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Sample records for ag nw networks

  1. Floating compression of Ag nanowire networks for effective strain release of stretchable transparent electrodes

    NASA Astrophysics Data System (ADS)

    Pyo, Jun Beom; Kim, Byoung Soo; Park, Hyunchul; Kim, Tae Ann; Koo, Chong Min; Lee, Jonghwi; Son, Jeong Gon; Lee, Sang-Soo; Park, Jong Hyuk

    2015-10-01

    Manipulation of the configuration of Ag nanowire (NW) networks has been pursued to enhance the performance of stretchable transparent electrodes. However, it has remained challenging due to the high Young's modulus and low yield strain of Ag NWs, which lead to their mechanical failure when subjected to structural deformation. We demonstrate that floating a Ag NW network on water and subsequent in-plane compression allows convenient development of a wavy configuration in the Ag NW network, which can release the applied strain. A greatly enhanced electromechanical stability of Ag NW networks can be achieved due to their wavy configuration, while the NW networks maintain the desirable optical and electrical properties. Moreover, the produced NW networks can be transferred to a variety of substrates, offering flexibility for device fabrication. The Ag NW networks with wavy configurations are used as compliant electrodes for dielectric elastomer actuators. The study demonstrates their promising potential to provide improved performance for soft electronic devices.Manipulation of the configuration of Ag nanowire (NW) networks has been pursued to enhance the performance of stretchable transparent electrodes. However, it has remained challenging due to the high Young's modulus and low yield strain of Ag NWs, which lead to their mechanical failure when subjected to structural deformation. We demonstrate that floating a Ag NW network on water and subsequent in-plane compression allows convenient development of a wavy configuration in the Ag NW network, which can release the applied strain. A greatly enhanced electromechanical stability of Ag NW networks can be achieved due to their wavy configuration, while the NW networks maintain the desirable optical and electrical properties. Moreover, the produced NW networks can be transferred to a variety of substrates, offering flexibility for device fabrication. The Ag NW networks with wavy configurations are used as compliant

  2. Morphological and optical data of AgNW embedded transparent conductive layer.

    PubMed

    Kim, Hong-Sik; Patel, Dipal B; Patel, Malkeshkumar; Kim, Joondong

    2016-12-01

    In this data article, morphological and optical data of AgNW encapsulated between ITO layers are presented to get insights into our article (DOI:10.1016/j.solmat.2016.04.038; Hong-Sik Kim, Pankaj Yadav, Malkeshkumar Patel, Hyunki Kim, Kavita Pandey, Joondong Kim, 2016) [1]. SEM images for the formation of AgNWs networks by number of spin coating are also presented. SEM photographs showing the surface morphologies before and after rapid thermal treatment of prepared samples have been presented. Apart from morphological data set, optical characteristics of this type of samples are given. The comparison plots of optical reflectance from AgNW encapsulated between ITO layers and bare ITO are given between the wavelength ranges from 300 to 1100 nm. At the end, transmittance and reflectance curves of native glass substrates used in this study are presented. PMID:27656670

  3. Transparent and conductive PEDOT:PSS/Ag NW/PEDOT:PSS hybrid films prepared by spin-coating at room temperature

    NASA Astrophysics Data System (ADS)

    Qingqing, Yue; Jinliang, Yan; Delan, Meng

    2015-12-01

    PEDOT:PSS/Ag NW/PEDOT:PSS hybrid films were deposited on PET substrates by the spin coating technique at room temperature. The optical transmittance, sheet resistance, crystallization and surface morphology were characterized by using the double beam spectrophotometer, Hall effect system, X-ray diffractometer and field emission scanning electron microscopy. XRD patterns of the hybrid films display characteristic diffraction peaks of Ag (111) and Ag (200), and the Ag NW networks have a polycrystalline structure with a Ag (111) preferred orientation. A high transmittance of 83.95% at the 550 nm wavelength and a low sheet resistance of 21.98 Ω/□ are achieved for 3-PEDOT:PSS/5-Ag NW/3-PEDOT:PSS hybrid films. Project supported by the National Natural Science Foundation of China (No. 10974077), and the Innovation Project of Shandong Graduate Education, China (No. SDYY13093).

  4. Ag nanowire percolating network embedded in indium tin oxide nanoparticles for printable transparent conducting electrodes

    SciTech Connect

    Jeong, Jin-A; Kim, Han-Ki

    2014-02-17

    Solution-based printable transparent conducting electrodes consisting of Ag nanowire (NW) and indium tin oxide (ITO) nanoparticles (NPs) were fabricated by simple brush painting at room temperature under atmospheric ambient conditions. Effectively embedding the Ag NW percolating network into the ITO NPs provided a conduction path, led to a metallic conduction behavior of the ITO NPs/Ag NW/ITO NPs multilayer and supplied electrons into the ITO NPs. The optimized ITO NPs/Ag NW/ITO NPs multilayer showed a sheet resistance of 16.57 Ω/sq and an optical transparency of 79.50% without post annealing. Based on high resolution transmission electron microscope analysis, we investigated the microstructure and interface structure of the ITO NPs/Ag NW/ITO NPs multilayer electrodes and suggested a possible mechanism to explain the low resistivity of the multilayers.

  5. Flexible transparent conducting composite films using a monolithically embedded AgNW electrode with robust performance stability

    NASA Astrophysics Data System (ADS)

    Im, Hyeon-Gyun; Jin, Jungho; Ko, Ji-Hoon; Lee, Jaemin; Lee, Jung-Yong; Bae, Byeong-Soo

    2013-12-01

    We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices.We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices. Electronic supplementary information (ESI) available: Further characteristics of AgNW-GFRHybrimer films and thermal oxidation of AgNW on glass. See DOI: 10.1039/c3nr05348b

  6. Reversibly Stretchable, Optically Transparent Radio-Frequency Antennas Based on Wavy Ag Nanowire Networks.

    PubMed

    Kim, Byoung Soo; Shin, Keun-Young; Pyo, Jun Beom; Lee, Jonghwi; Son, Jeong Gon; Lee, Sang-Soo; Park, Jong Hyuk

    2016-02-01

    We report a facile approach for producing reversibly stretchable, optically transparent radio-frequency antennas based on wavy Ag nanowire (NW) networks. The wavy configuration of Ag NWs is obtained by floating the NW networks on the surface of water, followed by compression. Stretchable antennas are prepared by transferring the compressed NW networks onto elastomeric substrates. The resulting antennas show excellent performance under mechanical deformation due to the wavy configuration, which allows the release of stress applied to the NWs and an increase in the contact area between NWs. The antennas formed from the wavy NW networks exhibit a smaller return loss and a higher radiation efficiency when strained than the antennas formed from the straight NW networks, as well as an improved stability in cyclic deformation tests. Moreover, the wavy NW antennas require a relatively small quantity of NWs, which leads to low production costs and provides an optical transparency. These results demonstrate the potential of these wavy Ag NW antennas in applications of wireless communications for wearable systems. PMID:26760896

  7. Reversibly Stretchable, Optically Transparent Radio-Frequency Antennas Based on Wavy Ag Nanowire Networks.

    PubMed

    Kim, Byoung Soo; Shin, Keun-Young; Pyo, Jun Beom; Lee, Jonghwi; Son, Jeong Gon; Lee, Sang-Soo; Park, Jong Hyuk

    2016-02-01

    We report a facile approach for producing reversibly stretchable, optically transparent radio-frequency antennas based on wavy Ag nanowire (NW) networks. The wavy configuration of Ag NWs is obtained by floating the NW networks on the surface of water, followed by compression. Stretchable antennas are prepared by transferring the compressed NW networks onto elastomeric substrates. The resulting antennas show excellent performance under mechanical deformation due to the wavy configuration, which allows the release of stress applied to the NWs and an increase in the contact area between NWs. The antennas formed from the wavy NW networks exhibit a smaller return loss and a higher radiation efficiency when strained than the antennas formed from the straight NW networks, as well as an improved stability in cyclic deformation tests. Moreover, the wavy NW antennas require a relatively small quantity of NWs, which leads to low production costs and provides an optical transparency. These results demonstrate the potential of these wavy Ag NW antennas in applications of wireless communications for wearable systems.

  8. Application of patterned Ag-nanowire networks to transparent thin-film heaters and electrodes for organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Rok; Triambulo, Ross E.; Kim, Jin-Hoon; Park, Jaeyoon; Jeong, Unyong; Park, Jin-Woo

    2016-06-01

    We present patterned Ag-nanowire (AgNW) networks for their application to transparent electrodes in flexible devices. Using capillary-force-based soft lithography (CFL), we formed 25- to 30-µm-wide line patterns of AgNWs on flexible polymer substrates. Organic light-emitting diodes (OLEDs) and transparent thin-film heaters (TFHs) were successfully fabricated on the patterned substrates, which verified the potential of AgNW patterns formed by CFL as interconnects in flexible devices.

  9. Large-scale fabrication and application of magnetite coated Ag NW-core water-dispersible hybrid nanomaterials.

    PubMed

    Wang, Baoyu; Zhang, Min; Li, Weizhen; Wang, Linlin; Zheng, Jing; Gan, Wenjun; Xu, Jingli

    2015-05-01

    In this work, we report a large scale synthetic procedure that allows attachment of magnetite nanoparticles onto Ag NWs in situ, which was conducted in a triethylene glycol (TREG) solution with iron acetylacetonate and Ag NWs as starting materials. The as-prepared Ag NW/Fe3O4 NP composites are well characterized by SEM, TEM, XRD, XPS, FT-IR, and VSM techniques. It was found that the mass ratio of iron acetylacetonate to Ag NWs plays a crucial role in controlling the amount of magnetite nanoparticles decorated on the Ag NWs. The resulting Ag NW/Fe3O4 NP composites exhibit superparamagnetic properties at room temperature, and can be well dispersed in aqueous and organic solutions, which is greatly beneficial for their application and functionality. Thus, the as-prepared magnetic silver nanowires show good catalytic activity, using the catalytic reduction of methylene blue (MB) as a model reaction. Furthermore, the Ag NW/Fe3O4 NP composites can be functionalized with polydopamine (Pdop), resorcinol-formaldehyde resin (PFR), and SiO2, respectively, in aqueous/ethanol solution. Meanwhile they can also be coated with polyphosphazene (PZS) in organic solution, resulting in a unique nanocable with well-defined core shell structures. Besides, taking Ag NW/Fe3O4@SiO2 as an example, a hollow magnetic silica nanotube can be obtained with the use of Ag NWs as physical templates and a solution of ammonium and H2O2. These can greatly improve the application of the Ag NW/Fe3O4 NP composites. The as-synthesized above nanocomposites have high potential for applications in the fields of polymers, wastewater treatment, sensors, and biomaterials.

  10. Large-scale fabrication and application of magnetite coated Ag NW-core water-dispersible hybrid nanomaterials.

    PubMed

    Wang, Baoyu; Zhang, Min; Li, Weizhen; Wang, Linlin; Zheng, Jing; Gan, Wenjun; Xu, Jingli

    2015-05-01

    In this work, we report a large scale synthetic procedure that allows attachment of magnetite nanoparticles onto Ag NWs in situ, which was conducted in a triethylene glycol (TREG) solution with iron acetylacetonate and Ag NWs as starting materials. The as-prepared Ag NW/Fe3O4 NP composites are well characterized by SEM, TEM, XRD, XPS, FT-IR, and VSM techniques. It was found that the mass ratio of iron acetylacetonate to Ag NWs plays a crucial role in controlling the amount of magnetite nanoparticles decorated on the Ag NWs. The resulting Ag NW/Fe3O4 NP composites exhibit superparamagnetic properties at room temperature, and can be well dispersed in aqueous and organic solutions, which is greatly beneficial for their application and functionality. Thus, the as-prepared magnetic silver nanowires show good catalytic activity, using the catalytic reduction of methylene blue (MB) as a model reaction. Furthermore, the Ag NW/Fe3O4 NP composites can be functionalized with polydopamine (Pdop), resorcinol-formaldehyde resin (PFR), and SiO2, respectively, in aqueous/ethanol solution. Meanwhile they can also be coated with polyphosphazene (PZS) in organic solution, resulting in a unique nanocable with well-defined core shell structures. Besides, taking Ag NW/Fe3O4@SiO2 as an example, a hollow magnetic silica nanotube can be obtained with the use of Ag NWs as physical templates and a solution of ammonium and H2O2. These can greatly improve the application of the Ag NW/Fe3O4 NP composites. The as-synthesized above nanocomposites have high potential for applications in the fields of polymers, wastewater treatment, sensors, and biomaterials. PMID:25815705

  11. Atmospheric-Pressure Processed Silver Nanowire (Ag-NW)/ZnO Composite Transparent Conducting Contacts

    SciTech Connect

    Perkins, John D.; Aggarwal, Shruti; van Hest, Maikel F. A. M.; Ginley, David S.

    2015-06-14

    Composite transparent contacts (TCs) based on metal nanowires and metal oxide matrix materials hold great promise for high performance transparent contacts for photovoltaics and opto-electronic technologies with the potential of all-atmospheric pressure processing. The metal nanowire mesh can provide both electrical conductivity and mechanical robustness against bending while the matrix material can both control the electrical interface and protect the metal nanowires. Here, we demonstrate all atmospheric pressure processed Ag-NW/ZnO composite TCs that are 90% transparent in the visible with sheet resistance Rs ~= 10 Ohms/sq. In addition, the composite TCs have higher infrared transmission than conventional TCO films with the same sheet resistance.

  12. Solution-processed highly conductive PEDOT:PSS/AgNW/GO transparent film for efficient organic-Si hybrid solar cells.

    PubMed

    Xu, Qiaojing; Song, Tao; Cui, Wei; Liu, Yuqiang; Xu, Weidong; Lee, Shuit-Tong; Sun, Baoquan

    2015-02-11

    Hybrid solar cells based on n-Si/poly(3,4-ethylenedioxythiophene):poly(styrene- sulfonate) (PEDOT:PSS) heterojunction promise to be a low cost photovoltaic technology by using simple device structure and easy fabrication process. However, due to the low conductivity of PEDOT:PSS, a metal grid deposited by vacuum evaporation method is still required to enhance the charge collection efficiency, which complicates the device fabrication process. Here, a solution-processed graphene oxide (GO)-welded silver nanowires (AgNWs) transparent conductive electrode (TCE) was employed to replace the vacuum deposited metal grid. A unique "sandwich" structure was developed by embedding an AgNW network between PEDOT:PSS and GO with a figure-of-merit of 8.6×10(-3) Ω(-1), which was even higher than that of sputtered indium tin oxide electrode (6.6×10(-3) Ω(-1)). A champion power conversion efficiency of 13.3% was achieved, because of the decreased series resistance of the TCEs as well as the enhanced built-in potential (Vbi) in the hybrid solar cells. The TCEs were obtained by facile low-temperature solution process method, which was compatible with cost-effective mass production technology. PMID:25599588

  13. Outer synchronization investigation between WS and NW small-world networks with different node numbers

    NASA Astrophysics Data System (ADS)

    Zhou, Guangye; Li, Chengren; Li, Tingting; Yang, Yi; Wang, Chen; He, Fangjun; Sun, Jingchang

    2016-09-01

    Some typical dual-ring erbium-doped fiber lasers with hyperchaos behaviors are taken as nodes to construct two kinds of small-world networks-NW and WS networks. Based on Lyapunov stability theorem, the appropriate controllers are designed and the outer synchronization between the small-world networks with diverse structures and different node numbers is further investigated. The simulation results show that the perfect synchronization between the complex small-world networks is realized, which is of potential application for all optical communication network.

  14. High-performance, bare silver nanowire network transparent heaters.

    PubMed

    Ergun, Orcun; Coskun, Sahin; Yusufoglu, Yusuf; Unalan, Husnu Emrah

    2016-11-01

    Silver nanowire (Ag NW) networks are one of the most promising candidates for the replacement of indium tin oxide (ITO) thin films in many different applications. Recently, Ag-NW-based transparent heaters (THs) showed excellent heating performance. In order to overcome the instability issues of Ag NW networks, researchers have offered different hybrid structures. However, these approaches not only require extra processing, but also decrease the optical performance of Ag NW networks. So, it is important to investigate and determine the thermal performance limits of bare-Ag-NW-network-based THs. Herein, we report on the effect of NW density, contact geometry, applied bias, flexing and incremental bias application on the TH performance of Ag NW networks. Ag-NW-network-based THs with a sheet resistance and percentage transmittance of 4.3 Ω sq(-1) and 83.3%, respectively, and a NW density of 1.6 NW μm(-2) reached a maximum temperature of 275 °C under incremental bias application (5 V maximum). With this performance, our results provide a different perspective on bare-Ag-NW-network-based transparent heaters. PMID:27678197

  15. High-performance, bare silver nanowire network transparent heaters.

    PubMed

    Ergun, Orcun; Coskun, Sahin; Yusufoglu, Yusuf; Unalan, Husnu Emrah

    2016-11-01

    Silver nanowire (Ag NW) networks are one of the most promising candidates for the replacement of indium tin oxide (ITO) thin films in many different applications. Recently, Ag-NW-based transparent heaters (THs) showed excellent heating performance. In order to overcome the instability issues of Ag NW networks, researchers have offered different hybrid structures. However, these approaches not only require extra processing, but also decrease the optical performance of Ag NW networks. So, it is important to investigate and determine the thermal performance limits of bare-Ag-NW-network-based THs. Herein, we report on the effect of NW density, contact geometry, applied bias, flexing and incremental bias application on the TH performance of Ag NW networks. Ag-NW-network-based THs with a sheet resistance and percentage transmittance of 4.3 Ω sq(-1) and 83.3%, respectively, and a NW density of 1.6 NW μm(-2) reached a maximum temperature of 275 °C under incremental bias application (5 V maximum). With this performance, our results provide a different perspective on bare-Ag-NW-network-based transparent heaters.

  16. High-performance, bare silver nanowire network transparent heaters

    NASA Astrophysics Data System (ADS)

    Ergun, Orcun; Coskun, Sahin; Yusufoglu, Yusuf; Emrah Unalan, Husnu

    2016-11-01

    Silver nanowire (Ag NW) networks are one of the most promising candidates for the replacement of indium tin oxide (ITO) thin films in many different applications. Recently, Ag-NW-based transparent heaters (THs) showed excellent heating performance. In order to overcome the instability issues of Ag NW networks, researchers have offered different hybrid structures. However, these approaches not only require extra processing, but also decrease the optical performance of Ag NW networks. So, it is important to investigate and determine the thermal performance limits of bare-Ag-NW-network-based THs. Herein, we report on the effect of NW density, contact geometry, applied bias, flexing and incremental bias application on the TH performance of Ag NW networks. Ag-NW-network-based THs with a sheet resistance and percentage transmittance of 4.3 Ω sq‑1 and 83.3%, respectively, and a NW density of 1.6 NW μm‑2 reached a maximum temperature of 275 °C under incremental bias application (5 V maximum). With this performance, our results provide a different perspective on bare-Ag-NW-network-based transparent heaters.

  17. Study of seismicity in the NW Himalaya and adjoining regions using IMS network

    NASA Astrophysics Data System (ADS)

    Ali, Sherif M.; Shanker, D.

    2016-08-01

    The Reviewed Event Bulletin (REB) of the International Data Center (IDC) has been used in order to investigate the seismicity of the Northwest Himalaya and its neighboring region for the time period June 1999 to March 2015 within the geographical coordinates 25-40° N latitude and 65-85° E longitude. We have used a very precisely located earthquake dataset recorded by the International Monitoring System (IMS) Network containing 7,583 events with body wave magnitudes from 2.5 to 6.3. The study area has been subdivided into six regions based on the Flinn-Engdahl (F-E) seismic and geographical regionalization scheme, which was used as the region classifications of the International Data Center catalog. The examined region includes NW India, Pakistan, Nepal, Xizang, Kashmir, and Hindukush. For each region, Magnitudes of completeness (Mc) and Gutenberg-Richter (GR) recurrence parameters (a and b values) have been estimated. The Gutenberg-Richter analysis is preceded by an overview of the seismotectonics of the study area. The obtained Mc values vary from 3.5 to 3.9. The lower value of Mc was found mainly in Xizang region whereas the higher Mc threshold is evident in Pakistan region. However, the b values vary from 1.19 to 1.48. The lowest b value is recorded in Xizang region, which is mostly related to the Main Karakoram Thrust (MKT) fault, whereas the highest b values are recorded in NW India and Kashmir regions, which are mostly related to the Main Frontal Thrust (MFT) fault. The REB for the selected period has been compared to the most renowned bulletin of global seismicity, namely that issued by the National Earthquake Information Center (NEIC) of the United States Geological Survey (USGS). A study of 4,821 events recorded by USGS in the study region indicates that about 36 % of seismic events were missed and the catalog is considered as complete for events with magnitudes ≥4.0. However, both a and b values are obviously higher than those of IMS catalog. The a

  18. Electrically robust metal nanowire network formation by in-situ interconnection with single-walled carbon nanotubes.

    PubMed

    Woo, Jong Seok; Han, Joong Tark; Jung, Sunshin; Jang, Jeong In; Kim, Ho Young; Jeong, Hee Jin; Jeong, Seung Yol; Baeg, Kang-Jun; Lee, Geon-Woong

    2014-01-01

    Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3 wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules. The electrical stabilisation mechanism of AgNW networks involves the modulation of the electrical transportation pathway by the SWCNTs through the SWCNT-AgNW junctions, which results in a relatively lower junction resistance than the NW-NW junction in the network film. In addition, we propose that good contact and Fermi level matching between AgNWs and modified SWCNTs lead to the modulation of the current pathway. The SWCNT-induced stabilisation of the AgNW networks was also demonstrated by irradiating the film with microwaves. The development of the high-throughput fabrication technology provides a robust and scalable strategy for realizing high-performance flexible transparent conductor films.

  19. Electrically Robust Metal Nanowire Network Formation by In-Situ Interconnection with Single-Walled Carbon Nanotubes

    PubMed Central

    Woo, Jong Seok; Han, Joong Tark; Jung, Sunshin; Jang, Jeong In; Kim, Ho Young; Jeong, Hee Jin; Jeong, Seung Yol; Baeg, Kang-Jun; Lee, Geon-Woong

    2014-01-01

    Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3 wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules. The electrical stabilisation mechanism of AgNW networks involves the modulation of the electrical transportation pathway by the SWCNTs through the SWCNT-AgNW junctions, which results in a relatively lower junction resistance than the NW-NW junction in the network film. In addition, we propose that good contact and Fermi level matching between AgNWs and modified SWCNTs lead to the modulation of the current pathway. The SWCNT-induced stabilisation of the AgNW networks was also demonstrated by irradiating the film with microwaves. The development of the high-throughput fabrication technology provides a robust and scalable strategy for realizing high-performance flexible transparent conductor films. PMID:24763208

  20. Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels

    PubMed Central

    Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

    2016-01-01

    We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30–70 Ohm/square), optical transmittance values (89–90%), and haze (0.5–1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle. PMID:27677410

  1. Contact-enhanced transparent silver nanowire network for all solution-based top-contact metal-oxide thin-film transistors.

    PubMed

    Kim, Yong-Hoon; Kim, Tae-Hyoung; Lee, Yeji; Kim, Jong-Woong; Kim, Jaekyun; Park, Sung Kyu

    2014-11-01

    In this paper, we investigate contact-enhanced transparent silver nanowire (Ag NW) network for solution-processed metal-oxide thin-film transistors (TFTs). Mechanical roll pressing was applied to a bar-coated Ag NW film to enhance the inter-nanowire connectivity. As a result, the sheet resistance of the Ag NW film was decreased from 119.5 ψ/square to 92.4 ψ/square, and more stable and enhanced TFT characteristics were achieved when the roll-pressed Ag NW was employed as source/drain electrodes. In addition, a non-acidic wet etching method was developed to pattern the Ag NW electrodes to construct top-contact geometry indium-gallium-zinc oxide TFTs. From the results, it is believed that the mechanical roll pressing and non-acidic wet etching method may be utilized in realizing all solution-based transparent metal-oxide TFTs. PMID:25958491

  2. Facile Patterning of Ag Nanowires Network by Micro-Contact Printing of Siloxane.

    PubMed

    Yoon, Sung-Soo; Khang, Dahl-Young

    2016-09-01

    A simple, low-cost, scalable patterning method has been demonstrated for chemically welded Ag nanowires (AgNWs) network. The chemically welded network of AgNWs on substrates has been patterned by modified microcontact printing (μCP). As an ink for the μCP, uncured high-viscosity siloxane polymer has been applied. Using elastomeric polydimethylsiloxane (PDMS) stamp that has been replicated from micromachined Si master mold by metal-assisted chemical etching, the printed siloxane ink materials have been cured by simple UV/ozone exposure for 3 min, which acts as an etch barrier in ensuing wet-removal of exposed AgNWs network. The proposed patterning technique has no limitation in the choice of substrates and pattern shape, in addition to high resolution. The patterned AgNWs network electrodes have shown excellent optical, electrical, and mechanical performances, such as high flexibility (up to ∼10%) and stretchability (up to 40%). Finally, the patterned AgNWs network electrodes have been applied as a transparent heater, which can be used for rapid raindrop removal or deicing of car windows and outside mirrors. This can be a valuable help for driving safety under harsh weather conditions. PMID:27548278

  3. Facile Patterning of Ag Nanowires Network by Micro-Contact Printing of Siloxane.

    PubMed

    Yoon, Sung-Soo; Khang, Dahl-Young

    2016-09-01

    A simple, low-cost, scalable patterning method has been demonstrated for chemically welded Ag nanowires (AgNWs) network. The chemically welded network of AgNWs on substrates has been patterned by modified microcontact printing (μCP). As an ink for the μCP, uncured high-viscosity siloxane polymer has been applied. Using elastomeric polydimethylsiloxane (PDMS) stamp that has been replicated from micromachined Si master mold by metal-assisted chemical etching, the printed siloxane ink materials have been cured by simple UV/ozone exposure for 3 min, which acts as an etch barrier in ensuing wet-removal of exposed AgNWs network. The proposed patterning technique has no limitation in the choice of substrates and pattern shape, in addition to high resolution. The patterned AgNWs network electrodes have shown excellent optical, electrical, and mechanical performances, such as high flexibility (up to ∼10%) and stretchability (up to 40%). Finally, the patterned AgNWs network electrodes have been applied as a transparent heater, which can be used for rapid raindrop removal or deicing of car windows and outside mirrors. This can be a valuable help for driving safety under harsh weather conditions.

  4. Low-haze, annealing-free, very long Ag nanowire synthesis and its application in a flexible transparent touch panel

    NASA Astrophysics Data System (ADS)

    Moon, Hyunjin; Won, Phillip; Lee, Jinhwan; Ko, Seung Hwan

    2016-07-01

    Since transparent conducting films based on silver nanowires (AgNWs) have shown higher transmittance and electrical conductivity compared to those of indium tin oxide (ITO) films, the electronics industry has recognized them as promising substitutes. However, due to the higher haze value of AgNW transparent conducting films compared to ITO films, the clarity is decreased when AgNW films are applied to optoelectronic devices. In this study, we develop a highly transparent, low-haze, very long AgNW percolation network. Moreover, we confirm that analyzed chemical roles can easily be applied to different AgNW synthesis methods, and that they have a direct impact on the nanowire shape. Consequently, the lengths of the wires are increased up to 200 μm and the diameters of the wires are decreased up to 45 nm. Using these results, we fabricate highly transparent (96%) conductors (100 Ω/sq) with low-haze (2%) without any annealing process. This electrode shows enhanced clarity compared to previous results due to the decreased diffusive transmittance and scattering. In addition, a flexible touchscreen using a AgNW network is demonstrated to show the performance of modified AgNWs.

