bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and tunable photoluminescence of NaYF4:Eu/Ba nanocrystals
Authors: Wang Guofeng , Peng Qing
Published: November 2010

Sub-10 nm monodispersed NaYF4:Eu/Ba nanocrystals were synthesized by a hydrothermal method. Under 396-nm excitation, in addition to the characteristic emissions of Eu3+ ions, an intense emission band originating from the d–f transition of the Eu2+ ions is also observed, indicating that Eu3+ and Eu2+ coexist in Eu/Ba-codoped NaYF4 nanocrystals. The dependence of the luminescence on the Ba2+ concentration was studied. Tunable photoluminescence of NaYF4:Eu nanocrystals was successfully achieved by codoping with Ba2+ ions. In addition, when the Ba/Ln ratio is 3:7 and 4:1, pure cubic Ba0.92Y2.15F8.29:Eu and tetragonal BaYF5:Eu nanocrystals were obtained, respectively.
In situ high-energy x-ray diffraction observation of structural evolution in a Ti-based bulk metallic glass upon heating
Authors: Zheng N. , Wang G. , Zhang L.C. , Calin M. , Stoica M. , Vaughan G. , Mattern N. , Eckert J.
Published: November 2010

The structural evolution of the Ti40Zr10Cu34Pd14Sn2 bulk metallic glass (BMG) upon was investigated by means of in situ high-energy x-ray diffraction. The position, width, and intensity of the first peak in diffraction patterns are fitted through Voigt function below 800 K. All the peak position, width, and intensity values show a nearly linear increase with the increasing temperature to the onset temperature of structural relaxation, Tr = 510 K. However, these values start to deviate from the linear behavior between Tr and Tg (the glass transition temperature). The changes in free volume and the coefficient of volume thermal expansion prove that the aforementioned phenomenon is closely related to the structural relaxation releasing excess free volume arrested during rapid quenching of the BMG. Above 800 K, three crystallization events are detected and the first exothermic event is due to the formation of metastable nanocrystals.
Nanoscale strength distribution in amorphous versus crystalline metals
Authors: Packard C.E. , Franke O. , Homer E.R. , Schuh C.A.
Published: November 2010

Low-load nanoindentation can be used to assess not only the plastic yield point, but the distribution of yield points in a material. This paper reviews measurements of the so-called nanoscale strength distribution (NSD) on two classes of materials: crystals and metallic glasses. In each case, the yield point has a significant spread (10–50% of the mean normalized stress), but the origins of the distribution are shown to be very different in the two materials classes. In crystalline materials the NSD can arise from thermal fluctuations and is attended by significant rate and temperature dependence. In metallic glasses well below their glass-transition temperature, the NSD is reflective of fluctuations in the sampled structure and is not very sensitive to rate or temperature. Computer simulations using shear transformation zone dynamics are used to separate the effects of thermal and structural fluctuations in metallic glasses, and support the latter as dominating the NSD of those materials at low temperatures. Finally, the role of the NSD as a window on structural changes due to annealing or prior deformation is discussed as a direction for future research on metallic glasses in particular.
Preparation and characterization of the defect–conductivity relationship of Ga-doped ZnO thin films deposited by nonreactive radio-frequency–magnetron sputtering
Authors: Lalanne M. , Soon J.M. , Barnabé A. , Presmanes L. , Pasquet I. , Tailhades Ph.
Published: November 2010

Ga-doped ZnO (ZnO:Ga) thin films were prepared by radio-frequency–magnetron sputtering on conventional glass substrates at room temperature. The structural, electrical, and optical properties of these films as a function of argon pressure and film thicknesses were studied. All the films crystallized with the hexagonal wurtzite structure. The x-ray diffraction studies show that the ZnO:Ga films are highly oriented with their crystallographic c-axis perpendicular to the substrate. We discuss a methodology of using a “standardized platform” for comparison of samples deposited at different pressures, which provides an insight into the defect–resistivity relationship of each sample with respect to their microstructure. After the first annealing, the electrical properties of the films are dependent on the atmosphere used during postdeposition annealing treatment. A resistivity of 2.5 × 10−3 Ω · cm was obtained after vacuum annealing, and the films became an insulator after air annealing. The reproducibility of this treatment was verified. The average transmittance of all ZnO:Ga thin films is more than 85% in the visible range.
Improved dehydrogenation of LiBH4 supported on nanoscale SiO2 via liquid phase method
Authors: Chen X.Y. , Guo Y.H. , Gao L. , Yu X.B.
Published: November 2010

A wet loading method was developed to produce nano-sized LiBH4 combined with nano-SiO2 templates. The multicomponent LiBH4/SiO2 material synthesized by the wet method has been found to dehydrogenate at much lower temperatures than the pure LiBH4, as well as LiBH4/SiO2 mixtures prepared by ball milling. For example, the onset of dehydrogenation was decreased to about 200 °C for a wet-treated LiBH4/SiO2 mixture with a mass ratio of 1:1, and the majority of the hydrogen could be released below 350 °C. The improved dehydrogenation of the wet-treated LiBH4/SiO2 mixtures can be attributed to the destabilization of SiO2, resulting in the formation of lithium metasilicate (Li2SiO3) upon heating, and the confinement of LiBH4 to form nanoscale particles.
Nucleation and growth rate influence on microstructure and critical currents of TFA-YBa2Cu3O7 under low-pressure conditions
Authors: Chen H. , Zalamova K. , Pomar A. , Granados X. , Puig T. , Obradors X.
Published: November 2010

