang, Chien-Hsiang

    2015-01-01

    In this study, the interfacial properties of biosurfactant rhamnolipid were investigated and were applied to remove adsorbed heavy metal ions from sand surfaces with flushing operations. The surface tension-lowering activity, micelle charge characteristic, and foaming ability of rhamnolipid were identified first. For rhamnolipid in water, the negatively charged characteristic of micelles or aggregates was confirmed and the foaming ability at concentrations higher than 40 mg/L was evaluated. By using the rhamnolipid solutions in a batch washing approach, the potential of applying the interfacial properties of rhamnolipid to remove adsorbed copper ions from sand surfaces was then demonstrated. In rhamnolipid solution flushing operations for sand-packed medium, higher efficiency was found for the removal of adsorbed copper ions with residual type than with inner-sphere interaction type, implying the important role of interaction type between the copper ion and the sand surface in the removal efficiency. In addition, the channeling effect of rhamnolipid solution flow in the sand-packed medium was clearly observed in the solution flushing operations and was responsible for the low removal efficiency with low contact areas between solution and sand. By using rhamnolipid solution with foam to flush the sand-packed medium, one could find that the channeling effect of the solution flow was reduced and became less pronounced with the increase in the rhamnolipid concentration, or with the enhanced foaming ability. With the reduced channeling effect in the flushing operations, the removal efficiency for adsorbed copper ions was significantly improved. The results suggested that the foam-enhanced rhamnolipid solution flushing operation was efficient in terms of surfactant usage and operation time.

  3. Transport properties of interfacial Si-rich layers formed on silicate minerals during weathering: Implications for environmental concerns

    Science.gov (United States)

    Daval, Damien; Rémusat, Laurent; Bernard, Sylvain; Wild, Bastien; Micha, Jean-Sébastien; Rieutord, François; Fernandez-Martinez, Alejandro

    2015-04-01

    The dissolution of silicate minerals is of primary importance for various processes ranging from chemical weathering to CO2 sequestration. Whether it determines the rates of soil formation, CO2 uptake and its impact on climate change, channeling caused by hydrothermal circulation in reservoirs of geothermal power plants, durability of radioactive waste confinement glasses or geological sequestration of CO2, the same strategy is commonly applied for determining the long term evolution of fluid-rock interactions. This strategy relies on a bottom-up approach, where the kinetic rate laws governing silicate mineral dissolution are determined from laboratory experiments. However, a long-standing problem regarding this approach stems from the observation that laboratory-derived dissolution rates overestimate their field counterparts by orders of magnitude, casting doubt on the accuracy and relevance of predictions based on reactive-transport simulations. Recently [1], it has been suggested that taking into account the formation of amorphous Si-rich surface layers (ASSL) as a consequence of mineral dissolution may contribute to decrease the large gap existing between laboratory and natural rates. Our ongoing study is aimed at deciphering the extent to which ASSL may represent a protective entity which affects the dissolution rate of the underlying minerals, both physically (passivation) and chemically (by promoting the formation of a local chemical medium which significantly differs from that of the bulk solution). Our strategy relies on the nm-scale measurement of the physicochemical properties (diffusivity, thickness and density) of ASSL formed on cleavages of a model mineral (wollastonite) and their evolution as a function of reaction progress. Our preliminary results indicate that the diffusivity of nm-thick ASSL formed on wollastonite surface is ~1,000,000 times smaller than that reported for an aqueous medium, as estimated from the monitoring of the progression of a

  4. Structural phases, magnetic properties and Maxwell-Wagner type relaxation of CoFe2O4/Sr2Co2Fe12O22 ferrite composites

    Science.gov (United States)

    Patel, Chirag K.; Solanki, Neha P.; Singh, Charanjeet; Jotania, Rajshree B.; Chauhan, Chetna C.; Kulkarni, Shailja D.; Shirsath, Sagar E.

    2017-07-01

    CoFe2O4 (S:Y-1:0) and Sr2Co2Fe12O22 (S:Y-0:1) ferrites were synthesized separately by using chemical coprecipitation technique and calcined at 1000 °C for 5 h. The mixed ferrite composites (S:Y-3:7, 4:6, 5:5, 6:4 and 7:3) were prepared by physical mixing of individual ferrite powders in required weight proportions. The prepared composites were heated at 1150 °C for 5 h in a muffle furnace and then slowly cooled to room temperature. The prepared ferrites were characterized using various instrumental techniques like FTIR, XRD, SEM, VSM and dielectric measurements. The x-ray diffraction studies of pure Sr2Co2Fe12O22 ferrite sample show the presence of M and Y-type hexagonal phases, while the composites consist of spinel and Y-type phases. FTIR spectra of all samples show two bands of Fe-O stretching vibrations. VSM results of composites reveal that the values of the saturation magnetization (M s) vary from 50.44 emu g-1 to 31.21 emu g-1, while remanent magnetization values found from 11.18 emu g-1 to 3.70 emu g-1. A higher value of coercivity (H c  =  562 emu g-1) is observed in the composite S:Y-3:7 but M r/M s ratio of pure and composites is found to be less than 0.5. The dielectric behavior is explained using Maxwell-Wegner type interfacial polarization and N. Rezlescu’s model.

  5. Properties of plasma induced by pulsed CO2 laser on a copper target under different ambient conditions

    Science.gov (United States)

    Kuzmanovic, M.; Momcilovic, M.; Ciganovic, J.; Rankovic, D.; Savovic, J.; Milovanovic, D.; Stoiljkovic, M.; Pavlovic, M. S.; Trtica, M.

    2014-09-01

    Optical emission spectroscopy was applied for investigation of copper plasma induced by a nanosecond transversely excited atmospheric CO2 laser, operating at 10.6 μm. The effect of the background gas (air, Ar, He and N2) and pressure (1-25 mbar) on plasma formation was examined. The plasma shielding effect was more pronounced for background gases with lower ionization potential than for He. The increase of He pressure from 1 to 25 mbar resulted in fivefold increase of Cu atomic line intensity.

  6. PEI改性介孔分子筛KIT-6对CO2吸附性能的研究%Study on CO2 Adsorption Properties of PEI-Modified Mesoporous Molecular Sieve KIT-6

    Institute of Scientific and Technical Information of China (English)

    张中正; 王慧; 魏伟; 孙予罕

    2014-01-01

    CO2 capture has gained great attention due to its accumulation in the atmosphere, which is widely agreed as the predominant cause of greenhouse effect. In order to find an efficient adsorbent with high CO2 adsorption capacity and separation selectivity, mesoporous silica KIT-6 was synthesized by hydrothermal method and its amine-functionalized by impregnating it with PEI (polyethylenimine). The CO2 adsorption performances of KIT-6 and its modified ones were evaluated by using a dynamic adsorption apparatus. The effects of different PEI-loading ratioes on the adsorption of CO2 were investigated by the changes of breakthrough time, adsorption capacity and separation coefficient. The results show that PEI-modified KIT-6 adsorbent could greatly enhance CO2 adsorption amount and the separation coefficient between CO2 and N2. The CO2 adsorption performance increases with PEI-loading and then decreases. When the PEI-loading ratio is 0.6, the adsorption amount of CO2 and the separation selectivity reach their maximum value of 2.09 mmol×g-1 and 30.56, respectively, which are 6.0 times and 7.2 times higher than that of KIT-6 without PEI loading. Moreover, the CO2 adsorption capacity of PEI-modifies KIT-6 increases with temperature. Besides, the saturated PEI-modified adsorbent can be fully regenerated at 378 K and the regenerated adsorbent shows fairly good stability in 20 cycles of adsorption/regeneration.%CO2的大量排放是造成温室效应的主要因素,对全球排放的CO2进行捕集非常重要。今采用浸渍法将PEI(聚乙烯亚胺)负载到KIT-6介孔分子筛孔道表面上,使孔的吸附作用和胺的吸收作用相结合,制备出吸附容量大和选择性高的CO2吸附剂,从穿透时间、吸附量、分离因子等方面研究了PEI负载率对CO2吸附性能的影响。结果表明:KIT-6介孔分子筛经PEI改性后对CO2的吸附量和选择性增强。随着PEI负载量的增大,吸附剂对CO2的吸附性能先增大

  7. STABILITY OF WATER-IN-OIL-IN-WATER MULTIPLE EMULSIONS: INFLUENCE OF THE INTERFACIAL PROPERTIES OF MILK FAT GLOBULE MEMBRANE

    OpenAIRE

    J.G. Dzul-Cauich; C. Lobato-Calleros; J.P. Pérez-Orozco; J. Alvarez-Ramirez; E.J. Vernon-Carter

    2013-01-01

    The interfacial shear viscosity (r¡iJlt) and the creep compliance-time (J(t» behavior of mi1k fat globule membrane (MFGM) films (4, 5 and 6% w/w) formed at the water-oil interface were evaluated. Films with higher MFGM concentration displayed higher r¡int and interfacial viscoelastic properties. When esters of polyglycerol and polyriciniolate fatty acids (PGPR) were added to the oil phase, a competitive adsorption at the interface took place between PGPR and MFGM which caused a decrease in th...

  8. High visible light photocatalytic property of Co2+-doped TiO2 nanoparticles with mixed phases

    Science.gov (United States)

    Zhao, Cong; Shu, Xin; Zhu, Da-chuan; Wei, Shang-hai; Wang, Yu-xin; Tu, Ming-jing; Gao, Wei

    2015-12-01

    Mixed phases Co2+-doped TiO2 nanoparticles have been prepared by a novel method combined with sol-gel and hydrothermal methods. The section of sol-gel method, sol, provides an unstable colloidal reaction system for the next reaction process. The hydrothermal method is to treat the above reaction system to prepare undoped and doped samples. The as-prepared samples have been characterized by XRD, SEM, TEM, HRTEM and UV-vis spectroscopy. The results show that the as-prepared samples contain three titania polymorphs: brookite, rutile and anatase phases. These titania polymorphs probably form polymorph-junctions that can extend the lifetime of photogenerated electron-hole pairs. The photocatalytic activity has been evaluated by the photocatalytic degradation of Rhodamine B in air under visible-light irradiation. The degradation results indicate that the photocatalytic activity of as-prepared samples is higher than that of Degussa P25, especially the doped sample. This is ascribed to the fact that the phases with smaller band gap can enhance visible-light photocatalytic activity, the polymorph-junctions effectively extend the photoelectron lifetime and the nano size effect and Co-doping induce the shift of the absorption edge into the visible-light region. Furthermore, the XRD, SEM, and TEM data indicate that Co2+-doping results in the decrease of particle size.

  9. Supercritical CO2 extraction of candlenut oil: process optimization using Taguchi orthogonal array and physicochemical properties of the oil.

    Science.gov (United States)

    Subroto, Erna; Widjojokusumo, Edward; Veriansyah, Bambang; Tjandrawinata, Raymond R

    2017-04-01

    A series of experiments was conducted to determine optimum conditions for supercritical carbon dioxide extraction of candlenut oil. A Taguchi experimental design with L9 orthogonal array (four factors in three levels) was employed to evaluate the effects of pressure of 25-35 MPa, temperature of 40-60 °C, CO2 flow rate of 10-20 g/min and particle size of 0.3-0.8 mm on oil solubility. The obtained results showed that increase in particle size, pressure and temperature improved the oil solubility. The supercritical carbon dioxide extraction at optimized parameters resulted in oil yield extraction of 61.4% at solubility of 9.6 g oil/kg CO2. The obtained candlenut oil from supercritical carbon dioxide extraction has better oil quality than oil which was extracted by Soxhlet extraction using n-hexane. The oil contains high unsaturated oil (linoleic acid and linolenic acid), which have many beneficial effects on human health.

  10. CO2 -Responsive polymers.

    Science.gov (United States)

    Lin, Shaojian; Theato, Patrick

    2013-07-25

    This Review focuses on the recent progress in the area of CO2 -responsive polymers and provides detailed descriptions of these existing examples. CO2 -responsive polymers can be categorized into three types based on their CO2 -responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli-responsive polymers, CO2 -responsive polymers provide the advantage to use CO2 as a "green" trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2 -responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2 -responsive polymers are considered to have a prosperous future in various scientific areas.

  11. Interfacial and foaming properties of prolylenglycol alginates. Effect of degree of esterification and molecular weight.

    Science.gov (United States)

    Baeza, Rosa; Sanchez, Cecilio Carrera; Pilosof, Ana M R; Patino, Juan M Rodríguez

    2004-08-01

    In the present work we have studied the characteristics of propylene glycol alginates (PGA) adsorption at the air-water interface and the viscoelastic properties of the films in relation to its foaming properties. To evaluate the effect of the degree of PGA esterification and viscosity, different commercial samples were studied--Kelcoloid O (KO), Kelcoloid LVF (KLVF) and Manucol ester (MAN). The temperature (20 degrees C) and pH (7.0) were maintained constant. For time-dependent surface pressure measurements and surface dilatational properties of adsorbed PGA at the air-water interface an automatic drop tensiometer was used. The foam was generated by whipping and then the foam capacity and stability was determined. The results reveal a significant interfacial activity for PGA due to the hydrophobic character of the propylene glycol groups. The kinetics of adsorption at the air-water interface can be monitored by the diffusion and penetration of PGA at the interface. The adsorbed PGA film showed a high viscoelasticity. The surface dilatational modulus depends on the PGA and its concentration in the aqueous phase. Foam capacity of PGA solutions increased in the order KO > MAN > KLVF, which followed the increase in surface pressure and the decrease in the viscosities of PGA solutions. The stability of PGA foams monitored by the drainage rate and collapse time follows the order MAN > KLVF > KO. The foam stability depends on the combined effect of molecular weight/degree of esterification of PGA, solution viscosity and viscoelasticity of the adsorbed PGA film.

  12. High temperature thermoelectric properties of highly c-axis oriented Bi2Sr2Co2Oy thin films fabricated by pulsed laser deposition

    Institute of Scientific and Technical Information of China (English)

    Chen Shan-Shan; Wang Shu-Fang; Liu Fu-Qiang; Yan Guo-Ying; Chen Jing-Chun; Wang Jiang-Long; Yu Wei; Fu Guang-Sheng

    2012-01-01

    High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co2Oy thin films prepared by pulsed laser deposition on LaAlO3 (001).Both the electric resistivity p and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m·Ω· cm and 202 μV/K at 980 K,resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples.A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature.The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application in high temperature thin film thermoelectric devices.

  13. Transport properties of a binary mixture of CO2-N2 from the pair potential energy functions based on a semi-empirical inversion method

    Institute of Scientific and Technical Information of China (English)

    Song Bo; Wang Xiao-Po; Yang Fu-Xin; Liu Zhi-Gang

    2012-01-01

    The potential energy surface of a CO2-N2 mixture is determined by using an inversion method,together with a new collision integral correlation [J.Phys.Chem.Ref.Data 19 1179 (1990)].With the new invert potential,the transport properties of CO2-N2 mixture are presented in a temperature range from 273.15 K to 3273.15 K at low density by employing the Chapman-Enskog scheme and the Wang Chang-Uhlenbeck-de Boer theory,consisting of a viscosity coefficient,a thermal conductivity coefficient,a binary diffusion coefficient,and a thermal diffusion factor.The accuracy of the predicted results is estimated to be 2% for viscosity,5% for thermal conductivity,and 10% for binary diffusion coefficient.

  14. Calculation of 2-temperature plasma thermo-physical properties considering condensed phases: application to CO2-CH4 plasma: part 2. Transport coefficients

    Science.gov (United States)

    Niu, Chunping; Chen, Zhexin; Rong, Mingzhe; Wang, Chunlin; Wu, Yi; Yang, Fei; Wang, Xiaohua; Pang, Qingping

    2016-10-01

    The transport coefficients, namely thermal conductivity, viscosity and electrical conductivity, of CO2-CH4 mixture in and out of LTE are calculated in this paper. The calculation was based on local chemical equilibrium (LCE) and local phase equilibrium assumption. The 2-temperature composition results obtained with consideration of condensed phase in the previous paper (Part I) of this series were used in this calculation. The transport coefficients were calculated by classical Chapman-Enskog method simplified by Devoto. The results are presented for different temperatures (300-30 000 K), pressures (0.1-10 atm), non-equilibrium degrees (1-5), and CH4 molar proportions (0-100%). The influence of condensed graphite, non-LTE effect, mixture ratio and pressure on the composition and thermodynamic properties has been discussed. The results will serve as reliable reference data for computational simulation of CO2-CH4 plasmas.

  15. Effect of Coulomb interactions and Hartree-Fock exchange on structural, elastic, optoelectronic and magnetic properties of Co2MnSi Heusler: A comparative study

    Science.gov (United States)

    Lantri, T.; Bentata, S.; Bouadjemi, B.; Benstaali, W.; Bouhafs, B.; Abbad, A.; Zitouni, A.

    2016-12-01

    Using the first-principle calculations, we have investigated the structural, elastic, optoelectronic and magnetic properties of Co2MnSi Heusler alloy. Based on the density functional theory (DFT) and hiring the full-potential linearized augmented plane wave (FP-LAPW) method, we have used five approaches: the Hybrid on-site exact exchange, the Local Spin Density Approximation (LSDA), the LSDA+U, the Generalized Gradient Approximation GGA and GGA+U; where the Hubbard on-site Coulomb interaction correction U is calculated by constraint local density approximation for Co and Mn atoms. Our results show that the highly-ordered Co2MnSi alloy is a ductile, stiff and anisotropic material. It has a half-metallic ferromagnetic character with an integer magnetic moment of 5 μB which is in good agreement with the Slater-Pauling rule.

  16. Thickness dependent structural, magnetic, and electronic properties of the epitaxial films of transparent conducting oxide NiCo2O4

    Science.gov (United States)

    Silwal, Punam; Miao, Ludi; Hu, Jin; Spinu, Leonard; Ho Kim, Dae; Talbayev, Diyar

    2013-09-01

    We present the thickness dependent structural, magnetic, and transport properties of transparent conducting spinel NiCo2O4 thin films on MgAl2O4 (001) substrates. The structural examination of the films reveals that the epitaxial stain is independent of the films' thickness. Electric and magnetic measurements show that the films are metallic with p-type conduction and ferrimagnetic down to 2 unit cells with an enhanced coercive field in the films thinner than 30 unit cells. The low-temperature resistivity data indicate that the observed resistivity minimum results from the disorder-induced quantum interference effects. Our results demonstrate that NiCo2O4 may provide an alternative magnetic conducting medium for spintronics devices.

  17. Characterization of the surface and interfacial properties of the lamina splendens

    Science.gov (United States)

    Rexwinkle, Joe T.; Hunt, Heather K.; Pfeiffer, Ferris M.

    2017-06-01

    Joint disease affects approximately 52.5 million patients in the United States alone, costing 80.8 billion USD in direct healthcare costs. The development of treatment programs for joint disease and trauma requires accurate assessment of articular cartilage degradation. The articular cartilage is the interfacial tissue between articulating surfaces, such as bones, and acts as low-friction interfaces. Damage to the lamina splendens, which is the articular cartilage's topmost layer, is an early indicator of joint degradation caused by injury or disease. By gaining comprehensive knowledge on the lamina splendens, particularly its structure and interfacial properties, researchers could enhance the accuracy of human and animal biomechanical models, as well as develop appropriate biomimetic materials for replacing damaged articular cartilage, thereby leading to rational treatment programs for joint disease and injury. Previous studies that utilize light, electron, and force microscopy techniques have found that the lamina splendens is composed of collagen fibers oriented parallel to the cartilage surface and encased in a proteoglycan matrix. Such orientation maximizes wear resistance and proteoglycan retention while promoting the passage of nutrients and synovial fluid. Although the structure of the lamina splendens has been explored in the literature, the low-friction interface of this tissue remains only partially characterized. Various functional models are currently available for the interface, such as pure boundary lubrication, thin films exuded under pressure, and sheets of trapped proteins. Recent studies suggest that each of these lubrication models has certain advantages over one another. Further research is needed to fully model the interface of this tissue. In this review, we summarize the methods for characterizing the lamina splendens and the results of each method. This paper aims to serve as a resource for existing studies to date and a roadmap of the

  18. Characterization of the surface and interfacial properties of the lamina splendens

    Science.gov (United States)

    Rexwinkle, Joe T.; Hunt, Heather K.; Pfeiffer, Ferris M.

    2017-01-01

    Joint disease affects approximately 52.5 million patients in the United States alone, costing 80.8 billion USD in direct healthcare costs. The development of treatment programs for joint disease and trauma requires accurate assessment of articular cartilage degradation. The articular cartilage is the interfacial tissue between articulating surfaces, such as bones, and acts as low-friction interfaces. Damage to the lamina splendens, which is the articular cartilage's topmost layer, is an early indicator of joint degradation caused by injury or disease. By gaining comprehensive knowledge on the lamina splendens, particularly its structure and interfacial properties, researchers could enhance the accuracy of human and animal biomechanical models, as well as develop appropriate biomimetic materials for replacing damaged articular cartilage, thereby leading to rational treatment programs for joint disease and injury. Previous studies that utilize light, electron, and force microscopy techniques have found that the lamina splendens is composed of collagen fibers oriented parallel to the cartilage surface and encased in a proteoglycan matrix. Such orientation maximizes wear resistance and proteoglycan retention while promoting the passage of nutrients and synovial fluid. Although the structure of the lamina splendens has been explored in the literature, the low-friction interface of this tissue remains only partially characterized. Various functional models are currently available for the interface, such as pure boundary lubrication, thin films exuded under pressure, and sheets of trapped proteins. Recent studies suggest that each of these lubrication models has certain advantages over one another. Further research is needed to fully model the interface of this tissue. In this review, we summarize the methods for characterizing the lamina splendens and the results of each method. This paper aims to serve as a resource for existing studies to date and a roadmap of the

  19. Effect of the interfacial layer composition on the properties of emulsion creams.

    Science.gov (United States)

    Mackie, Alan R; Ridout, Michael J; Moates, Graham; Husband, Fiona A; Wilde, Peter J

    2007-07-11

    We have quantified observed differences in the microstructure and rheology of creaming emulsions stabilized by protein and low molecular weight surfactants. In this study, we made two sets of emulsions from a single parent emulsion, which differed only in their interfacial composition (i.e., either protein or surfactant). The protein studied was whey protein isolate. The zeta potential of the surfactant-stabilized emulsion was controlled by mixing anionic (SDS) and nonionic (Brij 35) surfactants to match the zeta potential of the protein-stabilized emulsion. Despite this, ultrasonic creaming measurements and confocal microscopy showed that the structures within the cream layers were different between the two sets of emulsions. The protein-stabilized emulsions appeared to slow or arrest the packing within the cream, leading to a lower density network of emulsion droplets, whereas the surfactant emulsion droplets rearranged more quickly into a well-packed, concentrated cream layer. Rheological analysis of the creams showed that despite the protein-stabilized emulsions having a lower dispersed phase volume fraction, their elastic modulus was approximately 30 times greater than that of a comparable surfactant-stabilized emulsion. These differences were caused by the ability of the protein to form a highly viscoelastic interfacial network around the droplets which may include intermolecular covalent cross-links. At close range the adhesive nature of the interaction between the layers contributes to the microstructure and rheology of concentrated emulsions. This is the first time that such well-defined emulsion systems have been studied in detail both noninvasively to look at the impact on creaming and also invasively to look at the impact on bulk rheological properties.

  20. CO2 laser modeling

    Science.gov (United States)

    Johnson, Barry

    1992-01-01

    The topics covered include the following: (1) CO2 laser kinetics modeling; (2) gas lifetimes in pulsed CO2 lasers; (3) frequency chirp and laser pulse spectral analysis; (4) LAWS A' Design Study; and (5) discharge circuit components for LAWS. The appendices include LAWS Memos, computer modeling of pulsed CO2 lasers for lidar applications, discharge circuit considerations for pulsed CO2 lidars, and presentation made at the Code RC Review.

  1. Approaches to the quantification and investigation of interfacial systems and their materials properties using sum frequency generation spectroscopy

    Science.gov (United States)

    Hurrey, Michael Laird

    The focus of this thesis is the use and methods development of sum frequency generation (SFG) spectroscopy as an analytical tool for studying surfaces of CO2-philic molecules. The specific set of molecules used for analysis in this project was peracetylated carbohydrates due to their inherent solubility in liquid and supercritical CO2. The goal of the project was to investigate the specific interactions present at the surface of these materials in contact with CO2 under varying conditions. To accomplish this task however, it was necessary to study the materials properties of these compounds using a variety of techniques and relate the SFG data collected under ambient conditions to changes in the long range order. During the analysis of the materials properties the sensitivity of diffuse reflectance sum frequency generation (DR-SFG) spectroscopy to changes in crystallinity was elucidated. In addition, a method was developed and validated for quantitative analysis of changes in concentration of bulk mixtures. Specifically, mixtures of materials differing only in crystal structure were studied and linear calibration plots were created allowing the determination of an unknown samples mole fraction. The last set of control experiments included study of the CO2 adsorption of peracetylated carbohydrates using a high pressure quartz crystal microbalance (QCM) to understand how these surface interactions occur below each material's deliquescence point. By understanding the molecular interactions of this class of CO2-philes in terms of the adsorption thermodynamics and the importance of long range order, deconvolution of subsequent SFG experiments involving changes in CO2 pressure can be accomplished. Finally, the first pressurized SFG experiment was performed on thin films to see how changes in the viscosity and density of CO2 effect the specific interactions at the surface. By relating information collected previously with SFG data collected under varying CO2 environments

  2. Formation of graphene-like 2D spinel MnCo2O4 and its lithium storage properties

    DEFF Research Database (Denmark)

    Huang, Guoyong; Guo, Xueyi; Cao, Xiao

    2017-01-01

    Two-dimensional (2D) materials fulfill the requirements for fast lithium storage due to the large exposed surface area and the open shortened path for Li insertion/extraction. Novel graphene-like 2D spinel MnCo2O4 powders have been synthesized, which inherit the morphology and structure of special.......0 mAhg-1 at 0.4 Ag-1 after 200 cycles). Remarkably, the 2D layered structure is retained perfectly after 200 cycles at 0.4 Ag-1. Hence, the type of unique self-assembly metal-organic precursors could provide a flexible and general way to synthesize 2D layered metal oxides as templates for high...

  3. Interfacial characteristics and dynamic mechanical properties of Wf/Zr-based metallic glass matrix composites

    Institute of Scientific and Technical Information of China (English)

    MA Wei-feng; KOU Hong-chao; CHEN Chun-sheng; LI Jin-shan; HU Rui; XING Li-qian; ZHOU Lian; FU Heng-zhi

    2008-01-01

    Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting. Their dynamic compressive tests were performed using a Hopkinson bar. The relationship between the interfacial characteristics and the dynamic compressive behavior was investigated. The results indicate that the interface characteristics of composites include interfacial diffusion and interfacial reaction, and the interfacial shear strength increases when the interfacial reaction is serious. The dynamic plastic performance are improved obviously if the suitable interface reaction occurs. The failure occurs by shear and the fibers split longitudinally if there is no interface reaction or a little reaction; in contrast, holistic failure occurs if there is too much interface reaction.

  4. Regularization Method to the Parameter Identification of Interfacial Heat Transfer Coefficient and Properties during Casting Solidification

    Institute of Scientific and Technical Information of China (English)

    SUI Da-shan; CUI Zhen-shan

    2007-01-01

    The accurate material physical properties, initial and boundary conditions are indispensable to the numerical simulation in the casting process, and they are related to the simulation accuracy directly.The inverse heat conduction method can be used to identify the mentioned above parameters based on the temperature measurement data.This paper presented a new inverse method according to Tikhonov regularization theory.A regularization functional was established and the regularization parameter was deduced, the Newton-Raphson iteration method was used to solve the equations.One detailed case was solved to identify the thermal conductivity and specific heat of sand mold and interfacial heat transfer coefficient (IHTC) at the meantime.This indicates that the regularization method is very efficient in decreasing the sensitivity to the temperature measurement data, overcoming the illposedness of the inverse heat conduction problem (IHCP) and improving the stability and accuracy of the results.As a general inverse method, it can be used to identify not only the material physical properties but also the initial and boundary conditions' parameters.

  5. Preparation and microwave properties of Ba4ZnzCo2_zFe36O60 hexaferrites by a sol-gel process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haijun; JIA Xiaolin; YAO Xi; ZHANG Liangying

    2004-01-01

    Ba4ZnzCo2_zFe36O60 hexaferrites with Z = 2.0, 1.5, 1.0, 0.5, and 0.0 were prepared by a citrate sol-gel process.The complex dielectric constant and complex permeability of hexaferrite-paraffin wax composites were measured in the range from 0.1 to 6.0 GHz. Measured results showed that both the complex dielectric constant and the dielectric loss exhibited no significant change as the measuring frequency increasing except for the sample with Z = 0.0. The real part of permeability decreased with increasing frequency for all samples in the whole measuring frequency range, and the natural resonance phenomena were observed in allμ" spectrum but Co2U. The results also indicate that the content of zinc closely affects the microwave properties of Ba4ZnzCo2_zFe36O60 felTites, and the greater the zinc content, the lower the natural resonance frequency is.

  6. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  7. Dielectric and magnetic properties of 0.4PZT+0.6NiCuZn-ferrite composites modified with P2O5-Co2O3

    Science.gov (United States)

    Jia, Lijun; Zhang, Huaiwu; Li, Tao; Liu, Yingli; Wen, Qiye; Shen, Jian

    2010-05-01

    P2O5 and Co2O3 have been introduced to 0.4PZT+0.6NiCuZn-ferrite composites in order to improve their electromagnetic properties, particularly for the suppression of electromagnetic interference. The nonlinear fitting of the results of permeability dispersion has revealed the relationships between domain wall resonance, spin rotation relaxation mechanisms, microstructure, and local induced anisotropy. The P2O5 additive can enhance the bulk density and static permeability due to its instantaneous liquid phase at low temperature. The existence of local induced anisotropy caused by ordering of Co ions results in a decrease in static permeability and an increase in the Q-factor. Meanwhile, the addition of Co2O3 can improve the dielectric constant and the loss tangent (tan δe) by increasing the oxygen vacancy concentration. The further decrease in tan δe of the samples codoped with P2O5 and Co2O3 is mainly attributed to P5+ in the grain boundary which can increase cation vacancies in the grain boundary region.

  8. Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of Dy0.5Ho0.5Co2

    Science.gov (United States)

    Chzhan, V. B.; Tereshina, E. A.; Mikhailova, A. B.; Politova, G. A.; Tereshina, I. S.; Kozlov, V. I.; Ćwik, J.; Nenkov, K.; Alekseeva, O. A.; Filimonov, A. V.

    2017-06-01

    The effect of Tb and Al substitution within the rare earth and cobalt sublattices on structural and magnetothermal properties of Dy0.5Ho0.5Co2 has been studied. Multicomponent Laves phase alloys Tbx(Dy0.5Ho0.5)1-xCo2-yAly (x = 0, 0.3, 0.4, 0.5; y = 0, 0.25) synthesized using high-purity metals have been studied using X-ray diffraction analysis, heat capacity and magnetocaloric measurements. Dy0.5Ho0.5Co2 has a first order phase transition at the Curie temperature TC ≈ 110 K. Both Tb and Al substitution leads to increase of the TC. The increasing Tb content leads to the decreases slightly the MCE and all the transitions near the Curie temperature are of the first order. As for the Al-containing compounds, MCE measurements show that the phase transition type changes from the first to the second-order. The advantage of Tbx(Dy0.5Ho0.5)1-xCo1.75Al0.25 as compared with Al-free alloys is 'table-like' behavior of MCE.