  5. Low-haze, annealing-free, very long Ag nanowire synthesis and its application in a flexible transparent touch panel.

    PubMed

    Moon, Hyunjin; Won, Phillip; Lee, Jinhwan; Ko, Seung Hwan

    2016-07-22

    Since transparent conducting films based on silver nanowires (AgNWs) have shown higher transmittance and electrical conductivity compared to those of indium tin oxide (ITO) films, the electronics industry has recognized them as promising substitutes. However, due to the higher haze value of AgNW transparent conducting films compared to ITO films, the clarity is decreased when AgNW films are applied to optoelectronic devices. In this study, we develop a highly transparent, low-haze, very long AgNW percolation network. Moreover, we confirm that analyzed chemical roles can easily be applied to different AgNW synthesis methods, and that they have a direct impact on the nanowire shape. Consequently, the lengths of the wires are increased up to 200 μm and the diameters of the wires are decreased up to 45 nm. Using these results, we fabricate highly transparent (96%) conductors (100 Ω/sq) with low-haze (2%) without any annealing process. This electrode shows enhanced clarity compared to previous results due to the decreased diffusive transmittance and scattering. In addition, a flexible touchscreen using a AgNW network is demonstrated to show the performance of modified AgNWs.

  6. Low-haze, annealing-free, very long Ag nanowire synthesis and its application in a flexible transparent touch panel.

    PubMed

    Moon, Hyunjin; Won, Phillip; Lee, Jinhwan; Ko, Seung Hwan

    2016-07-22

    Since transparent conducting films based on silver nanowires (AgNWs) have shown higher transmittance and electrical conductivity compared to those of indium tin oxide (ITO) films, the electronics industry has recognized them as promising substitutes. However, due to the higher haze value of AgNW transparent conducting films compared to ITO films, the clarity is decreased when AgNW films are applied to optoelectronic devices. In this study, we develop a highly transparent, low-haze, very long AgNW percolation network. Moreover, we confirm that analyzed chemical roles can easily be applied to different AgNW synthesis methods, and that they have a direct impact on the nanowire shape. Consequently, the lengths of the wires are increased up to 200 μm and the diameters of the wires are decreased up to 45 nm. Using these results, we fabricate highly transparent (96%) conductors (100 Ω/sq) with low-haze (2%) without any annealing process. This electrode shows enhanced clarity compared to previous results due to the decreased diffusive transmittance and scattering. In addition, a flexible touchscreen using a AgNW network is demonstrated to show the performance of modified AgNWs. PMID:27276174

  7. Modeling of ionosphere time series using wavelet neural networks (case study: N-W of Iran)

    NASA Astrophysics Data System (ADS)

    Ghaffari Razin, Mir Reza; Voosoghi, Behzad

    2016-07-01

    Wavelet neural networks (WNNs) are important tools for analyzing time series especially when it is non-linear and non-stationary. It takes advantage of high resolution of wavelets and feed forward nature of neural networks (NNs). Therefore, in this paper, WNNs is used for modeling of ionosphere time series in Iran. To apply the method, observations collected at 22 GPS stations in 12 successive days of 2012 (DOY# 219-230) from Azerbaijan local GPS network are used. For training of WNN, back-propagation (BP) algorithm is used. The results of WNN compared with results of international reference ionosphere 2012 (IRI-2012) and international GNSS service (IGS) products. To assess the error of WNN, statistical indicators, relative and absolute errors are used. Minimum relative error for WNN compared with GPS TEC is 6.37% and maximum relative error is 12.94%. Also the maximum and minimum absolute error computed 6.32 and 0.13 TECU, respectively. Comparison of diurnal predicted TEC values from the WNN model and the IRI-2012 with GPS TEC revealed that the WNN provides more accurate predictions than the IRI-2012 model and IGS products in the test area.

  8. Thermally induced percolational transition and thermal stability of silver nanowire networks studied by THz spectroscopy.

    PubMed

    Chen, Jing-Zhi; Ahn, Hyeyoung; Yen, Shin-Chun; Tsai, Yao-Jiun

    2014-12-10

    Great demand toward flexible optoelectronic devices finds metal nanowires (NWs) the most promising flexible transparent conducting material with superior mechanical properties. However, ultrathin metal nanowires suffer from relatively poor thermal stability and sheet conductance, attributed to the poor adhesivity of the ohmic contact between nanowires. Thermal heating and annealing at 200 °C increase the conductivity of the metal network, but prolonged annealing accelerates the breakage of NWs near the NW junction and the formation of Ag droplets. In this study, the thermal stability of silver NW (AgNW) films is investigated through the in situ measurements of sheet resistance and terahertz (THz) conductivity. With the improved ohmic contact at the NW junctions by heating, a characteristic transition from the subpercolative to percolative network is observed by in situ THz spectroscopy. It is found that stamp-transferred graphene incorporated with a near-percolative AgNW network can dramatically enhance the thermal stability of the graphene-AgNW (GAgNW) hybrid film. In both in situ measurements, little variation of physical parameters in GAgNW film is observed for up to 3 h of annealing. The presented results offer the potential of graphene-incorporated metal nanowire film as a highly conductive electrode that also has high thermal stability and excellent transparency for next-generation electronics and optoelectronics on flexible substrates. PMID:25402346

  9. Distribution of deformation on an active normal fault network, NW Corinth Rift

    NASA Astrophysics Data System (ADS)

    Ford, Mary; Meyer, Nicolas; Boiselet, Aurélien; Lambotte, Sophie; Scotti, Oona; Lyon-Caen, Hélène; Briole, Pierre; Caumon, Guillaume; Bernard, Pascal

    2013-04-01

    Over the last 20-25 years, geodetic measurements across the Gulf of Corinth have recorded high extension rates varying from 1.1 cm/a in the east to a maximum of 1.6 cm/a in the west. Geodetic studies also show that current deformation is confined between two relatively rigid blocks defined as Central Greece (to the north) and the Peloponnesus to the south. Active north dipping faults (<1 Ma) define the south coast of the subsiding Gulf, while high seismicity (major earthquakes and micro-seismicity) is concentrated at depth below and to the north of the westernmost Gulf. How is this intense deformation distributed in the upper crust? Our objectives here are (1) to propose two models for the distribution of deformation in the upper crust in the westernmost rift since 1 Ma, and (2) to place the tectonic behaviour of the western Gulf in the context of longer term rift evolution. Over 20 major active normal faults have been identified in the CRL area based specific characteristics (capable of generating earthquakes M> 5.5, active in the last 1 M yrs, slip rate >0.5 mm/a). Because of the uncertainty related to fault geometry at depth two models for 3D fault network geometry in the western rift down to 10 km were constructed using all available geophysical and geological data. The first model assumes planar fault geometries while the second uses listric geometries for major faults. A model for the distribution of geodetically-defined extension on faults is constructed along five NNE-SSW cross sections using a variety of data and timescales. We assume that the role of smaller faults in accommodating deformation is negligible so that extension is fully accommodated on the identified major faults. Uncertainties and implications are discussed. These models provide estimates of slip rate for each fault that can be used in seismic hazard models. A compilation of onshore and offshore data shows that the western Gulf is the youngest part of the Corinth rift having initiated

  10. Temperature-controlled metal/ligand stoichiometric ratio in Ag-TCNE coordination networks

    SciTech Connect

    Rodríguez-Fernández, Jonathan; Lauwaet, Koen; Herranz, Maria Ángeles; Miranda, Rodolfo; Otero, Roberto

    2015-03-14

    The deposition of tetracyanoethylene (TCNE) on Ag(111), both at Room Temperature (RT, 300 K) and low temperatures (150 K), leads to the formation of coordination networks involving silver adatoms, as revealed by Variable-Temperature Scanning Tunneling Microscopy. Our results indicate that TCNE molecules etch away material from the step edges and possibly also from the terraces, which facilitates the formation of the observed coordination networks. Moreover, such process is temperature dependent, which allows for different stoichiometric ratios between Ag and TCNE just by adjusting the deposition temperature. X-ray Photoelectron Spectroscopy and Density Functional Theory calculations reveal that charge-transfer from the surface to the molecule and the concomitant geometrical distortions at both sides of the organic/inorganic interface might facilitate the extraction of silver atoms from the step-edges and, thus, its incorporation into the observed TCNE coordination networks.

  11. Silver nanowire percolation network soldered with graphene oxide at room temperature and its application for fully stretchable polymer light-emitting diodes.

    PubMed

    Liang, Jiajie; Li, Lu; Tong, Kwing; Ren, Zhi; Hu, Wei; Niu, Xiaofan; Chen, Yongsheng; Pei, Qibing

    2014-02-25

    Transparent conductive electrodes with high surface conductivity, high transmittance in the visible wavelength range, and mechanical compliance are one of the major challenges in the fabrication of stretchable optoelectronic devices. We report the preparation of a transparent conductive electrode (TCE) based on a silver nanowire (AgNW) percolation network modified with graphene oxide (GO). The monatomic thickness, mechanical flexibility, and strong bonding with AgNWs enable the GO sheets to wrap around and solder the AgNW junctions and thus dramatically reduce the inter-nanowire contact resistance without heat treatment or high force pressing. The GO-soldered AgNW network has a figure-of-merit sheet resistance of 14 ohm/sq with 88% transmittance at 550 nm. Its storage stability is improved compared to a conventional high-temperature annealed AgNW network. The GO-soldered AgNW network on polyethylene terephthalate films was processed from solutions using a drawdown machine at room temperature. When bent to 4 mm radius, its sheet resistance was increased by only 2-3% after 12,000 bending cycles. GO solder can also improve the stretchability of the AgNW network. Composite TCE fabricated by inlaying a GO-soldered AgNW network in the surface layer of polyurethane acrylate films is stretchable, by greater than 100% linear strain without losing electrical conductivity. Fully stretchable white polymer light-emitting diodes (PLEDs) were fabricated for the first time, employing the stretchable TCE as both the anode and cathode. The PLED can survive after 100 stretching cycles between 0 and 40% strain and can be stretched up to 130% linear strain at room temperature. PMID:24471886

  12. Self-assembled Ag nanoparticle network passivated by a nano-sized ZnO layer for transparent and flexible film heaters

    SciTech Connect

    Seo, Ki-Won; Kim, Han-Ki; Kim, Min-Yi; Chang, Hyo-Sik

    2015-12-15

    We investigated a self-assembled Ag nanoparticle network electrode passivated by a nano-sized ZnO layer for use in high-performance transparent and flexible film heaters (TFFHs). The low temperature atomic layer deposition of a nano-sized ZnO layer effectively filled the uncovered area of Ag network and improved the current spreading in the self-assembled Ag network without a change in the sheet resistance and optical transmittance as well as mechanical flexibility. The time-temperature profiles and heat distribution analysis demonstrate that the performance of the TFTH with the ZnO/Ag network is superior to that of a TFFH with Ag nanowire electrodes. In addition, the TFTHs with ZnO/Ag network exhibited better stability than the TFFH with a bare Ag network due to the effective current spreading through the nano-sized ZnO layer.

  13. Metal dispersion and mobility in soils from the Lik Zn-Pb-Ag massive sulphide deposit, NW Alaska: Environmental and exploration implications

    USGS Publications Warehouse

    Kelley, K.D.; Kelley, D.L.

    2003-01-01

    The Lik deposit in northern Alaska is a largely unexposed shale-hosted Zn-Pb-Ag massive sulphide deposit that is underlain by continuous permafrost. Residual soils overlying the mineralized zone have element enrichments that are two to six times greater than baseline values. The most prominent elements are Ag, Mo, P, Se, Sr, V by total 4-acid digestion and Tl by a weak partial digestion (Enzyme Leach or EL) because they show multi-point anomalies that extend across the entire mineralized zone, concentration ranges are 0.5-2.6 ppm Ag, 4-26 ppm Mo, 0.1-0.3% P, 3-22 ppm Se, 90-230 ppm Sr, 170-406 ppm V, and 1.6-30 ppb Tl. Lead, Sb, and Hg are also anomalous (up to 178 ppm, 30 ppm, and 1.9 ppm, respectively), but all are characterized by single point anomalies directly over the mineralized zone, with only slightly elevated concentrations over the lower mineralized section. Zinc (total) has a consistent baseline response of 200 ppm, but it is not elevated in soils overlying the mineralized zone. However, Zn by EL shows a distinct single-point anomaly over the ore zone that suggests it was highly mobile and partly adsorbed on oxides or other secondary phases during weathering. In situ analyses (by laser ablation ICP-MS) of pyrite and sphalerite from drill core suggest that sphalerite is the primary residence for Ag, Cd, and Hg in addition to Zn, and pyrite contains As, Fe, Sb, and Tl. The level and degree of oxidation, and the proportion of reacting pyrite and carbonate minerals are two factors that affected the mobility and transport of metals. In oxidizing conditions, Zn is highly mobile relative to Hg and Ag, perhaps explaining the decoupling of Zn from the other sphalerite-hosted elements in the soils. Soils are acidic (to 3.9 pH) directly over the deposit due to the presence of acid-producing pyrite, but acid-neutralizing carbonate away from the mineralized zone yield soils that are near neutral. The soils therefore formed in a complex system involving oxidation and

  14. Effects of alkali treatments on Ag nanowire transparent conductive films

    NASA Astrophysics Data System (ADS)

    Kim, Sunho; Kang, Jun-gu; Eom, Tae-yil; Moon, Bongjin; Lee, Hoo-Jeong

    2016-06-01

    In this study, we employ various alkali materials (alkali metals with different base strengths, and ammonia gas and solution) to improve the conductivity of silver nanowire (Ag NW)-networked films. The alkali treatment appears to remove the surface oxide and improve the conductivity. When applied with TiO2 nanoparticles, the treatment appears more effective as the alkalis gather around wire junctions and help them weld to each other via heat emitted from the reduction reaction. The ammonia solution treatment is found to be quick and aggressive, damaging the wires severely in the case of excessive treatment. On the other hand, the ammonia gas treatment seems much less aggressive and does not damage the wires even after a long exposure. The results of this study highlight the effectiveness of the alkali treatment in improving of the conductivity of Ag NW-networked transparent conductive films.

  15. From hydrogen bonding to metal coordination and back: Porphyrin-based networks on Ag(111)

    SciTech Connect

    Studener, F. Müller, K.; Stöhr, M.; Marets, N.; Bulach, V. Hosseini, M. W.

    2015-03-14

    The self-assembly of a metal-free porphyrin bearing two pyridyl coordinating sites and two pentyl chains at trans meso positions was investigated under ultrahigh vacuum on a Ag(111) surface by scanning tunneling microscopy (STM). The STM measurements revealed a well-ordered close-packed structure with a rhombic unit cell for coverages ≤1 monolayer with their molecular plane parallel to the surface. The growth direction of the molecular islands is aligned along the step edges, which are restructured due to molecule-substrate interactions. The shorter unit cell vector of the molecular superstructure follows the 〈1-10〉 direction of the Ag(111) substrate. Hydrogen bonds between pyridyl and pyrrole groups of neighboring molecules as well as weak van der Waals forces between the pentyl chains stabilize the superstructure. Deposition of cobalt atoms onto the close-packed structure at room temperature leads to the formation of a hexagonal porous network stabilized by metal-ligand bonding between the pyridyl ligands and the cobalt atoms. Thermal annealing of the Co-coordination network at temperatures >450 K results in the transformation of the hexagonal network into a second close-packed structure. Changes in the molecule-substrate interactions due to metalation of the porphyrin core with Co as well as intermolecular interactions can explain the observed structural transformations.

  16. Influence of structural position on fracture networks in the Torridon Group, Achnashellach fold and thrust belt, NW Scotland

    NASA Astrophysics Data System (ADS)

    Watkins, Hannah; Butler, Robert W. H.; Bond, Clare E.; Healy, Dave

    2015-05-01

    In fold-and-thrust belts rocks undergo deformation as fold geometries evolve. Deformation may be accommodated by brittle fracturing, which can vary depending on structural position. We use 2D forward modelling and 3D restorations to determine strain distributions throughout folds of the Achnashellach Culmination, Moine Thrust Belt, NW Scotland. Fracture data is taken from the Torridon Group; a thick, coarse grained fluviatile sandstone deposited during the Proterozoic. Modelling infers a correlation between strain and simple curvature; we use simple curvature to infer how structural position and strain control fracture attribute variations in a fold and thrust belt. In high curvature regions, such as forelimbs, fracture intensities are high and fractures are short and oriented parallel to fold hinges. In low curvature regions fractures have variable intensities and are longer. Fracture orientations in these regions are scattered and vary over short distances. These variations do not relate to strain; data suggests lithology may influence fracturing. The strain history of fold structures also influences fracturing; structures with longer deformation histories exhibit consistent fracture attributes due to moderate-high strain during folding, despite present day low curvature. This is in contrast to younger folds with similar curvatures but shorter deformation histories. We suggest in high strain regions fracturing is influenced by structural controls, whereas in low strain regions lithology becomes more important in influencing fracturing.

  17. Flexible, silver nanowire network nickel hydroxide core-shell electrodes for supercapacitors

    NASA Astrophysics Data System (ADS)

    Yuksel, Recep; Coskun, Sahin; Kalay, Yunus Eren; Unalan, Husnu Emrah

    2016-10-01

    We present a novel one-dimensional coaxial architecture composed of silver nanowire (Ag NW) network core and nickel hydroxide (Ni(OH)2) shell for the realization of coaxial nanocomposite electrode materials for supercapacitors. Ag NWs are formed conductive networks via spray coating onto polyethylene terephthalate (PET) substrates and Ni(OH)2 is gradually electrodeposited onto the Ag NW network to fabricate core-shell electrodes for supercapacitors. Synergy of highly conductive Ag NWs and high capacitive Ni(OH)2 facilitate ion and electron transport, enhance electrochemical properties and result in a specific capacitance of 1165.2 F g-1 at a current density of 3 A g-1. After 3000 cycles, fabricated nanocomposite electrodes show 93% capacity retention. The rational design explored in this study points out the potential of nanowire based coaxial energy storage devices.

  18. Large scale silver nanowires network fabricated by MeV hydrogen (H+) ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Honey, S.; Naseem, S.; Ishaq, A.; Maaza, M.; Bhatti, M. T.; Wan, D.

    2016-04-01

    A random two-dimensional large scale nano-network of silver nanowires (Ag-NWs) is fabricated by MeV hydrogen (H+) ion beam irradiation. Ag-NWs are irradiated under H+ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H+ ion beam-induced welding of Ag-NWs at intersecting positions. H+ ion beam induced welding is confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the structure of Ag NWs remains stable under H+ ion beam, and networks are optically transparent. Morphology also remains stable under H+ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H+ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps: ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices. Project supported by the National Research Foundation of South Africa (NRF), the French Centre National pour la Recherche Scientifique, iThemba-LABS, the UNESCO-UNISA Africa Chair in Nanosciences & Nanotechnology, the Third World Academy of Science (TWAS), Organization of Women in Science for the Developing World (OWSDW), the Abdus Salam ICTP via the Nanosciences African Network (NANOAFNET), and the Higher Education Commission (HEC) of Pakistan.

  19. Dynamics of Spatially Confined Bisphenol A Trimers in a Unimolecular Network on Ag(111).

    PubMed

    Lloyd, Julian A; Papageorgiou, Anthoula C; Fischer, Sybille; Oh, Seung Cheol; Saǧlam, Özge; Diller, Katharina; Duncan, David A; Allegretti, Francesco; Klappenberger, Florian; Stöhr, Martin; Maurer, Reinhard J; Reuter, Karsten; Reichert, Joachim; Barth, Johannes V

    2016-03-01

    Bisphenol A (BPA) aggregates on Ag(111) shows a polymorphism between two supramolecular motifs leading to formation of distinct networks depending on thermal energy. With rising temperature a dimeric pairing scheme reversibly converts into a trimeric motif, which forms a hexagonal superstructure with complex dynamic characteristics. The trimeric arrangements notably organize spontaneously into a self-assembled one-component array with supramolecular BPA rotors embedded in a two-dimensional stator sublattice. By varying the temperature, the speed of the rotors can be controlled as monitored by direct visualization. A combination of scanning tunneling microscopy and dispersion-corrected density-functional tight-binding (DFTB-vdW(surf)) based molecular modeling reveals the exact atomistic position of each molecule within the assembly as well as the driving force for the formation of the supramolecular rotors. PMID:26849384

  20. Application of transit data analysis and artificial neural network in the prediction of discharge of Lor River, NW Spain.

    PubMed

    Astray, G; Soto, B; Lopez, D; Iglesias, M A; Mejuto, J C

    2016-01-01

    Transit data analysis and artificial neural networks (ANNs) have proven to be a useful tool for characterizing and modelling non-linear hydrological processes. In this paper, these methods have been used to characterize and to predict the discharge of Lor River (North Western Spain), 1, 2 and 3 days ahead. Transit data analyses show a coefficient of correlation of 0.53 for a lag between precipitation and discharge of 1 day. On the other hand, temperature and discharge has a negative coefficient of correlation (-0.43) for a delay of 19 days. The ANNs developed provide a good result for the validation period, with R(2) between 0.92 and 0.80. Furthermore, these prediction models have been tested with discharge data from a period 16 years later. Results of this testing period also show a good correlation, with R(2) between 0.91 and 0.64. Overall, results indicate that ANNs are a good tool to predict river discharge with a small number of input variables. PMID:27054749

  1. 3D hierarchical MnO2 nanorod/welded Ag-nanowire-network composites for high-performance supercapacitor electrodes.

    PubMed

    Qiao, Zhensong; Yang, Xiaopeng; Yang, Shuhua; Zhang, Liqiang; Cao, Bingqiang

    2016-06-28

    3D MnO2 nanorod/welded Ag-nanowire-network supercapacitor electrodes were prepared. Welding treatment of the Ag nanowire-network leads to low resistance and long lifetime. Galvanostatic charge/discharge (GCD) induces an ever-lasting morphology changing from flower-like to honeycomb-like for MnO2, which manifests as increasing specific capacitance to 663.4 F g(-1) after 7000 GCD cycles. PMID:27263832

  2. 3D hierarchical MnO2 nanorod/welded Ag-nanowire-network composites for high-performance supercapacitor electrodes.

    PubMed

    Qiao, Zhensong; Yang, Xiaopeng; Yang, Shuhua; Zhang, Liqiang; Cao, Bingqiang

    2016-06-28

    3D MnO2 nanorod/welded Ag-nanowire-network supercapacitor electrodes were prepared. Welding treatment of the Ag nanowire-network leads to low resistance and long lifetime. Galvanostatic charge/discharge (GCD) induces an ever-lasting morphology changing from flower-like to honeycomb-like for MnO2, which manifests as increasing specific capacitance to 663.4 F g(-1) after 7000 GCD cycles.

  3. Polymer-facilitated low temperature fusing of spray-coated silver nanowire networks as transparent top and bottom electrodes in small molecule organic photovoltaics (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Selzer, Franz; Weiß, Nelli; Kneppe, David; Bormann, Ludwig; Sachse, Christoph; Gaponik, Nikolai; Eychmüller, Alexander; Leo, Karl; Müller-Meskamp, Lars

    2015-10-01

    Networks of silver nanowires (AgNWs) are promising candidates for transparent conducting electrodes in organic photovoltaics (OPV), as they achieve similar performance as the commonly used indium tin oxide (ITO) at lower cost and increased flexibility. The initial sheet resistance (Rs) of AgNW electrodes typically needs to be reduced by a post-annealing step (90 min@200 °C), being detrimental for processing on polymeric substrates. We present novel low temperature-based methods to integrate AgNWs in organic small molecule-based photovoltaics, either as transparent and highly conductive bottom-electrode or, for the first time, as spray-coated AgNW top-electrode. The bottom-electrodes are prepared by organic matrix assisted low-temperature fusing. Here, selected polymers are coated below the AgNWs to increase the interaction between NWs and substrate. In comparison to networks without these polymeric sublayers, the Rs is reduced by two orders of magnitude. AgNW top-electrodes are realized by dispersing modified high-quality AgNWs in inert solvents, which do not damage small molecule layers. Accordingly, our AgNW dispersion can be spray-coated onto all kind of OPV devices. Both bottom- and top-electrodes show a Rs of <11 Ω/ at >87 % transparency directly after spray-coating at very low substrate temperatures of <80 °C. We also demonstrate the implementation of our AgNW electrodes in organic solar cells. The corresponding devices show almost identical performance compared to organic solar cells exploiting ITO as bottom or thermally evaporated thin-metal as top-electrode.

  4. Nano-morphology induced additional surface plasmon resonance enhancement of SERS sensitivity in Ag/GaN nanowall network

    NASA Astrophysics Data System (ADS)

    Sharvani, S.; Upadhayaya, Kishor; Kumari, Gayatri; Narayana, Chandrabhas; Shivaprasad, S. M.

    2015-11-01

    The GaN nanowall network, formed by opening the screw dislocations by kinetically controlled MBE growth, possesses a large surface and high conductivity. Sharp apexed nanowalls show higher surface electron concentration in the band-tail states, in comparison to blunt apexed nanowalls. Uncapped silver nanoparticles are vapor deposited on the blunt and sharp GaN nanowall networks to study the morphological dependence of band-edge plasmon-coupling. Surface enhanced Raman spectroscopy studies performed with a rhodamine 6G analyte on these two configurations clearly show that the sharp nanowall morphology with smaller Ag nanoparticles shows higher enhancement of the Raman signal. A very large enhancement factor of 2.8 × 107 and a very low limit of detection of 10-10 M is observed, which is attributed to the surface plasmon resonance owing to the high surface electron concentration on the GaN nanowall in addition to that of the Ag nanoparticles. The significantly higher sensitivity with same-sized Ag nanoparticles confirms the unconventional role of morphology-dependent surface charge carrier concentration of GaN nanowalls in the enhancement of Raman signals.

  5. Nano-morphology induced additional surface plasmon resonance enhancement of SERS sensitivity in Ag/GaN nanowall network.

    PubMed

    Sharvani, S; Upadhayaya, Kishor; Kumari, Gayatri; Narayana, Chandrabhas; Shivaprasad, S M

    2015-11-20

    The GaN nanowall network, formed by opening the screw dislocations by kinetically controlled MBE growth, possesses a large surface and high conductivity. Sharp apexed nanowalls show higher surface electron concentration in the band-tail states, in comparison to blunt apexed nanowalls. Uncapped silver nanoparticles are vapor deposited on the blunt and sharp GaN nanowall networks to study the morphological dependence of band-edge plasmon-coupling. Surface enhanced Raman spectroscopy studies performed with a rhodamine 6G analyte on these two configurations clearly show that the sharp nanowall morphology with smaller Ag nanoparticles shows higher enhancement of the Raman signal. A very large enhancement factor of 2.8 × 10(7) and a very low limit of detection of 10(-10) M is observed, which is attributed to the surface plasmon resonance owing to the high surface electron concentration on the GaN nanowall in addition to that of the Ag nanoparticles. The significantly higher sensitivity with same-sized Ag nanoparticles confirms the unconventional role of morphology-dependent surface charge carrier concentration of GaN nanowalls in the enhancement of Raman signals. PMID:26502004

  6. Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs.