The effects of variable conversion parameters on the microstructure and critical currents of TFA-derived YBa2Cu3O7 (YBCO) films annealed under low-pressure conditions were investigated, accompanied by the analysis of their relationship with the nucleation process and the growth rate. It is found that non-c-axis oriented YBCO grains are formed under high supersaturation conditions, i.e., by increasing oxygen pressure, water pressure, or temperature. The optimal PH2O–PO2 window for preparation of completely c-axis oriented YBCO films expands as the total pressure rises from 50 to 100 mbar due to the decrease of supersaturation at enhanced total pressure; the corresponding maximum growth rate is only slightly increased up to 0.6 nm/s. Additionally, it is shown that the gas flow needs to be high enough to avoid random nucleation of YBCO grains. A single gas-flow–water-pressure diagram, showing simultaneously the film-growth rate, allows visualizing the cross-linked influence of processing parameters to achieve c-axis oriented YBCO films with Jc above 1 MA/cm2 in one single growth step.
Metastable nanosized diamond formation from a C-H-O fluid system
Authors: Simakov S.K.
Published: November 2010

The model of nanosized diamond particles formation at metastable P-T parameters from a C-H-O fluid system is presented. It explains the hydrothermal formation and growth of diamond and the specifics of chemical vapor deposition (CVD) diamond synthesis gas mixtures at low P-T parameters. Further, the model explains the genesis of interstellar nanodiamond formations in space and the genesis of metamorphic microdiamonds in shallow depth Earth rocks. In contrast to models where many possible reactions are considered, the present model makes the simplest possible assumptions about the key processes, and is then able to account for various tendencies seen in experimental data.
Abnormal spalling phenomena in the Sn-0.7Cu/Au/Ni/SUS304 interfacial reactions
Authors: Lin Shih-kang , Chen Kuen-da , Chen Hao , Liou Wei-kai , Yen Yee-wen
Published: November 2010

The interfacial reactions in Sn-0.7wt%Cu/ENIG SUS304 couples at 240, 255, and 270 °C are examined in this study. The Ni-containing ternary Cu6Sn5 phase is formed at the Ni/liquid interface in the early reaction stage then it detaches massively from the SUS304 substrate and splits into two layers in the molten solder as the reaction time increases. This phase finally disintegrates and disappears. The square pillar-shaped FeSn2 phase is found on top of the SUS304 substrate when the Cu6Sn5 layer detaches. The reaction phase formation, detachment, and split mechanisms are proposed. The spalling phenomenon is reviewed and discussed. The growth mechanism of the FeSn2 phase obeys the parabolic law, and the activation energy is determined to be 112.5 KJ/mol.
Microstructure and electrical properties in three-component (Al2O3–TiO2)/polyimide nanocomposite films
Authors: Zha Jun-Wei , Fan Ben-Hui , Dang Zhi-Min , Li Sheng-Tao , Chen George
Published: November 2010

Polyimide (PI)-matrix composite films containing inorganic nanoparticles (nano-Al2O3 and nano-TiO2) have been fabricated. A proposed model is used to explain different structures of the (Al2O3–TiO2)/PI (ATP) films synthesized by employing in situ polymerization. Dependences of dielectric permittivities of the ATP films on frequency and temperature were studied. Results show the breakdown strength of the films decreases with prolonging the corona aging time. The incorporation of the nano-Al2O3 and nano-TiO2 particles significantly improves the corona resistance of the films. The corona aging also influences the infrared absorbance, the glass transition temperature (Tg), and loss factor (tanδ) of the ATP films.
Enhanced photocatalytic activity of (Mo, C)-codoped anatase TiO2 nanoparticles for degradation of methyl orange under simulated solar irradiation
Authors: Dong Pengyu , Liu Bin , Wang Yuhua , Pei Huanhuan , Yin Shu
Published: November 2010

C-doped, Mo-doped, and (Mo, C)-codoped TiO2 photocatalysts were prepared by a sol-gel process. The photocatalytic activity was evaluated by the photocatalytic degradation of methyl orange (MO) under simulated solar irradiation. Results indicated that both monodoped and codoped TiO2 exhibited better visible light absorption behavior and narrower energy gap than pure TiO2, and codoped TiO2 showed a slightly higher adsorption property in the dark because of higher Brunauer–Emmett–Teller-specific surface area. The photocatalytic activity of monodoped TiO2 was also enhanced, and the (0.04% Mo, C)-codoped sample had the best photocatalytic activity for degrading MO among all of the samples. The reason can be ascribed to the synergistic effect due to Mo and C doping. Furthermore, the transfer pathways of photoinduced carriers and photocatalytic reaction mechanism of (Mo, C)-codoped TiO2 was first investigated.
Effect of BaCu(B2O5) on the sintering temperature and microwave dielectric properties of Ba(Nd0.8Bi0.2)2Ti4O12 ceramics
Authors: Zeng Yi , Wang Hong , Zhou Huanfu
Published: November 2010