  9. Influence of an Optimized Fibre Coating on Interfacial and Mechanical Properties of Glass Fibre/Polypropylene Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of pretreatment of fibre on interfacial and mechanical properties of glass fibre/polypropylene composites was investigated. Firstly, the glass fibres were coated with the blends of m-IPP (maleic anhydride grafting isotatic polypropylene) and m-APP (maleic anhydride grafting amorphous polypropylene) in different ratios.Secondly, the interfacial reaction of the coated composites was analysed by FTIR, which shows that the interfacial chemical reaction between m-IPP/m-APP in the fibre coating and the fibre surface-bound coupling agent is in existence.Thirdly, the microstructure of the coated composites was studied by SEM. The results indicate that the coating treatment is effective on improving interfacial adhesion of the fibre-matrix and the right amount of m-APP added to the coat impels the plastic deformation surrounding the point of cracks, which makes cracks turn to region and prevents from further interface debonding. Lastly, the mechanical properties were evaluated by measurement of the flexural strength and impact strength of the composites. It was found that the flexural strength and impact strength of the composites with coating fibre are higher than those of uncoating fibre composite. The results of these investigations draw the conclusion that the pretreatment of fibre with m-IPP/m-APP blends can form an optimize interlayer between the fibre and the PP matrix, which improves both the strength and toughness of the composites.

  10. Effect of plasma surface treatment of recycled carbon fiber on carbon fiber-reinforced plastics (CFRP) interfacial properties

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hooseok, E-mail: hooseok.lee@gmail.com; Ohsawa, Isamu; Takahashi, Jun

    2015-02-15

    Highlights: • Plasma treatment was used to improve the adhesion property between the recycled CF and polymer matrix. • In order to evaluate the adhesion between plasma treated recycled CF and polymer, micro droplet test was conducted. • The interfacial shear strength and the interfacial adhesion of recycled carbon fiber increased. - Abstract: We studied the effects of plasma surface treatment of recycled carbon fiber on adhesion of the fiber to polymers after various treatment times. Conventional surface treatment methods have been attempted for recycled carbon fiber, but most require very long processing times, which may increase cost. Hence, in this study, plasma processing was performed for 0.5 s or less. Surface functionalization was quantified by X-ray photoelectron spectroscopy. O/C increased from approximately 11% to 25%. The micro-droplet test of adhesion properties and the mechanical properties of CFRP were also investigated.

  11. Evaluating interfacial adhesion properties of Pt/Ti thin-film by using acousto-optic technique

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Sung [Graduate School of Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of); Didie, David; Yoshida, Sanichiro [Dept. of Chemistry and Physics, Southeastern Louisiana University, Hammond (United States); Park, Ik Keun [Dept. of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2016-06-15

    We propose an acousto-optic technique for the nondestructive evaluation of adhesion properties of a Pt/Ti thin-film interface. Since there are some problems encountered when using prevailing techniques to nondestructively evaluate the interfacial properties of micro/nano-scale thin-films, we applied an interferometer that combined the acoustic and optical methods. This technique is based on the Michelson interferometer but the resultant surface of the thin film specimen makes interference instead of the mirror when the interface is excited from the acoustic transducer at the driving frequency. The thin film shows resonance-like behavior at a certain frequency range, resulting in a low-contrast fringe pattern. Therefore, we represented quantitatively the change in fringe pattern as a frequency spectrum and discovered the possibility that the interfacial adhesion properties of a thin film can be evaluated using the newly proposed technique.

  12. Different CO2 absorbents-modified SBA-15 sorbent for highly selective CO2 capture

    Science.gov (United States)

    Liu, Xiuwu; Zhai, Xinru; Liu, Dongyang; Sun, Yan

    2017-05-01

    Different CO2 absorbents-modified SBA-15 materials are used as CO2 sorbent to improve the selectivity of CH4/CO2 separation. The SBA-15 sorbents modified by physical CO2 absorbents are very limited to increasing CO2 adsorption and present poor selectivity. However, the SBA-15 sorbents modified by chemical CO2 absorbents increase CO2 adsorption capacity obviously. The separation coefficients of CO2/CH4 increase in this case. The adsorption and regeneration properties of the SBA-15 sorbents modified by TEA, MDEA and DIPA have been compared. The SBA-15 modified by triethanolamine (TEA) presents better CO2/CH4 separation performance than the materials modified by other CO2 absorbents.

  13. Monitoring the bio-stimulation of hydrocarbon-contaminated soils by measurements of soil electrical properties, and CO2 content and its 13C/12C isotopic signature

    Science.gov (United States)

    Noel, C.; Gourry, J.; Ignatiadis, I.; Colombano, S.; Dictor, M.; Guimbaud, C.; Chartier, M.; Dumestre, A.; Dehez, S.; Naudet, V.

    2013-12-01

    Hydrocarbon contaminated soils represent an environmental issue as it impacts on ecosystems and aquifers. Where significant subsurface heterogeneity exists, conventional intrusive investigations and groundwater sampling can be insufficient to obtain a robust monitoring of hydrocarbon contaminants, as the information they provide is restricted to vertical profiles at discrete locations, with no information between sampling points. In order to obtain wider information in space volume on subsurface modifications, complementary methods can be used like geophysics. Among geophysical methods, geoelectrical techniques such as electrical resistivity (ER) and induced polarization (IP) seem the more promising, especially to study the effects of biodegradation processes. Laboratory and field geoelectrical experiments to characterize soils contaminated by oil products have shown that mature hydrocarbon-contaminated soils are characterized by enhanced electrical conductivity although hydrocarbons are electrically resistive. This high bulk conductivity is due to bacterial impacts on geological media, resulting in changes in the chemical and physical properties and thus, to the geophysical properties of the ground. Moreover, microbial activity induced CO2 production and isotopic deviation of carbon. Indeed, produced CO2 will reflect the pollutant isotopic signature. Thus, the ratio δ13C(CO2) will come closer to δ13C(hydrocarbon). BIOPHY, project supported by the French National Research Agency (ANR), proposes to use electrical methods and gas analyses to develop an operational and non-destructive method for monitoring in situ biodegradation of hydrocarbons in order to optimize soil treatment. Demonstration field is located in the South of Paris (France), where liquid fuels (gasoline and diesel) leaked from some tanks in 1997. In order to stimulate biodegradation, a trench has been dug to supply oxygen to the water table and thus stimulate aerobic metabolic bioprocesses. ER and

  14. Catalytic Hydrogenation of CO2 to Methanol: Study of Synergistic Effect on Adsorption Properties of CO2 and H2 in CuO/ZnO/ZrO2 System

    Directory of Open Access Journals (Sweden)

    Chunjie Huang

    2015-11-01

    Full Text Available A series of CuO/ZnO/ZrO2 (CZZ catalysts with different CuO/ZnO weight ratios have been synthesized by citrate method and tested in the catalytic hydrogenation of CO2 to methanol. Experimental results showed that the catalyst with the lowest CuO/ZnO weight ratio of 2/7 exhibited the best catalytic performance with a CO2 conversion of 32.9%, 45.8% methanol selectivity, and a process delivery of 193.9 gMeOH·kgcat−1·h−1. A synergetic effect is found by systematic temperature-programmed-desorption (TPD studies. Comparing with single and di-component systems, the interaction via different components in a CZZ system provides additional active sites to adsorb more H2 and CO2 in the low temperature range, resulting in higher weight time yield (WTY of methanol.

  15. Progress of CO2 Adsorption Properties of Zinc Based Metal Organic Frameworks%锌基金属-有机框架材料 CO2吸附性能研究进展

    Institute of Scientific and Technical Information of China (English)

    王胜; 刘鹏成

    2016-01-01

    The research background of the zinc based metal-organic frameworks ( MOFs) materials was summarized.Then the research progresses on the characteristics and preparation of metal-organic framework materials,as well as CO2 adsorp-tion of metal organic framework materials were reviewed.The development prospect and research direction of the material was also discussed in the end.%本文概述近几年国内外Zn-MOFs材料吸附CO2的研究进展,综述Zn-MOFs材料的特性、制备方法及其CO2吸附的研究,最后展望该材料的研究方向和发展前景。

  16. Preparation and Properties of Co2+/TiO2 Nano-films%Co2+/TiO2纳米复合薄膜的制备及亲水性研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    采用液相法制备了一系列 Co2+掺杂 TiO 2纳米复合薄膜,利用 X 射线粉末衍射(XRD)、扫描电镜(SEM)、紫外-可见(UV-Vis)光谱、可见光透过光谱等手段对复合薄膜进行了表征,运用接触角测量仪考察了各薄膜的亲水性能。结果表明,Co2+的掺杂大幅度提高了 TiO 2薄膜的亲水性,当掺杂 Co2+的质量分数为1.5%时,薄膜与水的接触角几乎为0°。%A series of novel Co2+/ TiO 2 Nano-films were synthesized by a liquid phase method.The as-synthesized products were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),UV-Vis diffuse reflec-tance spectroscopy (DRS),visible light spectrum.Influence of doping Co2+ content,saving time in dark place and UV illumination time on the hydrophilicity of the film were investigated by contact goniometer.The results indicate that doping Co2+ content of 1.5% (w,mass fraction),the TiO 2 film shows the best hydrophilicity.The contact angle of the film is almost 0.

  17. Investigation of optical and interfacial properties of Ag/Ta{sub 2}O{sub 5} metal dielectric multilayer structure

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, P., E-mail: piyali.sarkar4@gmail.com; Jena, S.; Tokas, R. B.; Thakur, S.; Sahoo, N. K. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Rao, K. D.; Misal, J. S.; Prathap, C. [Optics and Thin Film Laboratory, BARC-Vizag, Autonagar, Visakhapatnam-530012 (India)

    2015-06-24

    One-dimensional periodic metal-dielectric multilayer thin film structures consisting of Ag and Ta{sub 2}O{sub 5} alternating layers are deposited on glass substrate using RF magnetron sputtering technique. The spectral property of the multilayers has been investigated using spectrophotometry technique. The optical parameters such as refractive index, extinction coefficient, band gap etc., along with film thickness as well as the interfacial layer properties which influence these properties have been probed with spectroscopic ellipsometry technique. Atomic force microscopy has been employed to characterize morphological properties of this metal-dielectric multilayer.

  18. First-Principles Study on the Structural, Electronic, Magnetic and Thermodynamic Properties of Full Heusler Alloys Co2VZ (Z = Al, Ga)

    Science.gov (United States)

    Bentouaf, Ali; Hassan, Fouad H.; Reshak, Ali H.; Aïssa, Brahim

    2017-01-01

    We report on the investigation of the structural and physical properties of the Co2VZ (Z = Al, Ga) Heusler alloys, with L21 structure, through first-principles calculations involving the full potential linearized augmented plane-wave method within density functional theory. These physical properties mainly revolve around the electronic, magnetic and thermodynamic properties. By using the Perdew-Burke-Ernzerhof generalized gradient approximation, the calculated lattice constants and spin magnetic moments were found to be in good agreement with the experimental data. Furthermore, the thermal effects using the quasi-harmonic Debye model have been investigated in depth while taking into account the lattice vibrations, the temperature and the pressure effects on the structural parameters. The heat capacities, the thermal expansion coefficient and the Debye temperatures have also been determined from the non-equilibrium Gibbs functions. An application of the atom in molecule theory is presented and discussed in order to analyze the bonding nature of the Heusler alloys. The focus is on the mixing of the metallic and covalent behavior of Co2VZ (Z = Al, Ga) Heusler alloys.

  19. Ferromagnetic resonance, transverse bias initial inverse susceptibility and torque studies of magnetic properties of Co2MnSi thin films

    Directory of Open Access Journals (Sweden)

    Devolder T.

    2013-01-01

    Full Text Available Magnetic properties of Co2MnSi thin films of 20 nm and 50 nm in thickness grown by radio frequency sputtering on a-plane sapphire substrates have been studied. X-ray diffraction (XRD revealed that the cubic Co2MnSi axis is normal to the substrate and that well defined preferential in-plane orientations are present. The static magnetic properties were studied at room temperature by conventional magneto-optical Kerr effect (MOKE, transverse bias initial inverse susceptibility and torque (TBIIST MOKE. The dynamic magnetic properties were investigated by micro-strip ferromagnetic resonance (MS-FMR at room temperature. The resonance and TBIIST measurements versus the direction of the in-plane applied magnetic field reveal that the in-plane anisotropy results from the superposition of a two-fold and a four-fold symmetry. The directions of the principal axes of the twofold anisotropy are sample dependent. The angular dependence of remanent normalized magnetizations and coercive fields, studied by MOKE are analyzed within the frame of a coherent rotation model. A good agreement is observed between the field anisotropy values obtained from MSFMR and from TBIIST data. Frequency and angular dependence of FMR linewidth has been studied. Apparent damping coefficient of 0.0112 has been measured for 50 nm thick sample.

  20. Nanodomain induced anomalous magnetic and electronic transport properties of LaBaCo2O5.5+δ highly epitaxial thin films.

    Science.gov (United States)

    Ruiz-Zepeda, F; Ma, C; Bahena Uribe, D; Cantu-Valle, J; Wang, H; Xu, Xing; Yacaman, M J; Chen, C; Lorenz, B; Jacobson, A J; Chu, P C W; Ponce, A

    2014-01-14

    A giant magnetoresistance effect (∼46% at 20 K under 7 T) and anomalous magnetic properties were found in a highly epitaxial double perovskite LaBaCo2O5.5+δ (LBCO) thin film on (001) MgO. Aberration-corrected Electron Microscopy and related analytical techniques were employed to understand the nature of these unusual physical properties. The as-grown film is epitaxial with the c-axis of the LBCO structure lying in the film plane and with an interface relationship given by (100)LBCO || (001)MgO and [001]LBCO || [100]MgO or [010]MgO. Orderly oxygen vacancies were observed by line profile electron energy loss spectroscopy and by atomic resolution imaging. Especially, oxygen vacancy and nanodomain structures were found to have a crucial effect on the electronic transport and magnetic properties.

  1. CO2NNIE

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2015-01-01

    We propose a system for calculating the personalized annual fuel consumption and CO2 emissions from transportation. The system, named CO2NNIE, estimates the fuel consumption on the fastest route between the frequent destinations of the user. The travel time and fuel consumption estimated are based......% of the actual fuel consumption (4.6% deviation on average). We conclude, that the system provides new detailed information on CO2 emissions and fuel consumption for any make and model....

  2. Wearable CO2 sensor

    OpenAIRE

    Radu, Tanja; Fay, Cormac; Lau, King-Tong; Waite, Rhys; Diamond, Dermot

    2009-01-01

    High concentrations of CO2 may develop particularly in the closed spaces during fires and can endanger the health of emergency personnel by causing serious physiological effects. The proposed prototype provides real-time continuous monitoring of CO2 in a wearable configuration sensing platform. A commercially available electrochemical CO2 sensor was selected due to its selectivity, sensitivity and low power demand. This was integrated onto an electronics platform that performed signal capture...

  3. Interfacial Reaction and Die Attach Properties of Zn-Sn High-Temperature Solders

    Science.gov (United States)

    Kim, Seongjun; Kim, Keun-Soo; Kim, Sun-Sik; Suganuma, Katsuaki

    2009-02-01

    Interfacial reaction and die attach properties of Zn- xSn ( x = 20 wt.%, 30 wt.%, and 40 wt.%) solders on an aluminum nitride-direct bonded copper substrate were investigated. At the interface with Si die coated with Au/TiN thin layers, the TiN layer did not react with the solder and worked as a good protective layer. At the interface with Cu, CuZn5, and Cu5Zn8 IMC layers were formed, the thicknesses of which can be controlled by joining conditions such as peak temperature and holding time. During multiple reflow treatments at 260°C, the die attach structure was quite stable. The shear strength of the Cu/solder/Cu joint with Zn-Sn solder was about 30 MPa to 34 MPa, which was higher than that of Pb-5Sn solder (26 MPa). The thermal conductivity of Zn-Sn alloys of 100 W/m K to 106 W/m K was sufficiently high and superior to those of Au-20Sn (59 W/m K) and Pb-5Sn (35 W/m K).

  4. The control of stoichiometry in Epitaxial semiconductor structures. Interfacial Chemistry: Property relations. A workshop review

    Science.gov (United States)

    Bachmann, Klaus J.

    1995-01-01

    A workshop on the control of stoichiometry in epitaxial semiconductor structures was held on August 21-26, 1995 in the hotel Stutenhaus at Vesser in Germany. The secluded location of the workshop in the forest of Thuringia and its informal style stimulated extensive private discussions among the participants and promoted new contacts between young scientists from Eastern and Western Europe and the USA. Topics addressed by the presentations were interactions of precursors to heteroepitaxy and doping with the substrate surface, the control of interfacial properties under the conditions of heteroepitaxy for selected materials systems, methods of characterization of interfaces and native point defects in semiconductor heterostructures and an in depth evaluation of the present status of the control and characterization of the point defect chemistry for one specific semiconductor (ZnGeP2), including studies of both heterostructures and bulk single crystals. The selected examples of presentations and comments given here represent individual choices - made by the author to highlight major points of the discussions.

  5. Interfacial and mechanical property analysis of waste printed circuit boards subject to thermal shock.

    Science.gov (United States)

    Li, Jinhui; Duan, Huabo; Yu, Keli; Wang, Siting

    2010-02-01

    Waste printed circuit boards (PCBs) are the focal points for handling electric and electronic waste. In this paper, a thermal shock method was used to pretreat waste PCBs for the improvement of crushing performance. The influence of the thermal shock process on interfacial modification and mechanical property attenuation of PCB waste was studied. The appearance and layer spacing of the basal plane began to change slightly when the temperature reached 200 degrees C. By 250 degrees C, apparent bulging, cracking, and delamination were observed. However, pyrolysis of PCBs occurred when the temperature reached 275 degrees C, where PCBs were carbonized. The thermogravimetric analysis of PCB particles under vacuum showed that 270 degrees C was the starting point of pyrolysis. The tensile and impact strength of PCBs were reduced as shock temperature rose gradually, with a reduction by 2.6 and 16.5%, respectively, at 250 degrees C from its unheated strength. The PCBs that were heated to 250 degrees C achieved 100% liberation, increasing linearly from 13.6% for unheated PCBs through a single-level shear-crusher (2-mm mesh) and resulting in an obvious reduction of 9.5% (dB) in dust and noise at 250 degrees C. These parameters could be helpful for establishing the operational setup for industrial-scale facilities with the aim of achieving a compact process and a highly efficient recovery for waste PCBs compared with those of the traditional combination mechanical technologies.

  6. Comparative study of kinetic and interfacial properties of a novel Rhizopus oryzae lipase and ROL29

    Directory of Open Access Journals (Sweden)

    Ben Salah Riadh

    2007-11-01

    Full Text Available We compared several kinetic and interfacial properties of a lipase from a novel strain of Rhizopus oryzae (ROLw with ROL29 lipase. In contrast to ROL29, ROLw was able to hydrolyze triolein emulsion in the absence of any additive, like bovine serum albumin (BSA. Furthermore, unlike Rhizopus oryzae lipase (ROL29, kinetic study of ROLw lipase shows linear dependency when using tributyrin emulsion as substrate. ROLw can tolerate, more efficiently than ROL29, the accumulation of long-chain free fatty acids at the interface when olive oil emulsion was used as substrate. The critical surface pressure πc of penetration into phosphatidyl choline from egg yolk films was found to be 23 mN/m with ROLw, in contrast to a value of 10 mN/m obtained with ROL29. The effect of calcium ion and synthetic detergent on the two lipases was studied. In contrast to ROL29, ROLw was activated in the presence of 100 lmoles TX-100. No significant difference on the two lipase activity was observed in presence or absence of calcium ion.

  7. Influence of acetone on nanostructure and electrochemical properties of interfacial synthesized polyaniline nanofibers

    Directory of Open Access Journals (Sweden)

    Jianyun Zhao

    2015-08-01

    Full Text Available The growth of polyaniline (PANI nanofibers through interfacial polymerization can be well controlled by adding a small amount of acetone in the water/chloroform system. It was found that the polymerization rate became slower in the presence of acetone, yielding PANI nanofibers with larger aspect ratios. The influences of the acetone addition on the morphology, microstructure and properties of as-prepared PANI nanofibers were studied by scanning electron microscope (FE-SEM, ultraviolet–visible spectra (UV–vis, Fourier transform infrared (FT-IR and Raman spectroscopy, X-ray diffraction (XRD, thermogravity analysis (TGA, and electrical and electrochemical measurements. The experimental results showed that PANI nanofibers prepared by using ammonium persulfate (APS as an oxidant with acetone exhibited slower growth, the larger ratio of length to diameter, and higher crystallinity (2θ=6°, 19°, 26° than that without acetone, meanwhile remained larger yield of 11.23% and higher conductivity 1.8×10−2 S/cm compared with that obtained by replacing APS with FeCl3. More importantly, these PANI nanofibers exhibited better electrochemical behaviors, which benefitted from their high crystallinity and good conductivity.

  8. Influence of acetone on nanostructure and electrochemical properties of interfacial synthesized polyaniline nanofibers

    Institute of Scientific and Technical Information of China (English)

    Jianyun Zhao; Zongyi Qin; Tao Li; Zhuozhan Li; Zhe Zhou; Meifang Zhu

    2015-01-01

    The growth of polyaniline (PANI) nanofibers through interfacial polymerization can be well controlled by adding a small amount of acetone in the water/chloroform system. It was found that the polymerization rate became slower in the presence of acetone, yielding PANI nanofibers with larger aspect ratios. The influences of the acetone addition on the morphology, microstructure and properties of as-prepared PANI nanofibers were studied by scanning electron microscope (FE-SEM), ultraviolet–visible spectra (UV–vis), Fourier transform infrared (FT-IR) and Raman spectroscopy, X-ray diffraction (XRD), thermogravity analysis (TGA), and electrical and electrochemical measurements. The experimental results showed that PANI nanofibers prepared by using ammonium persulfate (APS) as an oxidant with acetone exhibited slower growth, the larger ratio of length to diameter, and higher crystallinity (2θ¼ 61, 191, 261) than that without acetone, meanwhile remained larger yield of 11.23% and higher conductivity 1.8 ? 10 ? 2 S/cm compared with that obtained by replacing APS with FeCl3. More importantly, these PANI nanofibers exhibited better electrochemical behaviors, which benefitted from their high crystallinity and good conductivity.

  9. Impacts of land surface properties and atmospheric CO2 on the Last Glacial Maximum climate: a factor separation analysis

    Directory of Open Access Journals (Sweden)

    G. Munhoven

    2009-06-01

    Full Text Available Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in most previous studies, we applied the separation method of U. Stein et P. Alpert 1993, in order to determine rigorously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO2 and of the vegetation cover change on the LGM climate. The separation of the ice cover and orographic contributions shows that the ice albedo effect is the main contributor to the cooling of the Northern Hemisphere, whereas orography has only a local cooling impact over the ice sheets. The expansion of ice cover in the Northern Hemisphere causes a disruption of the tropical precipitation, and a southward shift of the ITCZ. The orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere, leading to a redistribution of the precipitation, but weakly impacts the tropics. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere that further affects the tropical precipitation and reinforce the southward shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non-linear interactions that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weaker than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the south-west to

  10. Impacts of land surface properties and atmospheric CO2 on the Last Glacial Maximum climate: a factor separation analysis

    Directory of Open Access Journals (Sweden)

    G. Munhoven

    2009-01-01

    Full Text Available Many sensitivity studies have been carried out, using simplified GCMs to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in previous studies, we applied the separation method of Stein and Alpert (1993, in order to determine rigourously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO2 and of the vegetation cover change on the LGM climate. The results clearly identify the ice cover forcing as the main contributor to the cooling of the Northern Hemisphere, and also to the tropical precipitation disruption, leading to the shouthward shift of the ITCZ, while the orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere, that is further sufficient to affect the tropical precipitation and reinforce the southwards shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non linear interactions, that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weaker than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the south-west to north-east temperature gradients over Eurasia.

  11. On interfacial properties of tetrahydrofuran: Atomistic and coarse-grained models from molecular dynamics simulation

    Science.gov (United States)

    Garrido, J. M.; Algaba, J.; Míguez, J. M.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.; Piñeiro, M. M.; Blas, F. J.

    2016-04-01

    We have determined the interfacial properties of tetrahydrofuran (THF) from direct simulation of the vapor-liquid interface. The molecules are modeled using six different molecular models, three of them based on the united-atom approach and the other three based on a coarse-grained (CG) approach. In the first case, THF is modeled using the transferable parameters potential functions approach proposed by Chandrasekhar and Jorgensen [J. Chem. Phys. 77, 5073 (1982)] and a new parametrization of the TraPPE force fields for cyclic alkanes and ethers [S. J. Keasler et al., J. Phys. Chem. B 115, 11234 (2012)]. In both cases, dispersive and coulombic intermolecular interactions are explicitly taken into account. In the second case, THF is modeled as a single sphere, a diatomic molecule, and a ring formed from three Mie monomers according to the SAFT-γ Mie top-down approach [V. Papaioannou et al., J. Chem. Phys. 140, 054107 (2014)]. Simulations were performed in the molecular dynamics canonical ensemble and the vapor-liquid surface tension is evaluated from the normal and tangential components of the pressure tensor along the simulation box. In addition to the surface tension, we have also obtained density profiles, coexistence densities, critical temperature, density, and pressure, and interfacial thickness as functions of temperature, paying special attention to the comparison between the estimations obtained from different models and literature experimental data. The simulation results obtained from the three CG models as described by the SAFT-γ Mie approach are able to predict accurately the vapor-liquid phase envelope of THF, in excellent agreement with estimations obtained from TraPPE model and experimental data in the whole range of coexistence. However, Chandrasekhar and Jorgensen model presents significant deviations from experimental results. We also compare the predictions for surface tension as obtained from simulation results for all the models with

  12. Molecular level computational studies of polyethylene and polyacrylonitrile composites containing single walled carbon nanotubes: effect of carboxylic acid functionalization on nanotube-polymer interfacial properties

    Directory of Open Access Journals (Sweden)

    Shayesteh eHaghighatpanah

    2014-09-01

    Full Text Available Molecular dynamics and molecular mechanics methods have been used to investigate additive-polymer interfacial properties in single walled carbon nanotube – polyethylene and single walled carbon nanotube – polyacrylonitrile composites. Properties such as the interfacial shear stress and bonding energy are similar for the two composites. In contrast, functionalizing the single walled carbon nanotubes with carboxylic acid groups leads to an increase in these properties, with a larger increase for the polar polyacrylonitrile composite. Increasing the percentage of carbon atoms that were functionalized from 1% to 5% also leads to an increase in the interfacial properties. In addition, the interfacial properties depend on the location of the functional groups on the single walled carbon nanotube wall.

  13. Synthesis and Electrical Properties of Polyaniline/Polyaniline Grafted Multiwalled Carbon Nanotube Mixture via In Situ Static Interfacial Polymerization

    Science.gov (United States)

    2010-01-01

    Banyeon, Ulsan 689-801, South Korea 2Nanostructured and Biological Materials Branch, Materials and Manufacturing Directorate, U.S. Air Force Research...Banyeon,Ulsan 689-798, South Korea , 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR...Synthesis and Electrical Properties of Polyaniline/Polyaniline Grafted Multiwalled Carbon Nanotube Mixture via In Situ Static Interfacial

  14. The Influence of Impurities in Tungsten and Matrix Composition on the Tungsten-Matrix Interfacial Properties of Heavy Metal Alloys.

    Science.gov (United States)

    1982-10-01

    Impurities in Tungsten and Nov 79 - Nov 82 Matrix Composition on the Tungsten-Matrix Interfacial Properties of Heavy Metal Alloys 6. PERFORMING ORG. REPORT...fundamental change both in structure of the heavy metal and in fracture behaviour: The samples which were merely pre-reduced or sintered for very short...features of a satisfactory heavy metal : mainly transgranular fracture, considerable binder deformation and only rather few and small sintering necks in

  15. Investigation of anti-corrosive properties of poly(aniline-co-2-pyridylamine-co-2,3-xylidine) and its nanocomposite poly(aniline-co-2-pyridylamine-co-2,3-xylidine)/ZnO on mild steel in 0.1 M HCl

    Science.gov (United States)

    Alam, Ruman; Mobin, Mohammad; Aslam, Jeenat

    2016-04-01

    A soluble terpolymer of aniline (AN), 2-pyridylamine (PA) and 2,3-xylidine (XY), poly(AN-co-PA-co-XY) and its nanocomposite with ZnO nanoparticles namely, poly(AN-co-PA-co-XY)/ZnO were synthesized by chemical oxidative polymerization employing ammonium persulfate as an oxidant. Nanocomposites of homopolymers, polyaniline/ZnO, poly(XY)/ZnO and poly(PA)/ZnO were also synthesized by following similar synthesis route. FTIR, XRD and SEM techniques were used to characterize the synthesized compounds. The synthesized compounds were chemically deposited on mild steel specimens by solvent evaporation method using N-methyl-2-pyrrolidone (NMP) as solvent and 10% epoxy resin (by weight) as binder. Anticorrosive properties of homopolymer nanocomposites, terpolymer and its nanocomposite coatings were studied in 0.1 M HCl by subjecting them to various corrosion tests which includes: free corrosion potential measurement (OCP), weight loss measurements, potentiodynamic polarization, and AC impedance technique. The surface morphology of the corroded and uncorroded coated steel specimens was evaluated using SEM. The corrosion protection performance of terpolymer nanocomposite coating was compared to the terpolymer and individual homopolymers nanocomposites coatings after 30 days immersion in corrosive medium.

  16. Interfacial effects in multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, T.W. Jr. [Lawrence Livermore National Lab., CA (United States). Chemistry and Materials Science Dept.

    1998-12-31

    Interfacial structure and the atomic interactions between atoms at interfaces in multilayers or nano-laminates have significant impact on the physical properties of these materials. A technique for the experimental evaluation of interfacial structure and interfacial structure effects is presented and compared to experiment. In this paper the impact of interfacial structure on the performance of x-ray, soft x-ray and extreme ultra-violet multilayer optic structures is emphasized. The paper is concluded with summary of these results and an assessment of their implications relative to multilayer development and the study of buried interfaces in solids in general.

  17. 超临界CO2处理对木薯淀粉结构和性质的影响%Effects of supercritical CO2 treatment on structures and properties of cassava starch

    Institute of Scientific and Technical Information of China (English)

    白俊; 李习都; 谢新玲; 张友全

    2016-01-01

    、热稳定性变化不明显。以上结果说明:木薯淀粉经超临界CO2处理,存在淀粉分子部分降解,直链淀粉与支链淀粉比例增大等现象,从而导致淀粉的微观结构及凝胶特性等发生改变。

  18. CO2 blood test

    Science.gov (United States)

    Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum ... Many medicines can interfere with blood test results. Your health care provider will tell you if you need to stop taking any medicines before you have this test. DO ...