    PubMed

    Zhang, Hui; Liu, Nishuang; Shi, Yuling; Liu, Weijie; Yue, Yang; Wang, Siliang; Ma, Yanan; Wen, Li; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

    2016-08-31

    Pressure sensors with high elasticity are in great demand for the realization of intelligent sensing, but there is a need to develope a simple, inexpensive, and scalable method for the manufacture of the sensors. Here, we reported an efficient, simple, facile, and repeatable "dipping and coating" process to manufacture a piezoresistive sensor with high elasticity, based on homogeneous 3D hybrid network of carbon nanotubes@silver nanoparticles (CNTs@Ag NPs) anchored on a skeleton sponge. Highly elastic, sensitive, and wearable sensors are obtained using the porous structure of sponge and the synergy effect of CNTs/Ag NPs. Our sensor was also tested for over 2000 compression-release cycles, exhibiting excellent elasticity and cycling stability. Sensors with high performance and a simple fabrication process are promising devices for commercial production in various electronic devices, for example, sport performance monitoring and man-machine interfaces. PMID:27482721

  7. Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs.

    PubMed

    Zhang, Hui; Liu, Nishuang; Shi, Yuling; Liu, Weijie; Yue, Yang; Wang, Siliang; Ma, Yanan; Wen, Li; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

    2016-08-31

    Pressure sensors with high elasticity are in great demand for the realization of intelligent sensing, but there is a need to develope a simple, inexpensive, and scalable method for the manufacture of the sensors. Here, we reported an efficient, simple, facile, and repeatable "dipping and coating" process to manufacture a piezoresistive sensor with high elasticity, based on homogeneous 3D hybrid network of carbon nanotubes@silver nanoparticles (CNTs@Ag NPs) anchored on a skeleton sponge. Highly elastic, sensitive, and wearable sensors are obtained using the porous structure of sponge and the synergy effect of CNTs/Ag NPs. Our sensor was also tested for over 2000 compression-release cycles, exhibiting excellent elasticity and cycling stability. Sensors with high performance and a simple fabrication process are promising devices for commercial production in various electronic devices, for example, sport performance monitoring and man-machine interfaces.

  8. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes.

    PubMed

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-01-01

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases. PMID:27620453

  9. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes.

    PubMed

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-01-01

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases.

  10. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes

    PubMed Central

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-01-01

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases. PMID:27620453

  11. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes

    NASA Astrophysics Data System (ADS)

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-09-01

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases.

  12. Transparent conductive PVP/AgNWs films for flexible organic light emitting diodes by spraying method

    NASA Astrophysics Data System (ADS)

    Hu, Jun-tao; Mei, Wen-juan; Ye, Kang-li; Wei, Qing-qing; Hu, Sheng

    2016-05-01

    In this study, a simple spraying method is used to prepare the transparent conductive films (TCFs) based on Ag nanowires (AgNWs). Polyvinylpyrrolidone (PVP) is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%—67.9% at 380—780 nm, and the sheet resistance is 30 Ω/□ which is equivalent to that of commercial indium tin oxide (ITO). During cyclic bending tests to 500 cycles with bending radius of 5 mm, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transparent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes (OLEDs).

  13. Enhanced light scattering and trapping effect of Ag nanowire mesh electrode for high efficient flexible organic solar cell.

    PubMed

    Wang, Byung-Yong; Yoo, Tae-Hee; Lim, Ju Won; Sang, Byoung-In; Lim, Dae-Soon; Choi, Won Kook; Hwang, Do Kyung; Oh, Young-Jei

    2015-04-24

    Ag nanowire (NW) mesh is used as transparent conducting electrode for high efficient flexible organic solar cells (OSCs). The Ag NW mesh electrode facilitates light scattering and trapping, allowing enhancement of light absorption in the active layer. OSCs incorporating Ag NW mesh electrode exhibit maximum power conversion efficiency (PCE) of 4.47%, 25%, higher than that of OSCs with a conventional ITO electrode (3.63%).

  14. ZnO-(Cu/Ag)TCNQ heterostructure network over flexible platform for enhanced cold cathode application

    NASA Astrophysics Data System (ADS)

    Pal, Shreyasi; Maiti, Soumen; Narayan Maiti, Uday; Chattopadhyay, Kalyan Kumar

    2016-07-01

    Multistage field emitters consisting of organic/inorganic hybrid nanostructures with branched geometry are designed via a two-step protocol: a simple wet chemical method followed by a vapor-solid-phase technique. (Cu/Ag)TCNQ (copper/silver-7,7,8,8-tetracyanoquinodimethane) nanowires (NWs) were grown hierarchically on zinc oxide (ZnO) nanorods (NRs) to form ZnO-(Cu/Ag)TCNQ heterostructure assemblies. By monitoring the metallic Cu and Ag coating thickness on ZnO NRs, precise control over the morphology and orientations of the secondary organic NWs is achieved. In-depth analysis of electron field emission (FE) behavior of the ZnO-(Cu/Ag)TCNQ-based hierarchy suggests highest emission performance with low turn-on as well as threshold fields of 1.15 and 3.75 V μm-1 respectively from the morphology-optimized hierarchy. Beneficial orientation of the branched organic NWs ensures sequential electric field enhancement in the consecutive stem and branches whereas its low work function eases electron emission; these aspects combined together render an overall enhancement in the emission behavior of the hybrid system. As compared to individual building units, the heterostructures show improved field electron emission. Additionally, successful construction of this novel hybrid over a fabric platform displays great potential in opening up new pathways in the highly-anticipated field of flexible electronics.

  15. Large Pulsed Electron Beam Welded Percolation Networks of Silver Nanowires for Transparent and Flexible Electrodes.

    PubMed

    Kim, Jisoo; Nam, Yun Seok; Song, Myoung Hoon; Park, Hyung Wook

    2016-08-17

    Mechanical properties of transparent electrodes, including flexibility, are important in flexible electronics for sustaining electrical conductivity under bending with small radius of curvature. Low contact resistance of junctions in metal nanowire percolation networks is the most important factor to produce electrodes with excellent optical, electrical and mechanical performance. Here, we report the fabrication of welded silver nanowire percolation networks using large pulsed electron beam (LPEB) irradiation as a welding process of silver nanowires (AgNWs). It results in modification of electrical and mechanical properties because of the low contact resistance at welded junctions. Consequently, the flexible and transparent AgNW electrodes fabricated by LPEB irradiation showed lower sheet resistance of 12.63 Ω sq(-1) at high transmittance of 93% (at 550 nm), and superb mechanical flexibility, compared with other AgNW electrodes prepared by thermal treatement and without any treatment. Polymer light-emitting diodes (PLEDs) using AgNWs by LPEB irradiation were fabricated to confirm that the AgNW electrode by LPEB irradiation was able to become alternative to indium tin oxide (ITO) and they showed good device performance as a maximum luminous efficiency of 7.37 cd A(-1), and excellent mechanical flexibility under bending with small radius of curvature. PMID:27463783

  16. Large Pulsed Electron Beam Welded Percolation Networks of Silver Nanowires for Transparent and Flexible Electrodes.

    PubMed

    Kim, Jisoo; Nam, Yun Seok; Song, Myoung Hoon; Park, Hyung Wook

    2016-08-17

    Mechanical properties of transparent electrodes, including flexibility, are important in flexible electronics for sustaining electrical conductivity under bending with small radius of curvature. Low contact resistance of junctions in metal nanowire percolation networks is the most important factor to produce electrodes with excellent optical, electrical and mechanical performance. Here, we report the fabrication of welded silver nanowire percolation networks using large pulsed electron beam (LPEB) irradiation as a welding process of silver nanowires (AgNWs). It results in modification of electrical and mechanical properties because of the low contact resistance at welded junctions. Consequently, the flexible and transparent AgNW electrodes fabricated by LPEB irradiation showed lower sheet resistance of 12.63 Ω sq(-1) at high transmittance of 93% (at 550 nm), and superb mechanical flexibility, compared with other AgNW electrodes prepared by thermal treatement and without any treatment. Polymer light-emitting diodes (PLEDs) using AgNWs by LPEB irradiation were fabricated to confirm that the AgNW electrode by LPEB irradiation was able to become alternative to indium tin oxide (ITO) and they showed good device performance as a maximum luminous efficiency of 7.37 cd A(-1), and excellent mechanical flexibility under bending with small radius of curvature.

  17. Oxidation of ethyl acetate by a high performance nanostructure (Ni, Mn)-Ag/ZSM-5 bimetallic catalysts and development of an artificial neural networks predictive modeling.

    PubMed

    Jodaei, Azadeh; Salari, Darush; Niaei, Ali; Khatamian, Masumeh; Hosseini, Seyed Ali

    2011-01-01

    The catalytic oxidation of ethyl acetate in low concentration was investigated over mono-metallic Ag/ZSM5 and bimetallic (Ni, Mn)-Ag/ZSM-5 catalysts. Catalytic studies were carried out in a catalytic fixed bed reactor under atmospheric pressure. The sequence of catalytic activity was as follows: Ni-Ag-ZSM-5 > Mn-Ag-ZSM-5 > Ag-ZSM-5 > H-ZSM-5. The catalysts were characterized by ICP-AES, X-ray diffraction (XRD), low temperature nitrogen adsorption, NH(3)-TPD, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and diffuse reflectance UV-vis spectra (UV-vis). An artificial neural networks (ANN) model was developed to predict the performance of catalytic oxidation process over bimetallic Ni-Ag/ZSM-5 catalyst based on experimental data. For this purpose the standard feed forward back propagation algorithm was employed to train the model by using laboratory experimental data. A good agreement was resulted between experimental results and those obtained by ANN. Following order for variables effects on conversion yield of ethyl acetate was predicted by ANN model: reaction temperature (32.99%) > Ag loading (27.38%) > initial ethyl acetate concentration (23.58%) > Ni loading (16.05%). PMID:21104495

  18. Transferable self-welding silver nanowire network as high performance transparent flexible electrode.

    PubMed

    Zhu, Siwei; Gao, Yuan; Hu, Bin; Li, Jia; Su, Jun; Fan, Zhiyong; Zhou, Jun

    2013-08-23

    High performance transparent electrodes (TEs) with figures-of-merit as high as 471 were assembled using ultralong silver nanowires (Ag NWs). A room-temperature plasma was employed to enhance the conductivity of the Ag NW TEs by simultaneously removing the insulating PVP layer coating on the NWs and welding the junctions tightly. Furthermore, we developed a general way to fabricate TEs regardless of substrate limitations by transferring the as-fabricated Ag NW network onto various substrates directly, and the transmittance can remain as high as 91% with a sheet resistivity of 13 Ω/sq. The highly robust and stable flexible TEs will have broad applications in flexible optoelectronic and electronic devices.

  19. Resistance of Single Ag Nanowire Junctions and Their Role in the Conductivity of Nanowire Networks.

    PubMed

    Bellew, Allen T; Manning, Hugh G; Gomes da Rocha, Claudia; Ferreira, Mauro S; Boland, John J

    2015-11-24

    Networks of silver nanowires appear set to replace expensive indium tin oxide as the transparent conducting electrode material in next generation devices. The success of this approach depends on optimizing the material conductivity, which until now has largely focused on minimizing the junction resistance between wires. However, there have been no detailed reports on what the junction resistance is, nor is there a known benchmark for the minimum attainable sheet resistance of an optimized network. In this paper, we present junction resistance measurements of individual silver nanowire junctions, producing for the first time a distribution of junction resistance values and conclusively demonstrating that the junction contribution to the overall resistance can be reduced beyond that of the wires through standard processing techniques. We find that this distribution shows the presence of a small percentage (6%) of high-resistance junctions, and we show how these may impact the performance of network-based materials. Finally, through combining experiment with a rigorous model, we demonstrate the important role played by the network skeleton and the specific connectivity of the network in determining network performance. PMID:26448205

  20. Inkjet printed silver nanowire network as top electrode for semi-transparent organic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Lu, Hui; Lin, Jian; Wu, Na; Nie, Shuhong; Luo, Qun; Ma, Chang-Qi; Cui, Zheng

    2015-03-01

    A method for direct inkjet printing of silver nanowire (Ag NW) to form transparent conductive network as the top electrode for inverted semi-transparent organic photovoltaic devices (OPV) was developed. The highest power conversion efficiency of the poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) based OPV was achieved to be 2.71% when the top electrode was formed by 7 times of printing. In general, devices with printed Ag NW top electrode had similar open-circuit voltage (VOC, around 0.60 V) but lower fill factor (FF, 0.33-0.54) than that of device with thermally deposited Ag opaque electrode (reference device). Both FF and short-circuit current density (JSC), however, were found to be increasing with the increase of printing times (3, 5, and 7), which could be partially attributed to the improved conductivity of Ag NW network electrodes. The solvent effect on device performances was studied carefully by comparing the current density-voltage (J-V) curves of different devices. The results revealed that solvent treatment on the anode buffer layer during printing led to a decrease of charge injection selectivity and an increase of charge recombination at the anode interface, which was considered to be the reason for the degrading of device performance.

  1. Enhanced transparent conducting networks on plastic substrates modified with highly oxidized graphene oxide nanosheets

    NASA Astrophysics Data System (ADS)

    Woo, Jong Seok; Sin, Dong Hun; Kim, Haena; Jang, Jeong In; Kim, Ho Young; Lee, Geon-Woong; Cho, Kilwon; Park, Soo-Young; Han, Joong Tark

    2016-03-01

    Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp2 domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite. We demonstrated that under-coated HOGO further decreases the sheet resistance of the SWCNT film top-coated with HOGO by increasing the contact area between the SWCNTs and HOGO nanosheets by generating hole carriers in the SWCNT as a result of charge transfer. Moreover, HOGO nanosheets with AgNWs contribute to the efficient thermal joining of AgNW networks on plastic substrates by limiting the thermal embedding of AgNWs into the plastic surface, resulting in efficient decrease of the sheet resistance. Furthermore, flexible organic photovoltaic cells with GO-modified AgNW anodes on a flexible substrate were successfully demonstrated.Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp2 domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite. We demonstrated that under-coated HOGO further decreases the sheet resistance of the SWCNT film top-coated with HOGO by increasing the contact area between the SWCNTs and HOGO nanosheets by generating hole carriers in the SWCNT as a result of charge

  2. Annealing-free and strongly adhesive silver nanowire networks with long-term reliability by introduction of a nonconductive and biocompatible polymer binder.

    PubMed

    Jin, Yunxia; Deng, Dunying; Cheng, Yuanrong; Kong, Lingqiang; Xiao, Fei

    2014-05-01

    As a promising candidate to replace the brittle and expensive transparent indium tin oxide (ITO) conductor, the use of silver nanowire (AgNW) networks still involves issues such as high-temperature post-treatments and poor substrate adhesion for industrial application. Here a room-temperature soldering and one-step solution method is developed to achieve high-performance Ag nanowire transparent conductive films (TCFs). A nonconductive binder is prepared from poly(dopamine) and alginic acid which contains abundant catechol and carboxylic acid functional groups. The drying of the binder on the Ag nanowire percolation networks induces tighter contact among the nanowires and strong adhesion to the substrate, simultaneously enhancing the electrical and mechanical properties without a high-temperature annealing process. As a result, a highly conductive and bendable AgNW film is demonstrated on a low-cost polyethylene glycol terephthalate (PET) substrate, showing an 89% optical transmittance at λ = 550 nm and a sheet resistance of 16.3 Ohm sq(-1). Its optical and electrical performances are superior to those obtained from the reported indium tin oxide (ITO) films. Moreover, the AgNW film exhibits strong adhesion to the substrate, maintaining its conductivity after 100 tape tests, and it still resists the tape test even after exposure to solvent for several hours. Most importantly, the film shows good reliability during long-term 85 °C/85% RH (relative humidity) aging, which has been rarely investigated although it is a critical requirement for industrial application. The advanced and wide-ranging features of the prepared AgNW film greatly contribute to its use as a transparent electrode in multifunctional flexible electronic devices.

  3. Annealing-free and strongly adhesive silver nanowire networks with long-term reliability by introduction of a nonconductive and biocompatible polymer binder

    NASA Astrophysics Data System (ADS)

    Jin, Yunxia; Deng, Dunying; Cheng, Yuanrong; Kong, Lingqiang; Xiao, Fei

    2014-04-01

    As a promising candidate to replace the brittle and expensive transparent indium tin oxide (ITO) conductor, the use of silver nanowire (AgNW) networks still involves issues such as high-temperature post-treatments and poor substrate adhesion for industrial application. Here a room-temperature soldering and one-step solution method is developed to achieve high-performance Ag nanowire transparent conductive films (TCFs). A nonconductive binder is prepared from poly(dopamine) and alginic acid which contains abundant catechol and carboxylic acid functional groups. The drying of the binder on the Ag nanowire percolation networks induces tighter contact among the nanowires and strong adhesion to the substrate, simultaneously enhancing the electrical and mechanical properties without a high-temperature annealing process. As a result, a highly conductive and bendable AgNW film is demonstrated on a low-cost polyethylene glycol terephthalate (PET) substrate, showing an 89% optical transmittance at λ = 550 nm and a sheet resistance of 16.3 Ohm sq-1. Its optical and electrical performances are superior to those obtained from the reported indium tin oxide (ITO) films. Moreover, the AgNW film exhibits strong adhesion to the substrate, maintaining its conductivity after 100 tape tests, and it still resists the tape test even after exposure to solvent for several hours. Most importantly, the film shows good reliability during long-term 85 °C/85% RH (relative humidity) aging, which has been rarely investigated although it is a critical requirement for industrial application. The advanced and wide-ranging features of the prepared AgNW film greatly contribute to its use as a transparent electrode in multifunctional flexible electronic devices.

  4. Single-Crystal to Single-Crystal Phase Transition and Segmented Thermochromic Luminescence in a Dynamic 3D Interpenetrated Ag(I) Coordination Network.

    PubMed

    Yan, Zhi-Hao; Li, Xiao-Yu; Liu, Li-Wei; Yu, Si-Qi; Wang, Xing-Po; Sun, Di

    2016-02-01

    A new 3D Ag(I)-based coordination network, [Ag2(pz)(bdc)·H2O]n (1; pz = pyrazine and H2bdc = benzene-1,3-dicarboxylic acid), was constructed by one-pot assembly and structurally established by single-crystal X-ray diffraction at different temperatures. Upon cooling from 298 to 93 K, 1 undergo an interesting single-crystal to single-crystal phase transition from orthorhombic Ibca (Z = 16) to Pccn (Z = 32) at around 148 K. Both phases show a rare 2-fold-interpenetrated 4-connected lvt network but incorporate different [Ag2(COO)2] dimeric secondary building units. It is worth mentioning that complex 1 shows red- and blue-shifted luminescences in the 290-170 and 140-80 K temperature ranges, respectively. The variable-temperature single-crystal X-ray crystallographic studies suggest that the argentophilic interactions and rigidity of the structure dominated the luminescence chromism trends at the respective temperature ranges. Upon being mechanically ground, 1 exhibits a slight mechanoluminescence red shift from 589 to 604 nm at 298 K.

  5. Crystalline Nanojoining Silver Nanowire Percolated Networks on Flexible Substrate.

    PubMed

    Nian, Qiong; Saei, Mojib; Xu, Yang; Sabyasachi, Ganguli; Deng, Biwei; Chen, Yong P; Cheng, Gary J

    2015-10-27

    Optoelectronic performance of metal nanowire networks are dominated by junction microstructure and network configuration. Although metal nanowire printings, such as silver nanowires (AgNWs) or AgNWs/semiconductor oxide bilayer, have great potential to replace traditional ITO, efficient and selective nanoscale integration of nanowires is still challenging owing to high cross nanowire junction resistance. Herein, pulsed laser irradiation under controlled conditions is used to generate local crystalline nanojoining of AgNWs without affecting other regions of the network, resulting in significantly improved optoelectronic performance. The method, laser-induced plasmonic welding (LPW), can be applied to roll-to-roll printed AgNWs percolating networks on PET substrate. First principle simulations and experimental characterizations reveal the mechanism of crystalline nanojoining originated from thermal activated isolated metal atom flow over nanowire junctions. Molecular dynamic simulation results show an angle-dependent recrystallization process during LPW. The excellent optoelectronic performance of AgNW/PET has achieved Rs ∼ 5 Ω/sq at high transparency (91% @λ = 550 nm).

  6. Improvement of polypyrrole nanowire devices by plasmonic space charge generation: high photocurrent and wide spectral response by Ag nanoparticle decoration

    NASA Astrophysics Data System (ADS)

    Lee, S.-H.; Bae, J.; Lee, S. W.; Jang, J.-W.

    2015-10-01

    In this study, improvement of the opto-electronic properties of non-single crystallized nanowire devices with space charges generated by localized surface plasmon resonance (LSPR) is demonstrated. The photocurrent and spectral response of single polypyrrole (PPy) nanowire (NW) devices are increased by electrostatically attached Ag nanoparticles (Ag NPs). To take advantage of plasmon-exciton coupling in the photocurrent of the device, 80 nm of Ag NPs (454 nm = λmax) were chosen for matching the maximum absorption with PPy NWs (442 nm = λmax). The photocurrent density is remarkably improved, up to 25.3 times (2530%), by the Ag NP decoration onto the PPy NW (PPyAgNPs NW) under blue light (λ = 425-475 nm) illumination. In addition, the PPyAgNPs NW shows a photocurrent decay time twice that of PPy NW, as well as an improved spectral response of the photocurrent. The improved photocurrent efficiency, decay time, and spectral response resulted from the space charges generated by the LSPR of Ag NPs. Furthermore, the increasing exponent (m) of the photocurrent (JPC ~ Vm) and finite-differential time domain (FDTD) simulation straightforwardly indicate relatively large plasmonic space charge generation under blue light illumination. These results prove that the performance of non-single crystallized polymer nanowire devices can also be improved by plasmonic enhancement.In this study, improvement of the opto-electronic properties of non-single crystallized nanowire devices with space charges generated by localized surface plasmon resonance (LSPR) is demonstrated. The photocurrent and spectral response of single polypyrrole (PPy) nanowire (NW) devices are increased by electrostatically attached Ag nanoparticles (Ag NPs). To take advantage of plasmon-exciton coupling in the photocurrent of the device, 80 nm of Ag NPs (454 nm = λmax) were chosen for matching the maximum absorption with PPy NWs (442 nm = λmax). The photocurrent density is remarkably improved, up to 25.3 times

  7. Structure and stability of acrolein and allyl alcohol networks on Ag(111) from density functional theory based calculations with dispersion corrections

    NASA Astrophysics Data System (ADS)

    Ferullo, Ricardo M.; Branda, Maria Marta; Illas, Francesc

    2013-11-01

    The interaction of acrolein and allyl alcohol with the Ag(111) surface has been studied by means of periodic density functional theory based calculations including explicitly dispersion terms. Different coverage values have been explored going from isolated adsorbed molecules to isolated dimers, interacting dimers or ordered overlayers. The inclusion of the dispersion terms largely affects the calculated values of the adsorption energy and also the distance between adsorbed molecule and the metallic surface but much less the adsorbate-adsorbate interactions. Owing to the large dipole moment of acrolein, the present calculations predict that at high coverage this molecule forms a stable extensive two-dimensional network on the surface, caused by the alignment of the adsorbate dipoles. For the case of allyl alcohol, dimers and complex networks exhibit similar stability.

  8. Spatial and temporal variation of surface-enhanced Raman scattering at Ag nanowires in aqueous solution

    SciTech Connect

    Clayton, Daniel A.; McPherson, Tyler; Pan, Shanlin; Chen, Mingyang; Dixon, David A.; Hu, Dehong

    2012-12-13

    We present surface enhanced Raman spectroscopy (SERS) and Raman imaging of small organic molecules at well-defined nanostructures formed by single silver nanowires (NWs). We show that SERS can be obtained at single, crossed, and bundled Ag NWs for mercaptopyridine, adenine, cytosine, guanine, and thymine. Crossed wires and parallel Ag NWs have SERS enhancement factors much higher than single Ag NWs. New additional junctions formed by a silver nanoparticle and a single Ag NW, and bundled NWs provide SERS intensity higher than a single Ag NW. The SERS signal of single Ag NWs can be further enhanced by decorating the Ag NW surface with gold nanoparticles using electroless deposition. Single Ag NW Raman imaging with a 10 ms time resolution when compared with photoluminescence (PL) imaging results reveal a different dynamic response of SERS and PL under steady state laser excitation. Dynamic photoluminescence blinking activities are suppressed in the presence of the surface coating of Raman active molecules (e.g., mercaptopyridine) and the SERS signal is quite stable in a wide field excitation configuration. The Discrete Dipole Approximation (DDA) method was used to calculate the local field intensity that can be applied to help understand the enhanced PL and SERS at the junction of Ag NWs

  9. Electrically and mechanically enhanced Ag nanowires-colorless polyimide composite electrode for flexible capacitive sensor

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Gon; Kim, Jiwan; Jung, Seung-Boo; Kim, Young-Sung; Kim, Jong-Woong

    2016-09-01

    Silver nanowire (AgNW) network is known for its low percolation threshold, high conductivity and good flexibility, therefore, considered one of the best candidates for fabrication of flexible and transparent electrodes. However, a general approach to make the AgNWs-based electrodes, an overcoating of nanowire dispersion onto a transparent polymer, should make an issue of poor mechanical stability, mainly caused by low adhesion between the nanowires and polymer. In addition, a thin insulating layer of polyvinylpyrrolidone (PVP) formed on the surface of AgNWs deteriorates the conductivity of their network, which means that a post-processing such as high temperature annealing is essentially needed. Here we employed a plasma treatment with an inert gas to remove the residual PVP layer, so that the conductivity could be enhanced without employing any high temperature processing. Interestingly, the optical transmittance in the wavelength near 400 nm was also increased, resulting in more neutral coloration of the electrode. An inverted layer processing made the nanowires to be partially buried at the surface of colorless polyimide (cPI), so that the enhancement of mechanical stability and connectivity with overlying materials were simultaneously achieved.

  10. Chemiluminescent lateral-flow immunoassays by using in-situ synthesis of CdS NW photosensor.

    PubMed

    An, Byoung-Gi; Kim, Hong-Rae; Kang, Min-Jung; Park, Jae-Gwan; Chang, Young Wook; Pyun, Jae-Chul

    2016-07-13

    A hypersensitive CdS nanowire (NW) photosensor was fabricated by an in-situ synthesis process that involved the direct synthesis of CdS NWs on an interdigitated electrode (IDE). Analysis of the photoresponse properties showed that the newly synthesized photosensor had enhanced sensitivity and a highly reproducible photoresponse compared to photosensors prepared from CdS NW suspensions. The NW photosensor was applied to measure the chemiluminescence of luminol, and the sensitivity was compared to a commercial photosensing system. Finally, the feasibility of the CdS NW photosensor for the application to the medical diagnosis of the human hepatitis B surface antigen (hHBsAg) was demonstrated using a lateral-flow immunoassay with a chemiluminescent signal band. PMID:27237842

  11. BaFe12O19-chitosan Schiff-base Ag (I) complexes embedded in carbon nanotube networks for high-performance electromagnetic materials

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; Xie, Yu; Guan, Dongsheng; Hua, Helin; Zhong, Rong; Qin, Yuancheng; Fang, Jing; Liu, Huilong; Chen, Junhong

    2015-07-01

    The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm-1, 28.20 emu g-1, 16.66 emu g-1 and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed.