The effect of BaCu(B2O5) (BCB) on the sintering temperature and microwave dielectric properties of Ba(Nd0.8Bi0.2)2Ti4O12 (BNBT) ceramics was investigated. The sintering temperature of the BNBT ceramics was significantly reduced from 1300 to 900 °C. Due to adding BCB into Ba(Nd1–xBix)2Ti4O12, the temperature coefficient of resonant frequency can be adjusted to zero with BCB content increasing. Good microwave dielectric properties of quality factor (Q×f) = 2600 GHz, εr = 75, and τf = 5 ppm/°C were obtained for BNBT with 7 wt% BCB sintered at 925 °C for 2 h, which make it a potential candidate for low temperature cofired ceramics applications.
Amorphization of nanocrystalline 3C-SiC irradiated with Si+ ions
Authors: Jiang W. , Wang H. , Kim I. , Zhang Y. , Weber W.J.
Published: November 2010

Irradiation-induced amorphization in nanocrystalline and single-crystal 3C-SiC has been studied using 1 MeV Si+ ions under identical irradiation conditions at room temperature and 400 K. The disordering behavior has been characterized using in situ ion channeling and ex situ x-ray diffraction methods. The results show that, compared with single-crystal 3C-SiC, full amorphization of small 3C-SiC grains (˜3.8 nm in size) at room temperature occurs at a slightly lower dose. Grain size decreases with increasing dose until a fully amorphized state is attained. The amorphization dose increases at 400 K relative to room temperature. However, at 400 K, the amorphization dose for 2.0 nm grains is about a factor of 4 and 8 smaller than for 3.0 nm grains and bulk single-crystal 3C-SiC, respectively. The behavior is attributed to the preferential amorphization at the interface.
Revealing the mechanism of the early stages of Ni–W RABiTS oxidation
Authors: Blednov Andrey V. , Gorbenko Oleg Yu. , Rodionov Dmitriy P. , Kaul Andrey R.
Published: November 2010

The early stages of surface oxidation of biaxially textured Ni–W tapes were studied using thermodynamic calculations along with experimental tape oxidation at low P(O2). Tape phase and chemical composition, surface morphology, and roughness were examined using x-ray diffraction (XRD), energy-dispersive x-ray analysis (EDX), secondary ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). For a Ni0.95W0.05 alloy tape, the precise position of the tape oxidation line in P(O2)–T coordinates was established. This line includes a break at T ≈ 650 °C that originates from the change of the W oxidation mechanism from internal oxidation to oxidation on a free surface accompanied by segregation of the alloy components in the tape near-surface region. The surface roughness of a polished tape increased drastically during internal oxidation of W; further tape oxidation did not affect the integral roughness parameters, but introduced numerous small (˜;100 nm) features on the tape surface comprising NiO precipitates.
Silicon nitride nanoceramics densified by dynamic grain sliding
Authors: Herrmann Mathias , Shen Zhijian , Schulz Ingrid , Hu Jianfeng , Jancar Bostjan
Published: November 2010

The densification behaviors of two silicon nitride nanopowder mixtures based respectively on α-Si3N4and β-Si3N4as the major phase constituent were studied by spark plasma sintering. Sintering conditions were established where a low viscous liquid not in equilibrium with the main crystalline constituent(s) stimulated the grain sliding yet did not activate the reprecipitation mechanism that unavoidably yields grain growth. By this way of dynamic grain sliding full densification of silicon nitride nanoceramics was achieved with no noticeable involvement of α- to β-Si3N4phase transformation and grain growth. This processing principle opens the way toward flexible and precise tailoring of the microstructures and properties of Si3N4ceramics. The obtained silicon nitride nanoceramics showed improved wear resistance, particularly under higher Hertzian stresses.
Co alloying and size effects on solidification and interfacial reactions in the Sn–Zn–(Co)/Cu couples
Authors: Huang Yu-chih , Chen Sinn-wen
Published: November 2010

Sn–Zn based alloys are promising as Pb-free solders, and Cu is commonly used in electronic products. Solidification and interfacial reactions of Sn–8.8wt%Zn, Sn–8.8wt%Zn–0.05wt%Co, and Sn–8.8wt%Zn–0.5wt%Co solders on Cu substrates are investigated. Two different masses of solders are used. The degrees of undercooling increase with increasing Co additions in the Sn–8.8wt%Zn alloys. The reaction products evolve with reaction time, and the timing of different reaction stages is influenced by both the minor Co alloying and the mass of solders. In the initial reaction stage, two reaction phases, γ-Cu5Zn8 and ε-CuZn5, are observed in the Sn–8.8wt%Zn/Cu and Sn–8.8wt%Zn-0.05wt%Co/Cu couples, and only the γ-Cu5Zn8 phase is found when the Co addition is up to 0.5 wt%. The reaction layers are thinner with higher Co alloying. The addition of Co into the Sn–Zn alloys consumes Zn, and this depletion of Zn in the Sn–Zn solders is the primary reason for the changes of reaction products and the thinner reaction layers.
Measurement of Carbon Dioxide Capillary Trapping in Core Analysis
Authors: Pentland C.H.. H. , Iglauer S.. , El-Maghraby R.. , Tsuchiya Y.. , Okabe H.. , Blunt M.J.. J.
Published: November 2010

Capillary trapping has been identified as a fast and effective method to render injected carbon dioxide (CO2) immobile as disconnected pore-scale droplets surrounded by brine. We measure trapped CO2 saturations in sandstones at conditions representative of storage locations. We compare the unsteady state and porous plate methods of achieving initial CO2 saturations before waterflooding to reach residual saturation. Brine and CO2 are equilibrated prior to injection to ensure immiscible displacements occur on the pore scale. The problems faced with un-equilibrated phases are discussed.