  19. CO2 laser resurfacing.

    Science.gov (United States)

    Fitzpatrick, R E

    2001-07-01

    The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

  20. Effect of sol–gel method on colour properties of the classical cobalt olivine (Co$_2$SiO$_4$) ceramic pigment

    Indian Academy of Sciences (India)

    M EL HADRI; H AHAMDANE; M A EL IDRISSI RAGHNI

    2017-04-01

    A sol–gel method based on (H$_2$S$_2$O$_5$)$_{aq}$ as silicon precursor in the presence of NaCl and KCl mineralizers was used for the synthesis of the classical cobalt olivine (Co2SiO4) ceramic pigment. The effect of this synthesisroute on the colour properties was studied. Highly pure olivine phase was obtained after firing at 1200$^{\\circ}$C for 3 h. The resulting powders exhibited very intense violet colour, while their addition at only 1 wt% to an industrial transparent glaze was enough to produce a very intense blue–violet colouration. Based on the aspect of glazed ceramics, addition of pigments even at 0.5 wt% to the glaze resulted in a very interesting colour and opacity. By this appropriateminimization of the used pigment amount without compromising the colouring properties required during application, the obtained Co olivine could be more efficient, less toxic and less expensive.

  1. Assessment of measurement techniques to determine the interfacial properties of bilayer dental ceramics

    Science.gov (United States)

    Anunmana, Chuchai

    The clinical success of all-ceramic dental restorations depends on the quality of interfacial bonding between ceramic layers. In addition, the residual stress in the structure that developed during ceramic processing is one of the important factors that contributes to the quality of the bond. Because all-ceramic restorations are usually fabricated as bilayer or trilayer structures and failures of all-ceramic restorations have been frequently reported as chipping or delamination of the veneer layers, the interfacial quality of bilayer dental ceramic restorations was investigated. However, most of the published bond test data reflect strength values that are inversely related to cross-sectional areas and failure locations are frequently disregarded or bond strength values are misinterpreted. In addition, residual tensile stresses that develop in the structures because of thermal expansion/contraction mismatches may also adversely affect interfacial fracture resistance. The first objective of this study was to determine the interfacial toughness of bonded bilayer ceramics using two different approaches. The results indicate that the short-bar chevron-notch test and a controlled-flaw microtensile test can induce interfacial failure that represents true bonding quality. The second objective of this study was to test the hypothesis that residual stresses estimated from an indentation technique are not significantly different from residual stresses that are calculated based on fractography and flexural strength. The indentation technique may be useful as a simplified method to determine residual stresses in bilayer dental ceramics. The results of this study demonstrate that there is no significant difference in mean residual stresses determined from the two techniques. Because of relationship between residual stresses and apparent interfacial toughness, estimates of residual stresses can now be estimated more rapidly by measuring the apparent interfacial toughness of

  2. Study on CO2 adsorption properties of tetraethylenepentamine modified mesoporous silica gel%四乙烯五胺修饰介孔硅胶吸附CO2性能的研究

    Institute of Scientific and Technical Information of China (English)

    陈琳琳; 王霞; 郭庆杰

    2015-01-01

    采用浸渍法将四乙烯五胺(TEPA)负载到介孔硅胶(SG)上,制备了一系列胺功能化的CO2吸附材料(TEPA-SG).利用傅里叶变换红外光谱(FT-IR)、热重分析(TGA)和N2吸脱附等分析方法对样品进行了表征,并在固定床反应器中考察了TEPA负载量、吸附温度对CO2吸附性能的影响,同时通过添加不同质量分数的聚乙二醇(PEG)考察了羟基对吸附性能及再生性能的促进作用.结果表明,当TEPA负载量为40%(质量分数)、吸附温度为70℃时,TEPA-SG的吸附量高达2.21 mmol/g;PEG的加入改变了氨基与CO2的相互作用机理,当TEPA与PEG的质量比为3∶1,总负载量为40%时,CO2的吸附量为2.70 mmol/g,且经过10次吸脱附循环实验后,CO2吸附量仍保持在2.66 mmol/g,表现出较好的循环稳定性.Clausius-Clapeyron方程计算得该过程的等量吸附热为30~40 kJ/mol,且随吸附量的增大等量吸附热逐渐减小,表明TEPA30/PEG10-SG吸附剂表面存在能量不均匀性.

  3. 缓冲气压对CO2激光Al靶等离子体参量的影响%Analysis of the properties of CO2 laser-induced aluminum plasma at different ambient pressures

    Institute of Scientific and Technical Information of China (English)

    吴涛; 王新兵; 唐建; 饶志明; 王少义

    2011-01-01

    为了研究缓冲气压对激光等离子体参量的影响,利用CO2激光烧蚀Al靶产生等离子体,缓冲气压变化范围为10-4pa ~2×103Pa,激光脉冲能量为180mJ/脉冲,在局域热平衡和光学薄等离子体假设下,采用发射光谱法计算了等离子体的电子温度和电子密度,并研究了缓冲气压对这些参量的影响.结果表明,等离子体的电子温度和电子密度分别在1.05eV ~2.47eV与1.95×1016cm-3~10.5×1016cm-3范围内,Al等离子体的电子温度随气压的增大而减少;低缓冲气压时,电子密度随气压增大而减小,当气压达到600Pa时,激光脉冲会击穿空气形成等离子体,电子密度又开始上升,当气压超过3000Pa时,空气等离子体会屏蔽激光脉冲能量,使到达靶面的激光能量急剧下降,Al原子的特征谱线也随之减弱而几乎消失.这一结果对理解缓冲气压对激光与物质相互作用过程的影响是有帮助的.%In order to study the properties of laser-induced plasma at different ambient pressures, emission spectroscopy was studied on aluminum plasma generated by C02 laser with energy of 180mJ/pulse at different air ambient pressures. The dependency of plasma temperature and density on ambient pressures were estimated from the analysis of spectral data by assuming the conditions of local thermodynamic equilibrium and optically thin plasma. Electron temperature was measured in the range of 1. 05eV ~2.47eV, and electron density was measured in the range of 1. 95 x 1016cm-3 ~ 10. 5 x 1016cm-3, as the ambient pressure was varied from 10-4Pa to 2 x 103Pa. The results show that the plasma temperature decreases with the ambient pressures. At first, the electron density decreases with the increase of ambient pressure under low pressure. When the pressure reaches 600Pa, the broken air plasma may interact with Al vapor and the electron density increases with the pressure increasing. For larger ambient pressure up to 3000Pa, the Al emission

  4. Fabrication of cubic spinel MnCo2O4 nanoparticles embedded in graphene sheets with their improved lithium-ion and sodium-ion storage properties

    Science.gov (United States)

    Chen, Chang; Liu, Borui; Ru, Qiang; Ma, Shaomeng; An, Bonan; Hou, Xianhua; Hu, Shejun

    2016-09-01

    Cubic Spinel MnCo2O4/graphene sheets (MCO/GS) nanocomposites are synthesized by a facile hydrothermal method with a subsequent annealing process. Nano-sized MnCo2O4 particles are evenly embedded in paper-like graphene sheets, possessing a unique nanoparticles-on-sheets hybrid nanostructure, with particle size around 20-50 nm. Owing to the special nanoparticles-on-sheets structures, MCO/GS nanocomposites have an outstanding electrochemical performance for rechargeable energy storage devices. As an anode material for lithium-ion batteries, MCO/GS electrodes exhibit high reversible discharge capacities (1350.4 mAh g-1 at the initial rate of 100 mA g-1), excellent rate capability (462.1 mAh g-1 at a current rate of 4000 mA g-1) and outstanding cycling performance (584.3 mAh g-1 at 2000 mA g-1 after 250 cycles). Meanwhile, as an anode material for sodium-ion batteries, MCO/GS electrodes also exhibit comparably promising electrochemical characteristics. Greatly improved electrochemical properties can be assigned to the special advantageous nanostructures. Besides, the existence of graphene sheets is beneficial to the transportation of ions/electrons during battery operation. The outstanding electrochemical performance demonstrates that the lithium/sodium storage capability of MCO/GS nanocomposites is highly promising for high-capacity batteries.

  5. Structural and magnetic properties of the Gd-based bulk metallic glasses GdFe2, GdCo2, and GdNi2 from first principles

    Science.gov (United States)

    Lizárraga, Raquel

    2016-11-01

    A structural and magnetic characterization of Gd-based bulk metallic glasses, GdFe2, GdCo2, and GdNi2, was performed. Models for the amorphous structures for two magnetic configurations, ferromagnetic and ferrimagnetic, were obtained by means of a first-principles-based method, the stochastic quenching. In all three cases, the ferrimagnetic configuration was energetically more stable than the ferromagnetic one, in perfect agreement with experiments. In the structural analysis, radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers were included. Structural properties are in good agreement with experiments and do not depend on the magnetic configuration. The distribution of magnetic moments shows that amorphous GdFe2 and GdCo2 are both ferrimagnets, with antiparallel alignment of the magnetic moments of the two magnetic sublattices, whereas Ni nearly loses its magnetic moment in amorphous GdNi2, similar to the situation in its crystalline counterpart.

  6. Crystal Structure and Magnetic Properties of an oxygen deficient n = 2 Ruddlesden-Popper phase Sr3Co2O5.67

    Science.gov (United States)

    Hill, Julienne M.; Mitchell, John F.; Dabrowski, Bogdan

    2006-03-01

    Interest in charge, orbital, and spin state phenomena in perovskite and related cobalt oxides is a growing area of transition metal oxide physics. Recently, J. Matsuno et al. have found that epitaxial films of the n = 1 Ruddlesden-Popper (R-P) phase Sr2CoO4 are metallic ferromagnets with relatively high TC ˜ 250 K. This is particularly interesting in light of the formal oxidation state of Co, Co^4+, offering no clear source of carriers. To extend the materials chemistry and physics of the R-P series of cobaltites, we have synthesized the n = 2 R-P phase Sr3Co2O7-δ in bulk form. The crystal structure [from neutron powder diffraction (NPD) data] of our most oxygen-deficient sample, Sr3Co2O5.67 is orthorhombic Immm with a = 3.94025(9) å, b = 3.67479(9) å and c = 20.6642(5) å. The magnetization versus temperature data show two antiferromagnetic transitions at approximately 170 K and 220 K. To further elucidate the magnetic properties of this material, we have conducted a temperature-dependent NPD study. The low temperature magnetic structure is surprisingly complex and suggestive of an incommensurate ordering wave vector. Full details and results of the NPD study will be given. J. Matsuno et al., PRL 93, 167202 (2004).

  7. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  8. Comparative study on dispersion and interfacial properties of single walled carbon nanotube/polymer composites using Hansen solubility parameters.

    Science.gov (United States)

    Ma, Jing; Larsen, Raino Mikael

    2013-02-01

    Dispersion and interfacial strain transfer of single walled carbon nanotubes (SWNTs) are two major challenges for the utilization of SWNTs as reinforcements in polymer composites. Surface modifications could help change the dispersion and interfacial properties. In this study, nanocomposites were fabricated by solution blending 1 wt % SWNTs with various modification (nonmodified, nitric acid functionalized, and amine functionalized SWNTs) and three kinds of polymeric materials (polycarbonate, polyvinylidene fluoride, and epoxy). Chemical compatibilities between SWNTs and solvents or polymers are calculated by the Hansen solubility parameters (HSP) method. The dispersion of the SWNTs in solvents is evaluated by dynamic light scattering. The dispersion of SWNTs in polymers evaluated by a light optical microscope (LOM) generally agrees with the HSP prediction. The strain transfer from the matrix to SWNTs is mainly related to the dispersion, the bundle size, the residual thermal stresses on the sample, and, to lesser degree, the HSP.

  9. Comparative Study on Dispersion and Interfacial Properties of Single Walled Carbon Nanotube/Polymer Composites Using Hansen Solubility Parameters

    DEFF Research Database (Denmark)

    Ma, Jing; Larsen, Mikael

    2013-01-01

    Dispersion and interfacial strain transfer of single walled carbon nanotubes (SWNTs) are two major challenges for the utilization of SWNTs as reinforcements in polymer composites. Surface modifications could help change the dispersion and interfacial properties. In this study, nanocomposites were...... fabricated by solution blending 1 wt % SWNTs with various modification (nonmodified, nitric acid functionalized, and amine functionalized SWNTs) and three kinds of polymeric materials (polycarbonate, polyvinylidene fluoride, and epoxy). Chemical compatibilities between SWNTs and solvents or polymers...... are calculated by the Hansen solubility parameters (HSP) method. The dispersion of the SWNTs in solvents is evaluated by dynamic light scattering. The dispersion of SWNTs in polymers evaluated by a light optical microscope (LOM) generally agrees with the HSP prediction. The strain transfer from the matrix...

  10. Properties of CO2 clathrate hydrates formed in the presence of MgSO4 solutions with implications for icy moons

    Science.gov (United States)

    Safi, E.; Thompson, S. P.; Evans, A.; Day, S. J.; Murray, C. A.; Parker, J. E.; Baker, A. R.; Oliveira, J. M.; van Loon, J. Th.

    2017-04-01

    Context. There is evidence to suggest that clathrate hydrates have a significant effect on the surface geology of icy bodies in the solar system. However the aqueous environments believed to be present on these bodies are likely to be saline rather than pure water. Laboratory work to underpin the properties of clathrate hydrates in such environments is generally lacking. Aims: We aim to fill this gap by carrying out a laboratory investigation of the physical properties of CO2 clathrate hydrates produced in weak aqueous solutions of MgSO4. Methods: We use in situ synchrotron X-ray powder diffraction to investigate clathrate hydrates formed at high CO2 pressure in ice that has formed from aqueous solutions of MgSO4 with varying concentrations. We measure the thermal expansion, density and dissociation properties of the clathrates under temperature conditions similar to those on icy solar system bodies. Results: We find that the sulphate solution inhibits the formation of clathrates by lowering their dissociation temperatures. Hysteresis is found in the thermal expansion coefficients as the clathrates are cooled and heated; we attribute this to the presence of the salt in solution. We find the density derived from X-ray powder diffraction measurements is temperature and pressure dependent. When comparing the density of the CO2 clathrates to that of the solution in which they were formed, we conclude that they should sink in the oceans in which they form. We also find that the polymorph of ice present at low temperatures is Ih rather than the expected Ic, which we tentatively attribute to the presence of the MgSO4. Conclusions: We (1) conclude that the density of the clathrates has implications for their behaviour in satellite oceans as their sinking and floating capabilities are temperature and pressure dependent; (2) conclude that the presence of MgSO4 inhibits the formation of clathrates and in some cases may even affect their structure and (3) report the dominance

  11. Interfacial microstructure and mechanical property of Ti6Al4V/A6061 dissimilar joint by direct laser brazing without filler metal and groove

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhihua, E-mail: zhsong@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, Osaka, Ibaraki 567-0047 (Japan); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education (China); Nakata, Kazuhiro [Joining and Welding Research Institute, Osaka University, Osaka, Ibaraki 567-0047 (Japan); Wu, Aiping [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education (China); Liao, Jinsun [Kurimoto Ltd., Osaka 559-0021 (Japan)

    2013-01-10

    Laser brazing of Ti6Al4V and A6061-T6 alloys with 2 mm thickness was conducted by focusing laser beam on aluminum alloy side, and the effect of laser offset distance on microstructure and mechanical properties of the dissimilar butt joint was investigated. Laser offset has a great influence on the thickness of interfacial intermetallic compound (IMC) layer and the mechanical property of joint. The thickness of interfacial IMC layer is less than 500 nm, and the average tensile strength of the joint reaches 64% of aluminum base material strength, when suitable welding conditions are used. The interfacial IMC is TiAl{sub 3}. The formation of interfacial IMC layer and its effect on mechanical property of the joint are discussed in the present study.

  12. The influence of filler on the properties of elastomeric materials based on poly(ethylene-co-propylene-co-2-ehylidene-5-norbornene rubber

    Directory of Open Access Journals (Sweden)

    Budinski-Simendić Jaroslava

    2006-01-01

    Full Text Available Crosslinked samples based on poly(ethylene-co-propylene-co-2-ehylidene5-norbornene EPDM rubber, carbon black as active filler and natural chalk as inactive filler were cured with sulphur. The content of carbon black was varied from 100 to 200 pph. The content of chalk was varied from 0 to 100 pph. The content of paraffin oil was also varied in some samples. The compounds were prepared by mixing ingredients on a laboratory two-roll mill. Vulcanizates were prepared by curing at 180°C. Various methods were used for the physical and mechanical characterizations. The dynamic mechanical properties of the elastomers were measured in the temperature range from -120 to 80°C.

  13. First-principles calculation of the effects of partial alloy disorder on the static and dynamic magnetic properties of Co2MnSi

    Science.gov (United States)

    Pradines, B.; Arras, R.; Abdallah, I.; Biziere, N.; Calmels, L.

    2017-03-01

    On the basis of fully relativistic Korringa-Kohn-Rostoker calculations and in conjunction with the coherent potential approximation and the linear response formalism, we present a complete ab initio study of the influence of alloy disorder on the static and dynamic (Gilbert damping) magnetic properties and on the electronic structure of the half-metallic full-Heusler alloy Co2MnSi . We discuss in particular partial atomic disorders intermediate between the main crystal phases L21 , B2, A2, and D03 of this alloy. We compare our results with homemade experiments and measurements from the literature, and conclude that the presence of a partial D03 -like disorder could explain the relatively high value of the Gilbert damping parameter and the lack of half-metallicity measured in real samples, in which alloy disorder cannot be totally avoided.

  14. Anomalous physical properties of Heusler-type Co2Cr (Ga,Si) alloys and thermodynamic study on reentrant martensitic transformation

    Science.gov (United States)

    Xu, Xiao; Nagasako, Makoto; Kataoka, Mitsuo; Umetsu, Rie Y.; Omori, Toshihiro; Kanomata, Takeshi; Kainuma, Ryosuke

    2015-03-01

    Electronic, magnetic, and thermodynamic properties of Co2Cr(Ga,Si) -based shape-memory alloys, which exhibit reentrant martensitic transformation (RMT) behavior, were studied experimentally. For electric resistivity (ER), an inverse (semiconductor-like) temperature dependence in the parent phase was found, along with anomalous behavior below its Curie temperature. A pseudobinary phase diagram was determined, which gives a "martensite loop" clearly showing the reentrant behavior. Differential scanning calorimetry and specific-heat measurements were used to derive the entropy change Δ S between martensite and parent phases. The temperature dependence of the derived Δ S was analyzed thermodynamically to confirm the appearances of both the RMT and normal martensitic transformation. Detailed studies on the specific heat in martensite and parent phases at low temperatures were also conducted.

  15. Static and dynamic properties of Co2FeAl thin films: Effect of MgO and Ta as capping layers

    Science.gov (United States)

    Husain, Sajid; Barwal, Vineet; Kumar, Ankit; Behera, Nilamani; Akansel, Serkan; Goyat, Ekta; Svedlindh, Peter; Chaudhary, Sujeet

    2017-05-01

    The influence of MgO and Ta capping layers on the static and dynamic magnetic properties of Co2FeAl (CFA) Heusler alloy thin films has been investigated. It is observed that the CFA film deposited with MgO capping layer is preeminent compared to the uncapped or Ta capped CFA film. In particular, the magnetic inhomogeneity contribution to the ferromagnetic resonance line broadening and damping constant are found to be minimal for the MgO capped CFA thin film i.e., 0.12±0.01 Oe and 0.0074±0.00014, respectively. The saturation magnetization was found to be 960±25emu/cc.

  16. Surface Properties of Poly[2-perfluorooctyl)ethyl acrylate] Deposited from Liquid CO2 High-Pressure Fee Meniscus Coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim,J.; Efimenko, K.; Genzer, J.; Carbonell, R.

    2007-01-01

    The surface characteristics of poly[2-(perfluorooctyl)ethyl acrylate] (PFOEA) films deposited using a high-pressure free meniscus coating (hFMC) process with liquid CO{sub 2} (l-CO{sub 2}) as the coating solvent on 12.5 cm diameter silicon wafer substrates were investigated using contact angle measurements, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy. The results were compared with surface property measurements of PFOEA films deposited from 1,1,2-trichlorotrifluoroethane (Freon 113) under normal dip coating conditions at atmospheric pressure. NEXAFS measurements showed that perfluoroalkyl groups in the films from l-CO{sub 2} and Freon 113 were well-organized and oriented normal to the substrate at the air/polymer interface. AFM images and XPS measurements revealed that a terrace-like structure of the PFOEA film from l-CO{sub 2} resulted in carbonyl group exposure at the air/polymer interface. This leads to smaller contact angles on the films cast from l-CO{sub 2} relative to the specimens deposited from Freon 113. Annealing the films deposited from the solvents resulted in droplet formation on the surface due to dewetting. The critical surface tension ({gamma}{sub c}) after annealing the film prepared from Freon 113 increased from 6.5 to 8.5 mJ/m{sup 2}, whereas {gamma}{sub c} of the film deposited from l-CO{sub 2} decreased slightly from 9.7 to 8.9 mJ/m{sup 2}. We discuss how surface morphology changes before and after annealing play a role in the variation of {gamma}{sub c}.

  17. 动力波洗涤器中碱液吸收低浓CO2的传质特性%Mass transfer properties of dilute CO2 absorption into NaOH solution in dynawave scrubber

    Institute of Scientific and Technical Information of China (English)

    占旺兵; 李秋萍; 程建伟; 邵国兴

    2012-01-01

    The experiment of dilute CO2 absorption into NaOH solution was carried out to study the gas-liquid mass transfer characteristics in a dynawave scrubber. Based on the mass transfer model of dilute CO2 absorption into NaOH solution in a packed tower, the volumetric mass transfer coefficient Kga of dilute CO2 absorption into NaOH solution and the absorption efficiency 77 in dynawave scrubber were investigated. The effects of gas flow velocity, the mass fraction of NaOH solution, and liquid-gas ratio on Kca were investigated. The result shows that Kca increases with the increase of gas flow velocity and the mass fraction of NaOH solution, but the effect of the mass fraction of NaOH solution on Kca is less than that of gas flow velocity. With the increasing of liquid-gas ratio, the Kca decreases gradually, and the C02 absorption efficiency 77 increases at the beginning, but to a certain value, the effect is not obvious. The correlations for the Kca were worked out. Based on the comprehensive effect of liquid-gas ratio on Kca and 77, it is proposed that when the diameter of scrubbing pipe is 100 mm, the mass fraction of NaOH is 10% and the operating range of liquid-gas ratio is about 0.005-0.025, the dynawave scrubber has a high mass transfer performance. It can be used as a reference for industry application.%为研究动力波洗涤器内的气液传质特性,在动力波洗涤器中,进行NaOH溶液吸收混合气体中微量CO2气体的吸收实验.参考填料塔中钠碱溶液吸收低浓气体的传质模型,测定了动力波洗涤器中NaOH溶液吸收低浓CO2的气相体积总传质系数KGα及吸收效率η.研究了气相速度、NaOH溶液质量分数及液气比对Kcα的影响,结果表明:Kcα随着气相速度及NaOH溶液质量分数的增加而增大,但NaOH溶液质量分数小于气相速度对Kca的影响;随着液气比的提高,kcα逐渐减小,η开始随着液气比的提高而增加,但到一定数值后,效果不明显;回归了Kcα的

  18. Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Teng, Baiyang

    2013-05-01

    Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.

  19. Synthesis and Properties of Reactive Interfacial Agents for Polycaprolactone-Starch Blends

    NARCIS (Netherlands)

    Sugih, Asaf K.; Drijfhout, Jan. P.; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2009-01-01

    The synthesis of two reactive interfacial agents for starch-polycaprolactone (PCL) blends, PCL-g-glycidyl methacrylate (PCL-g-GMA) and PCL-g-diethyl maleate (PCL-g-DEM) is described. The compounds were prepared by reacting a low molecular weight PCL. (M(w) 3000) with GMA or DEM in the presence of be

  20. Using maleic anhydride functionalized graphene oxide for improving the interfacial properties of carbon fiber/BMI composites

    Directory of Open Access Journals (Sweden)

    W. Li

    2016-11-01

    Full Text Available Maleic anhydride functionalized graphene oxide (MAH-GO was synthesized and then introduced into carbon fiber (CF reinforced bismaleimide (BMI composites, with the aim of improving the interfacial adhesion strength between CF and BMI resin. Various characterization techniques including Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectra (XPS and thermogravimetric analysis (TGA demonstrated that the maleic anhydride has been successfully grafted onto the GO surfaces. The study showed that the interlaminar shear strength (ILSS and flexural properties of CF/BMI composites were all improved by the incorporation of GO and MAH-GO, and the MAH-GO showed the substantially improved effect due to the strong interaction between the MAH-GO and the resin matrix. The maximum increment of the ILSS, flexural strength and flexural modulus of composites were 24.4, 28.7 and 49.7%, respectively. Scanning electron microscope (SEM photographs of the fracture surfaces revealed that the interfacial bonding between CF and resin matrix was significantly strengthened by the addition of MAH-GO. The results suggest that this feasible method may be an ideal substitute for the traditional method in the interfacial modification of composites.

  1. Effects of interfacial Fe electronic structures on magnetic and electronic transport properties in oxide/NiFe/oxide heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qianqian; Chen, Xi; Zhang, Jing-Yan [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yang, Meiyin [SKLSM, Institute of Semiconductors, CAS, P.O. Box 912, Beijing 100083 (China); Li, Xu-Jing; Jiang, Shao-Long; Liu, Yi-Wei; Cao, Yi [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Wu, Zheng-Long [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China); Feng, Chun [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Ding, Lei [School of Materials and Chemical Engineering, Hainan University, Haikou 570228 (China); Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-09-15

    Highlights: • The magnetic and transport properties of oxide/NiFe/oxide films were studied. • The oxide (SiO{sub 2}, MgO and HfO{sub 2}) has different elemental electronegativity. • Redox reaction at different NiFe/oxide interface is dependent on the oxide layer. • Different interfacial electronic structures shown by XPS influence the properties. - Abstract: We report that the magnetic and electronic transport properties in oxide/NiFe(2 nm)/oxide film (oxide = SiO{sub 2}, MgO or HfO{sub 2}) are strongly influenced by the electronic structure of NiFe/oxide interface. Magnetic measurements show that there exist magnetic dead layers in the SiO{sub 2} sandwiched film and MgO sandwiched film, whereas there is no magnetic dead layer in the HfO{sub 2} sandwiched film. Furthermore, in the ultrathin SiO{sub 2} sandwiched film no magnetoresistance (MR) is detected, while in the ultrathin MgO sandwiched film and HfO{sub 2} sandwiched film the MR ratios reach 0.35% and 0.88%, respectively. The investigation by X-ray photoelectron spectroscopy reveals that the distinct interfacial redox reactions, which are dependent on the oxide layers, lead to the variation of magnetic and transport properties in different oxide/NiFe/oxide heterostructures.

  2. Effects of surface treating methods of high-strength carbon fibers on interfacial properties of epoxy resin matrix composite

    Science.gov (United States)

    Ma, Quansheng; Gu, Yizhuo; Li, Min; Wang, Shaokai; Zhang, Zuoguang

    2016-08-01

    This paper aims to study the effects of surface treating methods, including electrolysis of anodic oxidation, sizing and heat treatment at 200 °C, on physical and chemical properties of T700 grade high-strength carbon fiber GQ4522. The fiber surface roughness, surface energy and chemical properties were analyzed for different treated carbon fibers, using atom force microscopy, contact angle, Fourier transformed infrared and X-ray photoelectron spectroscopy, respectively. The results show that the adopted surface treating methods significantly affect surface roughness, surface energy and active chemical groups of the studied carbon fibers. Electrolysis and sizing can increase the roughness, surface energy and chemical groups on surface, while heat treatment leads to decreases in surface energy and chemical groups due to chemical reaction of sizing. Then, unidirectional epoxy 5228 matrix composite laminates were prepared using different treated GQ4522 fibers, and interlaminar shear strength and flexural property were measured. It is revealed that the composite using electrolysis and sizing-fiber has the strongest interfacial bonding strength, indicating the important roles of the two treating processes on interfacial adhesion. Moreover, the composite using heat-treating fiber has lower mechanical properties, which is attributed to the decrease of chemical bonding between fiber surface and matrix after high temperature treatment of fiber.

  3. Mechanical and interfacial properties of poly(vinyl chloride) based composites reinforced by cassava stillage residue with different surface treatments

    Science.gov (United States)

    Zhang, Yanjuan; Gan, Tao; Li, Qian; Su, Jianmei; Lin, Ye; Wei, Yongzuo; Huang, Zuqiang; Yang, Mei

    2014-09-01

    Cassava stillage residue (CSR), a kind of agro-industrial plant fiber, was modified by coupling agent (CA), mechanical activation (MA), and MA-assisted CA (MACA) surface treatments, respectively. The untreated and different surface treated CSRs were used to prepare plant fibers/polymer composites (PFPC) with poly(vinyl chloride) (PVC) as polymer matrix, and the properties of these CSR/PVC composites were compared. Surface treated CSR/PVC composites possessed better mechanical properties, water resistance and dimensional stability compared with the untreated CSR/PVC composite, attributing to the improvement of interfacial properties between CSR and PVC matrix. MACA-treated CSR was the best reinforcement among four types of CSRs (untreated, MA-treated, CA-treated, and MACA-treated CSRs) because MACA treatment led to the significant improvement of dispersion, interfacial adhesion and compatibility between CSR and PVC. MACA treatment could be considered as an effective and green method for enhancing reinforcement efficiency of plant fibers and the properties of PFPC.

  4. Influence of primary crystallisation conditions on the mechanical and interfacial properties of micronised budesonide for dry powder inhalation.

    Science.gov (United States)

    Kubavat, Harshal A; Shur, Jagdeep; Ruecroft, Graham; Hipkiss, David; Price, Robert

    2012-07-01

    Investigate the influence of primary crystallisation conditions on the mechanical properties and secondary processing behaviour of budesonide for dry powder inhaler (DPI) formulations. Young's modulus of two batches of budesonide crystals (samples A and B) produced using different anti-solvents was determined using nanoindentation. Physicochemical and surface interfacial properties via the cohesive-adhesive balance (CAB) approach to colloid probe atomic force microscopy (AFM) of air-jet micronised budesonide crystals were also investigated. These data were correlated to in vitro aerosolization performance of carrier-based DPI formulations containing either budesonide samples A or B and lactose monohydrate. Young's modulus of budesonide samples A and B crystals was 0.95 and 4.04 GPa, respectively. Sample A crystals with low Young's modulus exhibited poorer micronisation efficiency than sample B. CAB analysis of micronised budesonide samples A and B, suggest that sample B budesonide had a greater adhesion to lactose than sample A. These data correlated with in vitro aerosolisation studies, which showed that the fine particle delivery of budesonide sample A was higher than that of sample B. In conclusion, crystallisation conditions may affect the mechanical properties of budesonide, and therefore secondary processing of the material and their interfacial properties and product performance in carrier based DPI formulations. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Volume dependence of magnetic properties in Co2Cr1-xYx Ga (Y=Ti-Ni) Heusler alloys: A first-principles study

    Science.gov (United States)

    Gonçalves, J. N.; Fortunato, N. M.; Amaral, J. S.; Amaral, V. S.