  12. BaFe12O19-chitosan Schiff-base Ag (I) complexes embedded in carbon nanotube networks for high-performance electromagnetic materials

    PubMed Central

    Zhao, Jie; Xie, Yu; Guan, Dongsheng; Hua, Helin; Zhong, Rong; Qin, Yuancheng; Fang, Jing; Liu, Huilong; Chen, Junhong

    2015-01-01

    The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm−1, 28.20 emu g−1, 16.66 emu g−1 and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed. PMID:26218269

  13. Fabrication of Ag nanowire and Al-doped ZnO hybrid transparent electrodes

    NASA Astrophysics Data System (ADS)

    You, Sslimsearom; Park, Yong Seo; Choi, Hyung Wook; Kim, Kyung Hwan

    2016-01-01

    Among the materials used as transparent electrodes, silver nanowires (AgNWs) have attracted attention because of their high transmittance and excellent conductivity. However, AgNWs have shortcomings, including their poor adhesion, oxidation by atmospheric oxygen, and unstable characteristics at high temperature. To overcome these shortcomings, multi-layer thin films with an aluminum-doped zinc oxide (AZO)/AgNW/AZO structure were fabricated using facing targets sputtering. The samples heated to 350 °C exhibited stable electrical characteristics. In addition, the adhesion to the substrate was improved compared with AgNWs layer. The AZO/AgNW/AZO thin films with multilayer structure overcame the shortcomings of AgNWs, and we propose their use as transparent electrodes with excellent properties for optoelectronic applications.

  14. Transparent capacitors with hybrid ZnO:Al and Ag nanowires as electrodes.

    PubMed

    Zhang, Guozhen; Wu, Hao; Wang, Xiao; Wang, Ti; Liu, Chang

    2016-03-11

    Transparent conducting films with a composite structure of AlZnO-Ag nanowires (AgNWs) have been prepared by atomic layer deposition. The sheet resistance was reduced from 120 to 9 Ω when the AgNW networks were involved. Transparent capacitors with Al2O3-TiO2-Al2O3 dielectrics were fabricated on the composite electrodes and demonstrated a capacitance density of 10.1 fF μm(-2), which was significantly higher than that of capacitors with AlZnO electrodes (8.8 fF μm(-1)). The capacitance density remained almost unchanged in a broad frequency range from 3 kHz to 1 MHz. Moreover, a low leakage current density of 2.4 × 10(-7) A cm(-2) at 1 V was achieved. Transparent and flexible capacitors were also fabricated using the composite electrodes, and demonstrated an improved bendability. The transparent capacitors showed an average optical transmittance over 70% in the visible range, and thus open the door to practical applications in transparent integrated circuits.

  15. Improvement of polypyrrole nanowire devices by plasmonic space charge generation: high photocurrent and wide spectral response by Ag nanoparticle decoration

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Hoon; Lee, Seung Woo; Jang, Jaw-Won

    In this study, improvement of the opto-electronic properties of non-single crystallized nanowire devices with space charges generated by localized surface plasmon resonance (LSPR) is demonstrated. The photocurrent and spectral response of single polypyrrole (PPy) nanowire (NW) devices are increased by electrostatically attached Ag nanoparticles (Ag NPs). The photocurrent density is remarkably improved, up to 25.3 times, by the Ag NP decoration onto the PPy NW (PPyAgNPs NW) under blue light illumination. In addition, the PPyAgNPs NW shows a photocurrent decay time twice that of PPy NW, as well as an improved spectral response of the photocurrent. The improved photocurrent efficiency, decay time, and spectral response resulted from the space charges generated by the LSPR of Ag NPs. Furthermore, the increasing exponent (m) of the photocurrent (JPC ~Vm) and finite-differential time domain (FDTD) simulation straightforwardly indicate relatively large plasmonic space charge generation. Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (no. 2013K1A3A1A32035429 and 2015R1A1A1A05027681).

  16. Development of Au-Ag nanowire mesh fabrication by UV-induced approach

    SciTech Connect

    Saggar, Siddhartha; Predeep, Padmanabhan

    2014-10-15

    In an attempt to overcome the limitations of the presently prevailing transparent conducting electrode (TCE) - indium tin oxide (ITO) - many materials have been considered for replacing ITO. Recently, a novel method has been reported for the synthesis of Au-Ag nanowire (NW) mesh, and tested successfully for organic-light-emitting-diodes (OLEDs). It employs UV-induced reduction of gold- and silver- precursors to form Au-Ag NW mesh. In this report, Au-Ag NW mesh thin films are synthesized on glass substrates with an objective for use as facing-electrode for Organic Photovoltaics. Various issues and factors affecting the fabrication-process have been improved, and are also discussed here. The electrode showed good transmitivity, of around 95% (excluding that of glass substrate). The advantage of the technique is its simple processing method and cost-effectiveness.

  17. NW CSC annual report fiscal year 2013

    USGS Publications Warehouse

    Bisbal, Gustavo A.

    2013-01-01

    The Northwest Climate Science Center (NW CSC) was established in 2010 as one of eight regional Climate Science Centers created by the Department of the Interior (DOI). The NW CSC encompasses Washing-ton, Oregon, Idaho, and western Montana and has overlapping boundaries with three Landscape Conservation Cooperatives (LCCs): the Great Northern, the Great Basin, and the North Pacific. With guidance from its Executive Stakeholder Advisory Committee (ESAC), the NW CSC and its partner LCCs are addressing the highest priority regional climate science needs of Northwest natural and cultural resource managers. Climate Science Centers tap into the scientific expertise of both the U.S. Geological Survey (USGS) and academic institutions. The NW CSC is supported by an academic consortium with the capacity to generate climate science and tools in a coordinated fashion, serving stakeholders across the Northwest region. This consortium is primarily represented by Oregon State University (OSU), the University of Id-ho (UI), and the University of Washington (UW). The academic consortium and USGS provide capabilities in climate science, ecology, impacts and vulnerability assessment, modeling, adaptation planning, and advanced information technology, all necessary to address and respond to climate change in the Northwest. University members also recruit and train graduate students and early-career scientists. This Annual Report summarizes progress for the goals set out in the NW CSC Strategic Plan for 2012-2015 (http://www.doi.gov/csc/northwest/upload/Northwest-CSC-Strategic-Plan.cfm) and the NW CSC Work-plan for Fiscal Year (FY) 2013 (October 1, 2012 through September 30, 2013). The report follows the structure of the Strategic Plan, which describes the five core services (Executive, Science, Data, Communications, and Education and Training) provided by the NW CSC in support of the stated vision: Our Vision: To become nationally recognized as a best-practice model for the provision

  18. AGS II

    SciTech Connect

    Palmer, R.B.

    1984-01-01

    Interest in rare K decays, neutrino oscillations and other fields have generated an increasing demand for running, and improved intensity and duty cycle, at the AGS. Current projects include acceleration of polarized protons and light ions (up to mass 32). Future plans are for a booster to increase intensity and allow heavy ions (up to mass 200), and a stretcher to give 100% duty cycle. A later upgrade could yield an average current of 32 ..mu.. amps. 6 figures, 2 tables.

  19. Heterojunction double dumb-bell Ag2Te-Te-Ag2Te nanowires

    NASA Astrophysics Data System (ADS)

    Som, Anirban; Pradeep, T.

    2012-07-01

    Growth of isolated axial heterojunction nanowires by a solution phase growth process is reported. The dumb-bell shaped nanowires contain two silver telluride sections at the extremes joined by a tellurium section. Reaction of silver nitrate with tellurium NWs in aqueous solution at a molar ratio of 1 : 1 leads to the formation of amorphous partially silver reacted Te NWs. Low temperature (75 °C) solution phase annealing of these silver deficient NWs results in phase segregation producing crystalline Ag2Te and Te phases with clear phase boundaries along the wire axis. Structural characterization of these dumb-bell shaped NWs was performed with different microscopic and spectroscopic tools. Solution phase silver concentration over the course of annealing indicated leaching of silver into the solution during the formation of biphasic NWs. Similar Ag : Te ratios were observed in both partially silver reacted Te NWs and phase segregated Ag2Te-Te-Ag2Te NWs and this was attributed to redeposition of leached silver on the amorphous NW tips which eventually resulted in complete phase segregation. Successful integration of different chemical components in single NWs is expected to open up new application possibilities as physical and chemical properties of the heterostructure can be exploited.Growth of isolated axial heterojunction nanowires by a solution phase growth process is reported. The dumb-bell shaped nanowires contain two silver telluride sections at the extremes joined by a tellurium section. Reaction of silver nitrate with tellurium NWs in aqueous solution at a molar ratio of 1 : 1 leads to the formation of amorphous partially silver reacted Te NWs. Low temperature (75 °C) solution phase annealing of these silver deficient NWs results in phase segregation producing crystalline Ag2Te and Te phases with clear phase boundaries along the wire axis. Structural characterization of these dumb-bell shaped NWs was performed with different microscopic and spectroscopic

  20. BiPO4 photocatalyst employing synergistic action of Ag/Ag3PO4 nanostructure and graphene nanosheets

    NASA Astrophysics Data System (ADS)

    Mohaghegh, N.; Rahimi, E.

    2016-06-01

    Graphene-supported BiPO4/Ag/Ag3PO4 photocatalyst has been fabricated by simple hydrothermal and impregnation reaction. In BiPO4/Ag/Ag3PO4 based on Reduced Graphene Oxide (RGO), this network renders numerous pathways for rapid mass transport, strong adsorption and multireflection of incident light; meanwhile, the interface between BiPO4/Ag/Ag3PO4 and RGO increases the active sites and electron transfer rate. BiPO4/Ag/Ag3PO4 based on RGO noticeably exhibited high photocatalytic activity than that of BiPO4/Ag/Ag3PO4 and P25 under visible light irradiation for cationic dye (Rhodamine B), anionic dye (methyl orange) and 4-chlorophenol (4-CP) as a neutral pollutant, which are usually difficult to be degraded over the other catalysts. This enhanced photocatalytic activity of Graphene-supported BiPO4/Ag/Ag3PO4 for all pollutants could be mainly ascribed to the reinforced charge transfer from BiPO4/Ag/Ag3PO4 to RGO, which suppresses the recombination of electron/hole pairs. Besides that, this photocatalyst can be used repetitively with a high photocatalytic activity and no apparent loss of activity occurs. The results reveal that the RGO nanosheets work as a photocatalyst promoter during the photocatalytic reaction, leading to an improved photocatalytic activity.

  1. Preparation, characterization, and photocatalytic activity of porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Tian, Baozhu; Zhang, Jinlong; Xiong, Tianqing; Wang, Tingting

    2014-02-01

    Porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts were synthesized by a multistep route, including a dealloying method to prepare porous Ag, a transformation from Ag to AgBr and AgBrI, and a photo-reduction process to form Ag nanoparticles on the surface of AgBr and AgBrI. It was found that the porous structure kept unchanged during Ag was transferred into AgBr, AgBrI, AgBr@Ag, and AgBrI@Ag. Both porous AgBr@Ag and porous AgBrI@Ag showed much higher visible-light photocatalytic activity than cubic AgBr@Ag for the degradation of methyl orange, which is because the interconnected pore channels not only provide more reactive sites but also favor the transportation of photo-generated electrons and holes. For AgBrI@Ag, AgBrI solid solution formed at the interface of AgBr and AgI, and the phase junction can effectively separate the photo-generated electrons and holes, favorable to the improvement of photocatalytic activity. The optimal I content for obtaining the highest activity is ∼10 at.%.

  2. 9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  3. Facile One-Step Synthesis of Three-Dimensional Pd-Ag Bimetallic Alloy Networks and Their Electrocatalytic Activity toward Ethanol Oxidation.

    PubMed

    Fu, Shaofang; Zhu, Chengzhou; Du, Dan; Lin, Yuehe

    2015-07-01

    The three-dimensional palladium networks and palladium-silver bimetallic alloy networks were synthesized at room temperature on a large scale using a rapid and simple strategy. The results revealed that the morphology of the networks is not affected by the composition. We demonstrated that the as-prepared unsupported networks exhibited excellent electrochemical activity and stability toward ethanol oxidation reaction in alkaline media due to the formation of palladium-silver alloys as well as the porous nanostructures. The results indicate that the well-defined three-dimensional palladium-silver bimetallic alloy networks are promising catalysts for fuel cells.

  4. AGS experiments - 1994, 1995, 1996

    SciTech Connect

    Depken, J.C.

    1997-01-01

    This report contains the following information on the Brookhaven AGS Accelerator complex: FY 1996 AGS schedule as run; FY 1997 AGS schedule (working copy); AGS beams 1997; AGS experimental area FY 1994 physics program; AGS experimental area FY 1995 physics program; AGS experimental area FY 1996 physics program; AGS experimental area FY 1997 physics program (in progress); a listing of experiments by number; two-phage summaries of each experiment begin here, also ordered by number; listing of publications of AGS experiments begins here; and listing of AGS experimenters begins here.

  5. Earthquakes, Uplift, and Landscape Evolution in the NW Himalayas

    NASA Astrophysics Data System (ADS)

    Shahzad, F.; Mahmood, S.; Gloaguen, R.

    2009-05-01

    The terrain between Main Mantle Thrust to Salt Range Thrust in the NW Himalayas has been characterized by surface and subsurface features with variable tectonic activity. These features show relatively variable tectonic activity, existence of blind faults and basement faulting. In the present study, we use seismological and remote sensing analysis backed by field observations to investigate the relationship between earthquakes, uplift, and landscape evolution. We use nonlinear analysis to understand the earthquake dynamics in relation to surface faults and blind faults. The fractal analysis of the seismicity in three subsurface features of the area is used to characterize the roughness of the faults' surface. We find a high fault surface roughness in the Indus Kohistan Seismic Zone (IKSZ). It is concluded that the area is in the process of being uplifted and landscape is evolving. This evolution is further investigated using a set of geomorphological analyses consisting of extracting a drainage network from digital elevation models (DEM). The extracted streams are analysed using to calculate geomorphic indices and relative uplift rates. These analyses were applied on Indus, Swat, Kabul, Kunhar, Kishanganga, Poonch, Jehlum, Swan and Kurram, Kabul Rivers and their associate tributaries. The analyses provide us with the spatial variation of relative uplift based upon specific streams. We found that the Hazara Kashmir Syntaxis and Nanga Parbat Haramosh Massif are subject to a relatively high uplift. It is observed that the neotectonic activities are linearizing the drainage network from meandering pattern. We analyse the complete drainage texture using fractal dimension and lacunarity analysis. The analysis of the fractal dimension (D) employing box counting methods is calculated with a moving window approach and the lower values of D demonstrate the effect of neotectonic activity. The locations with lower but similar D values are further differentiated using

  6. High-Performance Fully Nanostructured Photodetector with Single-Crystalline CdS Nanotubes as Active Layer and Very Long Ag Nanowires as Transparent Electrodes.

    PubMed

    An, Qinwei; Meng, Xianquan; Sun, Pan

    2015-10-21

    Long and single-crystalline CdS nanotubes (NTs) have been prepared via a physical evaporation process. A metal-semiconductor-metal full-nanostructured photodetector with CdS NTs as active layer and Ag nanowires (NWs) of low resistivity and high transmissivity as electrodes has been fabricated and characterized. The CdS NTs-based photodetectors exhibit high performance, such as lowest dark currents (0.19 nA) and high photoresponse ratio (Ilight/Idark ≈ 4016) (among CdS nanostructure network photodetectors and NTs netwok photodetectors reported so far) and very low operation voltages (0.5 V). The photoconduction mechanism, including the formation of a Schottky barrier at the interface of Ag NW and CdS NTs and the effect of oxygen adsorption process on the Schottky barrier has also been provided in detail based on the studies of CdS NTs photodetector in air and vacuum. Furthermore, CdS NTs photodetector exhibits an enhanced photosensitivity as compared with CdS NWs photodetector. The enhancement in performance is dependent on the larger surface area of NTs adsorbing more oxygen in air and the microcavity structure of NTs with higher light absorption efficiency and external quantum efficiency. It is believed that CdS NTs can potentially be useful in the designs of 1D CdS-based optoelectronic devices and solar cells.

  7. 4. Water treatment plant, view to NW, berm in foreground ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Water treatment plant, view to NW, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  8. 2. Oblique view of north corner shows mostly NW side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of north corner shows mostly NW side and how stack connects to NE side of building. - Pacific Creosoting Plant, Boiler Building, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  9. 10. Side view of cane mill looking NW with steam ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Side view of cane mill looking NW with steam engine in background. - Hacienda Azucarera La Esperanza, Steam Engine & Mill, 2.65 Mi. N of PR Rt. 2 Bridge over Manati River, Manati, Manati Municipio, PR

  10. 3. James Cant Ranch, view from NW showing Feed Storage ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. James Cant Ranch, view from NW showing Feed Storage Shed and Chicken Coop (in foreground), Barn, and Watchman's Hut - Cant Ranch, East side of State Route 19, North of U.S. 26, Dayville, Grant County, OR

  11. 8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED IN SEQUENCE TO REDUCE OR CONCENTRATE BEET JUICE. - Utah Sugar Company, Garland Beet Sugar Refinery, Factory Street, Garland, Box Elder County, UT

  12. 16. View looking NW from warehouse rooftop on Water Street ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. View looking NW from warehouse rooftop on Water Street in Brooklyn. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  13. 64. Detail view looking NW at masonry approach arches on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    64. Detail view looking NW at masonry approach arches on the Brooklyn side. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  14. 53. View looking NW showing underside of deck of Brooklyn ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. View looking NW showing underside of deck of Brooklyn side span. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  15. 11. Looking NW at the underside of the structure. Note ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Looking NW at the underside of the structure. Note the transverse floor beams, the longitudinal stringers supporting the timber deck, and the metal strap diagonal bracing. - Beachside Avenue Bridge, Westport, Fairfield County, CT

  16. 1. AERIAL VIEW FROM SE LOOKING NW, SHOWING BRIDGE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW FROM SE LOOKING NW, SHOWING BRIDGE AND SITE CONTEXT - Slates' Mill Bridge, Township Road 439 spanning South Branch of Tunkhannock Creek in Benton Township, Dalton, Lackawanna County, PA

  17. Perspective view NW by 310. Note the concrete pier extending ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view NW by 310. Note the concrete pier extending from the bridge in the foreground. This way to allow maximum water flow during floods and rainy periods. - Weaverland Bridge, Quarry Road spanning Conestoga Creek, Terre Hill, Lancaster County, PA

  18. 35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL RAIL AND ROAD CUT IN DISTANCE. MONTEZUMA VALLEY OVERLOOK IS JUST TO RIGHT OF DISTANT ROAD CUT. - Mesa Verde National Park Main Entrance Road, Cortez, Montezuma County, CO

  19. 2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. - Philadelphia & Reading Railroad, Pedestrian Suspension Bridge, Foot of Sixth Street at Schuylkill River (formerly spanned Philadelphia & Reading main line at Reading Depot), Reading, Berks County, PA

  20. 2. Photocopy of c. 1906 photograph looking NW at water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of c. 1906 photograph looking NW at water tower with mill pond and pump house in right center foreground; fuel oil storage tank in right background. - Laurel Valley Sugar Plantation, State Route 308, Thibodaux, Lafourche Parish, LA

  1. Self-assembly of 1D mixed-metal tubular network with coordination bonds through the interconnection of organometallic metallamacrocycles by Ag(I) centers.

    PubMed

    Wang, Guo-Liang; Lin, Yue-Jian; Jin, Guo-Xin

    2011-05-21

    The combination of a ditopic ligand containing a functional "third site" as a bridge and organometallic half-sandwich iridium unit Cp*Ir as the corner leads to the formation of the tetranuclear metallamacrocycle 1, which is reacted with silver compound, resulting in the formation of mixed-metal infinitely tubular coordination network 2.

  2. Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain.

    PubMed

    Sanchís, J; Sánchez-Andrade, R; Macchi, M I; Piñeiro, P; Suárez, J L; Cazapal-Monteiro, C; Maldini, G; Venzal, J M; Paz-Silva, A; Arias, M S

    2013-01-16

    The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors. In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR=3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR=3), the youngest bovines (<2.5 years) and dairy cattle (Friesians). Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5-7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years. It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.

  3. Geology of the Naturita NW quadrangle, Colorado

    USGS Publications Warehouse

    Cater, Fred W.; Vogel, J.D.

    1953-01-01

    The Naturita NW quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles were mapped by the U.S. Geological Survey on behalf of the U.S. Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear ro be related to certain sedimentary structures in sandstones of favorable composition.

  4. An Operational Coastal Forecasting System in Galicia (NW Spain)

    NASA Astrophysics Data System (ADS)

    Balseiro, C. F.; Carracedo, P.; Pérez, E.; Pérez, V.; Taboada, J.; Venacio, A.; Vilasa, L.

    2009-09-01

    The Galician coast (NW Iberian Peninsula coast) and mainly the Rias Baixas (southern Galician rias) are one of the most productive ecosystems in the world, supporting a very active fishing and aquiculture industry. This high productivity lives together with a high human pressure and an intense maritime traffic, which means an important environmental risk. Besides that, Harmful Algae Blooms (HAB) are common in this area, producing important economical losses in aquiculture. In this context, the development of an Operational Hydrodynamic Ocean Forecast System is the first step to the development of a more sophisticated Ocean Integrated Decision Support Tool. A regional oceanographic forecasting system in the Galician Coast has been developed by MeteoGalicia (the Galician regional meteorological agency) inside ESEOO project to provide forecasts on currents, sea level, water temperature and salinity. This system is based on hydrodynamic model MOHID, forced with the operational meteorological model WRF, supported daily at MeteoGalicia . Two grid meshes are running nested at different scales, one of ~2km at the shelf scale and the other one with a resolution of 500 m at the rias scale. ESEOAT (Puertos del Estado) model provide salinity and temperature fields which are relaxed at all depth along the open boundary of the regional model (~6km). Temperature and salinity initial fields are also obtained from this application. Freshwater input from main rivers are included as forcing in MOHID model. Monthly mean discharge data from gauge station have been provided by Aguas de Galicia. Nowadays a coupling between an hydrological model (SWAT) and the hydrodynamic one are in development with the aim to verify the impact of the rivers discharges. The system runs operationally daily, providing two days of forecast. First model verifications had been performed against Puertos del Estado buoys and Xunta de Galicia buoys network along the Galician coast. High resolution model results

  5. Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode.

    PubMed

    Nam, Sanggil; Song, Myungkwan; Kim, Dong-Ho; Cho, Byungjin; Lee, Hye Moon; Kwon, Jung-Dae; Park, Sung-Gyu; Nam, Kee-Seok; Jeong, Yongsoo; Kwon, Se-Hun; Park, Yun Chang; Jin, Sung-Ho; Kang, Jae-Wook; Jo, Sungjin; Kim, Chang Su

    2014-01-01

    Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode. PMID:24763248

  6. Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode.

    PubMed

    Nam, Sanggil; Song, Myungkwan; Kim, Dong-Ho; Cho, Byungjin; Lee, Hye Moon; Kwon, Jung-Dae; Park, Sung-Gyu; Nam, Kee-Seok; Jeong, Yongsoo; Kwon, Se-Hun; Park, Yun Chang; Jin, Sung-Ho; Kang, Jae-Wook; Jo, Sungjin; Kim, Chang Su

    2014-04-25

    Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode.

  7. Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode

    PubMed Central

    Nam, Sanggil; Song, Myungkwan; Kim, Dong-Ho; Cho, Byungjin; Lee, Hye Moon; Kwon, Jung-Dae; Park, Sung-Gyu; Nam, Kee-Seok; Jeong, Yongsoo; Kwon, Se-Hun; Park, Yun Chang; Jin, Sung-Ho; Kang, Jae-Wook; Jo, Sungjin; Kim, Chang Su

    2014-01-01

    Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode. PMID:24763248

  8. Deformation and Fluid Flow in the Etendeka Plateau, NW Namibia

    NASA Astrophysics Data System (ADS)

    Salomon, Eric; Koehn, Daniel; Passchier, Cees; Davis, Jennifer; Salvona, Aron; Chung, Peter

    2014-05-01

    We studied deformation bands in sandstone and breccia veins in overlying basalts of the Etendeka Plateau, NW Namibia, regarding their development and history of fluid flow within. The studied deformation bands can be divided into disaggregation bands and cataclastic bands. The former appear to develop in unsorted sandstone, whereas the latter form in well sorted sandstone. We estimated the porosity of the bands and host rock in thin sections using a simple image analysis software (ImageJ). Results show, that no or only a minor decrease in porosity occur in disaggregation bands, while the porosity in cataclastic bands is decreased by up to 82 % with respect to the host rock. These observations are in agreement with results of existing studies (e.g. Fossen et al., 2007). Hence the cataclastic bands form a seal to fluid flow in the host rock, yet it is observed in outcrops that deformation bands can develop into open fractures which in turn increase the permeability of the rock. Breccia veins in the overlying basalts show intense fracturing where the basalt is locally fractured into elongated chips. Mineral precipitation in these breccia veins indicates a hydrothermal origin of the fluids since the precipitates consist of extremely fine-grained quartz aggregates. Secondary mineralization with large crystals indicates that a long-lived fluid circulation through tubular networks was active at a later stage, which eventually sealed the veins completely. We propose that the Etendeka basalts on top of the sandstone formation produced a localized deformation along deformation bands and heated up fluid below the lavas. At a later stage fluid pressures were either high enough to break through the basalt or fracturing due to ongoing extension produced fluid pathways. References Fossen, H., Schultz, R., Shipton, Z. and Mair, K. (2007). Deformation bands in sandstone: a review. J. Geol. Soc., 164, 755-769.

  9. NW-MILO Acoustic Data Collection

    SciTech Connect

    Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.; Jones, Mark E.

    2010-02-17

    There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight of Juan de Fuca, which contains part of the border between the U.S. and Canada. Table 1 lists the specific components used for the NW-MILO system. The acoustic sensor is a hydrophone permanently deployed at a mean depth of about 3 meters. In addition to a hydrophone, the other sensors in the system are a marine radar, an electro-optical (EO) camera and an infra-red (IR) camera. The radar is integrated with a vessel tracking system (VTS) that provides position, speed and heading information. The data from all the sensors is recorded and saved to a central server. The data has been validated in terms of its usability for characterizing the

  10. AgRISTARS

    NASA Technical Reports Server (NTRS)

    1984-01-01

    An introduction to the overall AgRISTARS program, a general statement on progress, and separate summaries of the activities of each project, with emphasis on the technical highlights are presented. Organizational and management information on AgRISTARS is included in the appendices, as is a complete bibliography of publication and reports.

  11. AGS experiments: 1993 - 1994 - 1995

    SciTech Connect

    Depken, J.C.

    1996-04-01

    This report contains: FY 1995 AGS Schedule as Run; FY 1996-97 AGE Schedule (working copy); AGS Beams 1995; AGS Experimental Area FY 1993 Physics Program; AGS Experimental Area FY 1994 Physics Program; AGS Experimental Area FY 1995 Physics Program; AGS Experimental Area FY 1996 Physics Program (In progress); A listing of experiments by number; Two-page summaries of each experiment begin here, also ordered by number; Listing of publications of AGS experiments begins here; and Listing of AGS experimenters begins here. This is the twelfth edition.

  12. Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).

    SciTech Connect

    Thayer, Gayle Echo; de la Figuera, Juan; Bartelt, Norman Charles; Carter, C. Barrington; Hwang, R. Q.; Thurmer, Konrad; Ling, W. L.; Hamilton, John C.; McCarty, Kevin F.