The unsteady state and porous plate methods are shown to give different results in terms of maximum initial and residual saturations for Berea sandstone samples. With the unsteady state method maximum residual CO2 saturations of 25-28% are measured for corresponding maximum initial saturations of 35-40%. With the porous plate method a maximum residual saturation of 37% is measured for a maximum initial saturation of 90%. The implications for coreflood method selection during data gathering are discussed.

The porous plate results are compared with oil-brine porous plate saturations measured on the same samples. CO2-brine residual saturations are shown to be slightly lower than the corresponding oil-brine measurements. We suggest that considerable carbon dioxide capillary trapping is possible in clean sandstones and discuss the implications for carbon storage in aquifers.
CO2 Sequestration in Deepwater Subseabed Formations
Authors: Pilisi N.. , Ceyhan I.. , Vasantharajan S..
Published: November 2010

Recent studies have estimated that oceans have naturally sequestrated, by dissolving and mixing with deep waters, about 40% of the anthropogenic CO2 emitted since the start of the industrial revolution. Moreover, the International Maritime Organization has recently announced that storage of CO2 under the seabed would be allowed starting in 2007. To date, almost all studies, simulations and technical papers concerning carbon sequestration have focused on storing supercritical CO2 in deep saline aquifers or depleted oil and gas reservoirs. However, a critical limiting factor for such carbon sequestration is the need for proper physical trapping and the necessity for monitoring the upward migration due to buoyancy effects and mobility of supercritical CO2. Carbon sequestration in deepwater sub-seabed formations provides an attractive alternative.

This paper presents a feasibility study of carbon sequestration in deepwater formations in the Gulf of Mexico with the existing technologies available in the offshore industry. We describe each step of the carbon capture and storage process and discuss the technical limitations when trying to capture CO2 from industrial processes, transport it offshore via tanker, drill a CO2 injector well and then, inject the CO2 from floating facilities such as drill ships or semi-submersible vessels. Due to high pressures and low temperatures reigning at water depths deeper than 9,000 feet, the liquid CO2 injected in the first few hundred feet of deposits will have a higher density than the surrounding formation pore-fluid and therefore will be buoyantly trapped. In addition, CO2 hydrates that may form and fill up pore spaces will act as an additional trapping mechanism. Finally, at these great depths, the CO2 that could leak will dissolve by reacting with ocean waters and forming mainly bicarbonate compounds.

Because oceans cover about 70% of the Earth’s surface with an average water depth of 12,500 feet, deepwater sub-seabed sequestration provides an enormous storage capacity to counteract increasing world consumption of fossil fuels. However, large time and space-scale simulations need to be performed to estimate the impact of the change in geochemistry in the deepwater seabed region. Also, the injection of liquid CO2 will force and displace formation fluid into the seabed surface zone, which will change the ocean chemistry.
CO2 Storage Engineering: Real Solution to Real Problems
Authors: Kuuskraa V. A. , Koperna G. J. , Schepers K..
Published: November 2010

Deep saline aquifers offer the potential for storing large volumes of CO2. However, with conventional CO2 storage well design and operating practices, only a small fraction of this large CO2 storage potential can be productively used. Numerous alternative designs and practices, which utilize the reservoir’s internal architecture and draw on CO2 storage engineering expertise, could enable CO2 storage operators to more efficiently and fully utilize a saline formation’s storage capacity. This would help reduce the areal extent of the CO2 plume and its risk footprint. It would also help reduce the number of CO2 injection wells and patterns that would need to be developed.

This paper, entitled "CO2 Storage Engineering: Real Solution to Real Problems", discusses practical CO2 storage options that have been proposed for significantly increasing CO2 storage performance at three challenging saline reservoir settings.
Interpretation of CO2-Sequestration-Induced Surface Deformation at Krechba, Algeria
Authors: Davis E. J. , Marsic S. D.
Published: November 2010

The Krechba field is part of a multi-field gas development in central Algeria where CO2 is being injected rather than vented to develop carbon storage techniques within an active gas producing reservoir. Surface deformation monitoring has thus far proven to be one of the more useful of a wide array monitoring methods deployed at the site. Using differential interferometric synthetic aperture radar (InSAR), Pinnacle and MDA Geospatial services produced a high-resolution deformation time series of the Krechba field area over a 5 year period between 2004 and 2009. While the deformation measurements provide a qualitative visual assessment of the injection performance, the real goal of surface deformation monitoring is to determine the location of subsurface strain changes induced by the injected fluid. A geomechanical model is needed to determine the surface response to a given subsurface strain. An inversion routine modifies the strain source or sources to find a system that produces theoretical surface motion that best matches the measured deformation. This paper uses the example at injection well KB-501 to explore how the solution and associated uncertainty is affected by the choice of geomechanical model at this location. The best fit solution and sensitivity of that solution is derived from homogeneous and layered models of varying complexity using both linear and non-linear inversion techniques. The results place boundaries on the possible subsurface pressure distribution associated with CO2 injection and also quantify the possible benefit obtained from more complex geomechanical modelling for inversion of surface deformation data. The solutions suggest that the injected fluid at KB-501 remains near the intended depth and is spreading primarily along a northwest-southeast trajectory as anticipated.
Retardation of CO2 due to Capillary Pressure Hysteresis: a New CO2 Trapping Mechanism
Authors: Altundas Y. B. , Ramakrishnan T. S. , Chugunov Nikita , de Loubens Romain
Published: November 2010