    2017-04-01

    The magnetic properties tuning and volume dependence in the series of quaternary full Heusler alloys with formula Co2Cr1-xYx Ga (Y=Ti, V, Mn, Fe, Co, Ni) were studied with a detailed first-principles exploration. We employ the density functional KKR method with the coherent potential approximation, estimating effective Heisenberg exchange constants via the magnetic force theorem together with mean-field Curie temperature (TC) and magnetic moment for compositions in the whole concentration range. The volumetric dependency of these magnetic properties is studied, particularly the pressure derivatives of TC at equilibrium. Our ternary alloy calculations show good agreement with local-density and generalized gradient approximations in the literature. The quaternary alloys show a wide range of tunable magnetic properties, where magnetic moments range from 0.8 to 4.9 μB, TC from 130 K to 1250 K, and dTC / dV values range from -7 to + 6.3 KÅ-3 .

  6. Experimental studies on the surface and interfacial properties of polysiloxanes and their interaction with blood proteins

    Science.gov (United States)

    Stuart, James Oliver

    1998-12-01

    The research in this thesis is concerned with the surface and interfacial properties of polysiloxanes and their interaction with blood proteins, particularly fibrinogen. Polysiloxane properties at the polymer/air interface were investigated using secondary ion mass spectrometry (SIMS) and contact angle measurements. Polysiloxane properties at the polymer/water interface were studied using a Langmuir film balance. Interaction with blood proteins was investigated by SIMS and by aggregation studies of polysiloxanes emulsified in the presence of various blood components, namely serum, plasma, and fibrinogen solution upon exposure to the enzyme thrombin. Poly(dimethylsiloxane) (PDMS), poly(phenylmethylsiloxane) (PPMS), and poly(trifluoropropylmethylsiloxane) (PTFPMS) homopolymers and diblock copolymers thereof were studied using SIMS and contact angle measurements. Also studied were a newly synthesized series of random copolymers of poly(methyl(methyl undecanoate)siloxane)-co-poly(dimethylsiloxane) (PMMUS). Key findings include the resolution of discrepancies in SIMS mass fragment assignments in PDMS and establishment of mass peak assignments for PPMS, PTFPMS, and PMMUS. Also, it was shown by SIMS that complete surface saturation of the siloxane components of solution casts films of PDMS/PS and PTFPMS/PS diblock copolymers and blends with PS was achieved at siloxane concentrations as low as 2.0 percent by weight. On the other hand, PPMS/PS diblock copolymers show signature peaks of both polymers at siloxane concentrations as high as 51 percent by weight. All results correspond well with contact angle measurements on the same systems. Finally, the detection of trimethylsilyl end-groups was determined through systemic variation of chain termini and polymer molecular weight. The monolayer behavior of the PMMUS copolymer series of the siloxanes containing cholesteryl ester side-groups was examined using a langmuir film balance. The isotherms of the PMMUS polymers showed

  7. CO2-strategier

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2008-01-01

    I 2007 henvendte Lyngby-Taarbæk kommunens Agenda 21 koordinator sig til Videnskabsbutikken og spurgte om der var interesse for at samarbejde om CO2-strategier. Da Videnskabsbutikken DTU er en åben dør til DTU for borgerne og deres organisationer, foreslog Videnskabsbutikken DTU at Danmarks...... Naturfredningsforening’s lokalkomité for Lyngby blev en del af samarbejdet for at få borgerne i kommunen involveret i arbejdet med at udvikle strategier for reduktion af CO2. Siden sommeren 2007 har Videnskabsbutikken DTU, Lyngby-Taarbæk kommune og Danmarks Naturfredningsforening i Lyngby-Taarbæk samarbejdet om analyse...... og innovation i forhold til CO2-strategier....

  8. Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

    KAUST Repository

    Ma, Hongbin

    2016-01-01

    In this work, we accurately measure the electrical properties of individual Fe30Co61Cu9/Cu multilayered nanowires using nanomanipulators in in situ scanning electron microscopy to reveal that interfacial transition layers are influential in determining their transport behaviors. We investigate the morphology, crystal structure and chemistry of the Fe30Co61Cu9/Cu multilayered nanowires to characterize them at the nanoscale. We also compare the transport properties of these multilayered nanowires to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed analysis of the electrical data reveals that interfacial transition layers influence the electrical properties of multilayered nanowires and are likely to have a strong impact on the life of nanodevices. This work contributes to a basic understanding of the electrical parameters of individual magnetic multilayered nanowires for their application as functional building blocks and interconnecting leads in nanodevices and nanoelectronics, and also provides a clear physical picture of a single multilayered nanowire which explains its electrical resistance and its source of giant magnetoresistance. © The Royal Society of Chemistry 2016.

  9. Inverse analysis determining interfacial properties between metal film and ceramic substrate with an adhesive layer

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhao; Yueguang Wei

    2008-01-01

    In the present study, peel tests and inverse analysis were performed to determine the interfacial mechanical parameters for the metal film/ceramic system with an epoxy interface layer between film and ceramic. Al films with a series of thicknesses between 20 and 250μm and three peel angles of 90°,135°and 180°were considered. A finite element model with the cohesive zone elements was used to simulate the peeling process. The finite element results were taken as the training data of a neural network in the inverse analysis. The interfacial cohesive energy and the separation strength can be determined based on the inverse analysis and peel experimental result

  10. Fabrication of interfacial functionalized porous polymer monolith and its adsorption properties of copper ions.

    Science.gov (United States)

    Han, Jiaxi; Du, Zhongjie; Zou, Wei; Li, Hangquan; Zhang, Chen

    2014-07-15

    The interfacial functionalized poly (glycidyl methacrylate) (PGMA) porous monolith was fabricated and applied as a novel porous adsorbent for copper ions (Cu(2+)). PGMA porous material with highly interconnected pore network was prepared by concentrated emulsion polymerization template. Then polyacrylic acid (PAA) was grafted onto the interface of the porous monolith by the reaction between the epoxy group on PGMA and a carboxyl group on PAA. Finally, the porous monolith was interfacial functionalized by rich amount of carboxyl groups and could adsorb copper ions effectively. The chemical structure and porous morphology of the porous monolith were measured by Fourier transform infrared spectroscopy and scanning electron microscopy. Moreover, the effects of pore size distribution, pH value, co-existing ions, contacting time, and initial concentrations of copper ions on the adsorption capacity of the porous adsorbents were studied.

  11. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    KAUST Repository

    Kong, X.

    2012-11-03

    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  12. Interfacial (o/w) properties of naphthetic acids and metal naphthenates, naphtenic acid characterization and metal naphthenate inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Brandal, Oeystein

    2005-07-01

    Deposition of metal naphthenates in process facilities is becoming a huge problem for petroleum companies producing highly acidic crudes. In this thesis, the main focus has been towards the oil-water (o/w) interfacial properties of naphthenic acids and their ability to react with different divalent cations across the interface to form metal naphthenates. The pendant drop technique was utilized to determine dynamic interfacial tensions (IFT) between model oil containing naphthenic acid, synthetic as well as indigenous acid mixtures, and pH adjusted water upon addition of different divalent cations. Changes in IFT caused by the divalent cations were correlated to reaction mechanisms by considering two reaction steps with subsequent binding of acid monomers to the divalent cation. The results were discussed in light of degree of cation hydration and naphthenic acid conformation, which affect the interfacial conditions and thus the rate of formation of 2:1 complexes of acid and cations. Moreover, addition of non-ionic oil-soluble surfactants used as basis compounds in naphthenate inhibitors was found to hinder a completion of the reaction through interfacial dilution of the acid monomers. Formation and stability of metal naphthenate films at o/w interfaces were studied by means of Langmuir technique with a trough designed for liquid-liquid systems. The effects of different naphthenic acids, divalent cations, and pH of the subphase were investigated. The results were correlated to acid structure, cation hydration, and degree of dissociation, which all affect the film stability against compression. Naphthenic acids acquired from a metal naphthenate deposit were characterized by different spectroscopic techniques. The sample was found to consist of a narrow family of 4-protic naphthenic acids with molecular weights around 1230 g/mol. These acids were found to be very o/w interfacially active compared to normal crude acids, and to form Langmuir monolayers with stability

  13. Effects of surface treating methods of high-strength carbon fibers on interfacial properties of epoxy resin matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Quansheng; Gu, Yizhuo, E-mail: benniegu@buaa.edu.cn; Li, Min; Wang, Shaokai; Zhang, Zuoguang

    2016-08-30

    Highlights: • Effects of surface treating on T700 grade high strength carbon fiber were discussed. • The fiber surface roughness, surface energy and chemical properties are analyzed. • The surface treating significantly affect the properties of carbon fiber. • The composite with electrolysis and sizing-fiber has the highest mechanical properties. - Abstract: This paper aims to study the effects of surface treating methods, including electrolysis of anodic oxidation, sizing and heat treatment at 200 °C, on physical and chemical properties of T700 grade high-strength carbon fiber GQ4522. The fiber surface roughness, surface energy and chemical properties were analyzed for different treated carbon fibers, using atom force microscopy, contact angle, Fourier transformed infrared and X-ray photoelectron spectroscopy, respectively. The results show that the adopted surface treating methods significantly affect surface roughness, surface energy and active chemical groups of the studied carbon fibers. Electrolysis and sizing can increase the roughness, surface energy and chemical groups on surface, while heat treatment leads to decreases in surface energy and chemical groups due to chemical reaction of sizing. Then, unidirectional epoxy 5228 matrix composite laminates were prepared using different treated GQ4522 fibers, and interlaminar shear strength and flexural property were measured. It is revealed that the composite using electrolysis and sizing-fiber has the strongest interfacial bonding strength, indicating the important roles of the two treating processes on interfacial adhesion. Moreover, the composite using heat-treating fiber has lower mechanical properties, which is attributed to the decrease of chemical bonding between fiber surface and matrix after high temperature treatment of fiber.

  14. Predicting CO2-H2O Interfacial Tension Using COSMO-RS

    DEFF Research Database (Denmark)

    Silvestri, Alessandro; Stipp, Susan Louise Svane; Andersson, Martin Peter

    2017-01-01

    have studied the effect of the environmental variables on the IFT in the CO2–H2O system. However, experimental measurements above CO2 supercritical conditions are scarce and sometimes contradictory. Molecular modeling is a valuable tool for complementing experimental IFT determination, and it can help......Knowledge about the interaction between fluids and solids and the interfacial tension (IFT) that results is important for predicting behavior and properties in industrial systems and in nature, such as in rock formations before, during, and after CO2 injection for long-term storage. Many authors...... us interpret results and gain insight under conditions where experiments are difficult or impossible. Here, we report predictions for CO2–water interfacial tension performed using density functional theory (DFT) combined with the COSMO-RS implicit solvent model. We predicted the IFT dependence...

  15. Advanced Technologies for Monitoring CO2 Saturation and Pore Pressure in Geologic Formations: Linking the Chemical and Physical Effects to Elastic and Transport Properties

    Energy Technology Data Exchange (ETDEWEB)

    Mavko, G.; Vanorio, T.; Vialle, S.; Saxena, N.

    2014-03-31

    advection: because of an efficient mass transfer of reactants and products, the fluid remains acidic, far from thermodynamical equilibrium and the dissolution of calcite is important. These conclusions are consistent with the lab observations. Sandstones from the Tuscaloosa formation in Mississippi were also subjected to injection under representative in situ stress and pore pressure conditions. Again, both P- and S-wave velocities decreased with injection. Time-lapse SEM images indicated permanent changes induced in the sandstone microstructure by chamosite dissolution upon injection of CO2-rich brine. After injection, the sandstone showed an overall cleaner microstructure. Two main changes are involved: (a) clay dissolution between grains and at the grain contact and (b) rearrangement of grains due to compaction under pressure Theoretical and empirical models were developed to quantify the elastic changes associated with injection. Permanent changes to the rock frame resulted in seismic velocity-porosity trends that mimic natural diagenetic changes. Hence, when laboratory measurments are not available for a candidate site, these trends can be estimated from depth trends in well logs. New theoretical equations were developed to predict the changes in elastic moduli upon substitution of pore-filling material. These equations reduce to Gassmann’s equations for the case of constant frame properties, low seismic frequencies, and fluid changes in the pore space. The new models also predict the change dissolution or precipitation of mineral, which cannot be described with the conventional Gassmann theory.

  16. Reservoir quality and petrophysical properties of Cambrian sandstones and their changes during the experimental modelling of CO2 storage in the Baltic Basin

    Directory of Open Access Journals (Sweden)

    Kazbulat Shogenov

    2015-08-01

    Full Text Available The objectives of this study were (1 to review current recommendations on storage reservoirs and classify their quality using experimental data of sandstones of the Deimena Formation of Cambrian Series 3, (2 to determine how the possible CO2 geological storage (CGS in the Deimena Formation sandstones affects their properties and reservoir quality and (3 to apply the proposed classification to the storage reservoirs and their changes during CGS in the Baltic Basin. The new classification of the reservoir quality of rocks for CGS in terms of gas permeability and porosity was proposed for the sandstones of the Deimena Formation covered by Lower Ordovician clayey and carbonate cap rocks in the Baltic sedimentary basin. Based on permeability the sandstones were divided into four groups showing their practical usability for CGS (‘very appropriate’, ‘appropriate’, ‘cautionary’ and ‘not appropriate’. According to porosity, eight reservoir quality classes were distinguished within these groups. The petrophysical, geochemical and mineralogical parameters of the sandstones from the onshore South Kandava and offshore E6 structures in Latvia and the E7 structure in Lithuania were studied before and after the CO2 injection-like alteration experiment. The greatest changes in the composition and properties were determined in the carbonate-cemented sandstones from the uppermost part of the South Kandava onshore structure. Partial dissolution of pore-filling carbonate cement (ankerite and calcite and displacement of clay cement blocking pores caused significant increase in the effective porosity of the samples, drastic increase in their permeability and decrease in grain and bulk density, P- and S-wave velocity, and weight of the dry samples. As a result of these alterations, carbonate-cemented sandstones of initially ‘very low’ reservoir quality (class VIII, ‘not appropriate’ for CGS, acquired an ‘appropriate’ for CGS

  17. CO2-neutral fuels

    Science.gov (United States)

    Goede, A. P. H.

    2015-08-01

    The need for storage of renewable energy (RE) generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G) scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel cycle is

  18. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available The need for storage of renewable energy (RE generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel

  19. Quantification of 16S gene and its relation with the CO2 emission and soil properties in areas under management of sugarcane (Saccharum spp.)

    Science.gov (United States)

    Moitinho, Mara Regina; da Silva Bicalho, Elton; De Bortoli Teixeira, Daniel; La Scala, Newton, Jr.

    2015-04-01

    A diversity of microorganisms has an essential role in the recycling of soil chemical elements, controlling, for example, the dynamics of carbon de)ion and stabilization, and consequently the patterns of soil CO2 emission. In this sense, the objectives of this study were: (i) to estimate and compare the genetic diversity of microorganisms in soils under different sugarcane (Saccharum spp.) managements using molecular techniques based on metagenomic studies, and (ii) investigate the relationship of soil CO2 emission (FCO2) with microbiological results and soil chemical and physical properties in the evaluated managements. This study was conducted in agricultural areas located in southern Brazil, in which the following sugarcane managements were used: green and burned residues management, a sugarcane area under reform, and a native forest (used as a reference of the original soil condition). FCO2, soil temperature, and soil moisture were measured over 10 days, and at the end of the measurements soil samples were taken in order to determine the physical and chemical soil properties. The determination of the diversity of soil microorganisms was carried out by means of molecular techniques based on 16S rRNA gene sequencing. The highest mean value for FCO2 (3.25 μmol m-2s-1) was observed in the sugarcane area under reform, and the lowest values (1.85 and 1.27 μmol m-2s-1) were observed respectively in the green residue management and native forest areas. This same pattern was also observed when the 16S gene was quantified. In this case, the largest number of copies of this gene was found in the sugarcane area under reform (4.3x1010 copies of 16S rRNA gene per gram of dry soil), and its smallest number of copies was found in the green residues management area (1.7x1010 copies of 16S rRNA gene per gram of dry soil). The largest number of copies of the 16S gene associated to the highest values of FCO2, both observed in the sugarcane area under reform, could be related to

  20. Properties of nitrogen fertilization are decisive in determining the effects of elevated atmospheric CO2 on the activity of nitrate reductase in plants.

    Science.gov (United States)

    Zhang, Ranran; Du, Shaoting

    2016-01-01

    The concentration of atmospheric CO2 is predicted to double by the end of this century. The response of higher plants to an increase in atmospheric CO2 often includes a change in nitrate reductase (NR) activity. In a recent study, we showed that, under elevated CO2 levels, NR induction in low-nitrate plants and NR inhibition in high-nitrate plants are regulated by nitric oxide (NO) generated via nitric oxide synthases. This finding provides an explanation for the diverse responses of plants to elevated CO2 levels, and suggests that the use of nitrogen fertilizers on soil will have a major influence on the nitrogen assimilation capacity of plants in response to CO2 elevation.

  1. Influence of oxidation temperature on the interfacial properties of n-type 4H-SiC MOS capacitors

    Science.gov (United States)

    Jia, Yifan; Lv, Hongliang; Song, Qingwen; Tang, Xiaoyan; Xiao, Li; Wang, Liangyong; Tang, Guangming; Zhang, Yimen; Zhang, Yuming

    2017-03-01

    The effect of oxidation temperature on interfacial properties of n-type 4H-SiC metal-oxide-semiconductor capacitors has been systematically investigated. Thermal dry oxidation process with three different oxidation temperatures 1200 °C, 1300 °C and 1350 °C were employed to grow SiO2 dielectric, following by the standard post-oxidation annealing (POA) in NO ambience at 1175 °C for 2 h. The root mean square (RMS) roughness measured by Atomic Force Microscopy for the thermally grown SiO2 before POA process is reduced with increasing the oxidation temperature, obtaining an atomically flat surface with a RMS of 0.157 nm from the sample oxidized at 1350 °C. Several kinds of electrical measurements were used to evaluate the densities of near interface traps and effective fixed dielectric charge for the samples, exhibiting a trend reduced with increasing the oxidation temperature. The interface state density of 3 × 1011 cm-2eV-1 at 0.2 eV from the conduction band edge was achieved from conductance method measurement for the sample oxidized at 1350 °C. The results from Secondary Ion Mass Spectroscopy and X-ray Photoelectron Spectroscopy demonstrate that high oxidation temperature can reduce the width of transition layer, the excess Si and silicon suboxide compositions near the interface, leading to effective improvement of the interfacial properties.

  2. Investigating the use of coupling agents to improve the interfacial properties between a resorbable phosphate glass and polylactic acid matrix.

    Science.gov (United States)

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew J; Rudd, Chris D; Walker, Gavin S; Scotchford, Colin A

    2013-09-01

    Eight different chemicals were investigated as potential candidate coupling agents for phosphate glass fibre reinforced polylactic acid composites. Evidence of reaction of the coupling agents with phosphate glass and their effect on surface wettability and glass degradation were studied along with their principle role of improving the interface between glass reinforcement and polymer matrix. It was found that, with an optimal amount of coupling agent on the surface of the glass/polymer, interfacial shear strength improved by a factor of 5. Evidence of covalent bonding between agent and glass was found for three of the coupling agents investigated, namely: 3-aminopropyltriethoxysilane; etidronic acid and hexamethylene diisocyanate. These three coupling agents also improved the interfacial shear strength and increased the hydrophobicity of the glass surface. It is expected that this would provide an improvement in the macroscopic properties of full-scale composites fabricated from the same materials which may also help to retain these properties for the desired length of time by retarding the breakdown of the fibre/matrix interface within these composites.

  3. CO2 adsorption isotherm on clay minerals and the CO2 accessibility into the clay interlayer

    Science.gov (United States)

    Gensterblum, Yves; Bertier, Pieter; Busch, Andreas; Rother, Gernot; Krooß, Bernhard

    2013-04-01

    Large-scale CO2 storage in porous rock formations at 1-3 km depth is seen as a global warming mitigation strategy. In this process, CO2 is separated from the flue gas of coal or gas power plants, compressed, and pumped into porous subsurface reservoirs with overlying caprocks (seals). Good seals are mechanically and chemically stable caprocks with low porosity and permeability. They prevent leakage of buoyant CO2 from the reservoir. Caprocks are generally comprised of thick layers of shale, and thus mainly consist of clay minerals. These clays can be affected by CO2-induced processes, such as swelling or dissolution. The interactions of CO2 with clay minerals in shales are at present poorly understood. Sorption measurements in combination scattering techniques could provide fundamental insight into the mechanisms governing CO2-clay interaction. Volumetric sorption techniques have assessed the sorption of supercritical CO2 onto coal (Gensterblum et al., 2010; Gensterblum et al., 2009), porous silica (Rother et al., 2012a) and clays as a means of exploring the potential of large-scale storage of anthropogenic CO2 in geological reservoirs (Busch et al., 2008). On different clay minerals and shales, positive values of excess sorption were measured at gas pressures up to 6 MPa, where the interfacial fluid is assumed to be denser than the bulk fluid. However, zero and negative values were obtained at higher densities, which suggests the adsorbed fluid becomes equal to and eventually less dense than the corresponding bulk fluid, or that the clay minerals expand on CO2 charging. Using a combination of neutron diffraction and excess sorption measurements, we recently deduced the interlayer density of scCO2 in Na-montmorillonite clay in its single-layer hydration state (Rother et al., 2012b), and confirmed its low density, as well as the expansion of the basal spacings. We performed neutron diffraction experiments at the FRMII diffractometer on smectite, kaolinite and illite

  4. Structure, Optical Properties, and Photocatalytic Activity towards H2 Generation and CO2 Reduction of GaN Nanowires via Vapor-Liquid-Solid Process

    Directory of Open Access Journals (Sweden)

    Hong Pang

    2014-01-01

    Full Text Available High quality single crystalline GaN nanowires with large aspect ratio (>100 are synthesized on n-type Si (111 substrate via Au-catalyzed vapor-liquid-solid process. Morphology, crystal structure, and optical property of the as-synthesized GaN nanowires are characterized by means of X-ray diffraction, scanning/transmission electron microscopy, UV-vis diffuse reflection spectroscopy, and room temperature photoluminescence. The results indicate that the as-prepared GaN nanowires with a large aspect ratio are well crystallized in the hexagonal wurtzite structure, and a slight blue shift appears in both the absorption edge and emission peak probably due to the quantization effect. Photocatalytic H2 evolution over the as-prepared GaN nanowires is performed with the incorporation of Pt or Rh as the cocatalyst, exhibiting greatly enhanced capability compared to the GaN powder tested under the same conditions. Moreover, photocatalytic CO2 reduction over the GaN nanowires is also successfully realized using Pt or Rh as the cocatalyst, depending on which the products show a strong selectivity inherently related to the reductive electrons transferred by cocatalyst.

  5. Influence of magnesium content on structure and electrochemical properties of La1-xMgxNi1.75Co2.05hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    蔡鑫; 魏范松; 胥小丽; 张玉

    2016-01-01

    La1–xMgxNi1.75Co2.05 (x=0.07, 0.08, 0.10, 0.13, 0.15) alloys were prepared by high-frequency inductive method, and then their structure and electrochemical properties were investigated systematically. The XRD analysis revealed that the alloys consisted of LaNi5 phase and La4MgNi19 (Ce5Co19+ Pr5Co19) phase, and the introduction of Mg could promote the formation of La4MgNi19phase. The observation of microstructure showed that all the alloys processed dendritic structure, which was refined with the increase ofx value. The electrochemical measurements showed that all the alloys could be activated within 2 cycles, and with increasingx, the maximum discharge capacity obviously increased from 254.00 mAh/g (x=0.07) to 351.51 mAh/g (x=0.15), but the cycling stability (S80) decreased somehow from 78.4% to 73.9%. Meanwhile, the appropriate addition of Mg could improve the high-rate discharge capacity (HRD) of the alloy electrodes, which was mainly controlled by the electrochemical reaction rate on the surface of the alloys.

  6. Study on Properties of TBP-HNO3 Complex Used for Direct Dissolution of Lanthanide and Actinide Oxides in Supercritical Fluid CO2

    Institute of Scientific and Technical Information of China (English)

    DUAN Wu-Hua; ZHU Li-Yang; JING Shan; ZHU Yong-Jun; CHEN Jing

    2007-01-01

    The tri-n-butyl phosphate-nitric acid (TBP-HNO3) complex prepared by contacting the pure TBP with the concentrated HNO3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide (SCF-CO2). Properties of the TBP-HNO3 complex have been studied. Experimental results showed that when the initial HNO3/TBP volume ratio was varied from 1 : 7 to 5 : 1, the concentration of HNO3 in the TBP-HNO3 complex changed from 1.95 to 5.89 mol/L, the [HNO3]/[TBP] ratio of the TBP-HNO3 complex changed from 0.61 to 2.22, and the content of H2O in the TBP-HNO3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO3 complex changed with the concentration of HNO3 in the complex, and were higher than those of the pure TBP. The protons of HNO3 and H2O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO3 were formed that can be detected by NMR.

  7. Properties of TRPO-HNO3 complex used for direct dissolution of lanthanide and actinide oxides in supercritical fluid CO2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The mixed trialkylphosphine oxide-nitric acid (TRPO-HNO3) complex prepared by contacting pure TRPO with concentrated HNO3 may be used as additives for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide (SCF-CO2). Properties of the TRPO-HNO3 complex have been studied. Experimental results show when the initial HNO3/TRPO volume ratio is varied from 1:7 to 5:1, the concentration of HNO3 in the TRPO-HNO3 complex changes from 2.12 to 6.16 mol/L, the [HNO3]/[TRPO] ratio of the TRPO-HNO3 complex changes from 0.93 to 3.38, and the content of H2O in the TRPO-HNO3 complex changes from 0.97% to 2.70%. All of the density, viscosity and surface tension of the TRPO-HNO3 complex change with the concentration of HNO3 in the complex. The protons of HNO3 and H2O in the complex undergo rapid exchange to exhibit a singlet resonance peak in NMR spectra with D2O insert. When the TRPO-HNO3 complex dissolves in a low dielectric constant solvent, small droplets of HNO3 appear which can be detected by NMR.

  8. Facile preparation of novel dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes for excellent capacitive property in asymmetric supercapacitors

    Science.gov (United States)

    Liu, Li; Zhang, Huijuan; Fang, Ling; Mu, Yanping; Wang, Yu

    2016-09-01

    In this work, we successfully synthesized the dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes (Fe-NCO-M@N-1h) using a facile hydrothermal method, followed by calcinations. In the unique structure, numerous nanoneedles radially grow on the surface of microsphere and some porous nanomeshes orderly develop in the inside of microsphere, therefore dandelion-like Fe-NCO-M@N-1h displays large specific surface area (101.15 m2 g-1) and more active sites. Electrochemical properties of the Fe-NCO-M@N-1h have been tested for symmetric supercapacitors (SCs) and asymmetric supercapacitors (ASCs). Benefiting from the structural advantages, Fe-NCO-M@N-1h electrode exhibits outstanding capacitive behaviors, such as the desirable specific capacitance and eminent rate performance (2237 and 1810 F g-1 at the current densities of 1 and 20 A g-1, respectively) and remarkable cycling performance (95.8% retention after 4500 cycles). Besides, a Fe-NCO-M@N-1h//AC-ASCs device has been constructed successfully, presenting the highest energy density of 46.68 Wh kg-1. The results indicate that the Fe-NCO-M@N-1h is a potential material for SCs.

  9. Effect of d-block element Co2+ substitution on structural, Mössbauer and dielectric properties of spinel copper ferrites

    Science.gov (United States)

    Dar, M. A.; Varshney, Dinesh

    2017-08-01

    The present work focuses on the influence of replacement of d-block element Cu2+ ion by Co2+ in Cu-spinel ferrites [Cu1-xCoxFe2O4 (x = 0.0, 0.1, 0.2, 0.4, 0.6, and 1.0)] on the structural, vibrational and dielectric properties as synthesized by Solid-state reaction route. A structural transition from tetragonal (space group I41/amd)) to cubic (space group Fd3m) phase is observed due to introduction of cobalt. Cubic spinel- type structure at room temperature of Cu1-xCoxFe2O4 (0.4 ≤ x ≤ 1.0) is confirmed by Rietveld - refined X-ray powder diffraction patterns. Raman spectroscopic studies reveal 2 (5) optical active modes in CuFe2O4 (CoFe2O4) at room temperature. Transmission Mössbauer spectroscopy of Cu1-xCoxFe2O4 (x = 0.0, 0.2 and 0.6) shows two sets of six-line hyperfine patterns for all the three samples, indicating the presence of Fe in both A and B sites. Identification of sites is accomplished by evidence from hyperfine distribution and isomer-shift data. Dielectric constant and dielectric loss tangent measured in the frequency range from 1 KHz to 1 MHz at room temperature are found to be decreasing with the increase in frequency.

  10. Mechanical properties and interfacial characteristics of carbon-nanotube-reinforced epoxy thin films

    Science.gov (United States)

    Xu, Xiaojing; Thwe, Moe Moe; Shearwood, Christopher; Liao, Kin

    2002-10-01

    Multiwalled carbon nanotubes (MWNT) reinforced epoxy composite thin films were prepared by a microfabrication process and their elastic modulus was determined using a shaft-loaded blister test and linear and nonlinear elasticity models. Compared to net resin thin films, a 20% increase in elastic modulus was seen when 0.1 wt % MWNTs were added, suggesting MWNT alignment by spin coating. Electron microscopic observations of the fracture surfaces suggested high interfacial shear stress between MWNTs and the epoxy matrix, a result supported by both molecular mechanics simulation and micromechanics calculations.

  11. Properties of Ultra-Thin Hafnium Oxide and Interfacial Layer Deposited by Atomic Layer Deposition

    Institute of Scientific and Technical Information of China (English)

    Taeho Lee; Young-Bae Kim; Kyung-Il Hong; Duck-Kyun Choi; Jinho Ahn

    2004-01-01

    Ultra-thin hafnium-oxide gate dielectric films deposited by atomic layer deposition technique using HfCl4 and H2O precursor on a hydrogen-terminated Si substrate were investigated. X-ray photoelectron spectroscopy indicates that the interface layer is Hf-silicate rather than phase separated Hf-silicide and silicon oxide structure. The Hf-silicate interfacial layer partially changes into SiOx after high temperature annealing, resulting in a complex HfO2-silicate-SiOx dielectric structure. Electrical measurements confirms that HfO2 on Si is stable up to 700 ℃ for 30 s under N2 ambient.