    2008-10-01

    We have studied the dislocation structures that occur in films of Ag, Au, and Ag{sub 0.5}Au{sub 0.5} alloy on a Ru(0001) substrate. Monolayer (ML) films form herringbone phases while films two or more layers thick contain triangular patterns of dislocations. We use scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) to determine how the film composition affects the structure and periodicity of these ordered structures. One layer of Ag forms two different herringbone phases depending on the exact Ag coverage and temperature. Low-energy electron microscopy (LEEM) establishes that a reversible, first-order phase transition occurs between these two phases at a certain temperature. We critically compare our 1 ML Ag structures to conflicting results from an X-ray scattering study [H. Zajonz et al., Phys. Rev. B 67 (2003) 155417]. Unlike Ag, the herringbone phases of Au and AgAu alloy are independent of the exact film coverage. For two layer films in all three systems, none of the dislocations in the triangular networks thread into the second film layer. In all three systems, the in-plane atomic spacing of the second film layer is nearly the same as in the bulk. Film composition does, however, affect the details of the two layer structures. Ag and Au films form interconnected networks of dislocations, which we refer to as 'trigons.' In 2 ML AgAu alloy, the dislocations form a different triangular network that shares features of both trigon and moire structures. Yet another well-ordered structure, with square symmetry, forms at the boundaries of translational trigon domains in 2 ML Ag films but not in Au films.

  13. Mid-IR and far-IR investigation of AgI-doped silver diborate glasses

    SciTech Connect

    Hudgens, J.J.; Martin, S.W.

    1996-03-01

    The structures of {ital x}AgI+(1{minus}{ital x})Ag{sub 2}O{center_dot}2B{sub 2}O{sub 3} glasses, where 0.2{le}{ital x}{le}0.6, have been investigated using mid- and far-infrared spectroscopy. The mid-IR spectra revealed that in those glasses prepared using AgNO{sub 3} as the starting material for Ag{sub 2}O, the BO{sub 4}{sup {minus}}/BO{sub 3} ratio is constant with increasing amounts of AgI as would be expected form the proposed behavior of AgI in these glasses. However, a survey of the literature revealed those glasses prepared from pure Ag{sub 2}O show a strong linear dependence of the BO{sub 4}{sup {minus}}/BO{sub 3} ratio on AgI content. Most probably, in those glasses prepared with Ag{sub 2}O the Ag{sub 2}O/B{sub 2}O{sub 3} ratio changes with AgI content due to the decomposition of Ag{sub 2}O during melting. This different behavior is associated with AgNO{sub 3} decomposing to Ag{sub 2}O with heating followed by incorporation into the glassy network. For Ag{sub 2}O used directly, it is proposed that it decomposes to Ag metal and O{sub 2}(gas) with heating before it can be incorporated into the borate network. This latter behavior decreases with increasing AgI in the batch composition because AgI lowers the liquidus temperature of the melt considerably. The far-IR analysis of the AgI-doped silver diborate glasses suggests that there are three coordination environments for the Ag{sup +} ions; one with iodide anions and the other two with oxygen ions. It is proposed that the separate oxygen coordination environments for the Ag{sup +} ions arise from one with bridging oxygens of BO{sub 4}{sup {minus}} units, and the other with nonbridging oxygens on BO{sub 3}{sup {minus}} units. Furthermore, it is proposed that the Ag{sup +} ions in the iodide-ion environments progressively agglomerate into disordered regions of AgI, but do not form structures similar to {alpha}-AgI. (Abstract Truncated)

  14. Low temperature preparation of Ag-doped ZnO nanowire arrays for sensor and light-emitting diode applications

    NASA Astrophysics Data System (ADS)

    Lupan, O.; Viana, B.; Cretu, V.; Postica, V.; Adelung, R.; Pauporté, T.

    2016-02-01

    Transition metal doped-oxide semiconductor nanostructures are important to achieve enhanced and new properties for advanced applications. We describe the low temperature preparation of ZnO:Ag nanowire/nanorod (NW/NR) arrays by electrodeposition at 90 °C. The NWs have been characterized by SEM, EDX, transmittance and photoluminescence (PL) measurements. The integration of Ag in the crystal is shown. Single nanowire/nanorod of ZnO:Ag was integrated in a nanosensor structure leading to new and enhanced properties. The ultraviolet (UV) response of the nanosensor was investigated at room temperature. Experimental results indicate that ZnO:Ag (0.75 μM) nanosensor possesses faster response/recovery time and better response to UV light than those reported in literature. The sensor structure has been also shown to give a fast response for the hydrogen detection with improved performances compared to pristine ZnO NWs. ZnO:Ag nanowire/nanorod arrays electrochemically grown on p-type GaN single crystal layer is also shown to act as light emitter in LED structures. The emission wavelength is red-shifted compared to pristine ZnO NW array. At low Ag concentration a single UV-blue emission is found whereas at higher concentration of dopant the emission is broadened and extends up to the red wavelength range. Our study indicates that high quality ZnO:Ag NW/NR prepared at low temperature by electrodeposition can serve as building nanomaterials for new sensors and light emitting diodes (LEDs) structures with low-power consumption.

  15. Microstructure and thermal conduction properties of Al{sub 2}O{sub 3}-Ag composites

    SciTech Connect

    Liu, D.M.; Tuan, W.H.

    1996-02-01

    Microstructure and thermal conduction properties involving thermal diffusivity and conductivity of composite, Al{sub 2}O{sub 3}-Ag, were investigated. The Ag particles observed in the composites were spread sporadically throughout the composite with inclusion size increasing with Ag content, rather than forming a network of thin film foil. Thermal conductivity of the composite increased with Ag content and followed composite theory prediction with a negligible influence of interfacial contact resistance. The temperature dependence of the thermal conductivity became less pronounced with increasing Ag content reflecting the nature of electron contribution in Ag rather than the typical phonon contribution in polycrystalline Al{sub 2}O{sub 3}. The lower composite conductivity at higher Ag contents as compared to theoretical predictions is due primarily to the residual pore phase, associated with the cavity formation for the composite containing 10 vol.% Ag.

  16. Networks.

    ERIC Educational Resources Information Center

    Cerf, Vinton G.

    1991-01-01

    The demands placed on the networks transporting the information and knowledge generated by the increased diversity and sophistication of computational machinery are described. What is needed to support this increased flow, the structures already in place, and what must be built are topics of discussion. (KR)

  17. Silicon nanowire ion sensitive field effect transistor with integrated Ag/AgCl electrode: pH sensing and noise characteristics.

    PubMed

    Kim, Sungho; Rim, Taiuk; Kim, Kihyun; Lee, Unsang; Baek, Eunhye; Lee, Hojoon; Baek, Chang-Ki; Meyyappan, M; Deen, M Jamal; Lee, Jeong-Soo

    2011-12-01

    We have fabricated Si nanowire (SiNW) based ion-sensitive field effect transistors (ISFETs) for biosensing applications. The ability to prepare a large number of sensors on a wafer, the use of standard silicon microfabrication techniques resulting in cost savings, and potential high sensitivity are significant advantages in favor of nanoscale SiNW ISFETs. The SiNW ISFETs with embedded Ag/AgCl reference electrode were fabricated on a standard silicon-on-insulator wafer using electron-beam lithography and conventional semiconductor processing technology. The current-voltage characteristics show an n-type FET behavior with a relatively high on/off current ratio, reasonable sub-threshold swing value, and low gate-leakage current. The pH responses of the ISFETs with different pH solutions were characterized at room temperature which showed a clear lateral shift of the drain current vs. gate voltage curve with a change in the pH value of the solution and a sensitivity of 40 mV pH(-1). The low frequency noise characteristics were investigated to evaluate the signal to noise ratio and sensing limit of the devices. PMID:22068238

  18. Impedance studies of the cell Ag/AgI/Ag beta alumina/AgI/Ag. Technical report No. 15, August 1987-August 1988

    SciTech Connect

    Breiter, M.W.; Drstak, H.; Maly-Schreiber, M.

    1988-07-01

    The construction of the cell Ag/AgI/Ag beta alumina/AgI/Ag is described. The impedance of this cell was measured between .001 and 10000 Hz at temperatures between 20 and 550 C. At temperatures below 100 C the cell impedance is determined to a large extent by the bulk resistance of the AgI layer and to a smaller extent by the impedance of the interface Ag/Agi. At temperatures between 160 and 350 C the impedance is controlled by the bulk resistance of the Ag beta alumina and an impedance due to contact problems between Ag and AgI. The bulk resistance of the beta' alumina becomes predominant between 350 and 550 C. A hindrance due to the transfer of silver ions from AgI to Ag beta' alumina was not observable in the whole temperature range.

  19. Quo vadis NW Black Sea benthic ecosystems?

    NASA Astrophysics Data System (ADS)

    Traian Gomoiu, Marian

    2016-04-01

    / thalasoterapy. Black Sea ecosystem restoration - Certainties and Uncertainties: Pressure on the Danube and other rivers has decreased, chemical discharges have decreased obviously, and yet there appear phenomena of water flowering - "red waters", hypoxia is still present at times and there is mass mortality of fish and other benthic organisms. Why? Signs of recovery should be considered cautiously and uncertainties may be resolved only in a longer time by increasing our scientific efforts. The results of the EU FP7 Project PERSEUS led to the identification of three important issues that should be resolved in order to achieve good environmental status: • Applying an adaptive management to increase the resilience of the ecosystems and to diminish the vulnerability of biodiversity; • Necessity of participative approach by stakeholders; • Identifying and obtaining adequate financial support for new R-D-I projects. Who are the actors in addressing and implementing the actions? • Academic educational and research institutions for adequate working condition; • More specialists trained for taxonomic groups; • Reasonable diversity of coordinating specialists, capable team leaders / satisfactory work packages; • Attracting NGO members towards nature conservation issues; • Resonable stakeholders committed to environmental issues. Studying the results of researches carried out by GeoEcoMar on the Romanian Black Sea coast in recent years, the author concluded that the major problems hampering progress towards a good ecosystem in NW Bent Black Sea are: • lack of diversity in the fields of research, both in theoretical and applied realms; • structural and functional consequences of ecological pressures and the disordered state of the ecosystems in the periods of paroxysmal eutrophication / pollution at the end of the 20th Century; • scarcity of data and knowledge on the Social-Economic System; • high costs of the new marine technology used directly in the sea and

  20. View south up 27th Street rightofway NW (formerly Lyons Mill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View south up 27th Street right-of-way NW (formerly Lyons Mill Road) along western edge of Female Union Band Cemetery. Vegetation obscures the cemetery's terraces. - Mount Zion Cemetery/ Female Union Band Cemetery, Bounded by 27th Street right-of-way N.W. (formerly Lyons Mill Road), Q Street N.W., & Mill Road N.W., Washington, District of Columbia, DC

  1. MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON SE CORNER. NYSTROM VILLAGE, LIKE ATCHISON VILLAGE (HAER CA-326-N), HOUSED WORKERS DURING WORLD WAR II - Rosie the Riveter National Historical Park, Nystrom Village, Marina & Maine Streets, Richmond, Contra Costa County, CA

  2. 21. (Credit JTL) View looking NW at south elevations of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. (Credit JTL) View looking NW at south elevations of boiler room, old high service pumping room (1887) and beginning of 1900 filter room addition; wash water tank (1926) in background. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  3. 1. Creosote plant site (NW side) as viewed with a ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Creosote plant site (NW side) as viewed with a telephoto lens from Winslow ferry terminal. Eagle Harbor is in foreground. Buildings include Machine Shop on left, Boiler Building with stack, and Engine Room Building at center. Office is at far right next to tree. - Pacific Creosoting Plant, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  4. 42. View from top of Brooklyn Tower looking NW showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. View from top of Brooklyn Tower looking NW showing main cables and suspendors with lower Manhattan in the background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  5. 3. DETAIL VIEW OF ONE ARCH SPAN, LOOKING NW ALONG ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL VIEW OF ONE ARCH SPAN, LOOKING NW ALONG EAST BANK OF SUSQUEHANNA RIVER. NOTE FLOOD STAGE MARKINGS ON PIER, ALSO LONGITUDINAL CONSTRUCTION JOINT IN ARCH BARREL. - Philadelphia & Reading Railroad, Susquehanna River Bridge, Spanning Susquehanna River, North of I-83 Bridge, Harrisburg, Dauphin County, PA

  6. 70. View from Promenade looking NW towards Manhattan up one ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. View from Promenade looking NW towards Manhattan up one of the center main cables with Brooklyn Tower in background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  7. 4. General view looking NW along Richmond Branch Reading RR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. General view looking NW along Richmond Branch Reading RR tracks, showing Building 16 on left, stack associated with Building 3 and Building 22 on right. Building on far right is not part of the Dobson Mills complex (camera side of Scotts Lane). - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  8. 17. Detail of base of 'Flying Ram' in NW corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Detail of base of 'Flying Ram' in NW corner of foyer. Camera is looking SW. First doorway beyond fountain leads to basement and men's lounge seen in WA-197-44. Second doorway leads to storefront corner at Seventh Ave. and Olive Way. (Aug. 1991) - Fox Theater, Seventh Avenue & Olive Way, Seattle, King County, WA

  9. Switching behaviour of individual Ag-TCNQ nanowires: an in situ transmission electron microscopy study.

    PubMed

    Ran, Ke; Rösner, Benedikt; Butz, Benjamin; Fink, Rainer H; Spiecker, Erdmann

    2016-10-21

    The organic semiconductor silver-tetracyanoquinodimethane (Ag-TCNQ) exhibits electrical switching and memory characteristics. Employing a scanning tunnelling microscopy setup inside a transmission electron microscope, the switching behaviour of individual Ag-TCNQ nanowires (NWs) is investigated in detail. For a large number of NWs, the switching between a high (OFF) and a low (ON) resistance state was successfully stimulated by negative bias sweeps. Fitting the experimental I-V curves with a Schottky emission function makes the switching features prominent and thus enables a direct evaluation of the switching process. A memory cycle including writing, reading and erasing features is demonstrated at an individual NW. Moreover, electronic failure mechanisms due to Joule heating are discussed. These findings have a significant impact on our understanding of the switching behaviour of Ag-TCNQ. PMID:27622904

  10. Switching behaviour of individual Ag-TCNQ nanowires: an in situ transmission electron microscopy study

    NASA Astrophysics Data System (ADS)

    Ran, Ke; Rösner, Benedikt; Butz, Benjamin; Fink, Rainer H.; Spiecker, Erdmann

    2016-10-01

    The organic semiconductor silver-tetracyanoquinodimethane (Ag-TCNQ) exhibits electrical switching and memory characteristics. Employing a scanning tunnelling microscopy setup inside a transmission electron microscope, the switching behaviour of individual Ag-TCNQ nanowires (NWs) is investigated in detail. For a large number of NWs, the switching between a high (OFF) and a low (ON) resistance state was successfully stimulated by negative bias sweeps. Fitting the experimental I-V curves with a Schottky emission function makes the switching features prominent and thus enables a direct evaluation of the switching process. A memory cycle including writing, reading and erasing features is demonstrated at an individual NW. Moreover, electronic failure mechanisms due to Joule heating are discussed. These findings have a significant impact on our understanding of the switching behaviour of Ag-TCNQ.

  11. Switching behaviour of individual Ag-TCNQ nanowires: an in situ transmission electron microscopy study.

    PubMed

    Ran, Ke; Rösner, Benedikt; Butz, Benjamin; Fink, Rainer H; Spiecker, Erdmann

    2016-10-21

    The organic semiconductor silver-tetracyanoquinodimethane (Ag-TCNQ) exhibits electrical switching and memory characteristics. Employing a scanning tunnelling microscopy setup inside a transmission electron microscope, the switching behaviour of individual Ag-TCNQ nanowires (NWs) is investigated in detail. For a large number of NWs, the switching between a high (OFF) and a low (ON) resistance state was successfully stimulated by negative bias sweeps. Fitting the experimental I-V curves with a Schottky emission function makes the switching features prominent and thus enables a direct evaluation of the switching process. A memory cycle including writing, reading and erasing features is demonstrated at an individual NW. Moreover, electronic failure mechanisms due to Joule heating are discussed. These findings have a significant impact on our understanding of the switching behaviour of Ag-TCNQ.

  12. Evidence for volcanism in NW Ishtar Terra, Venus

    NASA Technical Reports Server (NTRS)

    Gaddis, L.; Greeley, Ronald

    1989-01-01

    Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

  13. Cysteine-Ag Cluster Hydrogel Confirmed by Experimental and Numerical Studies.

    PubMed

    Cui, Yanyan; Wang, Yaling; Zhao, Lina

    2015-10-01

    The native cysteine (Cys)-Ag3 cluster hydrogel is approved for the first time by both experimental and theoretical studies. From the detailed molecular structure and energy information, three factors are found to ensure the self-assembly of Cys and Ag3 , and result in the hydrogel. First, the Ag-S bonds make Cys and Ag3 form Cys-Ag3 -Cys monomer. Second, intermolecular hydrogen bonds between carboxyl groups of adjacent monomer push them self-assembled. Third, more monomer precisely self-assemble to produce the -[Cys-Ag3 -Cys]n multimer, e.g., a single molecular chain with the left-handed helix conformation, via a benign thermodynamic process. These multimers entangle together to form micro-network to trap water and produce hydorgel in situ. The hydrogen bonds of hydrogel are sensitive to thermal and proton stimuli, and the hydrogel presents lysosome targeting properties via fluorescent imaging with biocompatibility.

  14. Cysteine-Ag Cluster Hydrogel Confirmed by Experimental and Numerical Studies.

    PubMed

    Cui, Yanyan; Wang, Yaling; Zhao, Lina

    2015-10-01

    The native cysteine (Cys)-Ag3 cluster hydrogel is approved for the first time by both experimental and theoretical studies. From the detailed molecular structure and energy information, three factors are found to ensure the self-assembly of Cys and Ag3 , and result in the hydrogel. First, the Ag-S bonds make Cys and Ag3 form Cys-Ag3 -Cys monomer. Second, intermolecular hydrogen bonds between carboxyl groups of adjacent monomer push them self-assembled. Third, more monomer precisely self-assemble to produce the -[Cys-Ag3 -Cys]n multimer, e.g., a single molecular chain with the left-handed helix conformation, via a benign thermodynamic process. These multimers entangle together to form micro-network to trap water and produce hydorgel in situ. The hydrogen bonds of hydrogel are sensitive to thermal and proton stimuli, and the hydrogel presents lysosome targeting properties via fluorescent imaging with biocompatibility. PMID:26248576

  15. Ag Division States Philosophy

    ERIC Educational Resources Information Center

    American Vocational Journal, 1976

    1976-01-01

    The discussion which took place during the American Vocational Association's (AVA) Agriculture Division meeting at the 1975 AVA Convention is summarized, and the statement of vo-ag education philosophy (including 13 key concepts), which was passed during the convention, is presented. (AJ)

  16. 3D Full Seismic Waveform Tomography of NW Turkey and Surroundings

    NASA Astrophysics Data System (ADS)

    Cubuk, Yesim; Fichtner, Andreas; Taymaz, Tuncay

    2015-04-01

    Northward collision of the Arabian plate with the Eurasian plate, and interaction of the motion between dynamic processes originated from the subduction of the African plate beneath the Aegean generated very complex tectonic structures in the study region. Western Turkey is among one of the most active extensional regions in the world and the study area is mainly located where the extensional Aegean and the right-lateral strike-slip North Anatolian Fault Zone (NAFZ) intersects. Therefore, the tectonic framework of the NW Turkey and the Marmara region is mainly characterized by the transition between the strike-slip tectonics to the extensional tectonics. The Sea of Marmara region has been subjected to several active and passive seismic investigations, nevertheless the accurate knowledge on the heterogeneity in the crust and upper mantle beneath the study area still remains enigmatic. On small-scale tomography problems, seismograms strongly reflect the effects of heterogeneities and the scattering properties of the Earth. Thus, the knowledge of high-resolution seismic imaging with an improved 3D radially anisotropic crustal model of the NW Turkey will enable better localization of earthquakes, identification of faults as well as the improvement of the seismic hazard assessment. For this purpose, we aim to develop 3D radially anisotropic subsurface structure of the Sea of Marmara and NW Turkey crust based on full waveform adjoint tomography method. The earthquake data were principally obtained from the Kandilli Observatory and Earthquake Research Institute (KOERI) and Earthquake Research Center (AFAD-DAD) database. In addition to this, some of the seismic waveform data extracted from the Hellenic Unified Seismic Network (HUSN) stations that are located within our study region were also used in this study. We have selected and simulated waveforms of earthquakes with magnitudes 4.0 ≤ Mw ≤ 6.7 occurred in the period between 2007-2014 to determine the 3D velocity

  17. High-performance flexible Ag nanowire electrode with low-temperature atomic-layer-deposition fabrication of conductive-bridging ZnO film.

    PubMed

    Duan, Ya-Hui; Duan, Yu; Chen, Ping; Tao, Ye; Yang, Yong-Qiang; Zhao, Yi

    2015-01-01

    As material for flexible transparent electrodes for organic photoelectric devices, the silver nanowires (AgNWs) have been widely studied. In this work, we propose a hybrid flexible anode with photopolymer substrate, which is composed of spin-coating-processed AgNW meshes and of zinc oxide (ZnO) prepared by low-temperature (60°C) atomic layer deposition. ZnO effectively fills in the voids of the AgNW mesh electrode, which is thus able to contact to the device all over the active area, to allow for efficient charge extraction/injection. Furthermore, ZnO grown by low temperature mainly relies on hole conduction to make the anode play a better role. Hole-only devices are fabricated to certify the functionality of the low-temperature ZnO film. Finally, we confirm that the ZnO film grown at a low temperature bring a significant contribution to the performance of the modified AgNW anode.

  18. High-performance flexible Ag nanowire electrode with low-temperature atomic-layer-deposition fabrication of conductive-bridging ZnO film

    NASA Astrophysics Data System (ADS)

    Duan, Ya-Hui; Duan, Yu; Chen, Ping; Tao, Ye; Yang, Yong-Qiang; Zhao, Yi

    2015-02-01

    As material for flexible transparent electrodes for organic photoelectric devices, the silver nanowires (AgNWs) have been widely studied. In this work, we propose a hybrid flexible anode with photopolymer substrate, which is composed of spin-coating-processed AgNW meshes and of zinc oxide (ZnO) prepared by low-temperature (60°C) atomic layer deposition. ZnO effectively fills in the voids of the AgNW mesh electrode, which is thus able to contact to the device all over the active area, to allow for efficient charge extraction/injection. Furthermore, ZnO grown by low temperature mainly relies on hole conduction to make the anode play a better role. Hole-only devices are fabricated to certify the functionality of the low-temperature ZnO film. Finally, we confirm that the ZnO film grown at a low temperature bring a significant contribution to the performance of the modified AgNW anode.

  19. Gondwana to Pangea: a detrital zircons tale from NW Iberia

    NASA Astrophysics Data System (ADS)

    Pastor-Galán, Daniel; Gutiérrez-Alonso, Gabriel; Brendan Murphy, J.; Fernández-Suárez, Javier; Hofmann, Mandy; Linnemann, Ulf

    2013-04-01

    The Cantabrian Zone of NW Iberia preserves a voluminous, almost continuous, sedimentary sequence that ranges from Neoproterozoic to Early Permian in age. Its tectonic setting is controversial and recent hypotheses include (i) passive margin deposition along the northern margin of Gondwana or (ii) an active continental margin or (iii) a drifting ribbon continent. In this paper we present detrital zircon U-Pb laser ablation age data from 13 samples from the Cantabrian Zone sequence ranging from Early Silurian to Early Permian in depositional age, which, together with previously published detrital zircon ages from Ediacaran-Ordovician strata, allow a comprehensive analysis of changing provenance through time. Laser ablation U-Pb geochronological analysis of detrital zircons in thirteen samples of the Cantabrian Zone of the NW Iberian Variscan belt reveal that this portion of Iberia was part of the northern passive-margin of Gondwana from the Ordovician to Late Devonian, until the onset of collision between Gondwana and Laurentia. Zircon populations in these samples show important similarities with zircons found in coeval detrital rocks from central North Africa. Additionally, the populations found in NW Iberia are coherent with a Saharan source. We suggest that NW Iberia was situated from Ordovician to Late Devonian along the Gondwana northern passive margin close to the paleoposition of central North Africa and Saharan craton. Additionally, the Carboniferous-Permian samples studied record the provenance changes produced during the Variscan collision and basement exhumation, the Cantabrian orocline formation and the subsequent detachment of the lithospheric mantle. The provenance changes reflect major topographic variations due to the afore mentioned processes during Late Devonian to Early Permian times. Detrital zircon studies are a useful tool that can complement regional syntheses in deducing paleogeographic locations, the occurrence of major tectonic events such

  20. Freeze-dried PVP-Ag+ precursors to novel AgBr/AgCl-Ag hybrid nanocrystals for visible-light-driven photodegradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Chen, Deliang; Chen, Qianqian; Zhang, Wenjie; Ge, Lianfang; Shao, Gang; Fan, Bingbing; Lu, Hongxia; Zhang, Rui; Yang, Daoyuan; Shao, Guosheng

    2015-04-01

    AgBr/AgCl-Ag nanocrystals with various molar Br-to-Ag ratios (RBr/Ag = 0, 1/3, 1/2, 2/3, 1) and different photoreduction times (0-20 min) were synthesized via stepwise liquid-solid reactions using the freeze-dried PVP-Ag+ hybrid as the Ag source, followed by a photoreduction reaction. The AgBr/AgCl-Ag7.5(1:2) nanocrystals obtained take on a spherical morphology with a particle-size range of 58 ± 15 nm. The photocatalytic performance of AgBr/AgCl-Ag nanocrystals was evaluated by photodegrading organic dyes, 4-chlorophenol and isopropanol under artificial visible light (λ ⩾ 420 nm, 100 mW cm-2). For the decomposition of rhodamine B, the AgBr/AgCl-Ag7.5(1:2) nanocrystals has a photodegradation rate of ∼0.87 min-1, ∼159 times higher than that (∼0.0054 min-1) of TiO2 (P25), whereas the AgCl-Ag and AgBr-Ag nanocrystals have photodegradation rates of 0.35 min-1 and 0.45 min-1, respectively. The efficient separation of photogenerated electron-hole pairs in the ternary system consisting of AgBr, AgCl and Ag species plays a key role in the enhancement of photocatalytic performance.

  1. AGS experiments -- 1995, 1996 and 1997

    SciTech Connect

    Depken, J.C.; Presti, P.L.

    1997-12-01

    This report contains (1) FY 1995 AGS schedule as run; (2) FY 1996 AGS schedule as run; (3) FY 1997 AGS schedule as run; (4) FY 1998--1999 AGS schedule (proposed); (5) AGS beams 1997; (6) AGS experimental area FY 1995 physics program; (7) AGS experimental area FY 1996 physics program; (8) AGS experimental area FY 1997 physics program; (9) AGS experimental area FY 1998--1999 physics program (proposed); (10) a listing of experiments by number; (11) two-page summaries of each experiment, in order by number; and (12) listing of publications of AGS experiments.

  2. AGS experiments -- 1991, 1992, 1993. Tenth edition

    SciTech Connect

    Depken, J.C.

    1994-04-01

    This report contains: (1) FY 1993 AGS schedule as run; (2) FY 1994--95 AGS schedule; (3) AGS experiments {ge} FY 1993 (as of 30 March 1994); (4) AGS beams 1993; (5) AGS experimental area FY 1991 physics program; (6) AGS experimental area FY 1992 physics program; (7) AGS experimental area FY 1993 physics program; (8) AGS experimental area FY 1994 physics program (planned); (9) a listing of experiments by number; (10) two-page summaries of each experiment; (11) listing of publications of AGS experiments; and (12) listing of AGS experiments.