Trapping of CO2 improves containment security of geologically stored CO2. To be able to asses the potential of a storage site using reservoir simulators, it is necessary to include all of the possible trapping mechanisms in the numerical algorithms. Currently, four trapping mechanisms are identified in the CO2 sequestration literature: structural, residual, dissolution, and mineralization. Although capillary pressure hysteresis has been accounted for in the historical development of simulators, it has not been recognized as a process for hindering movement of the injected CO2. Capillary pressure hysteresis reduces the buoyancy driven plume movement significantly compared to relative permeability hysteresis; but it is the latter that has been emphasized in the published literature. In this paper, we focus on a quantitative measure for the contribution of hysteresis in reducing plume transport. Rocks with large pore body to throat size ratio are the best candidates for this mechanism to be operative.

In the present work, a self-consistent relative-permeability capillary-pressure hysteresis model is incorporated within a simulator. With this model, it is possible to compare and contrast hysteresis induced retardation to other mechanisms of trapping. The self-consistent parametrization of all of the transport properties is used to quantify sensitivity compactly. The sensitivity of the CO2 plume shape and the amount of CO2 trapped, to the strength of the capillary pressure hysteresis, is also described.

Simulated results show that CO2 plume shape with and without capillary pressure hysteresis are significantly different. As expected, capillary pressure hysteresis retards the buoyant transport of the CO2 plume. Although a portion of the CO2 is connected, and therefore not residual, the plume remains immobile for all practical purposes. Also, due to decreased driving potential, gravity tonguing below the caprock is reduced in comparison to the case without capillary pressure hysteresis, thus suggesting enhanced storage efficiency. However, the total dissolution of CO2 in saline water is reduced because of the reduced diffusive transport of CO2 within the brine. Thus, one mechanism of containment is offset by the other.

Inclusion of accurate hysteresis models is important for qualifying storage sites constrained by spatial domain limits. It is anticipated that site acceptability criteria would change as a result of this study, thus impacting risk evaluation.
Optimization of Geologic CO2 Storage in Heterogeneous Aquifers Through Improved Sweep Efficiency
Authors: Shamshiri H.. , Jafarpour B..
Published: November 2010

Optimization of waterflooding sweep efficiency has been widely applied in reservoir engineering to improve hydrocarbon recovery while delaying water breakthrough and minimizing the bypassed oil in reservoirs. We develop a new framework to optimize flooding sweep efficiency in geologic formations with heterogeneous properties and demonstrate its application to waterflooding and geological CO2 sequestration problems. The new method focuses on equalizing and delaying (under constant total injected volume) the breakthrough time of the injected fluid at production wells. For application to CO2 sequestration where producers may not be present, we introduce the concept of pseudo production wells that have insignificant production rates (with negligible effect on the overall flow regime) for quantification of hypothetical breakthrough curves that can be used for optimization purpose. We apply the new method to waterflooding and CO2 sequestration optimization using two heterogeneous reservoir models. We show that in water flooding experiments the proposed method improves the sweep efficiency by delaying the field breakthrough and equalizing breakthrough times in all production wells. In this case, the optimization results in increased oil recovery and decreased water production. We apply a modified version of the proposed algorithm to geologic CO2 sequestration problems to maximize the storage capacity of aquifers by enhancing the residual and dissolution trapping. The results from applying the proposed approach to optimization of geologic CO2 storage problems illustrate the effectiveness of the algorithm in improving residual and solubility trapping by increasing the contact between available fresh brine and the injected CO2 plume through a more uniform distribution of CO2 in the aquifer.
Effects of CO2 Storage in Saline Aquifers on Groundwater Supplies
Authors: Kalunka Johannes E. , LaForce Tara C. , Blunt Martin J.
Published: November 2010

The aim of this paper is to investigate the effects of CO2 sequestration on groundwater abstraction above the storage formation. Large-scale (10Mt/yr) CO2 injection in underlying saline aquifers is considered using a fully compositional simulator to study the pressure distribution, CO2 leakage and inter-layer brine flow. Structural, residual and solubility CO2 trapping are taken into account while the model domain is considered to have no-flow boundaries to simulate CO2 injection under the context of either pressure not being able to be dissipate quickly (due to other CO2 injection processes, for instance) or the formation being self-contained. Changes in salinity are affected by groundwater abstraction and although not caused by injection itself, can be magnified by such processes. We also conclude that the time at which CO2 leakage, pressure perturbations and upward brine flow are at their peak in overlying aquifers (layers above the injection site) may be significantly after injection has ceased (50-150 years in some cases) and could potentially cause groundwater movements, land surface uplift or rock fracturing long after the injection phase has ended.
The Social Evaluation of Intergenerational Policies and Its Application to Integrated Assessment Models of Climate Change
Authors: Kaplow Louis , Moyer Elisabeth , Weisbach David A
Published: November 2010