  12. SiC-Si interfacial thermal and mechanical properties of reaction bonded SiC/Si ceramic composites

    Science.gov (United States)

    Hsu, Chun-Yen; Deng, Fei; Karandikar, Prashant; Ni, Chaoying

    Reaction bonded SiC/Si (RBSC) ceramic composites are broadly utilized in military, semiconductor and aerospace industries. RBSC affords advanced specific stiffness, hardness and thermal. Interface is a key region that has to be considered when working with any composites. Both thermal and mechanical behaviors of the RBSC are highly dependent on the SiC-Si interface. The SiC-Si interface had been found to act as a thermal barrier in restricting heat transferring at room temperature and to govern the energy absorption ability of the RBSC. However, up to present, the role of the SiC-Si interface to transport heat at higher temperatures and the interfacial properties in the nanoscale have not been established. This study focuses on these critically important subjects to explore scientific phenomena and underlying mechanisms. The RBSC thermal conductivity with volume percentages of SiC at 80 and 90 vol% was measured up to 1,200 °C, and was found to decrease for both samples with increasing environmental temperature. The RBSC with 90 vol% SiC has a higher thermal conductivity than that of the 80 vol%; however, is still significantly lower than that of the SiC. The interfacial thermal barrier effect was found to decrease at higher temperatures close 1200 °C. A custom-made in-situ tensile testing device which can be accommodated inside a ZEISS Auriga 60 FIB/SEM has been setup successfully. The SiC-Si interfacial bonding strength was measured at 98 MPa. The observation and analysis of crack propagation along the SiC-Si interface was achieved with in-situ TEM.

  13. Interfacial reaction and electrical properties of HfO2 film gate dielectric prepared by pulsed laser deposition in nitrogen: role of rapid thermal annealing and gate electrode.

    Science.gov (United States)

    Wang, Yi; Wang, Hao; Ye, Cong; Zhang, Jun; Wang, Hanbin; Jiang, Yong

    2011-10-01

    The high-k dielectric HfO(2) thin films were deposited by pulsed laser deposition in nitrogen atmosphere. Rapid thermal annealing effect on film surface roughness, structure and electrical properties of HfO(2) film was investigated. The mechanism of interfacial reaction and the annealing atmosphere effect on the interfacial layer thickness were discussed. The sample annealed in nitrogen shows an amorphous dominated structure and the lowest leakage current density. Capacitors with high-k HfO(2) film as gate dielectric were fabricated, using Pt, Au, and Ti as the top gate electrode whereas Pt constitutes the bottom side electrode. At the gate injection case, the Pt- and Au-gated metal oxide semiconductor devices present a lower leakage current than that of the Ti-gated device, as well as similar leakage current conduction mechanism and interfacial properties at the metal/HfO(2) interface, because of their close work function and chemical properties.

  14. High Resolution X-ray CMT Imaging of Supercritical CO2 in Porous Media: Experimental Challenges, Solutions, and Results

    Science.gov (United States)

    Herring, A. L.; Andersson, L.; Newell, D. L.; Carey, J. W.; Wildenschild, D.

    2013-12-01

    Geologic carbon dioxide (CO2) sequestration has been proposed as a climate change mitigation strategy to limit emissions of CO2 to the atmosphere from large fossil-fuel burning CO2 point sources; however, there are concerns associated with the long-term stability of a mobile subsurface CO2 plume. Capillary trapping of supercritical CO2 (scCO2), wherein the CO2 is held within the pore structure of the geologic matrix by capillary forces, is a more secure form of subsurface storage than structural trapping, which relies on an impermeable caprock to contain the buoyant CO2 plume. To understand the multiphase physics of CO2 transport, and to subsequently produce quantitative estimates of potential CO2 capillary trapping, it is necessary to study field, core, and pore-scale processes. X-ray computed microtomography (x-ray CMT) allows for three-dimensional (3D) in-situ visualization of fluid phases within and the physical structure of a porous medium at the pore-scale. We have designed and built a mobile experimental set-up capable of running at pressures up to 2000 PSI and temperatures up to 50°C, made with materials that are compatible with corrosive fluids. Our experimental procedure includes pressurizing, mixing, and separating fluids; and subsequently running immiscible drainage and imbibition flow experiments with brine and supercritical CO2. With this set-up and procedure, we successfully conducted a brine-scCO2 drainage experiment in Bentheimer sandstone at 1200 PSI and 36°C, and confirmed and quantified CO2 flow in the sandstone core via synchrotron-based x-ray CMT with a resolution of 4.65 μm at the Advanced Photon Source at Argonne National Laboratory. We have proven that we can observe, on a pore-scale basis, the movement of supercritical CO2 within a porous media. The properties of supercritical CO2 (e.g. viscosity, density, interfacial tension and solubility in brine) vary significantly with changes in pressure and temperature; consequently, precise

  15. Incorporation of digestate selectively affects physical, chemical and biochemical properties along with CO2 emissions in two contrasting agricultural soils in the Mediterranean area.

    Science.gov (United States)

    Badagliacca, Giuseppe; Petrovičová, Beatrix; Zumbo, Antonino; Romeo, Maurizio; Gullì, Tommaso; Martire, Luigi; Monti, Michele; Gelsomino, Antonio

    2017-04-01

    Soil incorporation of digestate represents a common practice to dispose the solid residues from biogas producing plants. Although the digestate constitutes a residual biomass rich in partially decomposed organic matter and nutrients, whose content is often highly variable and unbalanced, its potential fertilizer value can vary considerably depending on the recipient soil properties. The aim of the work was to assess short-term changes in the fertility status of two contrasting agricultural soils in Southern Italy (Calabria), olive grove on a clay acid soil (Typic Hapludalfs) and citrus grove on a sandy loam slightly calcareous soil (Typic Xerofluvents), respectively located along the Tyrrhenian or the Ionian coast. An amount of 30 t ha-1 digestate was incorporated into the soil by ploughing. Unamended tilled soil was used as control. The following soil physical, chemical and biochemical variables were monitored during the experimental period: aggregate stability, pH, electrical conductivity, organic C, total N, Olsen-P, N-NH4+, N-NO3-, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and the mineralization quotient (qM). Moreover, in the olive grove soil CO2 emissions have been continuously measured at field scale for 5 months after digestate incorporation. Digestate application in both site exerted a significant positive effect on soil aggregate stability with a greater increase in clay than in sandy loam soil. Over the experimental period, digestate considerably affected the nutrient availability, namely Olsen-P, N-NH4+, N-NO3-, along with the electrical conductivity. The soil type increased significantly the soil N-NH4+ content, which was always higher in the olive than in citrus grove soil. N-NO3- content was markedly increased soon after the organic amendment, followed by a seasonal decline more evident in the sandy loam soil. Moreover, soil properties as CaCO3 content and the pH selectively affected the Olsen-P dynamics. No appreciable

  16. Surface relaxations as a tool to distinguish the dynamic interfacial properties of films formed by normal and diseased meibomian lipids.

    Science.gov (United States)

    Georgiev, Georgi As; Yokoi, Norihiko; Ivanova, Slavyana; Tonchev, Vesselin; Nencheva, Yana; Krastev, Rumen

    2014-08-14

    The surface properties of human meibomian lipids (MGS), the major constituent of the tear film (TF) lipid layer, are of key importance for TF stability. The dynamic interfacial properties of films by MGS from normal eyes (nMGS) and eyes with meibomian gland dysfunction (dMGS) were studied using a Langmuir surface balance. The behavior of the samples during dynamic area changes was evaluated by surface pressure-area isotherms and isocycles. The surface dilatational rheology of the films was examined in the frequency range 10(-5) to 1 Hz by the stress-relaxation method. A significant difference was found, with dMGS showing slow viscosity-dominated relaxation at 10(-4) to 10(-3) Hz, whereas nMGS remained predominantly elastic over the whole range. A Cole-Cole plot revealed two characteristic processes contributing to the relaxation, fast (on the scale of characteristic time τ 100 s), the latter prevailing in dMGS films. Brewster angle microscopy revealed better spreading of nMGS at the air-water interface, whereas dMGS layers were non-uniform and patchy. The distinctions in the interfacial properties of the films in vitro correlated with the accelerated degradation of meibum layer pattern at the air-tear interface and with the decreased stability of TF in vivo. These results, and also recent findings on the modest capability of meibum to suppress the evaporation of the aqueous subphase, suggest the need for a re-evaluation of the role of MGS. The probable key function of meibomian lipids might be to form viscoelastic films capable of opposing dilation of the air-tear interface. The impact of temperature on the meibum surface properties is discussed in terms of its possible effect on the normal structure of the film.

  17. First-principles study of the Al(001)-Al3Nb(001) interfacial properties

    Science.gov (United States)

    Ding, Yanhong; Xu, Rui

    2017-03-01

    The adhesion, interfacial energy and bonding on fcc-Al(001)/D022-Al3Nb(001) interface were investigated using density functional calculations. Considering different terminations of Al3Nb(001) (Al+Nb-terminated and Al-terminated) and stacking sites (top-, bridge- and center-sites), six Al(001)/Al3Nb(001) models were calculated. For the models with same stacking site, Al+Nb-terminated model has larger work of adhesion (Wad) than the Al-terminated one. For the models with same termination, the work of adhesion increases, and the interface energy decreases as the order of center-sited, bridge-sited and top-sited. Al+Nb-terminated-center-sited and Al-terminated-center-sited models are more stable among six models. The interfacial bonding was discussed with analysis of valence electron density distribution and partial density of states (PDOS). The bonding is mainly contributed from Al-Nb covalent bonds and Al-Al metallic interactions.

  18. Fabrication of interfacial functionalized porous polymer monolith and its adsorption properties of copper ions

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jiaxi; Du, Zhongjie; Zou, Wei; Li, Hangquan; Zhang, Chen, E-mail: zhangch@mail.buct.edu.cn

    2014-07-15

    Highlights: • Interface functionalized PGMA porous monolith was fabricated. • The adsorption capacity of Cu{sup 2+} was 35.3 mg/g. • The effects of porous structure on the adsorption of Cu{sup 2+} were studied. • The adsorption behaviors of porous monolith were studied. - Abstract: The interfacial functionalized poly (glycidyl methacrylate) (PGMA) porous monolith was fabricated and applied as a novel porous adsorbent for copper ions (Cu{sup 2+}). PGMA porous material with highly interconnected pore network was prepared by concentrated emulsion polymerization template. Then polyacrylic acid (PAA) was grafted onto the interface of the porous monolith by the reaction between the epoxy group on PGMA and a carboxyl group on PAA. Finally, the porous monolith was interfacial functionalized by rich amount of carboxyl groups and could adsorb copper ions effectively. The chemical structure and porous morphology of the porous monolith were measured by Fourier transform infrared spectroscopy and scanning electron microscopy. Moreover, the effects of pore size distribution, pH value, co-existing ions, contacting time, and initial concentrations of copper ions on the adsorption capacity of the porous adsorbents were studied.

  19. ECO2M: A TOUGH2 Fluid Property Module for Mixtures of Water, NaCl, and CO2, Including Super- and Sub-Critical Conditions, and Phase Change Between Liquid and Gaseous CO2

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.

    2011-04-01

    ECO2M is a fluid property module for the TOUGH2 simulator (Version 2.0) that was designed for applications to geologic storage of CO{sub 2} in saline aquifers. It includes a comprehensive description of the thermodynamics and thermophysical properties of H{sub 2}O - NaCl - CO{sub 2} mixtures, that reproduces fluid properties largely within experimental error for temperature, pressure and salinity conditions in the range of 10 C {le} T {le} 110 C, P {le} 600 bar, and salinity from zero up to full halite saturation. The fluid property correlations used in ECO2M are identical to the earlier ECO2N fluid property package, but whereas ECO2N could represent only a single CO{sub 2}-rich phase, ECO2M can describe all possible phase conditions for brine-CO{sub 2} mixtures, including transitions between super- and sub-critical conditions, and phase change between liquid and gaseous CO{sub 2}. This allows for seamless modeling of CO{sub 2} storage and leakage. Flow processes can be modeled isothermally or non-isothermally, and phase conditions represented may include a single (aqueous or CO{sub 2}-rich) phase, as well as two-and three-phase mixtures of aqueous, liquid CO{sub 2} and gaseous CO{sub 2} phases. Fluid phases may appear or disappear in the course of a simulation, and solid salt may precipitate or dissolve. TOUGH2/ECO2M is upwardly compatible with ECO2N and accepts ECO2N-style inputs. This report gives technical specifications of ECO2M and includes instructions for preparing input data. Code applications are illustrated by means of several sample problems, including problems that had been previously solved with TOUGH2/ECO2N.

  20. Interfacial interaction in monolayer transition metal dichalcogenide/metal oxide heterostructures and its effects on electronic and optical properties: The case of MX2/CeO2

    Science.gov (United States)

    Yang, Ke; Huang, Wei-Qing; Hu, Wangyu; Huang, Gui-Fang; Wen, Shuangchun

    2017-01-01

    Using the density functional theory (DFT), we systematically study the interfacial interaction in monolayer MX2 (M = Mo, W; X = S, Se)/CeO2 heterostructures and its effects on electronic and optical properties. The interfacial interaction in the MX2/CeO2 heterostructures depends largely on chalcogens, and its strength determines the band gap variation and important electronic states at the band edges of the heterostructures. The MX2/CeO2 heterostructures with the same chalcogen have similar absorption spectra, from ultraviolet to near-infrared regions. These results suggest that chalcogens importantly determine the properties of MX2/metal oxide heterostructures.

  1. Preparation of the Ni/NiCo2O4 Composite Electrode and Its Properties toward the Oxygen Evolution Reaction in Alkaline Media%Ni/NiCo2O4复合电极的制备及其在碱性介质中的析氧性能

    Institute of Scientific and Technical Information of China (English)

    鲍晋珍; 王森林

    2011-01-01

    采用共沉淀法制备尖晶石型复合氧化物NiCo2O4,然后将其加入瓦特镀镍液中,复合电沉积了Ni/NiCo2O4复合镀层.通过改变镀液pH值、阴极电流密度jk等条件,探索复合电沉积的最佳工艺条件.运用扫描电子显微镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)表征了复合镀层的表面形貌、颗粒含量和结构.结果表明:在镀液pH=6.2 和jk=100 mA·cm-2的条件下所得Ni/NiCo2O4复合镀层中,NiCo2O4的含量达到最高(30.6%,w).在5 mol·L-1的KOH溶液中,采用循环伏安、稳态极化和电化学阻抗法研究了电极的电催化析氧性能.与镍电极对比,Ni/NiCo2O4复合电极的电催化析氧性能更高,表观活化自由能降低了53.2 kJ·mol-1,其析氧反应的表观交换电流密度是镍电极的7倍.电化学阻抗谱分析表明,Ni/NiCo2O4复合电极在碱性溶液中析氧反应由电化学步骤和扩散步骤联合控制.恒电位长时间电解析氧实验表明,该Ni/NiCo2O4复合电极在碱性溶液中的析氧具有高的稳定性.%A NiCo2O4 spinel composite oxide was obtained by co-precipitation. A Ni/NiCo204 composite coating was prepared by composite electrodeposition in a Ni plating solution by mixing with NiCo2O4 powder. The best plating conditions for the composite electrodeposition were investigated by changing factors such as the plating bath pH and the cathode current density >. The surface morphology, the NiCo2O4 content, and the structure of the Ni/NiCo2O4 composite coating were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). As a result, the NiCo2O4 content in the Ni/NiCo204 composite coating was found to be the highest (30.6%, w) for a bath pH of 6.2 and a cathodic current density jk of 100 mA ? Cm2. In 5 mol ? L-1 KOH solution the electrocatalytic properties toward the oxygen evolution reaction (OER) of the Ni/NiCo2O4 composite electrode was studied using cyclic voltammetry

  2. Interfacial properties of oleosins and phospholipids from rapeseed for the stability of oil bodies in aqueous medium.

    Science.gov (United States)

    Deleu, Magali; Vaca-Medina, Guadalupe; Fabre, Jean-François; Roïz, Julie; Valentin, Romain; Mouloungui, Zéphirin

    2010-10-15

    Oleosins are plant proteins associated with phospholipids in seed oil bodies. The ability of oleosins to aid in the emulsification and stabilization of oil bodies is well known, but little information is available on their interaction with phospholipids at the interface between oil bodies and aqueous medium. Oil body reconstitution at various phospholipid/oleosin ratios was carried out to observe how rapeseed oleosins of 20kDa and rapeseed phospholipids affect oil body stability. Phospholipids are needed to stabilize oil droplets, but oleosins are mandatory to avoid coalescence. We thus characterized how phospholipids affect the interfacial properties of oleosins at pHs 5.5 and 8.5, by analyzing the adsorption kinetics and interfacial dilational rheology. We observed a synergic effect between oleosins and phospholipids in increasing surface pressure at both pHs. This kind of effect was also observed for the dilational modulus at pH 5.5. A thermodynamic approach highlights these synergic interactions between oleosins and phospholipids through a positive deviation from ideality.

  3. Investigation on interfacial and electrical properties of Ge MOS capacitor with different NH3-plasma treatment procedure

    Science.gov (United States)

    Liu, Xiaoyu; Xu, Jingping; Liu, Lu; Cheng, Zhixiang; Huang, Yong; Gong, Jingkang

    2017-08-01

    The effects of different NH3-plasma treatment procedures on interfacial and electrical properties of Ge MOS capacitors with stacked gate dielectric of HfTiON/TaON were investigated. The NH3-plasma treatment was performed at different steps during fabrication of the stacked gate dielectric, i.e. before or after interlayer (TaON) deposition, or after deposition of high-k dielectric (HfTiON). It was found that the excellent interface quality with an interface-state density of 4.79 × 1011 eV-1 cm-2 and low gate leakage current (3.43 × 10-5 A/cm2 at {V}{{g}}=1 {{V}}) could be achieved for the sample with NH3-plasma treatment directly on the Ge surface before TaON deposition. The involved mechanisms are attributed to the fact that the NH3-plasma can directly react with the Ge surface to form more Ge-N bonds, i.e. more GeO x Ny, which effectively blocks the inter-diffusion of elements and suppresses the formation of unstable GeO x interfacial layer, and also passivates oxygen vacancies and dangling bonds near/at the interface due to more N incorporation and decomposed H atoms from the NH3-plasma. Project supported by the National Natural Science Foundation of China (Nos. 61176100, 61274112).

  4. INTERFACIAL ADHESION AND MECHANICAL PROPERTIES OF PMMA-COATED CaCO3 NANOPARTICLE-REINFORCED PVC COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Xuehua Chen; Chunzhong Li; Shoufang Xu; Ling Zhang; Wei Shao; H. L. Du

    2006-01-01

    Polymethyl methacrylate (PMMA)-coated nano-CaCO3 particles were prepared by in-situ emulsion polymerization. The mechanical properties of nano-CaCO3 particles-reinforced PVC were investigated using an AG-2000A universal testing machine and an XJU-2.75 izod impact tester; interfacial adhesion between CaCO3 nanoparticles and PVC matrix by SEM, and structure of PMMA coated on the surface of CaCO3 by FTIR and 1H-NMR. The results indicate that the PMMA coated on the nano CaCO3 particles consists mainly of syndiotactic structure, and their three tacticity contents were rr 52.8%, mm 7.3% and mr 39.9%, respectively. The interfacial adhesion between CaCO3 nanoparticles and PVC matrix was significantly improved when the CaCO3 nanoparticles were coated with PMMA, which led to increased Young's moduli and tensile strengths of the PMMA-coated CaCO3/PVC composites. The izod impact strengths of the composites were strongly affected by the PMMA coating thickness and increased significantly with increasing the volume fraction of CaCO3 filler in the composites.

  5. Extraction of passion fruit seed oil using supercritical CO2: a study of mass transfer and rheological property by Bayesian inference

    Directory of Open Access Journals (Sweden)

    Cardoso de Oliveira, R.

    2013-09-01

    Full Text Available The extraction of oil from passion fruit seeds using supercritical CO2 was studied. Experimental data were obtained for extraction conducted at 15, 20 and 25 MPa; at temperatures of 40 and 50 °C with CO2 flow rates of 1.5 and 3.0 mL min–1. An increase in the pressure, temperature and CO2 flow rate increased the yield. The maximum extraction yield obtained was 18.5%. The mass transfer coefficients for passion fruit oil were found to be 8.496 3 10-5 s-1 at 25 MPa, 50 °C and 3 mL s–1 CO2 flow rate. Dilatant fluid behavior was observed in all tests of the rheological study.Se ha estudiado la extracción de aceite de semillas de frutos de la pasión con CO2 supercrítico. Los datos experimentales se obtuvieron para una extracción llevada a cabo a 15, 20 y 25 MPa; a temperaturas de 40 y 50 °C y a flujos de CO2 de 1,5 y 3,0 mL min–1. Un incremento de la presión, la temperatura y del flujo de CO2 aumentó el rendimiento. El máximo rendimiento de la extracción obtenida fue de 18,5%. Los coeficientes de transferencia de masa para el aceite de fruta de la pasión encontrados fueron 8,496 3 10-5 s–1 a 25 MPa, 50 °C y 3 mL s–1 de flujo de CO2. Se observó un comportamiento de fluido dilatante en todos los ensayos reológicos.

  6. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser Y.

    2016-01-05

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  7. CO2 Interaction with Geomaterials (Invited)

    Science.gov (United States)

    Romanov, V.; Howard, B. H.; Lynn, R. J.; Warzinski, R. P.; Hur, T.; Myshakin, E. M.; Lopano, C. L.; Voora, V. K.; Al-Saidi, W. A.; Jordan, K. D.; Cygan, R. T.; Guthrie, G. D.

    2010-12-01

    This work compares the sorption and swelling processes associated with CO2-coal and CO2-clay interactions. We investigated the mechanisms of interaction related to CO2 adsortion in micropores, intercalation into sub-micropores, dissolution in solid matrix, the role of water, and the associated changes in reservoir permeability, for applications in CO2 sequestration and enhanced coal bed methane recovery. The structural changes caused by CO2 have been investigated. A high-pressure micro-dilatometer was equipped to investigate the effect of CO2 pressure on the thermoplastic properties of coal. Using an identical dilatometer, Rashid Khan (1985) performed experiments with CO2 that revealed a dramatic reduction in the softening temperature of coal when exposed to high-pressure CO2. A set of experiments was designed for -20+45-mesh samples of Argonne Premium Pocahontas #3 coal, which is similar in proximate and ultimate analysis to the Lower Kittanning seam coal that Khan used in his experiments. No dramatic decrease in coal softening temperature has been observed in high-pressure CO2 that would corroborate the prior work of Khan. Thus, conventional polymer (or “geopolymer”) theories may not be directly applicable to CO2 interaction with coals. Clays are similar to coals in that they represent abundant geomaterials with well-developed microporous structure. We evaluated the CO2 sequestration potential of clays relative to coals and investigated the factors that affect the sorption capacity, rates, and permanence of CO2 trapping. For the geomaterials comparison studies, we used source clay samples from The Clay Minerals Society. Preliminary results showed that expandable clays have CO2 sorption capacities comparable to those of coal. We analyzed sorption isotherms, XRD, DRIFTS (infrared reflectance spectra at non-ambient conditions), and TGA-MS (thermal gravimetric analysis) data to compare the effects of various factors on CO2 trapping. In montmorillonite, CO2

  8. Physico-Chemical Behavior of Nanoparticles at CO2-Water-Rock Interfaces

    Science.gov (United States)

    Jun, Y.; Shao, H.; Hu, Y.; Matos, R.

    2009-12-01

    Recently, to help mitigate global climate-change and energy problems, much effort has recently been devoted to developing methods for sequestering anthropogenic CO2 from coal-fired power plants. One of the most promising methods is geological CO2 sequestration (GS). Some prior studies of geological CO2 sequestration have mainly examined the physical processes that occur during the sequestration of CO2. However, most of the relevant studies are based on hydrological transport, using simulation models rather than studying actual interfacial chemical reactions in the ground. The mechanisms, kinetics, and environmental impact of interfacial reactions among CO2-H2O-mineral surfaces at the molecular scale have not been well understood. Changes in the porosity of the mineral phases at the geological formation sites, especially the dissolution of the mineral phase or precipitation of secondary minerals in the pores, will affect the fate and transport of CO2 and the integrity of seals and the matrix within the reservoirs. So far, little is known about the kinetics of the possible geochemical reactions of supercritical CO2 in brine and pre-existing mineral interfaces, or about the ultimate fate and transport of the injected CO2. We investigated the physico-chemical property changes of reference mineral samples (clay minerals) as well as field site samples (sandstone and caprock from the Illinois Basin) by chemical reactions at CO2-H2O-mineral interfaces. We investigated whether reactions between caprock and CO2 can change the integrity of caprock. Our experimental results with caprock samples (CONSOL coal mine sites, West Virginia) indicate that after 14 days in contact with 1 atm CO2 saturated saline water at 80°C, the concentrations of dissolved metals have increased from zero to as high as 47,000 ppm. In our experiments with caprocks and sandstones from GS sites of the Midwest Geological Sequestration Consortium, we found that the most significant extent of dissolution

  9. Structure, transport properties and interfacial stability of PVdF/HFP electrolytes containing modified inorganic filler

    Energy Technology Data Exchange (ETDEWEB)

    Stolarska, M.; Niedzicki, L.; Borkowska, R.; Zalewska, A.; Wieczorek, W. [Department of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw (Poland)

    2007-12-31

    Gel polymer electrolyte membranes composed of poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) and surface modified aluminum or titanium oxide were prepared according to the so-called Bellcore process. Modifications were done by impregnating ceramic powder with 1-8% sulphuric acid aqueous solutions. Filler grain size varied from 10 to 12 {mu}m. The membranes were conditioned in liquid electrode - 1 mol/l LiClO{sub 4} in PC. The ionic conductivity of polymer membrane increased by more than one order of magnitude upon the addition of filler into polymer host. For electrolyte membrane containing modified aluminum or titanium oxide, the interfacial resistance is stable in time as opposed to unmodified gel electrolytes. An increase in lithium transference number is observed upon the addition of filler. Lithium transference number also increases with the fraction of acidic surface groups. (author)

  10. Interfacial properties of hydrides in α-Zr: a theoretical study

    Science.gov (United States)

    Louchez, M.-A.; Besson, R.; Thuinet, L.; Legris, A.

    2017-10-01

    In order to better understand hydride formation in zirconium alloys, heterophase interfaces between α-Zr and γ-ZrH are investigated by means of ab initio atomic-scale simulations of multilayers coupled with continuous elasticity. Our approach allows us to separate out the elastic contribution, leading to basal and prismatic α\\vert γ interface energies around 200 mJ \\cdot m-2 and 750 mJ \\cdot m-2 respectively, i.e. values noticeably higher than previously found for coherent particles such as ζ-Zr2H. By considering interfacial changes of H contents, the possibility of competing elasticity and chemistry effects for interface stability is analyzed. The effects of the strong anisotropy evident in α\\vert γ interface energies on the important practical issue of preferential habit planes are discussed, allowing us to propose a plausible explanation for the experimental results.

  11. SURFACE TENSION OF MOLTEN IF STEEL CONTAINING Ti AND ITS INTERFACIAL PROPERTIES WITH SOLID ALUMINA

    Institute of Scientific and Technical Information of China (English)

    L.C. Zhong; M. Zeze; K. Mukai

    2004-01-01

    Surface tension of molten IF steel containing Ti and contact angle between the liquid steel and solid alumina were measured with sessile droplet method under Ar gas atmosphere at 1500, 1575 and 1600℃. The results show that titanium decreases the surface tension of the molten IF steel and the contact angle. The interfacial tension between the molten IF steel containing Ti and solid alumina decreases with increase in titanium content. The work of adhesion between molten IF steel containing Ti and solid alumina decreases slightly at 1550℃, but increases at 1600℃ with increasing titanium content. It can be deduced that fine bubbles and fine alumina inclusions are easily entrapped in solidifying interface for IF steel containing Ti.

  12. Studies of Mn/ZnO (0001¯) Interfacial Formation and Electronic Properties with Synchrotron Radiation

    Science.gov (United States)

    Zou, C. W.; Xu, P. S.; Wu, Y. Y.; Sun, B.; Xu, F. Q.; Pan, H. B.; Yuan, H. T.; Du, X. L.

    2007-01-01

    The initial growth, interfacial reaction and Fermi level movement of Mn on the O-terminated Zn (000 1¯) surface have been investigated by using synchrotron radiation photoelectron spectroscopy (SRPES) and X-ray photoemission (XPS). Mn is found to be grown on the surface in the layer-by-layer (Frank-van der Merwe) mode and be quite stable on the O-terminated surface at room temperature. With increasing the coverage of Mn, a downward Fermi level movement in band structure measurement of SRPES is observed and the resultant Schottky Barrier Height (SBH) is calculated to be about 1.1eV. Annealing behavior of the interface is investigated and we find that annealing at 600 °C induces a pronounced Mn-Zn atoms exchange reaction at the interface.

  13. The physical chemistry of coordinated aqua-, ammine-, and mixed-ligand Co2+ complexes: DFT studies on the structure, energetics, and topological properties of the electron density.

    Science.gov (United States)

    Varadwaj, Pradeep R; Marques, Helder M

    2010-03-07

    Spin-unrestricted DFT-X3LYP/6-311++G(d,p) calculations have been performed on a series of complexes of the form [Co(H(2)O)(6-n)(NH(3))(n)](2+) (n = 0-6) to examine their equilibrium gas-phase structures, energetics, and electronic properties in their quartet electronic ground states. In all cases Co(2+) in the energy-minimised structures is in a pseudo-octahedral environment. The calculations overestimate the Co-O and Co-N bond lengths by 0.04 and 0.08 A, respectively, compared to the crystallographically observed mean values. There is a very small Jahn-Teller distortion in the structure of [Co(H(2)O)(6)](2+) which is in contrast to the very marked distortions observed in most (but not all) structures of this cation that have been observed experimentally. The successive replacement of ligated H(2)O by NH(3) leads to an increase in complex stability by 6 +/- 1 kcal mol(-1) per additional NH(3) ligand. Calculations using UB3LYP give stabilisation energies of the complexes about 5 kcal mol(-1) smaller and metal-ligand bond lengths about 0.005 A longer than the X3LYP values since the X3LYP level accounts for the London dispersion energy contribution to the overall stabilisation energy whilst it is largely missing at the B3LYP level. From a natural population analysis (NPA) it is shown that the formation of these complexes is accompanied by ligand-to-metal charge transfer the extent of which increases with the number of NH(3) ligands in the coordination sphere of Co(2+). From an examination of the topological properties of the electron charge density using Bader's quantum theory of atoms in molecules it is shown that the electron density rho(c) at the Co-O bond critical points is generally smaller than that at the Co-N bond critical points. Hence Co-O bonds are weaker than Co-N bonds in these complexes and the stability increases as NH(3) replaces H(2)O in the metal's coordination sphere. Several indicators, including the sign and magnitude of the Laplacian of the

  14. Temperature dependent effects of elevated CO2 on shell composition and mechanical properties of Hydroides elegans: insights from a multiple stressor experiment.