  3. Destabilization of Ag nanoislands on Ag(100) by adsorbed sulfur

    SciTech Connect

    Shen, Mingmin; Russell, Selena M.; Liu, Da-Jiang; Thiel, Patricia A.

    2011-10-17

    Sulfur accelerates coarsening of Ag nanoislands on Ag(100) at 300 K, and this effect is enhanced with increasing sulfur coverage over a range spanning a few hundredths of a monolayer, to nearly 0.25 monolayers. We propose that acceleration of coarsening in this system is tied to the formation of AgS{sub 2} clusters primarily at step edges. These clusters can transport Ag more efficiently than can Ag adatoms (due to a lower diffusion barrier and comparable formation energy). The mobility of isolated sulfur on Ag(100) is very low so that formation of the complex is kinetically limited at low sulfur coverages, and thus enhancement is minimal. However, higher sulfur coverages force the population of sites adjacent to step edges, so that formation of the cluster is no longer limited by diffusion of sulfur across terraces. Sulfur exerts a much weaker effect on the rate of coarsening on Ag(100) than it does on Ag(111). This is consistent with theory, which shows that the difference between the total energy barrier for coarsening with and without sulfur is also much smaller on Ag(100) than on Ag(111).

  4. AGS preinjector improvement

    SciTech Connect

    Alessi, J.G.; Brennan, J.M.; Brown, H.N.; Brodowski, J.; Gough, R.; Kponou, A.; Prelec, K.; Staples, J.; Tanabe, J.; Witkover, R.

    1987-01-01

    In 1984, a polarized H/sup -/ source was installed to permit the acceleration of polarized protons in the AGS, using a low current, 750 keV RFQ Linear Accelerator as the preinjector. This RFQ was designed by LANL and has proved to be quite satisfactory and reliable. In order to improve the reliability and simplify maintenance of the overall AGS operations, it has been decided to replace one of the two 750 keV Cockcroft-Waltons (C-W) with an RFQ. The design of a new high current RFQ has been carried out by LBL and is also being constructed there. This paper describes the preinjector improvement project, centered around that RFQ, which is underway at BNL.

  5. Potential for Great Thrust Earthquakes in NE Colombia & NW Venezuela

    NASA Astrophysics Data System (ADS)

    Bilham, R. G.; Mencin, D.

    2013-05-01

    Sixty-five percent of the ≈19 mm/yr eastward velocity of the Caribbean Plate north of Aruba and the Guajira peninsula relative to the South American plate is accommodated by dextral slip on the Bocono Fault system in NW Venezuela at 12±1 mm/yr, the remaining ~3 mm/yr of shear apparently distributed to the NW of the fault (Perez et al., 2011). The N40E strike of the Bocono fault system, however, requires that 10.6±1 mm/yr of convergence should accompany this partitioned dextral shear, but GPS measurements reveal that less than 25% of this convergence occurs across the Venezuelan Andes. The remaining 6-8 mm of convergence is presumably accommodated by incipient subduction between the Bocono fault and a trench 300 km NW of the northern coast of Colombia. Hence NW Venezuela and NE Colombia may occasionally host great earthquakes. Our current poor understanding of the geometry of the plate interface permits the plate to be locked 300 km down-dip and possibly 600 km along-strike, and if the plate slips in 10 m ruptures it could do so every 1200 years in a M~9 earthquake. No great earthquake has occurred since 1492, since when ~4 m of potential slip has developed, but should slip occur on just 10% of the hypothesized décollement (100x150 km) it could do so now in an Mw=8.2 earthquake. In that a potential Mw>8 earthquake poses a future seismic and tsunami threat to the Caribbean it is important to examine whether great earthquakes have occurred previously near the NW Venezuela coast. It is possible that creep accommodates the entire convergence signal, since there is no suggestion from microseismicity for an abrupt locked-to-sliding transition, as, for example, signifies its location in the Himalaya. An alternative measure of future potential seismic energy release is to identify the locus and rate of present-day strain contraction. To this end, Venezuelan, Colombian and US (CU and UNAVCO) investigators are installing an array of more than a dozen continuous operating

  6. High efficiency single Ag nanowire/p-GaN substrate Schottky junction-based ultraviolet light emitting diodes

    SciTech Connect

    Wu, Y.; Li, X.; Xu, P.; Wang, Y.; Shen, X.; Liu, X.; Yang, Q.; Hasan, T.

    2015-02-02

    We report a high efficiency single Ag nanowire (NW)/p-GaN substrate Schottky junction-based ultraviolet light emitting diode (UV-LED). The device demonstrates deep UV free exciton electroluminescence at 362.5 nm. The dominant emission, detectable at ultralow (<1 μA) forward current, does not exhibit any shifts when the forward current is increased. External quantum efficiency (EQE) as high as 0.9% is achieved at 25 μA current at room temperature. Experiments and simulation analysis show that devices fabricated with thinner Ag NWs have higher EQE. However, for very thin Ag NWs (diameter < 250 nm), this trend breaks down due to heat accumulation in the NWs. Our simple device architecture offers a potentially cost-effective scheme to fabricate high efficiency Schottky junction-based UV-LEDs.

  7. 14. Stairs in far NW corner of the North Section, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Stairs in far NW corner of the North Section, as viewed from atop pier. This photo, along with phot WA-116-E-1, are the only photographs of the North Section of Drydock 3 that were approved by the U.S. Navy for inclusion in this HAER report. The brick building in center distance is the Building 59, the Pattern Shop, which has been documented in the HAER report No. WA-116-A. - Puget Sound Naval Shipyard, Drydock No. 3, Farragut Avenue, Bremerton, Kitsap County, WA

  8. Preparation and antibacterial activities of Ag/Ag+/Ag3+ nanoparticle composites made by pomegranate (Punica granatum) rind extract

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Ren, Yan-yu; Wang, Tao; Wang, Chuang

    Nano-silver and its composite materials are widely used in medicine, food and other industries due to their strong conductivity, size effect and other special performances. So far, more microbial researches have been applied, but a plant method is rarely reported. In order to open up a new way to prepare AgNP composites, pomegranate peel extract was used in this work to reduce Ag+ to prepare Ag/Ag+/Ag3+ nanoparticle composites. UV-Vis was employed to detect and track the reduction of Ag+ and the forming process of AgNPs. The composition, structure and size of the crystal were analyzed by XRD and TEM. Results showed that, under mild conditions, pomegranate peel extract reacted with dilute AgNO3 solution to produce Ag/Ag+/Ag3+ nanoparticle composites. At pH = 8 and 10 mmol/L of AgNO3 concentration, the size of the achieved composites ranged between 15 and 35 nm with spherical shapes and good crystallinity. The bactericidal experiment indicated that the prepared Ag/Ag+/Ag3+ nanoparticles had strong antibacterial activity against gram positive bacteria and gram negative bacteria. FTIR analysis revealed that biological macromolecules with groups of sbnd NH2, sbnd OH, and others were distributed on the surface of the newly synthesized Ag/Ag+/Ag3+ nanoparticles. This provided a useful clue to further study the AgNP biosynthesis mechanism.

  9. Ag-modified silicon nanowires substrate for ultrasensitive surface-enhanced raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shao, Ming-Wang; Zhang, Ming-Liang; Wong, Ning-Bew; Ma, Dorothy Duo-duo; Wang, Hui; Chen, Weiwei; Lee, Shuit-Tong

    2008-12-01

    We report a unique substrate for surface-enhanced raman spectroscopy (SERS) based on silver nanoparticles-embedded silicon nanowires (SiNWs). The SiNWs were prepared by thermal evaporation of SiO powder via oxide-assisted growth, oxide removed with HF, and then used to reduce silver ions to form a highly decorated Ag-embedded surface. Such modified SiNWs substrates yielded ultrahigh SERS sensitivity, which could detect 25μl of 1×10-16M Rhodamine 6G, 1×10-16M crystal violet, and 1×10-14M nicotine in methanol solutions. An Ag-modified SiNW strand could also enable SERS detection of 25μl of 1×10-8mg/ml calf thymus DNA. The possible mechanisms for the ultrahigh SERS sensitivity were discussed.

  10. Ag-Air Service

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Econ, Inc.'s agricultural aerial application, "ag-air," involves more than 10,000 aircraft spreading insecticides, herbicides, fertilizer, seed and other materials over millions of acres of farmland. Difficult for an operator to estimate costs accurately and decide what to charge or which airplane can handle which assignment most efficiently. Computerized service was designed to improve business efficiency in choice of aircraft and determination of charge rates based on realistic operating cost data. Each subscriber fills out a detailed form which pertains to his needs and then receives a custom-tailored computer printout best suited to his particular business mix.

  11. Highly reliable ag nanowire flexible transparent electrode with mechanically welded junctions.

    PubMed

    Hwang, Byungil; Shin, Hae-A-Seul; Kim, Taegeon; Joo, Young-Chang; Han, Seung Min

    2014-08-27

    Deformation behavior of the Ag nanowire flexible transparent electrode under bending strain is studied and results in a novel approach for highly reliable Ag nanowire network with mechanically welded junctions. Bending fatigue tests up to 500,000 cycles are used to evaluate the in situ resistance change while imposing fixed, uniform bending strain. In the initial stages of bending cycles, the thermally annealed Ag nanowire networks show a reduction in fractional resistance followed by a transient and steady-state increase at later stages of cycling. SEM analysis reveals that the initial reduction in resistance is caused by mechanical welding as a result of applied bending strain, and the increase in resistance at later stages of cycling is determined to be due to the failure at the thermally locked-in junctions. Based on the observations from this study, a new methodology for highly reliable Ag nanowire network is proposed: formation of Ag nanowire networks with no prior thermal annealing but localized junction formation through simple application of mechanical bending strain. The non-annealed, mechanically welded Ag nanowire network shows significantly enhanced cyclic reliability with essentially 0% increase in resistance due to effective formation of localized wire-to-wire contact.

  12. Studies on properties of Ag/Co0.05Ti0.95O2 random nanocomposite as metamaterials

    NASA Astrophysics Data System (ADS)

    Khorshidi, Zahra; Gholipur, Reza; Bahari, Ali

    2016-10-01

    In this work, random metal-dielectric nanocomposites consisting of Ag nanorods embedded in Co0.05Ti0.95O2 are studied. The aspect ratio of Ag nanorods is about 15, and different contents of Ag nanorods are investigated. The nanocomposites with Ag content exceeding its percolation threshold, show metal-like behavior with negative permittivity. Moreover, in these nanocomposites, Ag nanorods form silver networks with diamagnetic response which combine with the magnetic resonance of ferromagnetic Co0.05Ti0.95O2 particles. The permeability spectra show that CTO-Ag15 33% nanocomposite has strongest diamagnetic behavior. These results indicate that the CTO-Ag15 33% sample is a promising candidate for the double negative materials.

  13. Communication: Structure, formation, and equilibration of ensembles of Ag-S complexes on an Ag surface

    SciTech Connect

    Russell, Selena M.; Kim, Yousoo; Liu, Da-Jiang; Evans, J. W.; Thiel, P. A.

    2013-02-15

    We have utilized conditions of very low temperature (4.7 K) and very low sulfur coverage to isolate and identify Ag-S complexes that exist on the Ag(111) surface. The experimental conditions are such that the complexes form at temperatures above the temperature of observation. These complexes can be regarded as polymeric chains of varying length, with an Ag4S pyramid at the core of each monomeric unit. Steps may catalyze the formation of the chains and this mechanism may be reflected in the chain length distribution.

  14. Paleofloods and ancient fishing weirs in NW Iberian rivers

    NASA Astrophysics Data System (ADS)

    Viveen, Willem; Sanjurjo-Sanchez, Jorge; Goy-Diz, Ana; Veldkamp, Antonie; Schoorl, Jeroen M.

    2014-07-01

    A 15-m-thick, fluvial sedimentary record of the NW Iberian lower Miño River was studied. Grain-size analyses were performed and twelve samples were dated using optically stimulated luminescence dating techniques, documenting a 1300-yr-old reconstructed fluvial record that does not match with known climate fluctuations in the area, but is linked instead to the construction of a series of ancient fishing weirs (pesqueiras). The sedimentation phases are in agreement with known episodes of increased population density, which suggests active use of the pesqueiras. A number of sedimentation hiatuses in the fluvial record point towards damage to the pesqueiras during large-scale flooding in the Miño River basin, and a sudden drop in population probably due to the arrival of the plague in the 13th century AD. The oldest sedimentation phases started just after 700 AD, and we infer that the first pesqueiras were constructed around this time. This timing coincides with the transition of the NW Iberian landscape towards a more intensively used agricultural landscape, as evidenced from other geo-archeological investigations. The results demonstrate that the pesqueiras are several hundreds of years older than known from historical records, but not so old as to date back to the Roman occupation.

  15. AGS Experiments: 1989, 1990, 1991

    SciTech Connect

    Depken, J.C.

    1992-02-01

    This report contains: Experimental areas layout; table of beam parameters and fluxes; experiment schedule as run''; proposed 1992 schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS Experiments begin here; and list of AGS Experimenters begins here.

  16. AGS Experiments: 1989, 1990, 1991

    SciTech Connect

    Depken, J.C.

    1992-02-01

    This report contains: Experimental areas layout; table of beam parameters and fluxes; experiment schedule ``as run``; proposed 1992 schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS Experiments begin here; and list of AGS Experimenters begins here.

  17. Draft genome sequences of two Campylobacter jejuni clinical isolates, NW and D2600.

    PubMed

    Jerome, John P; Klahn, Brian D; Bell, Julia A; Barrick, Jeffrey E; Brown, C Titus; Mansfield, Linda S

    2012-10-01

    The Campylobacter jejuni human clinical isolates NW and D2600 colonized C57BL/6 interleukin-10-deficient (IL-10(-/-)) mice without inducing a robust inflammatory response (J. A. Bell et al., BMC Microbiol. 9:57, 2009). We announce draft genome sequences of NW and D2600 to facilitate comparisons with strains that induce gastrointestinal inflammation in this mouse model.

  18. Microwave-assisted hydrothermal synthesis of Ag2(W1 -xMox)O4 heterostructures: Nucleation of Ag, morphology, and photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Silva, M. D. P.; Gonçalves, R. F.; Nogueira, I. C.; Longo, V. M.; Mondoni, L.; Moron, M. G.; Santana, Y. V.; Longo, E.

    2016-01-01

    Ag2W1 -xMoxO4 (x = 0.0 and 0.50) powders were synthesized by the co-precipitation (drop-by-drop) method and processed using a microwave-assisted hydrothermal method. We report the real-time in situ formation and growth of Ag filaments on the Ag2W1 -xMoxO4 crystals using an accelerated electron beam under high vacuum. Various techniques were used to evaluate the influence of the network-former substitution on the structural and optical properties, including photoluminescence (PL) emission, of these materials. X-ray diffraction results confirmed the phases obtained by the synthesis methods. Raman spectroscopy revealed significant changes in local order-disorder as a function of the network-former substitution. Field-emission scanning electron microscopy was used to determine the shape as well as dimensions of the Ag2W1 -xMoxO4 heterostructures. The PL spectra showed that the PL-emission intensities of Ag2W1 -xMoxO4 were greater than those of pure Ag2WO4, probably because of the increase of intermediary energy levels within the band gap of the Ag2W1 -xMoxO4 heterostructures, as evidenced by the decrease in the band-gap values measured by ultraviolet-visible spectroscopy.

  19. Geomorphometric mapping of spatio-temporal changes in Plio-Quaternary uplift in the NW European Alpine foreland

    NASA Astrophysics Data System (ADS)

    Demoulin, Alain; Bourdon, Hadrien

    2016-04-01

    A way to explore the causes of Plio-Quaternary uplift in NW Europe consists in identifying the distribution of uplifted areas and evaluating relative uplift ages. Here we use the composite metric R of fluvial landscapes, which involves three different hypsometric integrals (catchment, drainage network, and trunk stream), in order to get time information (Demoulin, 2011). Main controls on R are catchment size A and uplift age. To isolate the latter information, we use the derived SR index, which is the slope of the linear fit between R and ln(A). We calculate R for more than 7000 basins larger than 15 km2 and determine SR values for 60-km-wide regions in five N- to NW-trending zones of alternating Paleozoic massifs (Massif central-Brittany; Rhenish shield; Bohemian massif) and Meso-Cenozoic basins (Paris basin; Franconian basin) covering the whole NW European platform in front of the alpine arc. The resulting 350- to 750-km-long SR profiles seem to provide the most meaningful time information, better than that obtained with noisier higher-resolution SR maps. Preliminary results of the study especially evidence a systematic increase in SR from south to north across the Paris basin and Rhenish shield zones that suggests northward propagation of an uplift wave that started from ~200 km north of the alpine collision front in Pliocene times and travelled across this part of the European platform. The Bohemian Massif and the Massif central-Brittany zone show more complex SR patterns that might be linked to interferences between the uplift wave and more local phenomena (related, e.g., to WNW-oriented compression in front of the Carpathian arc). Surprisingly, the Franconian basin displays fairly uniform low to moderate SR values suggesting that no tectonic perturbation occurred there since at least the late Early Pleistocene. In conclusion, this new geomorphometric approach of uplift chronology provides a wealth of data, whose careful analysis will help get fresh insight

  20. Fast plasmonic laser nanowelding for a Cu-nanowire percolation network for flexible transparent conductors and stretchable electronics.

    PubMed

    Han, Seungyong; Hong, Sukjoon; Ham, Jooyeun; Yeo, Junyeob; Lee, Jinhwan; Kang, Bongchul; Lee, Phillip; Kwon, Jinhyeong; Lee, Seung S; Yang, Min-Yang; Ko, Seung Hwan

    2014-09-01

    A facile fast laser nanoscale welding process uses the plasmonic effect at a nanowire (NW) junction to suppress oxidation and successfully fabricate a Cu-NW-based percolation-network conductor. The "nanowelding" process does not require an inert or vacuum environment. Due to the low-temperature and fast-process nature, plasmonic laser nanowelding may form Cu-nanowire networks on heat-sensitive, flexible or even stretchable substrates.

  1. Facile synthesis of PdAgTe nanowires with superior electrocatalytic activity

    NASA Astrophysics Data System (ADS)

    Hong, Wei; Wang, Jin; Wang, Erkang

    2014-12-01

    In this work, ultrathin Te nanowires (NWs) with high-aspect-ratio are prepared by a simple hydrothermal method. By using Te NWs as the sacrificial template, we demonstrate a facile and efficient method for the synthesis of PdAgTe NWs with high-quality through the partly galvanic replacement between Te NWs and the corresponding noble metal salts precursors in an aqueous solution. The compositions of PdAgTe NWs can be tuned by simply altering the concentration of the precursors. After cyclic voltammetry treatment, multi-component PdAgTe NW with a highly active and stable surface can be obtained. The structure and composition of the as-prepared nanomaterials are analyzed by transmission electron microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, inductively coupled plasma-mass spectroscopy and X-ray photoelectron spectroscopy. Electrochemical catalytic measurement results prove that the as synthesized PdAgTe NWs present superior catalytic activity toward ethanol electrooxidation in alkaline solution than the commercial Pd/C catalyst, which making them can be used as effective catalysts for the direct ethanol fuel cells.

  2. 51. (Credit JTL) Interior view (looking NW) of new pumping ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. (Credit JTL) Interior view (looking NW) of new pumping room built in 1921. In the right foreground is #1 low service pump built in 1897. Installed at McNeil in 1898, it was not moved during the building of this room in 1921. Beyond is a 5 mgd capacity Worthington-Snow cross-compound, duplex crank-and-fly-wheel engine built in 1920. Behind the worthington is an 8 mgd Allis-Chalmers engine of the same configuration. it was built in 1911, but not installed at McNeil until 1927. Both engines have condensers. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  3. Silver indium diphosphate, AgInP(2)O(7).

    PubMed

    Zouihri, Hafid; Saadi, Mohamed; Jaber, Boujemaa; El Ammari, Lehcen

    2010-01-01

    Polycrystalline material of the title compound, AgInP(2)O(7), was synthesized by traditional high-temperature solid-state methods and single crystals were grown from the melt of a mixture of AgInP(2)O(7) and B(2)O(3) as flux in a platinium crucible. The structure consists of InO(6) octa-hedra, which are corner-shared to PO(4) tetra-hedra into a three-dimensional network with hexa-gonal channels running parallel to the c axis. The silver cation, located in the channel, is bonded to seven O atoms of the [InP(2)O(7)] framework with Ag-O distances ranging from 2.370 (2) to 3.015 (2) Å. The P(2)O(7) diphosphate anion is characterized by a P-O-P angle of 137.27 (9) and a nearly eclipsed conformation. AgInP(2)O(7) is isotypic with the M(I)FeP(2)O(7) (M(I) = Na, K, Rb, Cs and Ag) diphosphate family. PMID:21522510

  4. The AGS-Booster lattice

    SciTech Connect

    Lee, Y.Y.; Barton, D.S.; Claus, J.; Cottingham, J.G.; Courant, E.D.; Danby, G.T.; Dell, G.F.; Forsyth, E.B.; Gupta, R.C.; Kats, J.

    1987-01-01

    The AGS Booster has three objectives. They are to increase the space charge limit of the AGS, to increase the intensity of the polarized proton beam by accumulating many linac pulses (since the intensity is limited by the polarized ion source), and to reaccelerate heavy ions from the BNL Tandem Van de Graaff before injection into the AGS. The machine is capable of accelerating protons at 7.5 Hertz from 200 MeV to 1.5 GeV or to lower final energies at faster repetition rates. The machine will also be able to accelerate heavy ions from as low as 1 MeV/nucleon to a magnetic rigidity as high as 17.6 Tesla-meters with a one second repetition rate. As an accumulator for polarized protons, the Booster should be able to store the protons at 200 MeV for several seconds. We expect that the Booster will increase the AGS proton intensity by a factor of four, polarized proton intensity by a factor of twenty to thirty, and will also enable the AGS to accelerate all species of heavy ions (at present the AGS heavy ion program is limited to the elements lighter than sulfur because it can only accelerate fully stripped ions). The construction project started in FY 1985 and is expected to be completed in 1989. The purpose of this paper is to provide a future reference for the AGS Booster lattice.

  5. A Holocene climate record from palaeolakes in NW India

    NASA Astrophysics Data System (ADS)

    Dixit, Y.; Hodell, D. A.; Petrie, C.

    2011-12-01

    The plains of NW India encompasses arid, semi-arid to sub-humid zones and archaeological research indicate this region was intensively settled by the Indus Valley Civilization. The precise climatological and environmental history of this region during the Holocene period remain largely unknown. We present high-resolution isotope proxy records of local palaeoclimate change from lacustrine deposits in two different climatic zones from west to east; Palaeo-lake Riwasa in the semi-arid and paleo-lake Kotla Dahar in the sub-humid region in Haryana plains, India. The oxygen isotope record from palaeolake Riwasa indicates the inception of wet climate conditions and establishment of a deep, permanent lake in the basin at ~8870 14C yr BP, coinciding approximately with the early Holocene maximum in the Indian monsoon. A major desiccation event occurs after ~7000 14C yr BP. Our results from palaeolake Riwasa indicate that the permanent deep-water lake and major desiccation event in semi-arid region pre-dated the urban phase of the Indus Civilization. Palaeolake Kotla Dahar is located further east than Riwasa in the sub-humid zone, and receives 500-700mm rainfall. Calcium carbonate percent of bulk sediments from Kotla Dahar increases down section to a maximum of 72%, indicating the presence of a deep carbonate marl lake. Oxygen isotopes are currently being measured on gastropod and ostracod shells and radiocarbon dates are being obtained from this section. We speculate that the oxygen isotope record from Kotla Dahar may provide critical climate data for the period between 5000-3500 BP, the period of Harappan Urbanism. Our study of palaeo-lakes Riwasa and Kotla Dahar constitute the first oxygen isotope records from the plains of NW India to interpret the palaeoclimate history of this region.

  6. An Integrated 3S and Historical Materials Analysis of the Keriya Paleoriver, NW China

    NASA Astrophysics Data System (ADS)

    Luo, Lei; Wang, Xinyuan; Cai, Heng

    2014-03-01

    Combining analysis of 3S (RS, GIS and GPS) and historical materials (historical records, ancient map and academic and literary writings) allows mapping of the Keriya Paleoriver of Southern Xinjiang, NW China. Keriya Paleoriver, one of the ancient Four Green Corridors which passes through the Taklimakan Desert from south to north in the Tarim Basin, recorded changes of the climate-environment in the ancient Silk Road of the region. According to the archaeological data, historical materials and paleoclimates information, its eco-environment and climate have had great changes since the 1.09Ma B.P., especially during the last 2,000 years, which has led to many famous ancient cities to be abandoned and the route of the ancient Silk Road to be moved southward. Using RS (optical and radar imagery), GIS (mapping and spatial analysis) and GPS (study area investigation), we mapped a major paleodrainage system of Keriya River, which have linked the Kunlun Mountains to the Tienshan Mountains through the Taklimakan Desert, possibly as far back as the early Pleistocene. This study illustrates the capability of the 3S and historical materials, in mapping the Keriya Paleoriver drainage networks and archaeological study on the ancient Silk Road.

  7. Spatiotemporal analysis of vehicle collisions involving wild boar and roe deer in NW Spain.

    PubMed

    Rodríguez-Morales, Beatriz; Díaz-Varela, Emilio Rafael; Marey-Pérez, Manuel Francisco

    2013-11-01

    Ungulate-vehicle collisions pose a serious traffic safety hazard in the North of Spain. The understanding of underlying temporal and spatial structure of these non-random events is imperative to develop appropriate mitigation measures. This study analyses the temporal, spatial and spatiotemporal patterns of car crashes involving wild boar and roe deer in the province of Lugo (NW Spain) in the period 2006-2010 using geographic information systems (GIS) and spatial statistics. The temporal analysis--conducted at three scales: daily, weekly and seasonal--revealed that accidents are related to specific animal's life cycles and to interactions with human activities. The localization of collision points with GIS discovered the sections of the autonomic road network where accidents with the two studied species concentrate. Besides, the spatial arrangement of significant hotspots was mapped through kernel density estimation over two time scales (daily and seasonal), distinguishing among 41 sets, sequentially arranged to facilitate clustering comparison and determination of spatiotemporal risky areas. This work is of valuable help for road managers to design the appropriate mitigation measures that will improve traffic safety and animal welfare. PMID:24056283

  8. Crystal structure of Ag2(μ-SCN)2(NH3)4

    PubMed Central

    Müller, Thomas G.; Kraus, Florian

    2016-01-01

    Di-μ-thio­cyanato-bis­[diamminesilver(I)], [Ag2(μ-SCN)2(NH3)4], was synthesized by the reaction of AgSCN with anhydrous liquid ammonia. In the binuclear mol­ecule, the AgI atom is coordinated by two ammine ligands and the S atom of one thio­cyanate ligand. Two of these [Ag(SCN)(NH3)2] units are bridged by the S atoms of the thio­cyanate anions at longer distances, leading to a dimer with point group symmetry C 2. The distance between the AgI atoms in the dimer is at 3.0927 (6) Å within the range of argentophilic inter­actions. The crystal structure displays N—H⋯N and N—H⋯S hydrogen-bonding inter­actions that build up a three-dimensional network. PMID:27555922

  9. Crystal structure of Ag2(μ-SCN)2(NH3)4.

    PubMed

    Müller, Thomas G; Kraus, Florian

    2016-07-01

    Di-μ-thio-cyanato-bis-[diamminesilver(I)], [Ag2(μ-SCN)2(NH3)4], was synthesized by the reaction of AgSCN with anhydrous liquid ammonia. In the binuclear mol-ecule, the Ag(I) atom is coordinated by two ammine ligands and the S atom of one thio-cyanate ligand. Two of these [Ag(SCN)(NH3)2] units are bridged by the S atoms of the thio-cyanate anions at longer distances, leading to a dimer with point group symmetry C 2. The distance between the Ag(I) atoms in the dimer is at 3.0927 (6) Å within the range of argentophilic inter-actions. The crystal structure displays N-H⋯N and N-H⋯S hydrogen-bonding inter-actions that build up a three-dimensional network. PMID:27555922

  10. A time series deformation estimation in the NW Himalayas using SBAS InSAR technique

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Venkataraman, G.