Assessment of climate change policies requires aggregation of costs and benefits over time and across generations, a process ordinarily done through discounting. Choosing the correct discount rate has proved to be controversial and highly consequential. To clarify past analysis and guide future work, we decompose discounting along two dimensions. First, we distinguish discounting by individuals, an empirical matter that determines their behavior in models, and discounting by an outside evaluator, an ethical matter involving the choice of a social welfare function. Second, for each type of discounting, we distinguish it due to pure time preference from that attributable to curvature of the pertinent function: utility functions (of consumption) for individuals and the social welfare function (of utilities) for the evaluator. We apply our analysis to leading integrated assessment models used to evaluate climate policies. We find that past work often confounds different sources of discounting, and we offer suggestions for avoiding these difficulties. Finally, we relate the standard intergenerational framework that combines considerations of efficiency and distribution to more familiar modes of analysis that assess most policies in terms of efficiency, leaving distributive concerns to the tax and transfer system.
Dissolved oxygen fluxes and ecosystem metabolism in an eelgrass (Zostera marina) meadow measured with the eddy correlation technique
Authors: Hume Andrew C. , Berg Peter , McGlathery Karen J.
Published: November 2010

Dissolved oxygen (DO) fluxes were measured by eddy correlation to estimate net ecosystem metabolism (NEM) during summer in a restored eelgrass (Zostera marina) meadow and a nearby, unvegetated sediment. This technique measures benthic fluxes under true in situ light and hydrodynamic conditions, integrates over a large area (typically > 100 m2), and captures short‐term variations. DO fluxes measured through eight 24‐h periods showed pronounced temporal variation driven by light and local hydrodynamics on multiple scales: hour‐to‐hour, within each daily cycle, and between deployments. The magnitude of variation between hours during single deployments equaled that between deployments, indicating that short‐term variation must be included for metabolism estimates to be accurate. DO flux variability was significantly correlated to mean current velocity for the seagrass site and to significant wave height for the unvegetated site. Fluxes measured in low‐flow conditions analogous to many chamber and core incubations underestimated those measured in higher‐flow conditions typical of in situ conditions by a factor of 2–6. Rates of gross primary production (GPP), respiration (R), and NEM varied substantially between individual deployments, reflecting variations in light and hydrodynamic conditions, and daily values of GPP and R for individual deployments were tightly linked. Average daily NEM of the seagrass site was higher than that of the unvegetated site; the seagrass site was in metabolic balance, and the unvegetated site showed a tendency toward net heterotrophy during this midsummer period.
Quantitative dominance of seasonally persistent filamentous cyanobacteria (Planktothrix rubescens) in the microbial assemblages of a temperate lake
Authors: Van den Wyngaert Silke , Salcher Michaela M. , Pernthaler Jakob , Zeder Michael , Posch Thomas
Published: November 2010

The spatiotemporal changes in abundance and biomass of heterotrophic bacteria, of three major bacterial phylogenetic groups, and of picocyanobacteria in the upper 20 m of a deep prealpine lake (Lake Zurich, Switzerland) were monitored during a seasonally persistent bloom of the toxigenic filamentous cyanobacterium Planktothrix rubescens. In addition, bacterial 16S ribosomal deoxyribonucleic acid (rDNA) sequences were collected at one instance from the bloom layer and from waters above and below this zone. P. rubescens comprised up to 70% of particulate organic carbon during summer stratification and autumnal mixis and thus by far exceeded the total biomass both of other phytoplankton and of prokaryotes. A strong negative correlation was found between the estimated basin‐wide biomass of P. rubescens and of heterotrophic bacteria, and there was different spatial niche preference of filamentous vs. picocyanobacteria. Only members of the Cytophaga‐Flavobacterium lineage of Bacteroidetes showed an increasing tendency of association with the P. rubescens population, in particular at the onset of autumnal mixing. Although the filamentous cyanobacterium was the dominant primary producer throughout the year, it did not seem to be a carbon source for heterotrophic bacteria at all. We conclude that P. rubescens represents a powerful competitor of autotrophic and heterotrophic prokaryotes, likely due to both its specific physiological (photoheterotrophic) properties and its protection against zooplankton grazing. This competitiveness might be regarded as another reason for its mass occurrence in numerous lakes of the Northern hemisphere.
Manufacturing of Open‐Cell Metal Foams Using a Novel Leachable Pattern
Authors: Michailidis Nikolaos , Stergioudi Fani , Tsipas Dimitrios N.
Published: November 2010

A space‐holder method using crystalline carbohydrate particles, as a novel leachable pattern for manufacturing open‐cell metal foams is described. The method involves mixing and compaction, leaching and sintering processes. Open‐cell Al foams with porosity up to 70% can be produced. The removal of the carbohydrate particles from the green compact is achieved by water leaching at room temperature. An appropriate sintering leads to a very good result as far as the microstructure achieved is concerned.
Very Large Photoconduction Enhancement Upon Self‐Assembly of a New Triindole Derivative in Solution‐Processed Films
Authors: Gallego‐Gómez Francisco , García‐Frutos Eva M. , Villalvilla José M. , Quintana José A. , Gutierrez‐Puebla Enrique , Monge Angeles , Díaz‐García María A. , Gómez‐Lor Berta
Published: November 2010