    Directory of Open Access Journals (Sweden)

    Vera B S Chan

    Full Text Available The majority of marine benthic invertebrates protect themselves from predators by producing calcareous tubes or shells that have remarkable mechanical strength. An elevation of CO2 or a decrease in pH in the environment can reduce intracellular pH at the site of calcification and thus interfere with animal's ability to accrete CaCO3. In nature, decreased pH in combination with stressors associated with climate change may result in the animal producing severely damaged and mechanically weak tubes. This study investigated how the interaction of environmental drivers affects production of calcareous tubes by the serpulid tubeworm, Hydroides elegans. In a factorial manipulative experiment, we analyzed the effects of pH (8.1 and 7.8, salinity (34 and 27‰, and temperature (23°C and 29°C on the biomineral composition, ultrastructure and mechanical properties of the tubes. At an elevated temperature of 29°C, the tube calcite/aragonite ratio and Mg/Ca ratio were both increased, the Sr/Ca ratio was decreased, and the amorphous CaCO3 content was reduced. Notably, at elevated temperature with decreased pH and reduced salinity, the constructed tubes had a more compact ultrastructure with enhanced hardness and elasticity compared to decreased pH at ambient temperature. Thus, elevated temperature rescued the decreased pH-induced tube impairments. This indicates that tubeworms are likely to thrive in early subtropical summer climate. In the context of climate change, tubeworms could be resilient to the projected near-future decreased pH or salinity as long as surface seawater temperature rise at least by 4°C.

  15. CO2 laser in vitreoretinal surgery

    Energy Technology Data Exchange (ETDEWEB)

    Karlin, D.B.; Patel, C.K.; Wood, O.R.; Llovera, I.

    1980-01-01

    Radiation from a CO2 laser has the dual effect of phototransection and photocoagulation. Incisions have been made in scleral-chorioretinal tissue, lens tissue, and the vitreous body (with and without membrane formation). Results indicate that the CO2 laser may be useful in intravitreal surgery. Its simultaneous cutting and coagulating properties may make the experimental transvitreal chorioretinal biopsy and the full-thickness ocular wall resection for small melanosarcomas of the choroid clinical possibilities in the not too distant future. Finally, the effects of CO2 laser radiation on the normal human lens suggests the possibility of the dissolution of cataracts by laser irradiation.

  16. Dielectric studies on the heterogeneity and interfacial property of composites made of polyacene quinone radical polymers and sulfonated polyurethanes.

    Science.gov (United States)

    Zhu, Dan; Zhang, Juan; Bin, Yuezhen; Xu, Chunye; Shen, Jian; Matsuo, Masaru

    2012-03-01

    Sulfonated polyurethane (PUI, matrix) is synthesized and composited with polyacene quinone radical polymers (PAQRs, filler). The polarization mechanism of these polymers and composites were investigated in terms of their frequency, temperature, and filler-concentration-dependent dielectric properties. We found that PUI/PAQR composites have a high permittivity, which is attributed to the filler-matrix interfacial polarization and the contact effect. The PAQR-concentration-dependent permittivity of different PUI/PAQR composites reveals a percolation threshold at 20-30 wt % with scaling exponents that indicate the intercluster polarization. The frequency dependence of dielectric response is well-fitted by using the Debye and Cole-Cole functions on the basis of the structural diagrams and equivalent circuit, leading to a detailed evaluation on heterogeneous structures of different PUI/PAQR composites.

  17. Synthesis of fullerene nanowhiskers using the liquid-liquid interfacial precipitation method and their mechanical, electrical and superconducting properties

    Science.gov (United States)

    Miyazawa, Kun'ichi

    2015-02-01

    Fullerene nanowhiskers (FNWs) are thin crystalline fibers composed of fullerene molecules, including C60, C70, endohedral, or functionalized fullerenes. FNWs display n-type semiconducting behavior and are used in a diverse range of applications, including field-effect transistors, solar cells, chemical sensors, and photocatalysts. Alkali metal-doped C60 (fullerene) nanowhiskers (C60NWs) exhibit superconducting behavior. Potassium-doped C60NWs have realized the highest superconducting volume fraction of the alkali metal-doped C60 crystals and display a high critical current density (Jc) under a high magnetic field of 50 kOe. The growth control of FNWs is important for their success in practical applications. This paper reviews recent FNWs research focusing on their mechanical, electrical and superconducting properties and growth mechanisms in the liquid-liquid interfacial precipitation method.

  18. Dynamic interfacial properties of poly(ethylene glycol)-modified ferritin at the solid/liquid interface.

    Science.gov (United States)

    Kumashiro, Yoshikazu; Ikezoe, Yasuhiro; Tamada, Kaoru; Hara, Masahiko

    2008-07-17

    Poly(ethylene glycol)-modified ferritins (PEG-ferritins) with various molecular weights were synthesized by the grafting method, and their dynamic interfacial properties at the solid/liquid interface were investigated. The number of PEG grafted to ferritins was controlled by the amount of 1,1'-carbonyldiimidazole-modified PEG adding to the reaction solution. The adsorption kinetics and energy dissipation of PEG-ferritins onto bare Si substrate and amino-modified Si substrate were investigated with a quartz crystal microbalance (QCM) in 10 mM bis-Tris/HCl buffer (pH 5.8), while their morphologies were characterized by scanning electron microscopy (SEM). The adsorption dynamics of PEG-ferritins onto amino-modified Si substrate were quite different from those of unmodified ferritin, which can be reasonably interpreted by the desorption capability of PEG-ferritins on the surface attributed to amphiphilicity and the high-chain mobility of PEG chains.

  19. CO2 laser preionisation

    Science.gov (United States)

    Spiers, Gary D.

    1991-01-01

    The final report for work done during the reporting period of January 25, 1990 to January 24, 1991 is presented. A literature survey was conducted to identify the required parameters for effective preionization in TEA CO2 lasers and the methods and techniques for characterizing preionizers are reviewed. A numerical model of the LP-140 cavity was used to determine the cause of the transverse mode stability improvement obtained when the cavity was lengthened. The measurement of the voltage and current discharge pulses on the LP-140 were obtained and their subsequent analysis resulted in an explanation for the low efficiency of the laser. An assortment of items relating to the development of high-voltage power supplies is also provided. A program for analyzing the frequency chirp data files obtained with the HP time and frequency analyzer is included. A program to calculate the theoretical LIMP chirp is also included and a comparison between experiment and theory is made. A program for calculating the CO2 linewidth and its dependence on gas composition and pressure is presented. The program also calculates the number of axial modes under the FWHM of the line for a given resonator length. A graphical plot of the results is plotted.

  20. The Role of Interfacial Electronic Properties on Phonon Transport in Two-Dimensional MoS2 on Metal Substrates.

    Science.gov (United States)

    Yan, Zhequan; Chen, Liang; Yoon, Mina; Kumar, Satish

    2016-12-07

    We investigate the role of interfacial electronic properties on the phonon transport in two-dimensional MoS2 adsorbed on metal substrates (Au and Sc) using first-principles density functional theory and the atomistic Green's function method. Our study reveals that the different degree of orbital hybridization and electronic charge distribution between MoS2 and metal substrates play a significant role in determining the overall phonon-phonon coupling and phonon transmission. The charge transfer caused by the adsorption of MoS2 on Sc substrate can significantly weaken the Mo-S bond strength and change the phonon properties of MoS2, which result in a significant change in thermal boundary conductance (TBC) from one lattice-stacking configuration to another for same metallic substrate. In a lattice-stacking configuration of MoS2/Sc, weakening of the Mo-S bond strength due to charge redistribution results in decrease in the force constant between Mo and S atoms and substantial redistribution of phonon density of states to low-frequency region which affects overall phonon transmission leading to 60% decrease in TBC compared to another configuration of MoS2/Sc. Strong chemical coupling between MoS2 and the Sc substrate leads to a significantly (∼19 times) higher TBC than that of the weakly bound MoS2/Au system. Our findings demonstrate the inherent connection among the interfacial electronic structure, the phonon distribution, and TBC, which helps us understand the mechanism of phonon transport at the MoS2/metal interfaces. The results provide insights for the future design of MoS2-based electronics and a way of enhancing heat dissipation at the interfaces of MoS2-based nanoelectronic devices.

  1. Improved mechanical properties of polylactide nanocomposites-reinforced with cellulose nanofibrils through interfacial engineering via amine-functionalization.

    Science.gov (United States)

    Lu, Yuan; Cueva, Mario Calderón; Lara-Curzio, Edgar; Ozcan, Soydan

    2015-10-20

    One of the main factors responsible for the mechanical and physical properties of nanocomposites is the effectiveness of the interfacial region to transfer loads and mechanical vibrations between the nano-reinforcements and the matrix. Surface functionalization has been the preferred approach to engineer the interfaces in polymer nanocomposites in order to maximize their potential in structural and functional applications. In this study, amine-functionalized cellulose nanofibrils (mCNF-G1) were synthesized via silylation of the hydroxyl groups on the CNF surface using 3-aminopropyltrimethoxysilane (APTMS). To further increase the amine density (mCNF-G2), dendritic polyamidoamine (PAMAM) was grafted onto mCNF-G1 by the Michael addition of methacrylate onto mCNF-G1, followed by the transamidation of the ester groups of methacrylate using ethylenediamine. Compared to native CNF-reinforced, poly(l-lactide) (PLLA) nanocomposites, amine-functionalized CNF exhibited significantly improved dispersion and interfacial properties within the PLLA matrix due to the grafting of PLLA chains via aminolysis. It is also a more effective nucleating agent, with 15% mCNF-G1 leading to a crystallinity of 32.5%, compared to 0.1 and 8.7% for neat PLLA and native CNF-reinforced composites. We have demonstrated that APTMS-functionalized CNF (mCNF-G1) significantly improved the tensile strength compared to native CNF, with 10% mCNF-G1 being the most effective (i.e., >100% increase in tensile strength). However, we also found that excessive amines on the CNF surface (i.e., mCNF-G2) resulted in decreased tensile strength and modulus due to PLLA degradation via aminolysis. These results demonstrate the potential of optimized amine-functionalized CNF for future renewable material applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A DFT study on the effect of supporting titania on silica graphene epoxy graphene and carbon nanotubes - Interfacial properties and optical response

    CSIR Research Space (South Africa)

    Kiarii, EM

    2017-08-01

    Full Text Available Condensed Matter: https://doi.org/10.1016/j.cocom.2017.08.003 A DFT study on the effect of supporting titania on silica graphene epoxy graphene and carbon nanotubes - Interfacial properties and optical response Kiarii EM Govender, KK Ndung'u PG...

  3. Ferroic Properties in Individual and Multi-Component Nanostructures: The Influence of Size, Shape, and Interfacial Coupling

    Science.gov (United States)

    Johnson, Stephanie Howell

    Extrinsic magnetoelectric heterostructure materials receive increased interest because of the potential to tune the magnetoelectric properties through material selection and actively, through applied electric and magnetic field. Understanding the strength of the coupling of ferroic properties in composite solids and the roles of size, shape, and arrangement of the constituent phases is central to realizing high-performance magnetoelectrics and their applications. Nanoscale magnetoelectric materials are excellent candidate systems to study the aforementioned effects of shape and finite size, to meet the growing demand for faster, more efficient, low cost, and above all smaller device components for use in advanced magnetic memories, actuators, transducers, and sensors. Nanoscale materials offer increased interfacial surface area compared with bulk, making them appealing in the design of an enhanced magnetoelectric composite because the magnetoelectric effect in a composite system is driven by interfacial coupling mechanisms. However, nanoscale (approximately 100 nm or less) ferroic materials often exhibit a dimensionality-dependent suppression of ferroic and piezoelectric properties below a critical size. By controlling e.g. the surface chemical environment, introducing strain engineering of films through epitaxy or through the shape of a nanostructure, the ferroelectric phase stability can be tuned for a given material and temperature. In this dissertation nanoscale ferroic and multiferroic properties were investigated, highlighting five characteristic systems: ferromagnetic nanoparticles, ferroelectric nanocubes, extrinsic magnetoelectric nanowires, and resonant beams and resonant membranes. An experimental study of ferromagnetic nanoparticles is presented to underscore the importance of understanding the growth and interfacial coupling mechanisms in ferromagnetic nanoparticle systems. To investigate the finite-size driven ferroelectric phase transition at the

  4. Preparation of Epoxy/Montmorillonite Nanocomposite Coating and Investigation on Heat Resistance and Anticorrosion Properties in Oil- Gas Environment with H2S/CO2%环氧/蒙脱土复合涂层的制备及在H2S/CO2环境中的耐热防腐性能研究

    Institute of Scientific and Technical Information of China (English)

    胡银春; 马丽琴; 董玉华; 王献昉; 周琼

    2011-01-01

    The title anti -corrosive and heat resistant coating, which coud be used in oil -gas environment with H2S/CO2, has been developed by optimizing the curing process, clay content and resin component to improve heat - resistance and corrosion resistance of epoxy coating. The heat - resistant and anti - corrosive properties of the coating in oil - gas environment with H2S/CO2 was investigated with autoclave test.The results showed that heat pre treatment could significantly increase the Tg of the binder, and epoxy resin could be intercalated into the organic montmorillonite layers with mechanical stirring at 80 ℃. OMMT could be well dispersed in the binder when its content was 3% (m/m), and the nanocomposite showed an intercalation/stripping hybrid characteristic, which could ensure both the thermo -mechanical and barrier properties. When the Tg of the varnish coating was 153.7 ℃, its anti - corrosive property was good in oil - gas environment with H2S/CO2 at 150. 0 ℃, which meant the Tg could be used as the upper marging temperature for anti -corrosive coating.%通过优化固化工艺、有机蒙脱土含量及树脂组分改善环氧涂层的耐热性,制备应用于高温H2S/CO2腐蚀环境中的环氧耐热防腐涂层,采用高温高压釜试验测试了涂层的耐热防腐效果.结果表明:适当的高温处理能显著提高基体树脂的玻璃化转变温度;环氧树脂在80℃机械搅拌条件下插入有机蒙脱土的层间,质量分数为3%的有机蒙脱土在基体中分散均一,为插层/剥离混合型复合结构,兼顾材料的热机械性能和阻隔性能;清漆涂层的玻璃化转变温度为153.7℃,其防腐涂层在150℃以下含H2S/CO2的油气环境中的防腐效果良好,说明玻璃化转变温度作为防腐涂层的使用上限温度是可行的.

  5. Interfacial defects induced electronic property transformation at perovskite SrVO3/SrTiO3 and LaCrO3/SrTiO3 heterointerfaces.

    Science.gov (United States)

    Li, Junjie; Yin, Deqiang; Li, Qiang; Sun, Rong; Huang, Sumei; Meng, Fanzhi

    2017-03-08

    Unravelling the atomic structure and chemical species of interfacial defects is critical to understanding the origin of interfacial properties in many heterojunctions. Here, by combining advanced transmission electron microscopy, spectroscopy and first-principles calculations, we demonstrate interfacial Ti diffusion in SrVO3/SrTiO3 and LaCrO3/SrTiO3 heterointerfaces and uncover that the interfacial defects induce a significant change in electronic properties by showing an electronic transformation from the insulating state to metallic state at SrVO3/SrTiO3 heterointerfaces due to the hybridization of interfacial Ti d, O p and V d, and a metallic to insulating state transformation at LaCrO3/SrTiO3 because of Ti-Cr mixing induced charge redistribution in the interfacial layer.

  6. A cross-association model for CO2-methanol and CO2-ethanol mixtures

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A cross-association model was proposed for CO2-alcohol mixtures based on the statistical associating fluid theory (SAFT).CO2 was treated as a pseudo-associating molecule and both the self-association between alcohol hydroxyls and the cross-association between CO2 and alcohol hydroxyls were considered.The equilibrium properties from low temperature-pressure to high temperature-pressure were investigated using this model.The calculated p-x and p-p diagrams of CO2-methanol and CO2-ethanol mixtures agreed with the experimental data.The results showed that when the cross-association was taken into account for Helmholtz free energy,the calculated equilibrium properties could be significantly improved,and the error prediction of the three phase equilibria and triple points in low temperature regions could be avoided.

  7. A Polarizable and Transferable PHAST CO 2 Potential for Materials Simulation

    KAUST Repository

    Mullen, Ashley L.

    2013-12-10

    Reliable PHAST (Potentials with High Accuracy Speed and Transferability) intermolecular potential energy functions for CO2 have been developed from first principles for use in heterogeneous systems, including one with explicit polarization. The intermolecular potentials have been expressed in a transferable form and parametrized from nearly exact electronic structure calculations. Models with and without explicit many-body polarization effects, known to be important in simulation of interfacial processes, are constructed. The models have been validated on pressure-density isotherms of bulk CO 2 and adsorption in three metal-organic framework (MOF) materials. The present models appear to offer advantages over high quality fluid/liquid state potentials in describing CO2 interactions in interfacial environments where sorbates adopt orientations not commonly explored in bulk fluids. Thus, the nonpolar CO2-PHAST and polarizable CO 2-PHAST* potentials are recommended for materials/interfacial simulations. © 2013 American Chemical Society.

  8. Compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2 as substitutes for SF6 to reduce global warming potential

    Science.gov (United States)

    Zhong, Linlin; Rong, Mingzhe; Wang, Xiaohua; Wu, Junhui; Han, Guiquan; Han, Guohui; Lu, Yanhui; Yang, Aijun; Wu, Yi

    2017-07-01

    C5F10O has recently been found to be a very promising alternative to SF6. This paper is devoted to the investigation of compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2. Firstly, the partition functions and enthalpies of formation for a few molecules (CxFy and CxFyO) which are likely to exist in the mixtures, are calculated based on the G4(MP2) theory. The isomers of the above molecules are selected according to their Gibbs energy. The compositions of C5F10O-CO2-O2 mixtures are then determined using the minimization of the Gibbs free energy. Next, the thermodynamic properties (mass density, specific enthalpy, and specific heat) are derived from the previously calculated compositions. Lastly, the transport coefficients (electrical conductivity, viscosity, and thermal conductivity) are calculated based on Chapman-Enskog method. It is found that, as an arc quenching gas, C5F10O could not recombine into itself with the temperature decreasing down to room temperature after the arc extinction. Besides, the key species at room temperature are always CF4, CO2, and C4F6 if graphite is not considered. When taken into account, graphite will replace C4F6 as one of the dominate particles. The mixing of CO2 with C5F10O plasma significantly affects the thermodynamic properties (e.g. vanishing and/or shifting of the peaks in specific heat) and transport coefficients (e.g. reducing viscosity and changing the number of peaks in thermal conductivity), while the addition of O2 with C5F10O-CO2 mixtures has no remarkable influence on both thermodynamic and transport properties.

  9. Interfacial investigation and mechanical properties of glass-Al-glass anodic bonding process

    Science.gov (United States)

    Hu, Lifang; Xue, Yongzhi; Shi, Fangrong

    2017-10-01

    Glass-Al-glass with Al as common anode was successfully bonded together through the anodic bonding process. SEM and EDS were conducted to investigate the interfacial structure of the glass-Al-glass samples. Special attention was given to the element distribution after the bonding process. The element profile of the transitional layer was investigated by glow discharge optical emission microscopy. The results showed that ion migration played an important role during the anodic bonding process, Na+ would precipitate from the back of the glass, and a Na+ depletion region formed at the bonding interface. At the same time, O2‑ diffused into the bonding interface and reacted with the Al, which resulted in a successful bonding process. Furthermore, Al migrated into the glass, which could enhance the bonding process. The peak current of the glass-Al-glass bonding was two times larger than that of the Al-glass bonding, which meant that the glass-Al-glass bonding process could be considered equivalent to two individual Al-glass bonding processes. Tensile strength tests showed that the glass was fractured, and the fractures propagated into the bonding interface, which indicated a reliable bonding process.

  10. Enhancement of mechanical properties and interfacial adhesion by chemical odification of natural fibre reinforced polypropylene composites

    CSIR Research Space (South Africa)

    Erasmus, E

    2008-11-01

    Full Text Available Natural fibres are often used for reinforcing thermoplastics, like polypropylene, to manufacture composite materials exhibiting numerous advantages such as high mechanical properties, low density and biodegradability. The mechanical properties of a...

  11. Measurement and correlation of supercritical CO2 and ionic liquid systems for design of advanced unit operations

    Institute of Scientific and Technical Information of China (English)

    Hiroshi MACHIDA; Ryosuke TAGUCHI; Yoshiyuki SATO; Louw J.FLORUSSE; Cor J.PETERS; Richard L.SMITH,Jr

    2009-01-01

    Ionic liquids combined with supercritical fluid technology hold great promise as working solvents for developing compact processes. Ionic liquids, which are organic molten salts, typically have extremely low volatility and high functionality, but possess high viscos-ities, surface tensions and low diffusion coefficients, which can limit their applicability. CO2, on the other hand,especially in its supercritical state, is a green solvent that can be used advantageously when combined with the ionic liquid to provide viscosity and surface tension reduction and to promote mass transfer. The solubility of CO2 in the ionic liquid is key to estimating the important physical properties that include partition coefficients, viscosities,densities, interfacial tensions, thermal conductivities and heat capacities needed in contactor design. In this work, we examine a subset of available high pressure pure component ionic liquid PVT data and high pressure CO2-ionic liquid solubility data and report new correlations for CO2-ionic liquid systems with equations of state that have some industrial applications including: (1) general, (2) fuel desulfurization, (3) CO2 capture, and (4) chiral separation.New measurements of solubility data for the CO2 and 1-butyl-3-methylimidazolium octyl sulfate, [bmim][OcSO4] system are reported and correlated. In the correlation of the CO2 ionic liquid phase behavior, the Peng-Robinson and the Sanchez-Lacombe equations of state were considered and are compared. It is shown that excellent correlation of CO2 solubility can be obtained with either equation and they share some common characteristics regarding inter-action parameters. In the Sanchez-Lacombe equation,parameters that are derived from the supercritical region were found to be important for obtaining good correlation of the CO2-ionic liquid solubility data.

  12. Effects of Microporosity and Surface Chemistry on Separation Performances of N-Containing Pitch-Based Activated Carbons for CO2/N2 Binary Mixture

    Science.gov (United States)

    Lee, Min-Sang; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-03-01

    In this study, N-containing pitch-based activated carbons (NPCs) were prepared using petroleum pitch with a low softening point and melamine with a high nitrogen content. The major advantage of the preparation method is that it enables variations in chemical structures and textural properties by steam activation at high temperatures. The adequate micropore structures, appropriate chemical modifications, and high adsorption enthalpies of NPCs are favorable for CO2 adsorption onto carbon surfaces. Furthermore, the structure generates a considerable gas/N-containing carbon interfacial area, and provides selective access to CO2 molecules over N2 molecules by offering an increased number of active sites on the carbon surfaces. The highest CO2/N2 selectivity, i.e., 47.5, and CO2 adsorption capacity for a CO2/N2 (0.15:0.85) binary gas mixture, i.e., 5.30 wt%, were attained at 298 K. The NPCs also gave reversible and durable CO2-capturing performances. All the results suggest that NPCs are promising CO2 sorbents, which can meet the challenges of current CO2 capture and separation techniques.

  13. Effects of Microporosity and Surface Chemistry on Separation Performances of N-Containing Pitch-Based Activated Carbons for CO2/N2 Binary Mixture

    Science.gov (United States)

    Lee, Min-Sang; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-01-01

    In this study, N-containing pitch-based activated carbons (NPCs) were prepared using petroleum pitch with a low softening point and melamine with a high nitrogen content. The major advantage of the preparation method is that it enables variations in chemical structures and textural properties by steam activation at high temperatures. The adequate micropore structures, appropriate chemical modifications, and high adsorption enthalpies of NPCs are favorable for CO2 adsorption onto carbon surfaces. Furthermore, the structure generates a considerable gas/N-containing carbon interfacial area, and provides selective access to CO2 molecules over N2 molecules by offering an increased number of active sites on the carbon surfaces. The highest CO2/N2 selectivity, i.e., 47.5, and CO2 adsorption capacity for a CO2/N2 (0.15:0.85) binary gas mixture, i.e., 5.30 wt%, were attained at 298 K. The NPCs also gave reversible and durable CO2-capturing performances. All the results suggest that NPCs are promising CO2 sorbents, which can meet the challenges of current CO2 capture and separation techniques. PMID:26987683

  14. "a" interfacial parameter in Nicolais-Narkis model for yield strength of polymer particulate nanocomposites as a function of material and interphase properties.

    Science.gov (United States)

    Zare, Yasser

    2016-05-15

    In this paper, "a" interfacial parameter in Nicolais-Narkis model is expressed by thickness "ri" and strength "σi" of interphase between polymer and nanoparticles as well as material properties. "a" parameter is connected to "B1" interfacial parameter in modified Pukanszky model and the effects of "ri" and "σi" on "a" are explained. The negligible difference between "a" values calculated by fitting the experimental results to Nicolais-Narkis model and also, by "B1" results confirms the accurateness of the suggested relation between "a" and "B1" parameters. Additionally, an inverse relation is found between "a" and "B1" parameters for nanocomposites containing spherical nanoparticles. The results demonstrate that the slight levels of "ri" and "σi" data give a large value of "a" which indicates the poor interfacial adhesion.

  15. Metal-Organic Framework Templated Synthesis of Ultrasmall Catalyst Loaded ZnO/ZnCo2O4 Hollow Spheres for Enhanced Gas Sensing Properties

    Science.gov (United States)

    Koo, Won-Tae; Choi, Seon-Jin; Jang, Ji-Soo; Kim, Il-Doo

    2017-03-01

    To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2-3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo2O4, and ZnO-ZnCo2O4 were formed on each phase. The synthesized Pd-ZnO/ZnCo2O4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors.

  16. Metal-Organic Framework Templated Synthesis of Ultrasmall Catalyst Loaded ZnO/ZnCo2O4 Hollow Spheres for Enhanced Gas Sensing Properties

    Science.gov (United States)

    Koo, Won-Tae; Choi, Seon-Jin; Jang, Ji-Soo; Kim, Il-Doo

    2017-01-01

    To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2–3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo2O4, and ZnO-ZnCo2O4 were formed on each phase. The synthesized Pd-ZnO/ZnCo2O4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors. PMID:28327599

  17. Modulation of interfacial electronic properties in PbI2 and BN van der Waals heterobilayer via external electric field

    Science.gov (United States)

    Ma, Yaqiang; Zhao, Xu; Niu, Mengmeng; Dai, Xianqi; Li, Wei; Wang, Xiaolong; Zhao, Mingyu; Wang, Tianxing; Tang, Yanan

    2017-07-01

    The interfacial electronic properties of PbI2 and BN van der Waals (vdW) heterobilayer are explored by using density functional theory (DFT) method. An intrinsic type-II heterostructure with a wide bandgap is demonstrated. The spatial separation of the lowest energy electron-hole pairs can be actualised and make PbI2/BN heterostructure as a good candidate for applications in optoelectronics and solar cell. A simulation of Efield is actualized to modify its electronic properties. Band alignment converts from type-II to type-I heterostructure separated by a forward voltage with the value of about 0.07 V/Å. Three regions implying different Efield-sensitive properties are obtained from the variations of bandgap with Efield. The charge redistribution with an Efield is mainly on the surface of PbI2 and BN layers as well as the amount of electrons depends on the strength of Efield. In addition, the PbI2/BN heterobilayer exhibits more outstanding optical conductivity capability. Our results could bring forward a new perspective on sensor and shed light on the design of novel nano- and optoelectronics based on the PbI2/BN vdW heterostructure.

  18. Behavior of CO2/water flow in porous media for CO2 geological storage.

    Science.gov (United States)

    Jiang, Lanlan; Yu, Minghao; Liu, Yu; Yang, Mingjun; Zhang, Yi; Xue, Ziqiu; Suekane, Tetsuya; Song, Yongchen

    2017-04-01

    A clear understanding of two-phase fluid flow properties in porous media is of importance to CO2 geological storage. The study visually measured the immiscible and miscible displacement of water by CO2 using MRI (magnetic resonance imaging), and investigated the factor influencing the displacement process in porous media which were filled with quartz glass beads. For immiscible displacement at slow flow rates, the MR signal intensity of images increased because of CO2 dissolution; before the dissolution phenomenon became inconspicuous at flow rate of 0.8mLmin(-1). For miscible displacement, the MR signal intensity decreased gradually independent of flow rates, because supercritical CO2 and water became miscible in the beginning of CO2 injection. CO2 channeling or fingering phenomena were more obviously observed with lower permeable porous media. Capillary force decreases with increasing particle size, which would increase permeability and allow CO2 and water to invade into small pore spaces more easily. The study also showed CO2 flow patterns were dominated by dimensionless capillary number, changing from capillary finger to stable flow. The relative permeability curve was calculated using Brooks-Corey model, while the results showed the relative permeability of CO2 slightly decreases with the increase of capillary number.

  19. Influence of fiber surface-treatment on interfacial property of poly(L-lactic acid)/ramie fabric biocomposites under UV-irradiation hydrothermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Chen Dakai; Li Jing [Institute of Nano- and Bio-polymeric Materials, School of Material Science and Engineering, Tongji University, Shanghai 200092 (China); Ren Jie, E-mail: renjie6598@163.com [Institute of Nano- and Bio-polymeric Materials, School of Material Science and Engineering, Tongji University, Shanghai 200092 (China) and Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, Shanghai 200092 (China)

    2011-04-15

    Research highlights: {yields} Ramie fiber is used as reinforced material because it's lowest water absorption among sisal, jute, kenaf and ramie fiber. {yields} Fiber surface-treatment can cause an accelerated decline in mechanical properties of PLLA biocomposites after UV-irradiation hydrothermal aging. {yields} The swelling of ramie fibers reduce the interfacial adhesive strength in critical area of PLLA matrix-ramie fabric interface. - Abstract: The present study is devoted to the effect of fiber surface-treatment on the interfacial property of biocomposites based on poly(L-lactic acid) (PLLA) and ramie fabric. Ramie fiber is used as reinforced material because it's lowest water absorption among sisal, jute, kenaf and ramie fiber. Fiber surface-treatment can increase the water absorption of natural fibers. SEM images show that PLLA biocomposites with treated ramie fabric exhibit better interfacial adhesion character. DMA results show that the storage modulus of PLLA biocomposites with treated ramie increase compared to neat PLLA and PLLA biocomposites with untreated ramie. Unexpectedly, fiber surface-treatment can cause an accelerated decline in mechanical properties of PLLA biocomposites after UV-irradiation hydrothermal aging. Finally, GPC results show that there is no obvious decline in the molecular weight of PLLA. The main reason for this decline is the interfacial destructive effect induced by the water absorption of ramie fiber.

  20. Translucent CO2 ice on Mars ?

    Science.gov (United States)

    Schmidt, Frederic; Andrieu, Francois; Douté, Sylvain; Schmitt, Bernard

    2016-10-01

    The Martian climate is driven by the condensation/sublimation of CO2 representing 95% of the atmosphere. Many active surface features (such dark spot, dark flows), have been potentially linked to CO2 exchange. Understanding the surface/atmosphere interactions is a major issue, for both atmospheric but also surface science. This study aims at estimating the physical properties of the seasonal CO2 ice deposits. Are these deposits granular or compact? What is the thickness of the ice? How much impurities are included within the ice? These questions have been highly debated in the literature, in particular the presence of a translucent slab ice, the link with the H2O cycle. In particular the cold jet geyser model requires translucent CO2 ice. We use radiative transfer models to simulate spectroscopic data from the CRISM instrument and perform an inversion to estimate model's parameters though time. We then discuss the consistency of the results with other datasets.

  1. CO2-Brine-Iron-bearing Clay Mineral Interactions: Surface Area Changes and Fracture-Filling Potentials in Geologic CO2 Sequestration

    Science.gov (United States)

    Jun, Y.; Hu, Y.