    2012-12-01

    A time series land deformation studies in north western Himalayan region has been presented in this study. Synthetic aperture radar (SAR) interferometry (InSAR) is an important tool for measuring the land displacement caused by different geological processes [1]. Frequent spatial and temporal decorrelation in the Himalayan region is a strong impediment in precise deformation estimation using conventional interferometric SAR approach. In such cases, advanced DInSAR approaches PSInSAR as well as Small base line subset (SBAS) can be used to estimate earth surface deformation. The SBAS technique [2] is a DInSAR approach which uses a twelve or more number of repeat SAR acquisitions in different combinations of a properly chosen data (subsets) for generation of DInSAR interferograms using two pass interferometric approach. Finally it leads to the generation of mean deformation velocity maps and displacement time series. Herein, SBAS algorithm has been used for time series deformation estimation in the NW Himalayan region. ENVISAT ASAR IS2 swath data from 2003 to 2008 have been used for quantifying slow deformation. Himalayan region is a very active tectonic belt and active orogeny play a significant role in land deformation process [3]. Geomorphology in the region is unique and reacts to the climate change adversely bringing with land slides and subsidence. Settlements on the hill slopes are prone to land slides, landslips, rockslides and soil creep. These hazardous features have hampered the over all progress of the region as they obstruct the roads and flow of traffic, break communication, block flowing water in stream and create temporary reservoirs and also bring down lot of soil cover and thus add enormous silt and gravel to the streams. It has been observed that average deformation varies from -30.0 mm/year to 10 mm/year in the NW Himalayan region . References [1] Massonnet, D., Feigl, K.L.,Rossi, M. and Adragna, F. (1994) Radar interferometry mapping of

  11. Late Quaternary Climate Forcing of Rapid Sedimentation and Erosion Processes in the NW Himalaya (Invited)

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Scherler, D.; Strecker, M. R.

    2009-12-01

    The intensity of the Asian summer-monsoon circulation varies over decadal to millennial time scales and is reflected in changes in surface processes, terrestrial environments, and marine sediment records. The impact of climatic forcing on the landscape’s response and associated erosion processes varies, depending on magnitude and size of the climatic events, as well as on the tectonic and geomorphologic preconditioning of the landscape. Here, we present new surface-exposure ages combined with previously published data to quantify erosion and process rates and their changes through the time. The NW Himalaya is located at the end of the monsoonal conveyer belt that transports moisture from the Bay of Bengal to the Sutlej Valley and farther west. Along the Himalaya, orographic barriers force out rainfall with peak amounts located consistently at a 3-km-radius relief of ~1 km. The tail and northward end of the rainfall distribution decays rapidly with only little or no moisture reaching the southern Tibetan Plateau. However, during a generally stronger monsoon circulation in the early Holocene called the Intensified Monsoon Phase rainfall reached the today arid regions of the northern Himalaya and southern Tibetan Plateau as documented in numerous terrestrial sediment archives. During this time period in the NW Himalaya, the presently arid, high-elevation areas have been impacted by flooding and heavy landsliding ultimately leading to a significant increase in sediment-flux rates. Some of the sediment material has been derived from glaciers. We show that the transiently-stored sediments in these valleys have been rapidly removed during the early Holocene at the onset of the Intensified Monsoon Phase. The limiting factor for sediment removal and transport on millennial timescales are large bedrock landslides that impounded the river network and formed intramontane basins lasting for several thousands of years. We suggest a feedback process between sediment removal and

  12. Spin dynamics simulations at AGS

    SciTech Connect

    Huang, H.; MacKay, W.W.; Meot, F.; Roser, T.

    2010-05-23

    To preserve proton polarization through acceleration, it is important to have a correct model of the process. It has been known that with the insertion of the two helical partial Siberian snakes in the Alternating Gradient Synchrotron (AGS), the MAD model of AGS can not deal with a field map with offset orbit. The stepwise ray-tracing code Zgoubi provides a tool to represent the real electromagnetic fields in the modeling of the optics and spin dynamics for the AGS. Numerical experiments of resonance crossing, including spin dynamics in presence of the snakes and Q-jump, have been performed in AGS lattice models, using Zgoubi. This contribution reports on various results so obtained.

  13. Synthesis of Ag(2) S-Ag nanoprisms and their use as DNA hybridization probes.

    PubMed

    Liu, Bing; Ma, Zhanfang

    2011-06-01

    A simple synthetic route to prepare Ag(2) S-Ag nanoprisms consists of the facile addition of Na(2) S to a solution of triangular Ag nanoprisms. The resulting Ag(2) S-Ag nanoparticles are more stable in solution than the original Ag nanoprisms, and two surface plasmon resonance (SPR) bands of the original Ag nanoprisms still remain. In addition, the SPR bands of the Ag(2) S-Ag nanoprisms are tunable over a wide range. The Ag(2) S-Ag nanoprisms can be directly bioconjugated via well-established stable Ag(2) S surface chemistry with readily available sulfur coupling agents. The nanoprisms are used in the hybridization of functionalized oligonucleotides, and show promise as probes for future biosensing applications. PMID:21538868

  14. Late Cenozoic stress field distribution in Biga Peninsula, NW Turkey

    NASA Astrophysics Data System (ADS)

    Ozden, S.; Bekler, T.; Tutkun, S. Z.; Kurcer, A.; Ates, O.; Bekler, F. N.; Kalafat, D.

    2009-04-01

    Biga Peninsula is a seismically active region both in instrumental and historical period in NW Turkey. In this part, middle and southern branches of North Anatolian Fault are represented by Etili, Can-Biga, Yenice-Gonen, Manyas-Danisment, Lapseki, Sinekci, Terzialan, Dogruca, Uluabat, Edincik, Pazarkoy-Hamdibey-Kalkim, Edremit, Yigitler, Sarikoy-Inova, Troia and Karabiga Faults. All of these faults are responsible of the seismic activity in Biga Peninsula. Historical earthquakes happened in 29, 155, 170, 543, 620, 1440, 1737, 1855, 1865 and 1875. Furthermore, as for instrumental period, Saros Gulf-Murefte earthquakes (M:7.3 and M:6.3) in 1912, Erdek Gulf (M:6.4) and Can-Biga (M:6.3) in 1935, Edremit Gulf-Ayvaci k (M:6.8) in 1944, Yenice-Gonen (M:7.2) in 1953, Gonen (M:5.8) in 1964, Edremit-Baki rcay (M:5.5) in 1971, Biga (M:5.8) in 1983, Kusgolu-Manyas (M:5.2) and Bandirma (M:5.0) in 2006. In this study, we determined the Late Cenozoic stress field distribution and present-day tectonic regimes both fault-slip data (by 253 fault planes) and earthquake focal mechanism solutions (by 58 earthquakes) were investigated by the inversion methods. The results indicate that a transtensional stress regime is dominant with a NW-SE to WNW-ESE directed compression (1) and NE-SW to ENE-WSW directed extension (3), which yielded a NE-SW, ENE-WSW and also E-W trending strike-slip faulting faults with a normal component. While a transtensional tectonic regime has an active component in Biga Peninsula, a local and consistent transpressional tectonic regime were determined along an E-W trending narrow zone in the northern part of the Biga Peninsula also. The tectonic regime and stress field is resulted from interactions both continental collision of Eurasian/Anatolian/Arabian plate in the east and subduction processes (roll back and/or slab-pull) of the African plate along the Cyprus and Hellenic arc in the Mediterranean region.

  15. A solution-processed molybdenum oxide treated silver nanowire network: a highly conductive transparent conducting electrode with superior mechanical and hole injection properties.

    PubMed

    Chang, Jung-Hao; Chiang, Kai-Ming; Kang, Hao-Wei; Chi, Wei-Jung; Chang, Jung-Hung; Wu, Chih-I; Lin, Hao-Wu

    2015-03-14

    We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 °C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq(-1), a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole injection in optoelectronic applications. By utilizing these s-MoOx-treated AgNW TCEs as the anode in ITO-free organic light emitting diodes, promising performance of 29.2 lm W(-1) and 10.3% external quantum efficiency are demonstrated. The versatile, multi-functional s-MoOx treatment presented here paves the way for the use of low-temperature, solution-processed MoOx as both a nanowire linker and a hole injection interfacial layer for future flexible optoelectronic devices.

  16. Study of the oxygen transport through Ag (110), Ag (poly), and Ag 2.0 Zr

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Wu, D.; Davidson, M. R.; Hoflund, Gar B.

    1992-01-01

    The transport of oxygen through high-purity membranes of Ag (110), Ag (poly), Ag (nano), and Ag 2.0 Zr has been studied by an ultrahigh vacuum permeation method over the temperature range of 400-800 C. The data show that there are substantial deviations from ordinary diffusion-controlled transport. A surface limitation has been confirmed by glow-discharge studies where the upstream O2 supply has been partially converted to atoms, which, for the same temperature and pressure, gave rise to over an order of magnitude increase in transport flux. Further, the addition of 2.0 wt percent Zr to the Ag has provided increased dissociative adsorption rates, which, in turn, increased the transport flux by a factor of 2. It was also observed that below a temperature of 630 C, the diffusivity exhibits an increase in activation energy of over 4 kcal/mol, which has been attributed to trapping of the atomic oxygen and/or kinetic barriers at the surface and subsurface of the vacuum interface. Above 630 C, the activation barrier decreases to the accepted value of about 11 kcal/mol for Ag (poly), consistent with zero concentration at the vacuum interface.

  17. 14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED CONCRETE FORMS, August 1976 - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

  18. 52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR THE AMMONIA DISTILLATE IN FOREGROUND. MAY 21, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  19. 11. Building H9; 3/4 view, looking NW; showing relationship of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Building H-9; 3/4 view, looking NW; showing relationship of wheeling ramp to building. (Ryan and Harms) - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  20. Soil organic matter contribution to the NW Mediterranean (Invited)

    NASA Astrophysics Data System (ADS)

    Kim, J.; Buscail, R.; Blokker, J.; Kerhervé, P.; Schouten, S.; Ludwig, W.; Sinninghe Damsté, J. S.

    2009-12-01

    The BIT (Branched and Isoprenoid Tetraether) index has recently been introduced as a proxy for soil organic matter input and is based on the relative abundance of non-isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs) derived from organisms living in terrestrial environments versus a structurally related isoprenoid GDGT “crenarchaeol” produced by marine Crenarchaeota (Hopmans et al., 2004). In this study, detailed spatial distribution patterns of BIT index were investigated in combination with other organic parameters in the continental margin of the north western Mediterranean. Based on a transect sampling strategy from source (land) to sink (sea) via river, we analysed a variety of soils from the Têt and Rhône basins, suspended particulate matter in waters of the Têt and Rhône rivers flowing into the Gulf of Lions, and marine surface sediments from the Gulf of Lions collected before and after a flood occurred in June 2008. Our study allows us to track BIT values along the transport pathway of soil organic matter and thus to estimate soil organic matter contribution in marine sediments in the Gulf of Lions (NW Mediterranean), a river-dominated continental margin. Hopmans, E.C., Weijers, J.W.H., Schefuss, E., Herfort, L., Sinninghe Damsté, J.S., Schouten, S., 2004. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoidtetraether lipids. Earth and Planetary Science Letters 224, 107-116.

  1. Tectonic deformations of the NW Novaya Zemlya Archipelago

    NASA Astrophysics Data System (ADS)

    Prokopiev, Andrei; Ershova, Victoria; Khudoley, Andrey; Sobolev, Nikolay; Petrov, Eugeniy

    2016-04-01

    The Novaya Zemlya archipelago comprises two main islands (Northern and Southern). Structural studies were conducted in the northwestern part of Northern Island, composed mainly of Upper Proterozoic-Carboniferous rocks. The structural style is dominated by NW-striking folds, clearly recognized on geological maps. The folds are typically overturned to the northwest. Southeast-dipping axial-plane cleavage is widely distributed. Tectonic transportation in Mesozoic time was directed from southeast to northwest. The bedding-cleavage intersection lineation plunges to southeast and southwest, parallel to the axes of large and small folds. The dip angle of the lineation is high, ranging up to 30o or, rarely even more. Dip angle of the intersection lineation is highly variable over a short distance, pointing to occurrence of several stages of deformation. The intersection lineation plunge angels are likely close to dip angles of bedding on the early-stage fold limbs, most of which were gentle to open ones. The early folding is presumably related to Caledonian or Ellesmerian orogenies.

  2. Assessment of Quercus flowering trends in NW Spain.

    PubMed

    Jato, V; Rodríguez-Rajo, F J; Fernandez-González, M; Aira, M J

    2015-05-01

    This paper sought to chart airborne Quercus pollen counts over the last 20 years in the region of Galicia (NW Spain) with a view to detecting the possible influence of climate change on the Quercus airborne pollen season (APS). Pollen data from Ourense, Santiago de Compostela, Vigo and Lugo were used. The Quercus airborne pollen season was characterized in terms of the following parameters: pollen season start and end dates, peak pollen count, pollen season length and pollen index. Several methods, dates and threshold temperatures for determining the chill and heat requirements needed to trigger flowering were applied. A diverse APS onset timing sequence was observed for the four cities as Quercus flowers few days in advance in Vigo. The variations observed could be related to differences in the meteorological conditions or the thermal requirements needed for flowering. Thermal requirements differed depending on local climate conditions in the study cities: the lowest values for chilling accumulation were recorded in Vigo and the highest in Lugo, whereas the lowest heat accumulation was achieved in Vigo. Differences in APS trends between cities may reflect variations in weather-related trends. A significant trend towards rising Quercus pollen indices and higher maximum daily mean pollen counts was observed in Ourense, linked to the more marked temperature increase across southern Galicia. A non-uniform trend towards increased temperatures was noted over the study period, particularly in late summer and early autumn in all four study cities. Additionally, an increase in spring temperatures was observed in south-western Galicia.

  3. The Cape Ghir filament system in August 2009 (NW Africa)

    NASA Astrophysics Data System (ADS)

    Sangrà, Pablo; Troupin, Charles; Barreiro-González, Beatriz; Desmond Barton, Eric; Orbi, Abdellatif; Arístegui, Javier

    2015-06-01

    In the framework of the Canaries-Iberian marine ecosystem Exchanges (CAIBEX) experiment, an interdisciplinary high-resolution survey was conducted in the NW African region of Cape Ghir (30°38'N) during August 2009. The anatomy of a major filament is investigated on scales down to the submesoscale using in situ and remotely sensed data. The filament may be viewed as a system composed of three intimately connected structures: a small, shallow, and cold filament embedded within a larger, deeper, and cool filament and an intrathermocline anticyclonic eddy (ITE). The cold filament, which stretches 110 km offshore, is a shallow feature 60 m deep and 25 km wide, identified by minimal surface temperatures and rich in chlorophyll a. This structure comprises two asymmetrical submesoscale (˜18 km) fronts with jets flowing in opposite directions. The cold filament is embedded near the equatorward boundary of a much broader region of approximately 120 km width and 150 m depth that forms the cool filament and stretches at least 200 km offshore. This cool region, partly resulting from the influence of cold filament, is limited by two asymmetrical mesoscale (˜50 km) frontal boundaries. At the ITE, located north of the cold filament, we observe evidence of downwelling as indicated by a relatively high concentration of particles extending from the surface to more than 200 m depth. We hypothesize that this ITE may act as a sink of carbon and thus the filament system may serve dual roles of offshore carbon export and carbon sink.

  4. Solution-processed assembly of ultrathin transparent conductive cellulose nanopaper embedding AgNWs

    NASA Astrophysics Data System (ADS)

    Song, Yuanyuan; Jiang, Yaoquan; Shi, Liyi; Cao, Shaomei; Feng, Xin; Miao, Miao; Fang, Jianhui

    2015-08-01

    Natural biomass based cellulose nanopaper is becoming a promising transparent substrate to supersede traditional petroleum based polymer films in realizing future flexible paper-electronics. Here, ultrathin, highly transparent, outstanding conductive hybrid nanopaper with excellent mechanical flexibility was synthesized by the assembly of nanofibrillated cellulose (NFC) and silver nanowires (AgNWs) using a pressured extrusion paper-making technique. The hybrid nanopaper with a thickness of 4.5 μm has a good combination of transparent conductive performance and mechanical stability using bamboo/hemp NFC and AgNWs cross-linked by hydroxypropylmethyl cellulose (HPMC). The heterogeneous fibrous structure of BNFC/HNFC/AgNWs endows a uniform distribution and an enhanced forward light scattering, resulting in high electrical conductivity and optical transmittance. The hybrid nanopaper with an optimal weight ratio of BNFC/HNFC to AgNWs shows outstanding synergistic properties with a transmittance of 86.41% at 550 nm and a sheet resistance of 1.90 ohm sq-1, equal to the electronic conductivity, which is about 500 S cm-1. The BNFC/HNFC/AgNW hybrid nanopaper maintains a stable electrical conductivity after the peeling test and bending at 135° for 1000 cycles, indicating remarkably strong adhesion and mechanical flexibility. Of importance here is that the high-performance and low-cost hybrid nanopaper shows promising potential for electronics application in solar cells, flexible displays and other high-technology products.Natural biomass based cellulose nanopaper is becoming a promising transparent substrate to supersede traditional petroleum based polymer films in realizing future flexible paper-electronics. Here, ultrathin, highly transparent, outstanding conductive hybrid nanopaper with excellent mechanical flexibility was synthesized by the assembly of nanofibrillated cellulose (NFC) and silver nanowires (AgNWs) using a pressured extrusion paper-making technique. The

  5. TiO2 nanowire and TiO2 nanowire doped Ag-PVP nanocomposite for antimicrobial and self-cleaning cotton textile.

    PubMed

    Hebeish, A A; Abdelhady, M M; Youssef, A M

    2013-01-16

    The TiO(2) nanowire (TiO(2) Nw) was successfully prepared via hydrothermal method through TiO(2) nanoparticle (TiO(2) Np). TiO(2) Np doped silver and TiO(2) Nw doped silver were prepared via photo-reducing Ag(+) ions to Ag metal on the TiO(2) Np or TiO(2) Nw surfaces. The prepared nanomaterials were evaluated using X-ray (XRD) diffraction pattern, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Bleached untreated cotton fabric and PVP treated cotton fabrics were coated with the synthesized nanomaterials using pad-dry-cure method. Photocatalytic activity of untreated and coated cotton fabrics with TiO(2) nanomaterials was investigated through the fabric self cleaning of MB dye stains. Also, the PVP finished cotton fabric modified by nanomaterials demonstrated antimicrobial activity against Gram positive bacteria, Gram negative bacteria and fungi. The mechanical properties of coated cotton fabric (tear strength, surface roughness, tensile strength and elongation at break) were examined.

  6. AGS slow extracted beam improvement

    SciTech Connect

    Marneris, I.; Danowski, G.; Sandberg, J.; Soukas, A.

    1997-07-01

    The Brookhaven AGS is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton energy of 29 GeV. Since the late 1960`s it has been serving high energy physics (HEP - proton beam) users of both slow and fast extracted beams. The AGS fixed target program presently uses primary proton and heavy ion beams (HIP) in slowly extracted fashion over spill lengths of 1.5 to 4.0 seconds. Extraction is accomplished by flattoping the main and extraction magnets and exciting a third integer resonance in the AGS. Over the long spill times, control of the subharmonic amplitude components up to a frequency of 1 kilohertz is very crucial. One of the most critical contributions to spill modulation is due to the AGS MMPS. An active filter was developed to reduce these frequencies and it`s operation is described in a previous paper. However there are still frequency components in the 60-720 Hz sub-harmonic ripple range, modulating the spill structure due to extraction power supplies and any remaining structures on the AGS MMPS. A recent scheme is being developed to use the existing tune-trim control horizontal quadrupole magnets and power supply to further reduce these troublesome noise sources. Feedback from an external beam sensor and overcoming the limitations of the quadrupole system by lead/lag compensation techniques will be described.

  7. The Late Miocene Quaternary Antofalla volcanic complex, southern Puna, NW Argentina: Protracted history, diverse petrology, and economic potential

    NASA Astrophysics Data System (ADS)

    Richards, Jeremy P.; Ullrich, Thomas; Kerrich, Robert

    2006-04-01

    The Antofalla volcanic complex (AVC) is located on the southern Puna plateau of NW Argentina, ˜100 km east of the main axis of the Cordillera Occidental volcanic arc. It lies on the NW-SE Archibarca lineament, one of several transverse structures that cut across the Andes from Chile, and divert arc magmatism in SE-trending fingers across the Puna. 40Ar/ 39Ar dating of volcanic products from the AVC reveals a protracted magmatic history from 10.9 to ≤ 1.6 Ma. Initial volcanism was characterized by eruption of voluminous rhyolitic ignimbrites, deposited directly onto exposed crystalline basement and supracrustal sedimentary rocks. These rhyolites record significant geochemical evidence for crustal contamination, or derivation by crustal melting, which decreases upwards through the pyroclastic sequence. They were followed by extrusion of potassic lavas of the shoshonite-latite-trachydacite suite from 10.1 to 9.5 Ma. Subsequent magmatism (9.1-1.6 Ma) was of basaltic andesite-andesite-dacite composition, with localized, smaller volume, dacitic and rhyolitic ignimbrites. Monogenetic basaltic andesite cinder cones and lava flows were erupted in the Quaternary in response to a change to transtensional tectonics in the Puna. The volcanic sequence is interpreted to record the early development of a lower crustal MASH zone at ˜11 Ma, where mantle-derived arc magmas interacted extensively with felsic lower crustal rocks to produce evolved shoshonitic compositions, and crustal melts that erupted to form rhyolitic ignimbrites (common at this time throughout the Puna). After establishment of a steady-state MASH zone by ˜9 Ma, subsequent basaltic andesite-andesite magmas show less evidence of felsic crustal contamination, and may have developed largely by interaction with previous ultramafic-mafic fractionates of early magmas in the lower crust. More felsic dacitic magmas appear to have evolved largely by fractional crystallization from basaltic andesites and andesites, with

  8. Thermoelectric properties of semiconductor nanowire networks

    DOE PAGES

    Roslyak, Oleksiy; Piryatinski, Andrei

    2016-03-28

    To examine the thermoelectric (TE) properties of a semiconductor nanowire (NW) network, we propose a theoretical approach mapping the TE network on a two-port network. In contrast to a conventional single-port (i.e., resistor)network model, our model allows for large scale calculations showing convergence of TE figure of merit, ZT, with an increasing number of junctions. Using this model, numerical simulations are performed for the Bi2Te3 branched nanowire (BNW) and Cayley tree NW (CTNW) network. We find that the phonon scattering at the network junctions plays a dominant role in enhancing the network ZT. Specifically, disordered BNW and CTNW demonstrate anmore » order of magnitude higher ZT enhancement compared to their ordered counterparts. Formation of preferential TE pathways in CTNW makes the network effectively behave as its BNW counterpart. In conclusion, we provide formalism for simulating large scale nanowire networks hinged upon experimentally measurable TE parameters of a single T-junction.« less

  9. Transient erosion in the Valencia Trough turbidite systems, NW Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Amblas, David; Gerber, Thomas P.; Canals, Miquel; Pratson, Lincoln F.; Urgeles, Roger; Lastras, Galderic; Calafat, Antoni M.

    2011-07-01

    Submarine canyons can efficiently drain sediments from continental margins just as river systems do in subaerial catchments. Like in river systems, submarine canyons are often arranged as complex drainage networks that evolve from patterns of erosion and deposition. In the present paper we use a morphometric analysis of submarine canyon-channel long-profiles to study the recent sedimentary history of the Valencia Trough turbidite system (VTTS) in the NW Mediterranean Sea. The VTTS is unique in that it drains sediment from margins with contrasting morphologies through a single “trunk” conduit, the Valencia Channel. The Valencia Channel has been active since the late Miocene, evolving in response to Plio-Quaternary episodes of erosion and deposition. The integrated analysis of long-profiles obtained from high-resolution bathymetric data across the entire turbidite system shows evidence for transient canyon incision in the form of knickpoints and hanging tributaries. Multiple factors appear to have triggered these periods of incision. These include a large debris flow at 11,500 yr BP that disrupted the upper reaches of the VTTS and glacio-eustatic lowstands that forced shifting of sediment input to the VTTS. Based on these inferences, long-term time-averaged incision rates for the Valencia Channel have been estimated. The evidence we present strongly suggests that Foix Canyon has played a key role in the drainage dynamics of the VTTS in the past. This study builds conceptually on a recent modeling study that provides a morphodynamic explanation for the long-term evolution of submarine canyon thalweg profiles. The procedure and results from this work are of potential application to other submarine sediment drainage systems, past and present, including those containing mid-ocean type valleys like the Valencia Channel.

  10. Characterizing the surface circulation in Ebro Delta (NW Mediterranean) with HF radar and modeled current data

    NASA Astrophysics Data System (ADS)

    Lorente, P.; Piedracoba, S.; Sotillo, M. G.; Aznar, R.; Amo-Balandron, A.; Pascual, A.; Soto-Navarro, J.; Alvarez-Fanjul, E.

    2016-11-01

    Quality-controlled current observations from a High Frequency radar (HFR) network deployed in the Ebro River Delta (NW Mediterranean) were combined with outputs from IBI operational ocean forecasting system in order to comprehensively portray the ocean state and its variability during 2014. Accurate HFR data were used as benchmark for a rigorous validation of the Iberia-Biscay-Ireland (IBI) regional system, routinely operated in the frame of the Copernicus Marine Environment Monitoring Service (CMEMS). The analysis of skill metrics and monthly averaged current maps showed that IBI reasonably captured the prevailing dynamic features of the coastal circulation previously observed by the HFR, according to the moderate resemblance found in circulation patterns and the spatial distribution of eddy kinetic energy. The model skill assessment was completed with an exploration of dominant modes of spatiotemporal variability. The EOF analysis confirmed that the modeled surface current field evolved both in space and time according to three significantly dominant modes of variability which accounted for the 49.2% of the total variance, in close agreement with the results obtained for HFR (46.1%). The response of the subtidal surface current field to prevailing wind regime in the study area was examined in terms of induced circulation structures and immediacy of reaction by performing a conditional averaging approach and a time-lagged vector correlation analysis, respectively. This observations-model synergistic strategy has proved to be valid to operationally monitor the complex coastal circulation in Ebro Delta despite the observed model drawbacks in terms of reduced energy content in surface currents and some inaccuracies in the wind-driven low frequency response. This integrated methodology aids to improve the prognostic capabilities of IBI ocean forecasting system and also to facilitate high-stakes decision-making for coastal management in the Ebro River Delta marine

  11. Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey

    USGS Publications Warehouse

    Bulut, Fatih; Bohnhoff, Marco; Ellsworth, William L.; Aktar, Mustafa; Dresen, Georg

    2009-01-01

    The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a “seismic gap” where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çınarcık Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çınarcık Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çınarcık Basin merge to one single master fault below ∼17 km depth. On the basis of a cross-correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right-lateral strike-slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike-slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara.