A new carbazole‐related small molecule exhibiting self‐assembly into ordered nanostructures in solution‐processed cast films has been synthesized and its charge‐photogeneration and ‐transport properties have been investigated. Large photoconductivity was measured in the amorphous state while an enormous improvement in the photoconduction properties was observed when the molecules spontaneously organized. Photocurrents increased upon self‐assembly by up to four orders of magnitude, mostly due to the drastic enhancement of the charge photogeneration. A greatly favorable arrangement of the aromatic cores in the resulting nanostructures, which were characterized by X‐ray analysis, may explain these improvements. Photocurrents of mA cm−2, on/off ratios of 104 and quantum efficiencies of unity at low field and light intensity, which are among the best values reported to date, along with the simplicity of fabrication, give this readily‐available organic system great potential for use in plastic optoelectronic devices.
A 4‐year intervention to increase adoption of safer dairy farming work practices
Authors: Chapman Larry J. , Brunette Christopher M. , Karsh Ben‐Tzion , Taveira Alvaro D. , Josefsson K. Gunnar
Published: November 2010

Background

Traumatic and musculoskeletal injury rates have been high in dairy farming compared to other industries. Previous work has shown that social marketing efforts can persuade farm managers to adopt practices that reduce injury hazards compared to traditional practices if the new practices maintain profits.

Methods

The intervention disseminated information to 4,300 Northeast Wisconsin dairy farm managers about three safer and more profitable production practices (barn lights, silage bags, and calf feed mixing sites) using information channels that these managers were known to rely on. We evaluated rolling, independent, community‐based samples, at baseline and then again after each of four intervention years. We also evaluated samples from Maryland's 1,200 dairy farms after the second through the fourth year of the intervention. Maryland dairy managers read many of the same nationally distributed print mass media that we used in the intervention and so were a “partially exposed” comparison group.

Results

The intervention to disseminate information about the innovations was successful. In comparisons before and after the intervention, Wisconsin managers reported getting more information about calf sites from public events and equipment dealers, about silage bags from other farmers and equipment dealers, and about barn lights from public events, other farmers, equipment dealers, consultants, and electrical suppliers. Wisconsin managers also reported getting more information than Maryland managers from public events for barn lights and silage bags. During years three and four, the intervention managed to sustain, but not improve, earlier increases in adoption and awareness from the first 2 years. After adjusting for farm manager and operation variables, intervention years was associated with increased Wisconsin manager adoption of two of three practices in comparisons between the baseline and the fourth intervention year: barn lights (odds ratio = 5.58, 95% confidence interval = 3.39–9.17) and silage bags (OR = 2.94, CI = 1.84–4.70). There were similar results for awareness of barn lights and the calf feeding sites. Compared to Maryland managers, Wisconsin managers reported greater awareness of barn lights.

Conclusions

Disseminating information to managers through information channels that they usually consulted was associated with increased reports of getting information and with greater adoption and awareness of safer, profit‐enhancing work practices in a high hazard industry. Am. J. Ind. Med. 54:232–243, 2011. © 2010 Wiley‐Liss, Inc.
Trends in common rhinologic illnesses: Analysis of U.S. healthcare surveys 1995–2007
Authors: Mattos Jose L. , Woodard Charles R. , Payne Spencer C.
Published: November 2010

Background

Up to date information on the epidemiology of, and recent changes in, allergic rhinitis (AR), acute sinusitis (AS), and chronic sinusitis (CS) office and emergency department (ED) visits and prevalence is sparse. Current studies may quote data that is outdated or based solely on patient self‐report. The purpose of this work was to describe basic epidemiologic measures of office and ED visits for AR, AS, and CS between 1995 and 2007, and to analyze trends over time for each of these diseases.

Methods

Survey data from the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) were examined from 1995 to 2007 for AR, AS, and CS by International Classification of Diseases, 9th edition (ICD‐9) code, using the STATA statistical package survey‐specific commands to obtain appropriate estimates. Subgroup analyses were performed for age, sex (male and female), race (white and black), and region. Logistic regression was used in order to investigate the predictors mentioned above in a multivariate model, and to analyze trends over time.

Results

For AR, there has been an increase in visits in both the office and ED settings between 1995 and 2007. For CS, there has been a decrease in the proportion of both office and ED visits over this time period, as well as in the visit rate. For CS office visits, there has been an increase in the total number of visits. For AS, descriptive data show an increase in both the total number and proportion of office visits, but logistic regression did not validate these findings. There has been a decrease in ED visits for AS. Age, sex, race, and region have differing effects on each these diseases, and these factors appear to be setting‐dependent as well.

Conclusion

While regression did not show statistically significant changes for AS, the odds ratio along with the number and proportion of visits suggests that an increase for AS at a similar rate of AR is possible, lending support to a relationship between these disease processes. The relatively small increase in the prevalence of AR in the United States when compared with the worldwide increase in developing countries suggests that the hygiene theory and environmental factors play a leading role in the development of AR. The relative decrease in the prevalence of CS may be the result of successful medical therapy with the increased use of nasal steroids and nasal saline irrigation. © 2011 ARS‐AAOA, LLC.
Expression of Matrix Metalloproteinase‐9 mRNA and Vascular Endothelial Growth Factor Protein in Gastric Carcinoma and Its Relationship to Its Pathological Features and Prognosis
Authors: Yang Qiong , Ye Zai‐Yuan , Zhang Jing‐Xia , Tao Hou‐Quan , Li Shu‐Guang , Zhao Zhong‐Sheng
Published: November 2010