    2011-12-01

    Geologic carbon dioxide sequestration (GCS) is a promising option to reduce anthropogenic CO2 emission from coal-fired power plants. The injected CO2 in GCS sites can induce dissolution of rocks and secondary mineral formation, potentially change the physical properties of the geological formations, and thus influence the transport and injectivity of CO2. However, most of the relevant studies are based on hydrological transport, using simulation models rather than studying actual interfacial chemical reactions. The mechanisms and kinetics of interfacial reactions among supercritical CO2 (scCO2)-saline water-rock surfaces at the molecular scale and their impacts on CO2 leakage have not been well understood. This research investigated the effects of various environmental factors (such as temperature, pressure, salinity, and different metal ion and organic-containing brine) on the dissolution and surface morphological changes of clay minerals. In this work, iron-bearing clay mineral, biotite [K(Mg,Fe)3AlSi3O10(OH,F)2], was used for model clay minerals in potential GCS sites. Both fluid/solid chemistry analysis and interfacial topographic studies were conducted to investigate the dissolution/precipitation on clay mineral surfaces under GCS conditions in high salinity systems. Using atomic force microscopy (AFM) and scanning electron microscopy (SEM), the interfacial surface morphology changes were observed. Shortly after a CO2 pressure of 102 atm is applied at 95oC, in situ pH of solutions was 3.15 ± 0.10. The early intrinsic dissolution rates of biotite were 8.4 ± 2.8 × 10-13 and 11.2 ± 3.0 × 10-13 mol Si m-2s-1 in water and NaCl solution, respectively. At the early stage of reaction, fast growth of fibrous illite on biotite basal planes was observed. After 22-70 h reaction, the biotite basal surface cracked, resulting in illite detaching from the surfaced. Later, the cracked surface layer was released into solution, thus the inner layer was exposed as a renewed

  2. Multi-technique monitoring of CO2 leakage from an engineered CO2 leakage experiment

    Science.gov (United States)

    Zhou, X.; Apple, M. E.; Dobeck, L.; Cunningham, A. B.; Spangler, L.

    2012-12-01

    Monitoring of canopy and soil geophysical and geochemical properties in vadose zone by multiple techniques were carried out from 1999 to 2012 using an engineered CO2 release to simulate the CO2 leakage from CO2 storage at an agricultural plot at Bozeman, MT. The CO2 release was based on a horizontally-drilled well of 100 m at a depth of about 2.0-2.3m (Fig.1). Techniques utilized include hyperspectral and infrared radiation of various vegetations, electric conductivity in soil, magnetic field at the ground surface, and soil gas composition and dynamics using various gas sensors and soil moisture sensors. Measurements were made at several sites along a transect perpendicular to the releasing well, along which the soil CO2 concentration attenuated from high to normal condition at control site. The response of the canopy hyperspectral reflectance, infrared radiation, soil geophysical properties such as soil electric conductivity, top soil magnetic susceptibility and magnetic field, soil gas composition such as CO2 and O2 concentration to CO2 release at different rates were quantified and will be shown at this presentation. Fig.2 shows some examples of the results. The different responses at the impact and control sites are used to assess the effectiveness for CO2 surface and near-surface detection when a possible CO2 leakage occurs.ig.1. A schematic showing the injection and release of CO2 at an agricultral plot in Bozeman, MT. ig.2. Some examples of results showing the response of vegetation, hyperspectral reflectance, soil electric conductivity, soil O2 concentration to the release of CO2.

  3. Effect of High Concentration of CO2 Invasion on Soil Physical and Chemical Properties%高浓度二氧化碳入侵对土壤理化性质的影响

    Institute of Scientific and Technical Information of China (English)

    裴宇; 赵晓红; 邓红章; 李春荣; 韩枫; 张青海; 张徽

    2016-01-01

    In the impact of the leakage of CO2 geological storage on the ecological environment, especially, the soil, it is the main medium of the exchange of substances and energy in ecological system, so studying the soil physical and chemical properties are very significant. This experiment artificially simulated the leakage of CO2 to the soil surface, and then the changes in soil organic carbon, nitrogen, phosphorus, potassium and water-soluble salts and the responses of plants were analyzed. The results show that, after the invasion of CO2, compared with the controlled area, the soil total organic carbon increases by 1.56%~43.75%, total nitrogen decreases by 0.88%~13.25%, ammonia and nitrate reduce as well, phosphorus, potassium and water-soluble salts also decline in general, while the pH of the soil is up,and every plant grows well, particularly, peas and radish. Conclusion:the invasion of high concentration of CO2 has some impacts on soil physical and chemical properties, in addition, can promote the growth of plants.%在地质储存CO2(GCS)泄漏对生态环境的影响中,土壤作为生态系统中物质与能量交换的主要介质,其理化性质的变化研究尤为重要。采用人工模拟CO2泄漏地表的方式,并分析土壤pH值、总有机碳、氮、磷、钾、水溶性盐浓度的变化及地表植物响应。结果表明:CO2入侵使土壤总有机碳相比于对照增加了1.56%~43.75%,总氮下降了0.88%~13.25%,氨氮与硝氮也同比下降,磷、钾、水溶性盐总体也是减少的,但土壤pH值有所上升,且各植物长势均较好,尤其是豌豆与萝卜的生长较好。结论:高浓度CO2入侵会对土壤理化性质产生一定影响,而且对植物的生长有促进作用。

  4. Correlation of Interfacial Transportation Properties of CdS/CdTe Heterojunction and Performance of CdTe Polycrystalline Thin-Film Solar Cells

    OpenAIRE

    Guanggen Zeng; Jingquan Zhang; Wenwu Wang; Lianghuan Feng

    2015-01-01

    The light and dark output performances of CdS/CdTe solar cells made by close-spaced sublimation (CSS) were investigated to elucidate the transportation properties of carriers at CdS/CdTe heterojunction interface. It has been found that the interfacial transportation properties were relatively sensitive to variations of the characteristics of heterojunction due to the series resistance and shunting effects. For the high quality cell with 12.1% efficiency, narrow depletion region of ~1.1 micron...

  5. Lattice Boltzmann simulations of supercritical CO2-water drainage displacement in porous media: CO2 saturation and displacement mechanism.

    Science.gov (United States)

    Yamabe, Hirotatsu; Tsuji, Takeshi; Liang, Yunfeng; Matsuoka, Toshifumi

    2015-01-06

    CO2 geosequestration in deep aquifers requires the displacement of water (wetting phase) from the porous media by supercritical CO2 (nonwetting phase). However, the interfacial instabilities, such as viscous and capillary fingerings, develop during the drainage displacement. Moreover, the burstlike Haines jump often occurs under conditions of low capillary number. To study these interfacial instabilities, we performed lattice Boltzmann simulations of CO2-water drainage displacement in a 3D synthetic granular rock model at a fixed viscosity ratio and at various capillary numbers. The capillary numbers are varied by changing injection pressure, which induces changes in flow velocity. It was observed that the viscous fingering was dominant at high injection pressures, whereas the crossover of viscous and capillary fingerings was observed, accompanied by Haines jumps, at low injection pressures. The Haines jumps flowing forward caused a significant drop of CO2 saturation, whereas Haines jumps flowing backward caused an increase of CO2 saturation (per injection depth). We demonstrated that the pore-scale Haines jumps remarkably influenced the flow path and therefore equilibrium CO2 saturation in crossover domain, which is in turn related to the storage efficiency in the field-scale geosequestration. The results can improve our understandings of the storage efficiency by the effects of pore-scale displacement phenomena.

  6. Ordered oxygen deficient ‘112’ perovskites, LnBaCo2O5.50+: complex magnetism and transport properties

    Indian Academy of Sciences (India)

    B Raveau; Md Motin Seikh; V Pralong; V Caignaert

    2009-06-01

    The ordered oxygen deficient `112’ perovskites, LnBaCo2O5.50+ (Ln = lanthanide or Y), exhibit a very flexible structure which can either uptake ( > 0) or release oxygen ( < 0) depending on the experimental conditions of synthesis and on the size of the lanthanide. These compounds exhibit remarkably complex magnetic transitions, metal–insulator transition and exceptionally high magnetoresistance. We show herein that their physics is mainly dominated by three different ferromagnetic states, depending on the cobalt valency: FM1 for = 0 (Co3+), FM2 for < 0 (Co2+/Co3+) and FM3 for > 0 (Co3+/Co4+). The competition between ferromagnetism and antiferromagnetism in these phases and the various transitions are discussed taking into consideration the spin state of cobalt, the issue of phase separation and the effect of cobalt coordination and disproportionation.

  7. Single fiber push-out characterization of interfacial mechanical properties in unidirectional CVI-C/SiC composites by the nano-indentation technique

    Science.gov (United States)

    Zhang, Lifeng; Ren, Chengzu; Zhou, Changling; Xu, Hongzhao; Jin, Xinmin

    2015-12-01

    The characterization of interfaces in woven ceramic matrix composites is one of the most challenging problems in composite application. In this investigation, a new model material consisting of the chemical vapor infiltration unidirectional C/SiC composites with PyC fiber coating were prepared and evaluated to predict the interfacial mechanic properties of woven composites. Single fiber push-out/push-back tests with the Berkovich indenter were conducted on the thin sliced specimens using nano-indentation technique. To give a detailed illustration of the interfacial crack propagation and failure mechanism, each sector during the push-out process was analyzed at length. The test results show that there is no detectable difference between testing a fiber in a direct vicinity to an already tested fiber and testing a fiber in vicinity to not-pushed fibers. Moreover, the interface debonding and fiber sliding mainly occur at the PyC coating, and both the fiber and surrounding matrix have no plastic deformation throughout the process. Obtained from the load-displacement curve, the interfacial debonding strength (IDS) and friction stress (IFS) amount to, respectively, 35 ± 5 MPa and 10 ± 1 MPa. Based on the findings, the interfacial properties with PyC fiber coating can be predicted. Furthermore, it is expected to provide a useful guideline for the design, evaluation and optimal application of CVI-C/SiC.

  8. Effect of interfacial layers on physical and electrical properties of dinaphtho[2,3-b:2‧,3‧-d]thiophene organic thin-film transistors

    Science.gov (United States)

    Shaari, Safizan; Naka, Shigeki; Okada, Hiroyuki

    2017-03-01

    We fabricated hexyl-substituted dinaphtho[2,3-b:2‧,3‧-d]thiophene (C6-DNT-V) organic thin-film transistors (OTFTs) with different interfacial layers. The interfacial layers comprised various types of polymers, polyimide, self-assembled monolayers, and high-κ materials. We investigated the effect of interfacial layers on the physical and electrical properties of C6-DNT-V OTFTs. The relationships between mobility and contact angle, threshold voltage and contact angle, on/off ratio and contact angle, mobility and X-ray diffraction intensity, and mobility and dielectric constant were investigated. We found that the contact angle strongly affected the threshold voltage, and the correlation coefficient was calculated to be 0.88. This is due to the fact that use of interfacial layers on the dielectric surface changes the contact angle and hence the surface energy. The altered surface energy will contribute to a change in the grain boundary of C6-DNT-V and affect the shift in threshold voltage. The relationships between other properties showed correlation coefficients of lower than 0.51.

  9. Hydrogenation reactions using scCO2 as a solvent in microchannel reactors.

    Science.gov (United States)

    Kobayashi, Juta; Mori, Yuichiro; Kobayashi, Shū

    2005-05-28

    We have developed an effective microfluidic system for hydrogenation reactions in scCO(2); the reactions proceeded very rapidly (within 1 second), by making the best use of scCO(2) and utilizing the large specific interfacial area of the microchannel reactor, and high reaction productivity was attained in each channel.

  10. Effect of Sr doping on the electrochemical properties of bi-functional oxygen electrode PrBa1-xSrxCo2O5+δ

    Science.gov (United States)

    Wu, Zhouling; Sun, Li-Ping; Xia, Tian; Huo, Li-Hua; Zhao, Hui; Rougier, Aline; Grenier, Jean-Claude

    2016-12-01

    Sr-doped double perovskite oxides PrBa1-xSrxCo2O5+δ (x = 0.0-1.0) are prepared and characterized by X-ray diffraction, X-ray photoelectron spectra, cyclic voltammetry and linear sweep voltammetry, respectively. Sr2+ doping is found to promote the electrocatalytic activity towards both oxygen evolution reduction and oxygen reduction reaction, due to the concentration enhancement of Co4+ (eg = 1) on the oxide surface. The PrBa0.25Sr0.75Co2O5.95 catalyst, with the highest concentration of Co4+, exhibits the superior electrocatalytic activity. The onset potential, Tafel slope and the overpotential at given current density of 10.0 mA·cmgeom-2 for the OER are 1.52 V, 75.8 mV·dec-1 and 0.42 V, respectively, comparable to the currently reported high performance OER catalysts. At the same time, the onset potential, Tafel slope, limiting current density and electron transfer number of PrBa0.25Sr0.75Co2O5.95 for ORR are 0.753 V, 58.3 mV·dec-1, 4.081 mA·cmgeom-2 and n = 3.92, respectively, implying much improved ORR activity.

  11. Effects of CO2-induced pH reduction on the exoskeleton structure and biophotonic properties of the shrimp Lysmata californica.

    Science.gov (United States)

    Taylor, Jennifer R A; Gilleard, Jasmine M; Allen, Michael C; Deheyn, Dimitri D

    2015-06-01

    The anticipated effects of CO2-induced ocean acidification on marine calcifiers are generally negative, and include dissolution of calcified elements and reduced calcification rates. Such negative effects are not typical of crustaceans for which comparatively little ocean acidification research has been conducted. Crustaceans, however, depend on their calcified exoskeleton for many critical functions. Here, we conducted a short-term study on a common caridean shrimp, Lysmata californica, to determine the effect of CO2-driven reduction in seawater pH on exoskeleton growth, structure, and mineralization and animal cryptic coloration. Shrimp exposed to ambient (7.99 ± 0.04) and reduced pH (7.53 ± 0.06) for 21 days showed no differences in exoskeleton growth (percent increase in carapace length), but the calcium weight percent of their cuticle increased significantly in reduced pH conditions, resulting in a greater Ca:Mg ratio. Cuticle thickness did not change, indicating an increase in the mineral to matrix ratio, which may have mechanical consequences for exoskeleton function. Furthermore, there was a 5-fold decrease in animal transparency, but no change in overall shrimp coloration (red). These results suggest that even short-term exposure to CO2-induced pH reduction can significantly affect exoskeleton mineralization and shrimp biophotonics, with potential impacts on crypsis, physical defense, and predator avoidance.

  12. Structural evaluation and nonlinear optical properties of Ni/NiO, Ni/NiCo2O4 and Co/Co3O4 nanocomposites

    Science.gov (United States)

    Rahulan, K. Mani; Padmanathan, N.; Philip, Reji; Balamurugan, S.; Kanakam, Charles C.

    2013-10-01

    Nanocomposites of Ni/NiO, Ni/NiCo2O4 and Co/Co3O4 have been synthesized by a chemical reduction technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) images confirm the mixed composite nature of the sample and uniform particle size of approximately 13 nm. Formation of Ni/NiCo3O4 solid solution or NiCo2O4 spinel phase in the mixed composite is confirmed by energy dispersive X-ray (EDX) spectrum. Magnetic hysteresis (M-H) curves of the nanocomposites show excellent ferromagnetic (FM) nature at room temperature. Nonlinear optical transmission of the nanocomposites is measured using the open aperture Z-scan technique employing 7 nanosecond laser pulses at 532 nm. Experimental results show that NiO/NiO-Co3O4/Co3O4 nanocomposites exhibit good optical limiting performance. From the measurements and numerical fitting of the data to theory, it is found that nonlinear absorption has contributions from excited state absorption and two-photon absorption. Optical limiting is enhanced in Co3O4 and Ni/NiCo2O4 in which the Co3O4 content has a larger volume ratio.

  13. Modification of PSf membrane nanostructure using different fabrication parameters and investigation of the CO2 separation properties of PDMS-coated PSf composite membranes

    Directory of Open Access Journals (Sweden)

    M. Pakizeh

    2013-06-01

    Full Text Available The effects of preparation parameters on the performance and morphology of polydimethylsiloxane/ polysulfone (PDMS/PSf membranes were investigated. The PDMS layer is mainly used for sealing the defects of the PSf selective layer. The membrane morphologies were characterized by using scanning electron microscopy (SEM. The CO2/CH4 separation performance of membranes was studied by a pure gas permeation experimental set up. According to the SEM results, decreasing the water/N,N-dimethylacetamide (DMAc ratio as the coagulation medium from pure water to mixture of 90 vol.% DMAc and 10 vol.% water resulted in complete disappearance of macrovoids and also a lowering of the membrane selectivity. Permselectivity results showed that the ideal CO2/CH4 separation factor of the membranes was improved by the presence of the non-solvent additive to the polymer solution. It was also observed that reduction of the coagulation bath temperature (CBT led to elimination of macrovoids which affect gas separation performance. Using methanol as a coagulant resulted in a less selective membrane compared with ethanol and water as coagulants and the CO2 permeance was about 3 and 9 times greater than with ethanol and water as coagulants, respectively.

  14. Clay/Polyaniline Hybrid through Diazonium Chemistry: Conductive Nanofiller with Unusual Effects on Interfacial Properties of Epoxy Nanocomposites.

    Science.gov (United States)

    Jlassi, Khouloud; Chandran, Sarath; Poothanari, Mohammed A; Benna-Zayani, Mémia; Thomas, Sabu; Chehimi, Mohamed M

    2016-04-12

    The concept of conductive network structure in thermoset matrix without sacrificing the inherent mechanical properties of thermoset polymer (e.g., epoxy) is investigated here using "hairy" bentonite fillers. The latter were prepared through the in situ polymerization of aniline in the presence of 4-diphenylamine diazonium (DPA)-modified bentonite (B-DPA) resulting in a highly exfoliated bentonite-DPA/polyaniline (B-DPA/PANI). The nanocomposite filler was mixed with diglycidyl ether of bisphenol A (DGEBA), and the curing agent (4,4'-diaminodiphenylsulfone) (DDS) at high temperature in order to obtain nanocomposites through the conventional melt mixing technique. The role of B-DPA in the modification of the interface between epoxy and B-DPA/polyaniline (B-DPA/PANI) is investigated and compared with the filler B/PANI prepared without any diazonium modification of the bentonite. Synergistic improvement in dielectric properties and mechanical properties points to the fact that the DPA aryl groups from the diazonium precursor significantly modify the interface by acting as an efficient stress transfer medium. In DPA-containing nanocomposites, unique fibril formation was observed on the fracture surface. Moreover, dramatic improvement (210-220%) in fracture toughness of epoxy composite was obtained with B-DPA/PANI filler as compared to the weak improvement of 20-30% noted in the case of the B/PANI filler. This work shows that the DPA diazonium salt has an important effect on the improvement of the interfacial properties and adhesion of DGEBA and clay/PANI nanofillers.

  15. Comparison of hydrolytic and non-hydrolytic atomic layer deposition chemistries: Interfacial electronic properties at alumina-silicon interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Marstell, Roderick J.; Strandwitz, Nicholas C., E-mail: strand@lehigh.edu [Department of Materials Science and Engineering and Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, Pennsylvania 18015 (United States)

    2015-11-14

    We report the differences in the passivation and electronic properties of aluminum oxide (Al{sub 2}O{sub 3}) deposited on silicon via traditional hydrolytic atomic layer deposition (ALD) and non-hydrolytic (NH) ALD chemistries. Traditional films were grown using trimethylaluminum (TMA) and water and NHALD films grown using TMA and isopropanol at 300 °C. Hydrolytically grown ALD films contain a smaller amount of fixed charge than NHALD films (oxide fixed charge Q{sub f} {sub Traditional} = −8.1 × 10{sup 11 }cm{sup −2} and Q{sub f} {sub NHALD} = −3.6 × 10{sup 12 }cm{sup −2}), and a larger degree of chemical passivation than NHALD films (density of interface trap states, D{sub it} {sub Traditional} = 5.4 × 10{sup 11 }eV{sup −1 }cm{sup −2} and D{sub it} {sub NHALD} = 2.9 × 10{sup 12 }eV{sup −1 }cm{sup −2}). Oxides grown with both chemistries were found to have a band gap of 7.1 eV. The conduction band offset was 3.21 eV for traditionally grown films and 3.38 eV for NHALD. The increased D{sub it} for NHALD films may stem from carbon impurities in the oxide layer that are at and near the silicon surface, as evidenced by both the larger trap state time constant (τ{sub Traditional} = 2.2 × 10{sup −9} s and τ{sub NHALD} = 1.7 × 10{sup −7} s) and the larger carbon concentration. We have shown that the use of alcohol-based oxygen sources in NHALD chemistry can significantly affect the resulting interfacial electronic behavior presenting an additional parameter for understanding and controlling interfacial electronic properties at semiconductor-dielectric interfaces.

  16. Density of aqueous solutions of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Julio E.

    2001-10-10

    In this report, we present a numerical representation for the partial molar volume of CO2 in water and the calculation of the corresponding aqueous solution density. The motivation behind this work is related to the importance of having accurate representations for aqueous phase properties in the numerical simulation of carbon dioxide disposal into aquifers as well as in geothermal applications. According to reported experimental data the density of aqueous solutions of CO2 can be as much as 2-3% higher than pure water density. This density variation might produce an influence on the groundwater flow regime. For instance, in geologic sequestration of CO2, convective transport mixing might occur when, several years after injection of carbon dioxide has stopped, the CO2-rich gas phase is concentrated at the top of the formation, just below an overlaying caprock. In this particular case the heavier CO2 saturated water will flow downward and will be replaced by water with a lesser CO2 content.

  17. Forecasting global atmospheric CO2

    Directory of Open Access Journals (Sweden)

    A. Agustí-Panareda

    2014-05-01

    Full Text Available A new global atmospheric carbon dioxide (CO2 real-time forecast is now available as part of the pre-operational Monitoring of Atmospheric Composition and Climate – Interim Implementation (MACC-II service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF Integrated Forecasting System (IFS. One of the strengths of the CO2 forecasting system is that the land surface, including vegetation CO2 fluxes, is modelled online within the IFS. Other CO2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO2 fluxes also lead to accumulating errors in the CO2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO2 fluxes compared to total optimized fluxes and the atmospheric CO2 compared to observations. The largest biases in the atmospheric CO2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO2 analyses based on the assimilation of CO2 satellite retrievals, as they

  18. STUDY ON PREPARATION, COMPLEX PERMITTIVITY,PERMEABILITY AND MICROWAVE PROPERTIES OF BaZnzCo2- zFe16O27/SiO2 MICROCRYSTALLINE GLASS CERAMICS

    Institute of Scientific and Technical Information of China (English)

    H.J. Zhang; X.L. Jia; X. Yao; L. Y. Zhang

    2003-01-01

    BaZnz Co2- z Fe16 O27 /SiO2 microcrystalline glass ceramics with Z=0.0, 0.5, 0.8 and 1.1 were prepared at temperature 1200℃ for 5h by citrate sol-gel process. The complex dielectric constant and complex permeability of BaZnzCo2-zFe16O27/SiO2-paraffin wax composites had been measured. Both the complex dielectric constant and dielectric loss exhibit almost no variation with frequency in 0.1-6.0GHz. The real part of permeability decreases with increasing frequency for all samples, and the imaginary part of permeability exhibits a clear resonance peak at 1.44GHz for Co2 W/SiO2,1.32GHz for Zn0.5 Co1.5 W/SiO2, 1.20GHz for Zn0.8Co1.2 W/SiO2, and 1.08GHz for Zn1.1 Co0.9 W/SiO2. It is also showed that the content of zinc has a close effect on the magnetic properties of BaZnz Co2-zFe16 O27/SiO2 microcrystalline glass ceramics,the greater the zinc content, the higher the values of imaginary part of permeability and magnetic loss.

  19. CuO-ZnO-ZrO2的柠檬酸燃烧法制备及其催化CO2加氢合成甲醇的性能%Preparation of CuO-ZnO-ZrO2 by Citric Acid Combustion Method and Its Catalytic Property for Methanol Synthesis from CO2 Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    郭晓明; 毛东森; 卢冠忠; 王嵩

    2012-01-01

    采用柠檬酸燃烧法制备了CuO-ZnO-ZrO2 (CZZ)催化剂,并将其用于CO2加氢合成甲醇反应.按推进剂化学原理对燃烧反应进行了分析,并采用热重-差热分析(TG-DTA)技术记录了其燃烧行为.采用X射线衍射(XRD)、氮吸附、程序升温还原(TPR)及氧化亚氮(N2O)反应吸附技术对制得的催化剂进行了表征.结果表明:柠檬酸燃烧法的燃烧过程比较温和,燃料用量对催化剂物化和催化性能的影响不大,并结合燃烧反应的特点进行了解释.此外,还对三种燃料(柠檬酸、尿素和甘氨酸)的用量与CZZ性能之间的关系进行了比较,表明柠檬酸作燃料具有更好的工艺可控性.柠檬酸燃烧法是一种简单、快速且有效的制备CZZ催化剂的方法.%CuO-ZnO-ZrO2 (CZZ) catalysts for methanol synthesis from CO2 hydrogenation were prepared by a citric acid combustion method. The combustion reactions were analyzed in terms of propellant chemistry and the combustion behavior was recorded by thermo-gravimetric/differential thermal analysis (TG-DTA). The as-prepared CZZ powders were investigated with X-ray diffraction (XRD), N2 adsorption, temperature-programmed reduction (TPR), and reactive N2O adsorption techniques and the catalytic activities were evaluated for methanol synthesis from CO2 hydrogenation. The results show that the influence of citric acid quantity on the physicochemical and catalytic properties of CZZ is subtle, and the reason is related to the characteristics of the combustion reaction. Furthermore, the relationship between the quantity of fuel (citric acid, urea, and glycine) and the properties of the catalysts was determined. The citric acid combustion method exhibits better controllability and it is a simple, fast, and valuable route for the preparation of the CZZ catalyst for methanol synthesis from CO2 hydrogenation.

  20. India Co2 Emissions

    Science.gov (United States)

    Sharan, S.; Diffenbaugh, N. S.

    2010-12-01

    created a balance in between the “developed” and developing countries. If India was producing the same amounts of emissions per capita as the it would have a total of 20 billion metric tons of CO2 emissions annually.

  1. Interfacial effects on the behavior of partially bonded metal matrix composite properties

    Science.gov (United States)

    Caruso, J. J.; Chamis, C. C.

    1990-01-01

    A novel computational method developed at NASA-Lewis in order to predict the behavior of unidirectional composites has been used to explore the effects of partial debonding and fiber fracture on the behavior of room temperature and high temperature metal-matrix composites. Attention is presently given to the influence of disbonding, which occurs with fractured fibers, on the ply properties of metal-matrix composites with orthotropic fibers, in the case of a graphite fiber-reinforced copper-matrix composite. It is shown that, for small amounts of partial bonding on fractured fibers, composite material properties are not significantly affected.

  2. CO2 sequestration in basalts: laboratory measurements

    Science.gov (United States)

    Otheim, L. T.; Adam, L.; van Wijk, K.; McLing, T. L.; Podgorney, R. K.

    2010-12-01

    Geologic sequestration of CO2 is proposed as the only promising large-scale method to help reduce CO2 gas emission by its capture at large point sources and subsequent long-term storage in deep geologic formations. Reliable and cost-effective monitoring will be important aspect of ensuring geological sequestration is a safe, effective, and acceptable method for CO2 emissions mitigation. Once CO2 injection starts, seismic methods can be used to monitor the migration of the carbon dioxide plume. To calibrate changes in rock properties from field observations, we propose to first analyze changes in elastic properties on basalt cores. Carbon dioxide sequestration in basalt rocks results in fluid substitution and mixing of CO2 with water and rock mineralizations. Carbon dioxide sequestration in mafic rocks creates reactions such as Mg2SiO 4 + CaMgSi2O 6 + 4CO2 = Mg 3Ca(CO 3) 4 + 3SiO2 whereby primary silicate minerals within the basalt react with carbonic acid laden water to creating secondary carbonate minerals and silicates. Using time-lapse laboratory scale experiments, such as laser generated ultrasonic wave propagation; it is possible to observe small changes in the physical properties of a rock. We will show velocity and modulus measurements on three basalt core samples for different saturation. The ultimate goal of the project is to track seismic changes due to fluid substitution and mineralization. The porosity of our basalts ranges from 8% to 12%, and the P-wave velocity increases by 20% to 40% from dry to water saturated conditions. Petrographic analysis (CT-scans, thin sections, XRF, XRf) will aid in the characterization of the mineral structure in these basalts and its correlation to seismic properties changes resulting from fluid substitution and mineralization.

  3. Interfacial tension and wettability in water-carbon dioxide systems: Experiments and self-consistent field modeling

    NARCIS (Netherlands)

    Banerjee, S.; Hassenklover, E.; Kleijn, J.M.; Cohen Stuart, M.A.; Leermakers, F.A.M.

    2013-01-01

    This paper presents experimental and modeling results on water–CO2 interfacial tension (IFT) together with wettability studies of water on both hydrophilic and hydrophobic surfaces immersed in CO2. CO2–water interfacial tension (IFT) measurements showed that the IFT decreased with increasing pressur

  4. Electronic Structure, Phonon Dynamical Properties, and CO2 Capture Capability of Na2 -xMxZr O3 (M =Li ,K): Density-Functional Calculations and Experimental Validations

    Science.gov (United States)

    Duan, Yuhua; Lekse, Jonathan; Wang, Xianfeng; Li, Bingyun; Alcántar-Vázquez, Brenda; Pfeiffer, Heriberto; Halley, J. W.

    2015-04-01

    The electronic structural and phonon properties of Na2 -αMαZr O3 (M =Li ,K, α =0.0 ,0.5,1.0,1.5,2.0) are investigated by first-principles density-functional theory and phonon dynamics. The thermodynamic properties of CO2 absorption and desorption in these materials are also analyzed. With increasing doping level α , the binding energies of Na2 -αLiαZr O3 are increased while the binding energies of Na2 -αKαZrO3 are decreased to destabilize the structures. The calculated band structures and density of states also show that, at the same doping level, the doping sites play a significant role in the electronic properties. The phonon dispersion results show that few soft modes are found in several doped configurations, which indicates that these structures are less stable than other configurations with different doping levels. From the calculated relationships among the chemical-potential change, the CO2 pressure, and the temperature of the CO2 capture reactions by Na2 -αMαZr O3 , and from thermogravimetric-analysis experimental measurements, the Li- and K-doped mixtures Na2 -αMαZr O3 have lower turnover temperatures (Tt ) and higher CO2 capture capacities, compared to pure Na2Zr O3 . The Li-doped systems have a larger Tt decrease than the K-doped systems. When increasing the Li-doping level α , the Tt of the corresponding mixture Na2 -αLiαZr O3 decreases further to a low-temperature range. However, in the case of K-doped systems Na2 -αKαZr O3 , although doping K into Na2Zr O3 initially shifts its Tt to lower temperatures, further increases of the K-doping level α causes Tt to increase. Therefore, doping Li into Na2Zr O3 has a larger influence on its CO2 capture performance than the K-doped Na2Zr O3 . Compared with pure solids M2Zr O3 , after doping with other elements, these doped systems' CO2 capture performances are improved.