To investigate matrix metalloproteinase‐9 (MMP‐9) mRNA and vascular endothelial growth factor (VEGF) protein expression in gastric carcinoma and its correlation with microvascular density, growth‐pattern, invasion, metastasis, and prognosis. In situ hybridization of MMP‐9 mRNA and immunohistochemistry of VEGF and CD34 proteins were performed on surgical specimens of gastric cancers from 118 patients compared with 20 nonmalignant gastric mucosae. Their relationships to pathological parameters and survival times were determined by statistical analysis. The positive rate of MMP‐9 in noncancerous gastric mucosae was significantly lower than that of gastric cancer tissue (60.17%, P < 0.01). In patients with cancers of the infiltrating type, at stage T3‐T4, with vessel invasion, lymphatic metastasis, hepatic, or peritoneal metastasis, the positive expression rates of MMP‐9 mRNA, VEGF protein, and CD34 were significantly higher than those for patients with tumors of the expanding type (P < 0.01), at stage T1–T2 (P < 0.01), with nonvessel invasion (P < 0.05), without lymphatic metastasis (P < 0.05), and without hepatic (P < 0.001) or peritoneal metastasis (P < 0.001), respectively. Expression of MMP‐9 mRNA was positively related to that of VEGF protein (P < 0.001) and microvascular density (P < 0.001). Patients with higher MMP‐9 mRNA and VEGF expression demonstrated vivid tumor angiogenesis and poor 5‐year survival rate. MMP‐9 and VEGF expression is associated with enhanced tumor angiogenesis and may play crucial roles in the invasion and metastasis of gastric carcinoma. Therefore, MMP‐9 and VEGF may represent prognostic biomarkers and promising targets for therapeutic intervention. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.
Vimentin Intermediate Filaments: the Central Base in Sinus Endothelial Cells of the Rat Spleen
Authors: Uehara Kiyoko , Uehara Akira
Published: November 2010

The ultrastructural distribution of vimentin intermediate filaments (IFs) and localizations of the related proteins in sinus endothelial cells of the rat spleen was examined by confocal laser scanning and electron microscopy with detergent extraction, myosin‐fragment 1 decoration, and immunogold labeling to elucidate their functions in endothelial cells. Vimentin IFs were extremely abundant over stress fibers in the basal part of the endothelial cells. Some of them were intermingled with actin filaments in stress fibers, and were associated with coated vesicles. Plectin was predominantly localized in the layers of vimentin and stress fibers of the endothelial cells, but rarely in the vicinity of adherens junctions in the lateral part and focal adhesions in the basal part of the cells. Neither plakoglobin nor desmoplakin, which is coupled VE‐cadherin to vimentin IFs, was detected in sinus endothelial cells. Vinculin was localized in the basal membranes of the endothelial cells. These data suggest that abundant vimentin IFs are associated with stress fibers by plectin in the basal part of the cells and form cytoskeletal cores of sinus endothelial cells only partially supported by the ring‐shaped basal lamina to have roles in scaffolding and the mechanical stabilization of the endothelial cells. Furthermore, taken in connection with recently revealed functions of vimentin and plectin, vimentin might play a cytoskeletal core of sinus endothelial cells. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.
Antiparkinsonian Effects of Novel Adenosine A2AReceptor Antagonists
Authors: Drabczyńska Anna , Zygmunt Małgorzata , Sapa Jacek , Filipek Barbara , Müller Christa E. , Kieć‐Kononowicz Katarzyna
Published: November 2010

The present work describes the synthesis of a pyrazinopurinedione derivative which was together with a series of pyrimidopurinedione derivatives tested for potential antiparkinsonian activity in two tests: the “oxotremorine” and the “reserpine” test. For the studies compounds which had shown affinity for the adenosine A2Areceptor were chosen. One compound, a pyrazinopurinedione derivative, without affinity for A2Areceptors, but showing adenosine A1receptor affinity was also investigated. The performed preliminary tests indicated that, contrary to the pyrazinopurinedione all pyrimidopurinediones demonstrated antiparkinsonian effects. As a result of present studies it may be concluded that antiparkinsonian effects of the examined compounds are correlated with the antagonistic activity toward adenosine A2Areceptors in this class of compounds. However a direct correlation of the potency of both effects was not observed possibly due to different pharmacokinetic properties of the compounds. The most active derivatives of the present series were aryl‐substituted pyrimidopurinediones.
Design, Synthesis and Evaluation of Cytotoxicity of Novel Chromeno[4,3‐b]quinoline Derivatives
Authors: Miri Ramin , Motamedi Radineh , Rezaei Mohammad Reza , Firuzi Omidreza , Javidnia Azita , Shafiee Abbas
Published: November 2010

In the present work 15 new 1,4‐dihydropyridines (DHPs) bearing a coumarin ring were synthesized and assessed on 4 different human cancer cell lines (HeLa, K562, LS180, and MCF‐7). Although, all the derivatives were inactive on LS180 cell line, the results on other cells showed that these compounds had weak to moderate antitumoral activities and their IC50 ranged from 25 to >100 µM. Among the synthesized compounds, 7‐(2‐nitrophenyl)‐8,9,10,12‐tetrahydro‐7H‐chromeno[4,3‐b]quinoline‐6,8‐dione (6a) demonstrated the highest activity (IC50 range in different cell lines: 25.4–58.6 µM). Furthermore, the calcium channel antagonist activity of the derivatives, an undesired effect when these compounds are used as antitumoral agents, was much lower than nifedipine, a reference antagonist. In conclusion, this group of compounds seems to have promising biological properties and further investigation on this group could potentially lead to the discovery of cytotoxic agents with low calcium channel blocking activity.