  5. Effect of electrostatic boundary conditions and system size on the interfacial properties of water and aqueous solutions

    Science.gov (United States)

    Spohr, E.

    1997-10-01

    The consequences of the choice of electrostatic boundary conditions on the interfacial properties of water and on the free energy of ion adsorption from aqueous solution have been investigated. The Ewald summation method for lattices, which are periodic in two dimensions, is considered to be the most adequate method in slabs of finite thickness in one dimension. In agreement with the physics of the problem a field-free region in the bulk phases is observed. The use of spherical truncation methods like the shifted-force method leads to unphysical results. The electrostatic potential depends on the size of the system. Ewald summation methods for three-dimensional lattices lead to results in qualitative agreement with the corresponding two-dimensional lattice sum. The computed value of the electrostatic potential depends on an additional parameter, namely the lattice constant c in the direction perpendicular to the interface. The results for Ewald summation in three dimensions converge to the results for Ewald summation in two dimensions for large c, the shifted-force results converge to the same limit, when the surface area of the simulation cell becomes very large and the cut-off distance increases accordingly.

  6. The Changes in Electrical and Interfacial Properties of Polyimide Exposed to Dielectric Barrier Discharge in SF6 Medium

    Directory of Open Access Journals (Sweden)

    Hafiz Z. Alisoy

    2013-01-01

    Full Text Available The formation mechanism of space charges in polyimide (PI which was exposed to dielectric barrier discharge (DBD in SF6 medium and the effects of the space charges on interfacial and electrical properties of PI were investigated. The variation of normalized surface charge density on PI sample was calculated and illustrated for different DBD exposure times. The surface potential was measured to determine the effect of the space charges on the sample. Then, the contact angle values were measured to obtain the relation between the surface energy and the surface charge density. The expressions for the total charge and the concentration of trapped electrons were derived by using Poisson and continuity equations at stationary state. The space charges were determined experimentally by using thermally stimulated depolarization current (TSDC method. Also, SEM image and FTIR spectrum of virgin and treated samples were presented to observe the structural variations. It was seen that the approach for the formation mechanism of the space charges agreed with the experimental data. However, it was concluded particularly for the short-time DBD treatments that the space charges accumulated in the sample should be considered besides the effects of surface functionalization in the determination of the surface energy.

  7. The Changes in Electrical and Interfacial Properties of Polyimide Exposed to Dielectric Barrier Discharge in SF6 Medium

    Science.gov (United States)

    Alisoy, Hafiz Z.; Koseoglu, Murat

    2013-01-01

    The formation mechanism of space charges in polyimide (PI) which was exposed to dielectric barrier discharge (DBD) in SF6 medium and the effects of the space charges on interfacial and electrical properties of PI were investigated. The variation of normalized surface charge density on PI sample was calculated and illustrated for different DBD exposure times. The surface potential was measured to determine the effect of the space charges on the sample. Then, the contact angle values were measured to obtain the relation between the surface energy and the surface charge density. The expressions for the total charge and the concentration of trapped electrons were derived by using Poisson and continuity equations at stationary state. The space charges were determined experimentally by using thermally stimulated depolarization current (TSDC) method. Also, SEM image and FTIR spectrum of virgin and treated samples were presented to observe the structural variations. It was seen that the approach for the formation mechanism of the space charges agreed with the experimental data. However, it was concluded particularly for the short-time DBD treatments that the space charges accumulated in the sample should be considered besides the effects of surface functionalization in the determination of the surface energy. PMID:23844414

  8. Interfacial Properties of Monolayer and Bilayer MoS2 Contacts with Metals: Beyond the Energy Band Calculations.

    Science.gov (United States)

    Zhong, Hongxia; Quhe, Ruge; Wang, Yangyang; Ni, Zeyuan; Ye, Meng; Song, Zhigang; Pan, Yuanyuan; Yang, Jinbo; Yang, Li; Lei, Ming; Shi, Junjie; Lu, Jing

    2016-01-01

    Although many prototype devices based on two-dimensional (2D) MoS2 have been fabricated and wafer scale growth of 2D MoS2 has been realized, the fundamental nature of 2D MoS2-metal contacts has not been well understood yet. We provide a comprehensive ab initio study of the interfacial properties of a series of monolayer (ML) and bilayer (BL) MoS2-metal contacts (metal = Sc, Ti, Ag, Pt, Ni, and Au). A comparison between the calculated and observed Schottky barrier heights (SBHs) suggests that many-electron effects are strongly suppressed in channel 2D MoS2 due to a charge transfer. The extensively adopted energy band calculation scheme fails to reproduce the observed SBHs in 2D MoS2-Sc interface. By contrast, an ab initio quantum transport device simulation better reproduces the observed SBH in 2D MoS2-Sc interface and highlights the importance of a higher level theoretical approach beyond the energy band calculation in the interface study. BL MoS2-metal contacts generally have a reduced SBH than ML MoS2-metal contacts due to the interlayer coupling and thus have a higher electron injection efficiency.

  9. Effects of surface pressure on the properties of Langmuir monolayers and interfacial water at the air-water interface.

    Science.gov (United States)

    Lin, Wei; Clark, Anthony J; Paesani, Francesco

    2015-02-24

    The effects of surface pressure on the physical properties of Langmuir monolayers of palmitic acid (PA) and dipalmitoylphosphatidic acid (DPPA) at the air/water interface are investigated through molecular dynamics simulations with atomistic force fields. The structure and dynamics of both monolayers and interfacial water are compared across the range of surface pressures at which stable monolayers can form. For PA monolayers at T = 300 K, the untilted condensed phase with a hexagonal lattice structure is found at high surface pressure, while the uniformly tilted condensed phase with a centered rectangular lattice structure is observed at low surface pressure, in agreement with the available experimental data. A state with uniform chain tilt but no periodic spatial ordering is observed for DPPA monolayers on a Na(+)/water subphase at both high and low surface pressures. The hydrophobic acyl chains of both monolayers pack efficiently at all surface pressures, resulting in a very small number of gauche defects. The analysis of the hydrogen-bonding structure/dynamics at the monolayer/water interface indicates that water molecules hydrogen-bonded to the DPPA head groups reorient more slowly than those hydrogen-bonded to the PA head groups, with the orientational dynamics becoming significantly slower at high surface pressure. Possible implications for physicochemical processes taking place on marine aerosols in the atmosphere are discussed.

  10. Mixing antiferromagnets to tune NiFe-[IrMn/FeMn] interfacial spin-glasses, grains thermal stability, and related exchange bias properties

    Energy Technology Data Exchange (ETDEWEB)

    Akmaldinov, K. [SPINTEC, UMR 8191 CNRS/INAC-CEA/UJF-Grenoble 1/Grenoble-INP, F-38054 Cedex (France); CROCUS Technology, F-38025 Grenoble (France); Ducruet, C.; Portemont, C. [CROCUS Technology, F-38025 Grenoble (France); Joumard, I.; Prejbeanu, I. L.; Dieny, B.; Baltz, V., E-mail: vincent.baltz@cea.fr [SPINTEC, UMR 8191 CNRS/INAC-CEA/UJF-Grenoble 1/Grenoble-INP, F-38054 Cedex (France)

    2014-05-07

    Spintronics devices and in particular thermally assisted magnetic random access memories require a wide range of ferromagnetic/antiferromagnetic (F/AF) exchange bias (EB) properties and subsequently of AF materials to fulfil diverse functionality requirements for the reference and storage. For the reference layer, large EB energies and high blocking temperature (T{sub B}) are required. In contrast, for the storage layer, mostly moderate T{sub B} are needed. One of the present issues is to find a storage layer with properties intermediate between those of IrMn and FeMn and in particular: (i) with a T{sub B} larger than FeMn for better stability at rest-T but lower than IrMn to reduce power consumption at write-T and (ii) with improved magnetic interfacial quality, i.e., with reduced interfacial glassy character for lower properties dispersions. To address this issue, the EB properties of F/AF based stacks were studied for various mixed [IrMn/FeMn] AFs. In addition to EB loop shifts, the F/AF magnetic interfacial qualities and the AF grains thermal stability are probed via measurements of the low- and high-temperature contributions to the T{sub B} distributions, respectively. A tuning of the above three parameters is observed when evolving from IrMn to FeMn via [IrMn/FeMn] repetitions.

  11. Study on the interfacial adhesion property of low-k thin film by the surface acoustic waves with cohesive zone model

    Science.gov (United States)

    Xiao, Xia; Qi, Haiyang; Tao, Ye; Kikkawa, Takamaro

    2016-12-01

    The cohesive zone model being increasingly used in discrete fracture processes simulation is adopted to study the interfacial adhesion property of low dielectric constant film deposited on the silicon substrate in this work. The two parameters, maximum normal traction and normal interface characteristic length in cohesive zone model, are taken into account to calculate the theoretical surface acoustic wave dispersion curves. Broadband surface acoustic wave signals with effective frequency up to 200 MHz are generated by short pulse ultraviolet laser source and detected by a piezoelectric transducer. The interfacial adhesion properties of dense and porous films determined accurately by matching the experimental dispersion curves with the calculated theoretical dispersion curves are 10.7 PPa/m and 2.8 PPa/m, respectively. The results show that the adhesion quality of dense low dielectric constant film is better than that of the porous. The study exhibits that the adhesion properties determined by improved laser-generated surface acoustic wave technique have the same trends with the test results of the nanoscratch technique, which indicates that the surface acoustic wave technique with cohesive zone model is a promising and nondestructive method for determining interfacial adhesion properties between low dielectric constant film and substrate.

  12. DFT study on structure, electronic properties, and reactivity of cis-isomers of [(NC5H4-S)2Fe(CO)2

    Indian Academy of Sciences (India)

    Charles A Mebi

    2011-09-01

    Three cis-isomers of [(NC5H4-S)2Fe(CO)2], models for the active site of [Fe] hydrogenase, have been examined by computational method at DFT B3LYP/6-311+G(d,p) level. The computed geometric parameters are remarkably close to experimental values. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential, and electrophilicity) are calculated for the isomers and used to predict their relative stability and reactivity. The chemical reactivity indices are found to be related to the bond angle defined by the cis carbonyls and the iron center.

  13. Magnetic properties and temperature-dependent half-metallicity of Co2Mn(Ga(1-x)Z(x)) (Z=Si, Ge, Sn) from first-principles calculation.

    Science.gov (United States)

    Luo, Hu-Bin; Hu, Qing-Miao; Li, Chun-Mei; Johansson, Börje; Vitos, Levente; Yang, Rui

    2013-04-17

    Using the first-principles exact muffin-tin orbitals method in combination with the coherent potential approximation, we investigated the magnetic properties, exchange interactions, and temperature-dependent half-metallicity of the Co2Mn(Ga1-xZx) (Z=Si, Ge, Sn) alloys. The total magnetic moment follows perfectly a previously proposed Slater-Pauling relation, i.e., μ0 = Nt - 24, with Nt being the number of valence electrons. The Co-Mn and Co1-Co2 (inter-sublattice) interactions are dominated by direct exchange, whereas the Co1-Co1 (intra-sublattice) interaction is characterized by superexchange. The Mn-Mn exchange interaction in Co2MnGa is of long-ranged RKKY-type. However, the Mn-Mn exchange interactions in Co2MnZ are relatively localized and can be attributed to superexchange. The Co-Mn, Co1-Co2 and Co1-Co1 total exchange interactions increase with x, whereas the Mn-Mn total exchange interactions show convex behavior. The calculated Curie temperature (TC) increases with x. The ability of Z to enhance TC follows the sequence of Si > Ge > Sn, in agreement with the experimental findings. The temperature dependence of the spin polarization at the Fermi level [P(T)] is investigated based on the disordered local moment model. P(T) drops abruptly at temperatures much lower than TC. At temperatures higher than 200 K, the composition with higher TC generally corresponds to larger P(T).

  14. A DFT study of the acid-base properties of anatase TiO2 and tetragonal ZrO2 by adsorption of CO and CO2 probe molecules

    Science.gov (United States)

    Chen, Hsin-Yi Tiffany; Tosoni, Sergio; Pacchioni, Gianfranco

    2016-10-01

    We have performed a comparative study of the acid-base characteristics of the surfaces of anatase TiO2 and tetragonal ZrO2. To this end we performed DFT + U calculations on CO and CO2 probe molecules adsorbed both on terraces and steps of the two oxides. For titania, CO adsorption results in a moderate adsorption energy (about - 0.3 eV) and in a positive shift of the Csbnd O stretching frequency (about + 40 cm- 1), typical of Lewis acid sites, with no clear difference in the acidity between terraces or steps. For zirconia we found a similar CO binding energy as for titania, and a CO vibrational shift that depends on the location of the Zr cation: negligible on terraces, similar to TiO2 on steps. We conclude that the acidic properties are similar in the two oxide surfaces. Things are different for CO2 adsorption. On titania the interaction is weak and surface carbonates compete with physisorbed CO2, indicating a weak basic character. On the contrary, on zirconia three types of stable carbonates have been identified. Their vibrational frequencies are consistent with IR measurements reported in the literature. The most stable species forms on steps of the t-ZrO2 surface and consists of a CO32 - unit which lies flat on the surface with the O atoms pointing towards three Zr ions. The species forms spontaneously by extraction of a lattice oxygen by an incoming CO2 molecule. The different reactivity points towards a much more pronounced basic character of zirconia compared to titania, at least if measured by CO2 adsorption.

  15. Electrical and physicochemical properties of atomic-layer-deposited HfO{sub 2} film on Si substrate with interfacial layer grown by nitric acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Hyun [Department of Advanced Materials Engineering, Hanyang University, Ansan 15588 (Korea, Republic of); Seok, Tae Jun; Jin, Hyun Soo [Department of Materials Science & Chemical Engineering, Hanyang University, Ansan 15588 (Korea, Republic of); Kim, Woo-Byoung, E-mail: woo7838@dankook.ac.kr [Department of Energy Engineering, Dankook University, Cheonan 330-714 (Korea, Republic of); Park, Tae Joo, E-mail: tjp@hanyang.ac.kr [Department of Advanced Materials Engineering, Hanyang University, Ansan 15588 (Korea, Republic of); Department of Materials Science & Chemical Engineering, Hanyang University, Ansan 15588 (Korea, Republic of)

    2016-03-01

    Graphical abstract: - Highlights: • Ultrathin SiO{sub 2} interfacial layers grown using nitric acid oxidation and O{sub 3} oxidation were adopted at the interface of HfO{sub 2}/Si. • Higher physical density of interfacial layer grown using nitric acid oxidation resulted in the suppressed Si diffusion from substrate into the film. • The interface properties as well as permittivity of the film were improved by adoption of interfacial layer grown using nitric acid oxidation. - Abstract: The ultrathin SiO{sub 2} interfacial layer (IL) was adopted at the interface between atomic-layer-deposited HfO{sub 2} gate dielectric film and a Si substrate, which was grown using nitric acid oxidation (NAO) and O{sub 3} oxidation (OZO) prior to HfO{sub 2} film deposition. X-ray photoelectron spectroscopy result revealed that Si diffusion from the substrate into the film was suppressed for the film with NAO compared to that with OZO, which was attributed to the higher physical density of IL. The electrical measurement using metal–insulator–semiconductor devices showed that the film with NAO exhibited higher effective permittivity and lower densities of fixed charge and slow state at the interface. Furthermore, the leakage current density at an equivalent electrical thickness was lower for the film with NAO than OZO.

  16. Physicochemical and mechanical interfacial properties of trifluorometryl groups containing epoxy resin cured with amine

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo-Jin [Advanced Materials Division, Korea Research Institute of Chemical Technology, PO Box 107, Yusong, Daejeon 305-600 (Korea, Republic of)]. E-mail: psjin@krict.re.kr; Jin, Fan-Long [Advanced Materials Division, Korea Research Institute of Chemical Technology, PO Box 107, Yusong, Daejeon 305-600 (Korea, Republic of); Shin, Jae-Sup [Department of Chemistry, Chungbuk National University, Chongju 361-763 (Korea, Republic of)

    2005-01-15

    A phenyl-trifluoromethyl (-Ph-CF{sub 3}) groups modified epoxy resin, diglycidylether of bisphenol A-fluorine (DGEBA-F), was synthesized and the physical properties, such as curing behaviors, thermal stabilities, and dielectric constant of the DGEBA-F/4,4'-diaminodiphenyl methane (DDM) system were investigated and compared with commercial DGEBA/DDM system. For the mechanical behaviors of the specimens, the fracture toughness and impact tests were performed, and their fractured surfaces were examined by using a scanning electron microscope (SEM). The dielectric constant values of the DGEBA-F/DDM system were lower than those of the DGEBA/DDM system and the mechanical properties of the casting DGEBA-F specimens were higher than those of the DGEBA specimens. This was probably due to the fact that the introduction of the -Ph-CF{sub 3} groups into the side chain of the epoxy resin resulted in improving the electrical properties and toughness of the cured DGEBA-F epoxy resin.

  17. Development of Novel CO2 Adsorbents for Capture of CO2 from Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Fauth, D.J.; Filburn, T.P. (University of Hartford, West Hartford, CT); Gray, M.L.; Hedges, S.W.; Hoffman, J.; Pennline, H.W.; Filburn, T.

    2007-06-01

    Capturing CO2 emissions generated from fossil fuel-based power plants has received widespread attention and is considered a vital course of action for CO2 emission abatement. Efforts are underway at the Department of Energy’s National Energy Technology Laboratory to develop viable energy technologies enabling the CO2 capture from large stationary point sources. Solid, immobilized amine sorbents (IAS) formulated by impregnation of liquid amines within porous substrates are reactive towards CO2 and offer an alternative means for cyclic capture of CO2 eliminating, to some degree, inadequacies related to chemical absorption by aqueous alkanolamine solutions. This paper describes synthesis, characterization, and CO2 adsorption properties for IAS materials previously tested to bind and release CO2 and water vapor in a closed loop life support system. Tetraethylenepentamine (TEPA), acrylonitrile-modified tetraethylenepentamine (TEPAN), and a single formulation consisting of TEPAN and N, N’-bis(2-hydroxyethyl)ethylenediamine (BED) were individually supported on a poly (methyl methacrylate) (PMMA) substrate and examined. CO2 adsorption profiles leading to reversible CO2 adsorption capacities were obtained using thermogravimetry. Under 10% CO2 in nitrogen at 25°C and 1 atm, TEPA supported on PMMA over 60 minutes adsorbed ~3.2 mmol/g{sorbent} whereas, TEPAN supported on PMMA along with TEPAN and BED supported on PMMA adsorbed ~1.7 mmol/g{sorbent} and ~2.3 mmol/g{sorbent} respectively. Cyclic experiments with a 1:1 weight ratio of TEPAN and BED supported on poly (methyl methacrylate) beads utilizing a fixed-bed flow system with 9% CO2, 3.5% O2, nitrogen balance with trace gas constituents were studied. CO2 adsorption capacity was ~ 3 mmols CO2/g{sorbent} at 40°C and 1.4 atm. No beneficial effect on IAS performance was found using a moisture-laden flue gas mixture. Tests with 750 ppmv NO in a humidified gas stream revealed negligible NO sorption onto the IAS. A high SO2

  18. Life cycle inventory of CO2 in an enhanced oil recovery system.

    Science.gov (United States)

    Jaramillo, Paulina; Griffin, W Michael; McCoy, Sean T

    2009-11-01

    Enhanced oil recovery (EOR) has been identified as a method of sequestering CO(2) recovered from power plants. In CO(2)-flood EOR, CO(2) is injected into an oil reservoir to reduce oil viscosity, reduce interfacial tension, and cause oil swelling which improves oil recovery. Previous studies suggest that substantial amounts of CO(2) from power plants could be sequestered in EOR projects, thus reducing the amount of CO(2) emitted into the atmosphere. This claim, however, ignores the fact that oil, a carbon rich fuel, is produced and 93% of the carbon in petroleum is refined into combustible products ultimately emitted into the atmosphere. In this study we analyze the net life cycle CO(2)emissions in an EOR system. This study assesses the overall life cycle emissions associated with sequestration via CO(2)-flood EOR under a number of different scenarios and explores the impact of various methods for allocating CO(2) system emissions and the benefits of sequestration.

  19. Structure and Magnetic Properties of Cu3Ni2SbO6 and Cu3Co2SbO6 Delafossites with Honeycomb Lattices

    DEFF Research Database (Denmark)

    Roudebush, J. H.; Andersen, Niels Hessel; Ramlau, R.;

    2013-01-01

    The crystal structures of two Delafossites, Cu3Ni2SbO6 and Cu3Co2SbO6, are determined by high-resolution synchrotron powder X-ray diffraction. The Ni and Co are ordered with respect to Sb in the layer of edge sharing octahedra, forming magnetic layers with honeycomb geometry. High-resolution elec......The crystal structures of two Delafossites, Cu3Ni2SbO6 and Cu3Co2SbO6, are determined by high-resolution synchrotron powder X-ray diffraction. The Ni and Co are ordered with respect to Sb in the layer of edge sharing octahedra, forming magnetic layers with honeycomb geometry. High......-resolution electron microscopy confirms ordering, and selected-area electron diffraction patterns identify examples of the stacking polytypes. Low temperature synthetic treatments result in disordered stacking of the layers, but heating just below their melting points results in nearly fully ordered stacking variants...... by temperature and field dependent magnetization, as well as specific heat. The sharp magnetic transitions support the presence of well developed 2:1 ordering of the Co:Sb or Ni:Sb ions in the honeycomb layers. Neutron diffraction measurements at 4 K are used to determine the magnetic structures. For both the Ni...

  20. PRODAN dual emission feature to monitor BHDC interfacial properties changes with the external organic solvent composition.

    Science.gov (United States)

    Agazzi, Federico M; Rodriguez, Javier; Falcone, R Dario; Silber, Juana J; Correa, N Mariano

    2013-03-19

    We have investigated the water/benzyl-n-hexadecyldimethylammonium chloride (BHDC)/n-heptane:benzene reverse micelles (RMs) interfaces properties using 6-propionyl-2-(N,N-dimethyl)aminonaphthalene, PRODAN, as molecular probe. We have used absorption and emission (steady-state and time-resolved) spectroscopy of PRODAN to monitor the changes in the RMs interface functionalities upon changing the external organic solvent blend. We demonstrate that PRODAN is a useful probe to investigate how the external solvent composition affects the micelle interface properties. Our results show that changes in the organic solvent composition in water/BHDC/n-heptane:benzene RMs have a dramatic effect on the photophysics of PRODAN. Thus, increasing the aliphatic solvent content over the aromatic one produces PRODAN partition and PRODAN intramolecular electron transfer (ICT) processes. Additionally, the water presence in these RMs makes the PRODAN ICT process favored with the consequent decreases in the LE emission intensity and a better definition of the charge transfer (CT) band. All this evidence suggests that the benzene molecules are expelled out of the interface, and the water-BHDC interactions are stronger with more presence of water molecules in the polar part of the interface. Thus, we demonstrate that a simple change in the composition of the external phase promotes remarkable changes in the RMs interface. Finally, the results obtained with PRODAN together with those reported in a previous work in our lab reveal that the external phase is important when trying to control the properties of RMs interface. It should be noted that the external phase itself, besides the surfactant and the polar solvent sequestrated, is a very important control variable that can play a key role if we consider smart application of these RMs systems.

  1. Chilled Ammonia Process for CO2 Capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

    2010-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...... perspectives for decreasing the heat requirement. However, a scientific understanding of the processes is required. The thermodynamic properties of the NH3–CO2–H2O system were described using the extended UNIQUAC electrolyte model developed by Thomsen and Rasmussen in a temperature range from 0 to 110°C...

  2. Molecular assembly, interfacial rheology and foaming properties of oligofructose fatty acid esters.

    Science.gov (United States)

    van Kempen, Silvia E H J; Schols, Henk A; van der Linden, Erik; Sagis, Leonard M C

    2014-01-01

    Two major types of food-grade surfactants used to stabilize foams are proteins and low molecular weight (LMW) surfactants. Proteins lower the surface tension of interfaces and tend to unfold and stabilize the interface by the formation of a visco-elastic network, which leads to high surface moduli. In contrast, LMW surfactants lower the surface tension more than proteins, but do not form interfaces with a high modulus. Instead, they stabilize the interface through the Gibbs-Marangoni mechanism that relies on rapid diffusion of surfactants, when surface tension gradients develop as a result of deformations of the interface. A molecule than can lower the surface tension considerably, like a LMW surfactant, but also provide the interface with a high modulus, like a protein, would be an excellent foam stabilizer. In this article we will discuss molecules with those properties: oligofructose fatty acid esters, both in pure and mixed systems. First, we will address the synthesis and structural characterization of the esters. Next, we will address self-assembly and rheological properties of air/water interfaces stabilized by the esters. Subsequently, this paper will deal with mixed systems of mono-esters with either di-esters and lauric acid, or proteins. Then, the foaming functionality of the esters is discussed.

  3. Synthesis and interfacial properties of monoacyl glyceric acids as a new class of green surfactants.

    Science.gov (United States)

    Fukuoka, Tokuma; Ikeda, Shintaro; Habe, Hiroshi; Sato, Shun; Sakai, Hideki; Abe, Masahiko; Kitamoto, Dai; Sakaki, Keiji

    2012-01-01

    Glyceric acid (GA) is one of the most promising functional hydroxyl acids, and it is abundantly obtained from glycerol by a bioprocess using acetic acid bacteria. In this study, several monoacyl GAs were synthesized by esterification of GA and saturated fatty acyl chlorides (C12, C14, C16, and C18), forming a new class of bio-based surfactants. By the present method, a mixture of two isomers, namely 2-O-acyl and 3-O-acyl GAs, was produced, in which the 2-O-acyl derivatives were obtained as a major product. These isomers were isolated, and their surface-active properties were investigated for the first time. The surface tensions of 2-O-acyl GAs with different chain lengths were determined by the Wilhelmy method. At concentrations below 10(-4) M, the 2-O-acyl GAs exhibited higher surface-active properties compared to commercially available synthetic surfactants. For example, 2-O-lauroyl GA reduced the surface tension of water to around 25 mN/m above the critical micelle concentration (3.0×10(-4) M). In addition, 2-O-acyl derivatives showed higher surface-tension-lowering activity than 3-O-acyl GAs. The monoacyl GAs synthesized herein can potentially be used as "green surfactants."

  4. Interfacial capacitance effects in magnetic tunneling junctions

    CERN Document Server

    Landry, G; Du, J; Xiao, J Q

    2001-01-01

    We have investigated the AC transport properties of magnetic tunnel junctions (MTJ) in order to characterize interfacial properties. One such property is interfacial charge accumulation, which leads to a voltage drop in the electrodes of the MTJ and the measured capacitance differing from the geometrical capacitance. Through measurement of capacitance spectra, we have extracted an interfacial capacitance of 16 mu F/cm sup 2 per interface and a screening length of 0.55 A for FeNi electrodes.

  5. Effects of property of reservoir on heat extraction in CO2 plume geothermal system%二氧化碳羽流地热系统中储层物性参数对热提取率的影响

    Institute of Scientific and Technical Information of China (English)

    封官宏; 李佳琦; 许天福; 石岩

    2013-01-01

    二氧化碳羽流地热是以超临界CO2作为地热系统的载热流体,利用天然孔隙介质,在进行CO2地质储存的同时实现深部地热资源的提取.CO2在注入地下储层后呈羽状扩散和分布,因此称这种地热开发系统为CO2羽流地热系统.在CO2羽流地热系统中,砂岩储层分布广泛,物性各异,对热提取率的影响较大.文章以松辽盆地中心凹陷区泉头组三、四段为地热储层,建立平面二维羽流地热模型,采用TOUGH2-MP软件进行数值模拟,定量评价储层物性对热提取率的影响.结果表明,温度对热提取率的影响最大,初始盐度的影响最小,故应按照“低压、低盐度、高温、高渗透、高比热”的标准选取储层,其中高温和高渗透率是应重点考虑的因素.%CO2 plume geothermal system (CPG),which utilizes supercritical CO2 as the underground heat-carrying fluid in natural porous medium,could achieve geologic sequestration as well as heat extraction of deep reservoir.The new geothermal system dubs CO2 plume geothermal system because CO2 is distributed as plume in the reservoir.In CPG,the broad distribution and various properties of the reservoir produce great effects on heat extraction.A 2D flow model is employed to analyze the effects,based on the geothermal reservoir of Klq3 and Klq4 of Quantou Formation in the central depression of Songliao basin.The effects of reservoir property on heat extraction are evaluated quantitatively by TOUGH2-MP software.The results indicate that the effect of temperature on heat extraction is the greatest,while salinity is the least.At last,the suggestion of reservoir selection is "low pressure,low salinity,high temperature,high permeability,high specific heat capacity".Among these standards,high temperature and permeability are the keys.

  6. Interfacial microstructure and mechanical properties of brazed aluminum / stainless steel - joints

    Science.gov (United States)

    Fedorov, V.; Elßner, M.; Uhlig, T.; Wagner, G.

    2017-03-01

    Due to the demand of mass and cost reduction, joints based on dissimilar metals become more and more interesting. Especially there is a high interest for joints between stainless steel and aluminum, often necessary for example for automotive heat exchangers. Brazing offers the possibilities to manufacture several joints in one step at, in comparison to fusion welding, lower temperatures. In the recent work, aluminum / stainless steel - joints are produced by induction brazing using an AlSi10 filler and a non-corrosive flux. The mechanical properties are determined by tensile shear tests as well as fatigue tests at ambient and elevated temperatures. The microstructure of the brazed joints and the fracture surfaces of the tested samples are investigated by SEM.

  7. Nanostructural Characteristics and Interfacial Properties of Polymer Fibers in Cement Matrix.

    Science.gov (United States)

    Shalchy, Faezeh; Rahbar, Nima

    2015-08-12

    Concrete is the most used material in the world. It is also one of the most versatile yet complex materials that humans have used for construction. However, an important weakness of concrete (cement-based composites) is its low tensile properties. Therefore, over the past 30 years many studies were focused on improving its tensile properties using a variety of physical and chemical methods. One of the most successful attempts is to use polymer fibers in the structure of concrete to obtain a composite with high tensile strength and ductility. The advantages of polymer fiber as reinforcing material in concrete, both with regard to reducing environmental pollution and the positive effects on a country's economy, are beyond dispute. However, a thorough understanding of the mechanical behavior of fiber-reinforced concrete requires a knowledge of fiber/matrix interfaces at the nanoscale. In this study, a combination of atomistic simulations and experimental techniques has been used to study the nanostructure of fiber/matrix interfaces. A new model for calcium-silicate-hydrate (C-S-H)/fiber interfaces is also proposed on the basis of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. Finally, the adhesion energy between the C-S-H gel and three different polymeric fibers (poly(vinyl alcohol), nylon-6, and polypropylene) were numerically studied at the atomistic level because adhesion plays a key role in the design of ductile fiber-reinforced composites. The mechanisms of adhesion as a function of the nanostructure of fiber/matrix interfaces are further studied and discussed. It is observed that the functional group in the structure of polymer macromolecule affects the adhesion energy primarily by changing the C/S ratio of the C-S-H at the interface and by absorbing additional positive ions in the C-S-H structure.

  8. CO2 Sequestration short course