  12. Geology and mineralogy of the Santo Nino Ag-Pb-Zn vein, Fresnillo District, Mexico

    SciTech Connect

    Gemmell, J.B.; Zantop, H.; Birnie, R.W.

    1985-01-01

    The Santo Nino Ag-Pb-Zn vein is the major producer of the Fresnillo District, located 750 km NW of Mexico City. It is over 2.4 km long, more than 480 m in vertical extent, more than 2.5 m wide overall, and has average grades of >600 gm/t Ag and <2% combined Pb and Zn. The vein is hosted by a tilted sequence of Cretaceous graywackes, shales and andesitic volcanics and extends upward into a Lower Tertiary conglomerate. Up to 5 separate opening events occurred along the vein, resulting in discontinuous stages of brecciation and crustiform banding. Ore mineral zonation is well developed both vertically and laterally and closely reflects metal and metal ratio distributions. Ore minerals are sphalerite, galena, pyrite, chalcopyrite, arsenopyrite, marcasite, pyrrhotite, acanthite, native silver, and three coexisting solid solution series, pyrargyrite-proustite, polybasite-arsenopolybasite, and tetrahedrite-tennantite in a gangue of quartz, calcite, clay, sericite,and chlorite. A 5-stage paragenetic sequence can be established: 1) pyrite, arsenopyrite, quartz, 2) sphalerite, galena, chalcopyrite, quartz, 3) tetrahedrite, pyrargyrite, polybasite, quartz, 4) acanthite, native silver, calcite, quartz, and 5) calcite. Preliminary microprobe analyses indicate that the Ag-rich solid solution series are Sb-rich in the central and upper portions of the vein and As-rich at deeper levels.

  13. Photoelectron spectroscopy of AgCl, AgBr, and AgI vapors

    SciTech Connect

    Berkowitz, J.; Batson, C.H.; Goodman, G.L.

    1980-06-01

    He I photoelectron spectra of AgCl, AgBr and AgI vapors have been obtained which differ significantly from earlier work. In each instance, the characteristic features of the diatomic molecule are prominent. The spectral features separate into a valence region, predominantly halogen p-like, and a deeper region, predominantly of Ag 4d character. The latter is split by spin--orbit and ligand field interactions, which are parametrized from the experimental data. Relativistic calculations of the X/sub ..cap alpha../--DVM--SCC type have been performed for these species. At the transition state level, they agree very well with the experimental peak positions. Nonrelativistic calculations of this type have been performed for CuCl and cyclic Cu/sub 3/Cl/sub 3/. Unlike the AgX species, the CuCl and Cu/sub 3/Cl/sub 3/ exhibit strong mixing of metal d and halogen p orbitals for the uppermost occupied orbital, and other Cu 3d-like orbitals above the Cl 3p-like orbitals. It is suggested that the occurrence of Cu 3d orbitals in the valence region may play a role in the anomalous diagmagnetic signal and large conductivity changes of CuCl condensed from the vapor.

  14. The AGS Booster control system

    SciTech Connect

    Frankel, R.; Auerbach, E.; Culwick, B.; Clifford, T.; Mandell, S.; Mariotti, R.; Salwen, C.; Schumburg, N.

    1988-01-01

    Although moderate in size, the Booster construction project requires a comprehensive control system. There are three operational modes: as a high intensity proton injector for the AGS, as a heavy ion accelerator and injector supporting a wide range of ions and as a polarized proton storage injector. These requirements are met using a workstation based extension of the existing AGS control system. Since the Booster is joining a complex of existing accelerators, the new system will be capable of supporting multiuser operational scenarios. A short discussion of this system is discussed in this paper.

  15. AG Draconis - a symbiotic mystery

    NASA Astrophysics Data System (ADS)

    Galis, R.; Hric, L.; Smelcer, L.

    2015-02-01

    Symbiotic system AG Draconis regularly undergoes quiescent and active stages which consist of the series of individual outbursts. The period analysis of new and historical photometric data, as well as radial velocities, confirmed the presence of the two periods. The longer one (~550 d) is related to the orbital motion and the shorter one (~355 d) could be due to pulsation of the cool component of AG Dra. In addition, the active stages change distinctively, but the outbursts are repeated with periods from 359 - 375 d.

  16. Grounding zone wedges, Kveithola Trough (NW Barents Sea)

    NASA Astrophysics Data System (ADS)

    Rebesco, Michele; Urgeles, Roger; Özmaral, Asli; Hanebuth, Till; Caburlotto, Andrea; Hörner, Tanja; Lantzsch, Hendrik; LLopart, Juame; Lucchi, Renata; Skøtt Nicolaisen, Line; Giacomo, Osti; Sabbatini, Anna; Camerlenghi, Angelo

    2014-05-01

    Swath bathymetry within Kveithola Trough (NW Barents Sea) shows a seafloor characterized by E-W trending megascale glacial lineations (MSGLs) overprinted by transverse Grounding Zone Wedges (GZWs), which give the trough a stair profile (Rebesco et al., 2011). GZWs are formed by deposition of subglacial till at temporarily stable ice-stream fronts in between successive episodic retreats (Rüther et al., 2012; Bjarnadóttir et al., 2012). Sub-bottom data show that present-day morphology is largely inherited from palaeo-seafloor topography of GZWs, which is draped by a deglacial to early Holocene glaciomarine sediments (about 15 m thick). The ice stream that produced such subglacial morphology was flowing from East to West inside Kveithola Trough during Last Glacial Maximum. Its rapid retreat was likely associated with progressive lift-offs, and successive rapid melting of the grounded ice, induced by the eustatic sea-level rise (Lucchi et al., 2013). References: Bjarnadóttir, L.R., Rüther, D.C., Winsborrow, M.C.M., Andreassen, K., 2012. Grounding-line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy. Boreas, 42, 84-107. Lucchi R.G., et al. 2013. Postglacial sedimentary processes on the Storfjorden and Kveithola TMFs: impact of extreme glacimarine sedimentation. Global and Planetary Change, 111, 309-326. Rebesco, M., et al. 2011. Deglaciation of the Barents Sea Ice Sheet - a swath bathymetric and subbottom seismic study from the Kveitehola Trough. Marine Geology, 279, 141-14. Rüther, D.C., Bjarnadóttir, L.R., Junttila, J., Husum, K., Rasmussen, T.L., Lucchi, R.G., Andreassen, K., 2012. Pattern and timing of the north-western Barents Sea Ice Sheet deglaciation and indications of episodic Holocene deposition. Boreas 41, 494-512.

  17. Mesozooplankton metabolism and feeding in the NW Iberian upwelling

    NASA Astrophysics Data System (ADS)

    Isla, José Alejandro; Ceballos, Sara; Anadón, Ricardo

    2004-09-01

    Mesozooplankton size-fractionated biomass, feeding, and metabolic rates were investigated during a cruise conducted off NW Spain in August 1998. Based on different hydrographic conditions observed throughout the study area (upwelling events nearshore and stratified waters offshore), the sampling area was divided into coastal and oceanic zones. Both phytoplankton and mesozooplankton biomass were higher in the coastal upwelling than in the offshore zone. Size structure analysis shows that the small fraction (200-500 μm) of mesozooplankton was more important than the larger fractions (500-1000 μm and >1000 μm) in the open ocean in terms of both biomass and grazing activity. The relationship between copepod ingestion rate and the concentration of chlorophyll a >5 μm resembled a type II functional response. Saturation occurred at the coastal stations, where copepod gut contents were highest. The grazing impact on both phytoplankton biomass and primary production seemed to be higher offshore (5.7 and 12.9%, respectively) than in upwelled waters (5.2 and 5.2%), although the differences were not statistically significant. Phytoplankton ingestion was enough to fulfil the basal metabolism of mesozooplankton in the upwelling area (102.1% of the minimum carbon requirements met) but not in the offshore (45.9%). Feeding activity and metabolic measurements on mesozooplankton point to a herbivorous food web in the coastal upwelling zone and a multivorous food web in the stratified open oceanic waters. The amount of metabolic end products released by mesozooplankton was higher in the coastal zone, but mesozooplankton played a more important role as nutrient regenerators in the multivorous food web (30.3 and 21.7% of the nitrogen and phosphorus phytoplankton demand accounted for ammonium and phosphate excretion, respectively) than in the herbivorous one (3.8% for ammonium and 2.6% for phosphate).

  18. Petrography, palynology and depositional environment of Gelibolu coals, NW Turkey

    NASA Astrophysics Data System (ADS)

    Demirtaş, Ferdi; Bozcu, Mustafa; Koşun, Erdal

    2014-05-01

    Upper Oligocene and Miocene coal samples collected from two outcrops in the Gelibolu Peninsula, NW Turkey were analyzed petrographically and palynologically to determine the depositional environment of the coals. Microscopic studies reveal that the studied coal samples from both locations are characterized by high amount of huminite group macerals, ranging from 46 to 78% (mineral-included basis). The prevailing maceral from this group is gelinite (31-65%), it can be easily seen on all studied samples, indicative of high gelification degree of organic matter. Relatively low amount of liptinite (does not exceed 9%) and inertinite (does not exceed 8%) are also observed in the coals. The mineral matter content is variable but generally high, varying from 5 to 37%, as in other Turkish coals and consists mostly of clay minerals, quartz, calcite and pyrite. The mean reflectance values range from 0.502 to 0.564% suggesting that rank of coal is subbituminous (ASTM). The chemical properties of coal including calorific value, volatile matter and fixed carbon content are also in accordance with rank of coal. Facies indices based on maceral ratios (Tissue Preservation Index vs. Gelification Index and ABC ternary diagrams) were used to interpret to depositional environment of coals. Low tissue preservation index (TPI) and high gelification index (GI) values are observed. These indices indicate that the coals deposited in limnic environment. High pH and strongly reducing conditions inferred from the presence of framboidal pyrite and also evidenced by low TPI values. The palynological assembly of the coals dominated by angiosperm pollen and spore, however, gymnosperms were rarely seen. Herbaceous/sedge plants are common in Miocene coal samples.

  19. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    PubMed

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin. PMID:25970617

  20. ERUPTIVE VARIABLE STARS AND OUTFLOWS IN SERPENS NW

    SciTech Connect

    Hodapp, Klaus W.; Chini, Rolf; Watermann, Ramon; Lemke, Roland

    2012-01-01

    We study the outflow activity, photometric variability, and morphology of three very young stellar objects in the Serpens NW star-forming region: OO Serpentis, EC 37 (V370 Ser), and EC 53 (V371 Ser). High spatial resolution Keck/NIRC2 laser guide star adaptive optics images obtained in 2007 and 2009 in broadband K and in a narrowband filter centered on the 1-0 S(1) emission line of H{sub 2} allow us to identify the outflows from all three objects. We also present new, seeing-limited data on the photometric evolution of the OO Ser reflection nebula and re-analyze previously published data. We find that OO Ser declined in brightness from its outburst peak in 1995 to about 2003, but that this decline has recently stopped and actually reversed itself in some areas of the reflection nebula. The morphology and proper motions of the shock fronts MHO 2218 near EC 37 suggest that they all originate in EC 37 and that this is an outflow seen nearly along its axis. We identify an H{sub 2} jet emerging from the cometary nebula EC 53. The star illuminating EC 53 is periodically variable with a period of 543 days and has a close-by, non-variable companion at a projected distance of 92 AU. We argue that the periodic variability is the result of accretion instabilities triggered by another very close, not directly observable, binary companion and that EC 53 can be understood in the model of a multiple system developing into a hierarchical configuration.

  1. DENSITY VARIATIONS IN THE NW STAR STREAM OF M31

    SciTech Connect

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W. E-mail: richer@astro.ubc.ca

    2011-04-20

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10{sup -5}. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study.

  2. Timing and Spatial Distribution of Loess in Xinjiang, NW China

    PubMed Central

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess–paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin. PMID:25970617

  3. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    PubMed

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin.

  4. A study of petroleum system in Chuhuangkeng anticline, NW Taiwan

    NASA Astrophysics Data System (ADS)

    Yiang, S.; Tsai, L. Y.

    2015-12-01

    Since energy demand is still increasing in the world, the exploration of unconventional fossil fuel becomes more and more important today. Miaoli area of the NW Western Foothill Belt, Taiwan, had been a major oil and gas producing field in the past, important oil/gas producing structures include Tiechenshen, Chinshui and Chuhuangkeng anticline. The reservoir rocks of unconventional resources need to be examined to illustrate the remaining hydrocarbon potential of Chuhuangkeng anticline. A standard evaluation procedure for assessing integrated geochemical parameters can thus be established. In this study, we combine various geochemical parameters including TOC, porosity, Rock-Eval pyrolysis, vitrinite reflectance measurement to assess the HC potential of shale gas reservoirs. The results show that Wuchishan and Mushan Formations possess the best hydrocarbon potential in Chuhuangkeng anticline. The maturation of Wuchishan and Mushan Formations are both in oil window (Ro of Wuchishan formation =1.7% , Ro of Mushan =1.01~1.53% ). The maturation of Shitih Formation barely reached oil window, however the shallower depth and less exploration cost are the advantages of Shitih Formation. Moreover, Wuchishan Formation is a dry gas field and Mushan Formation is a condensate gas field. The results of porosity show that there are secondary porosity existed in Mushan Formation which provides the extra storage space for hydrocarbon. Additionally, Piling Shale is a good cap rock on top of Mushan formation, it further benefits the conservation of oil and gas in Mushan Formation. In conclude, Mushan Formation is the most potential HC target in future shale gas exploration.

  5. The Pliocene-Pleistocene sedimentary tectonic history of NW California

    SciTech Connect

    Stone, L.; Moley, K.; Aalto, K.R. . Dept. of Geology); Renne, P.R. . Berkeley Geochronology Center)

    1993-04-01

    A thick sequence of Late Miocene to Pleistocene sediments thought to represent deposition in a Neogene forearc basin are preserved in the structural basin referred to as the Eel River basin' located offshore of NW California and SE Oregon. The southern portion of this structural basin comes on land in the vicinity of Eureka where the marine and fluvial Wildcat Group is exposed. Basal Wildcat Group sediments are fluvial and littorial. Marine sandstones of the Wildcat Group contain K-spar concentrations of 5.5% and are believed to represent a fresh source. [sup 40]Ar/[sup 39]Ar laser probe analyses of Wildcat Group micas yield dates of 52--57, 66--75, 128.5 and 299--303 Ma. The presence of Idaho detritus throughout the Neogene Wildcat Group indicates that the Klamath Mountains remained low during the Pliocene and early Pleistocene. Younger fluvial sediments in this region contain primarily locally derived detritus indicating local uplift of the Klamath Mountains. To the north, at Crescent City, thin remnants of the near-shore Saint George Formation and the eastern estuarine and fluvial Wimer Formation are lowermost Pliocene in age (5 ma). The presence of the highly erodible Wilmer Formation on uplifted plateaus in an area of extreme rainfall suggest that these sediments represent only the lowermost portion of an originally much thicker sequence. Consequently, the sediments confined to the present day Eel River basin do not represent the lateral extent of the original forearc basin. Sandstones and conglomerates of the Saint George and Wimer Formation indicate a local Klamath provenance derivation.

  6. Density Variations in the NW Star Stream of M31

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W.; Irwin, Mike; Ibata, Rodrigo A.; Dotter, Aaron L.; Chapman, Scott; Fardal, Mark; Ferguson, A. M. N.; Lewis, G. F.; Navarro, Julio F.; Puzia, Thomas H.; Valls-Gabaud, David

    2011-04-01

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10-5. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study. Based on observations obtained with MegaPrime / MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  7. Ag-Ag2S Hybrid Nanoprisms: Structural versus Plasmonic Evolution.

    PubMed

    Shahjamali, Mohammad M; Zhou, Yong; Zaraee, Negin; Xue, Can; Wu, Jinsong; Large, Nicolas; McGuirk, C Michael; Boey, Freddy; Dravid, Vinayak; Cui, Zhifeng; Schatz, George C; Mirkin, Chad A

    2016-05-24

    Recently, Ag-Ag2S hybrid nanostructures have attracted a great deal of attention due to their enhanced chemical and thermal stability, in addition to their morphology- and composition-dependent tunable local surface plasmon resonances. Although Ag-Ag2S nanostructures can be synthesized via sulfidation of as-prepared anisotropic Ag nanoparticles, this process is poorly understood, often leading to materials with anomalous compositions, sizes, and shapes and, consequently, optical properties. In this work, we use theory and experiment to investigate the structural and plasmonic evolution of Ag-Ag2S nanoprisms during the sulfidation of Ag precursors. The previously observed red-shifted extinction of the Ag-Ag2S hybrid nanoprism as sulfidation occurs contradicts theoretical predictions, indicating that the reaction does not just occur at the prism tips as previously speculated. Our experiments show that sulfidation can induce either blue or red shifts in the extinction of the dipole plasmon mode, depending on reaction conditions. By elucidating the correlation with the final structure and morphology of the synthesized Ag-Ag2S nanoprisms, we find that, depending on the reaction conditions, sulfidation occurs on the prism tips and/or the (111) surfaces, leading to a core(Ag)-anisotropic shell(Ag2S) prism nanostructure. Additionally, we demonstrate that the direction of the shift in the dipole plasmon is a function of the relative amounts of Ag2S at the prism tips and Ag2S shell thickness around the prism.

  8. Grain boundary diffusion of Ag through polycrystalline SiC in TRISO fuel particles

    NASA Astrophysics Data System (ADS)

    Deng, Jie; Ko, Hyunseok; Demkowicz, Paul; Morgan, Dane; Szlufarska, Izabela

    2015-12-01

    The effective diffusivity and release fraction of Ag in polycrystalline SiC are evaluated using a kinetic Monte Carlo model. The effects of various grain boundary network properties on the transport of Ag across the SiC layer have been examined, including fraction of grain boundary type, spread in grain boundary diffusivities and distribution of grain boundary types. It is shown that the effective diffusivity and release fraction of Ag can exhibit a large variability due to changes in the GB structure of SiC, and this variability is almost independent of temperature fluctuation. The present results suggest that the variation in properties of grain boundary networks in SiC may contribute to the spread in the Ag diffusivity and release fraction measured in TRISO particles. It is also found that the grain boundary diffusion alone may be insufficient to account for the Ag diffusivities and release fractions measured in integral release experiments. Additional factors such as irradiation and temperature distribution may also play an important role in Ag transport across the SiC layer.

  9. Ag nanotubes and Ag/AgCl electrodes in nanoporous membranes

    NASA Astrophysics Data System (ADS)

    Davenport, Matthew; Healy, Ken; Siwy, Zuzanna S.

    2011-04-01

    Miniaturization of the entire experimental setup is a key requirement for widespread application of nanodevices. For nanopore biosensing, integrating electrodes onto the nanopore membrane and controlling the pore length is important for reducing the complexity and improving the sensitivity of the system. Here we present a method to achieve these goals, which relies on electroless plating to produce Ag nanotubes in track-etched polymer nanopore templates. By plating from one side only, we create a conductive nanotube that does not span the full length of the pore, and thus can act as a nanoelectrode located inside the nanopore. To give optimal electrochemical behavior for sensing, we coat the Ag nanotube with a layer of AgCl. We characterize the behavior of this nanoelectrode by measuring its current-voltage response and find that, in most cases, the response is asymmetric. The plated nanopores have initial diameters between 100 and 300 nm, thus a range suitable for detection of viruses.

  10. Photoreduction of Ag+ in Ag/Ag2S/Au memristor

    NASA Astrophysics Data System (ADS)

    Mou, N. I.; Tabib-Azar, M.

    2015-06-01

    Silver halides and chalcogenides are excellent memristor materials that have been extensively used in the past as photosensitive layers in photography. Here we examine the effect of illumination on the operating voltages and switching speed of Ag/Ag2S/Au memristors using a green laser (473-523 nm). Our results indicate that illumination decreases the average switching time from high to low resistance states by ∼19% and decreases the turn-off voltages dramatically from -0.8 V to -0.25 V that we attribute to the change in sulfur valency and a photo-induced change in its oxidation/reduction potential. Photo-induced reduction of silver in Ag2S may be used in three dimensional optical memories that can be electronically read and reset.

  11. Ag-Ag dispersive interaction and physical properties of Ag3Co(CN)6

    NASA Astrophysics Data System (ADS)

    Fang, Hong; Dove, Martin T.; Refson, Keith

    2014-08-01

    We report a density functional theory (DFT) study of Ag3Co(CN)6, a material noted for its colossal positive and negative thermal expansion, and its giant negative linear compressibility. Here, we explicitly include the dispersive interaction within the DFT calculation, and find that it is essential to reproduce the ground state, the high-pressure phase, and the phonons of this material, and hence essential to understand this material's remarkable physical properties. New exotic properties are predicted. These include heat enhancement of the negative linear compressibility, a large reduction in the coefficient of thermal expansion on compression with change of sign of the mode Grüneisen parameters under pressure, and large softening of the material on heating. Our results suggest that these are associated with the weak Ag-Ag dispersive interactions acting with an efficient hinging mechanism in the framework structure.

  12. Laser-based synthesis of core Ag-shell AgI nanoparticles

    NASA Astrophysics Data System (ADS)

    Tan, Hua; Fan, Wai Yip

    2005-05-01

    A laser-controlled synthesis of silver iodide (AgI) nanoparticles with isolable AgI shell-Ag core stable intermediates is achieved via molecular iodine photodissociation in the presence of pure Ag nanoparticles dispersed in water. Ag nanoparticles were introduced into the solution containing sodium dodecylsulphate surfactants and iodine by ablating a piece of silver foil with a 532 nm pulsed Nd-YAG laser. Transmission electron microscopy images showed that different AgI shell-Ag core sizes could be achieved by controlling the photolysis of I 2 in solution. These nanoparticles were also found to catalyse an atom-economy Grignard-Barbier organic reaction.

  13. 78 FR 57621 - First Responder Network Authority Board Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... Responder Network Authority (FirstNet) will hold a Special Board meeting via teleconference on September 23...: Uzoma Onyeije, Secretary, FirstNet, U.S. Department of Commerce, 1401 Constitution Avenue NW...), created FirstNet as an independent authority within the NTIA. The Act directs FirstNet to establish...

  14. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications

    NASA Astrophysics Data System (ADS)

    Dong, Wenjun; Huang, Huandi; Zhu, Yanjun; Li, Xiaoyun; Wang, Xuebin; Li, Chaorong; Chen, Benyong; Wang, Ge; Shi, Zhan

    2012-10-01

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide-amine intermediate and Ag+ at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO3 nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag-MoO3 nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature.

  15. Preparation and characterization of BC/PAM-AgNPs nanocomposites for antibacterial applications.

    PubMed

    Yang, Guang; Wang, Caixia; Hong, Feng; Yang, Xuexia; Cao, Zhangjun

    2015-01-22

    In this work, a bacterial cellulose/polyacrylamide (BC/PAM) double network composite was prepared to act as the template for in situ synthesis of silver nanoparticles (AgNPs). Effects of reaction conditions of the BC/PAM composite were investigated on its microstructure, mechanical properties and thermal stabilities. Both the BC/PAM composite and pure BC were utilized to prepare the corresponding silver impregnated nanocomposites, i.e., BC/PAM-AgNPs and BC-AgNPs, by an environmental friendly method, UV irradiation. The influences of the templates were investigated on the AgNPs formation and the antibacterial activities of the nanocomposites by both the zone of inhibition and dynamic shake flask methods. It was shown that the BC/PAM composite displayed a denser microstructure and higher thermal stabilities than pure BC. The BC/PAM-AgNPs nanocomposite exhibited a bigger particle size and lower mass content of AgNPs than the BC-AgNPs one. For the antibacterial test, two nanocomposites exhibited a close antibacterial effect, with a high log reduction above 3 and killing ratio above 99.9%, respectively. PMID:25439942

  16. Preparation and characterization of BC/PAM-AgNPs nanocomposites for antibacterial applications.

    PubMed

    Yang, Guang; Wang, Caixia; Hong, Feng; Yang, Xuexia; Cao, Zhangjun

    2015-01-22

    In this work, a bacterial cellulose/polyacrylamide (BC/PAM) double network composite was prepared to act as the template for in situ synthesis of silver nanoparticles (AgNPs). Effects of reaction conditions of the BC/PAM composite were investigated on its microstructure, mechanical properties and thermal stabilities. Both the BC/PAM composite and pure BC were utilized to prepare the corresponding silver impregnated nanocomposites, i.e., BC/PAM-AgNPs and BC-AgNPs, by an environmental friendly method, UV irradiation. The influences of the templates were investigated on the AgNPs formation and the antibacterial activities of the nanocomposites by both the zone of inhibition and dynamic shake flask methods. It was shown that the BC/PAM composite displayed a denser microstructure and higher thermal stabilities than pure BC. The BC/PAM-AgNPs nanocomposite exhibited a bigger particle size and lower mass content of AgNPs than the BC-AgNPs one. For the antibacterial test, two nanocomposites exhibited a close antibacterial effect, with a high log reduction above 3 and killing ratio above 99.9%, respectively.

  17. AGS experiments: 1990, 1991, 1992. Ninth edition

    SciTech Connect

    Depken, J.C.

    1993-04-01

    This report contains a description of the following: AGS Experimental Area - High Energy Physics FY 1993 and Heavy Ion Physics FY 1993; Table of Beam Parameters and Fluxes; Experiment Schedule ``as run``; Proposed 1993 Schedule; A listing of experiments by number; Two-page summaries of each experiment begin here, also ordered by number; Publications of AGS Experiments; and List of AGS Experimenters.

  18. Development of microbial resistant thermosensitive Ag nanocomposite (gelatin) hydrogels via green process.

    PubMed

    Manjula, Bandla; Varaprasad, Kokkarachedu; Sadiku, Rotimi; Ramam, Koduri; Reddy, G Venkata Subba; Raju, Konduru Mohana

    2014-04-01

    In this investigation, an ecofriendly method for the synthesis of silver nanoparticles (AgNPs) using biodegradable gelatin as a stabilizing agent is reported. Here, we prepared thermosensitive silver nanocomposite hydrogels composed of gelatin and N-isopropylacrylamide. In this green process AgNPs were formed from Ag(+) ions and reduced with leaf [Azadirachta indica (neem leaf)] extracts, resulting in a hydrogel network. The Ag(0) nanoparticles affect the hydrogel strength and improved the biological activity (inactivation effect of bacteria) of the biodegradable hydrogels. The resulted hydrogel structure, morphology, thermal, swelling behavior, degradation, and antibacterial properties were systematically investigated. The biodegradable thermosensitive silver nanocomposite hydrogels developed were tested for antibacterial activities. The results indicate that these biodegradable silver nanocomposite hydrogels are suitable potential candidates for antibacterial applications.

  19. An efficient photocatalyst for degradation of various organic dyes: Ag@Ag2MoO4-AgBr composite.

    PubMed

    Bai, Yu-Yang; Lu, Yi; Liu, Jin-Ku

    2016-04-15

    The Ag2MoO4-AgBr composite was prepared by a facile in-situ anion-exchange method, then the Ag nanoparticles were coated on this composite through photodeposition route to form a novel Ag@Ag2MoO4-AgBr composite. The in-situ Br(-) replacement in a crystal lattice node position of Ag2MoO4 crystal allows for overcoming the resistance of electron transition effectively. Meanwhile silver nano-particles on the surface of Ag@Ag2MoO4-AgBr composite could act as electron traps to intensify the photogeneration electron-hole separation and the subsequent transfer of the trapped electron to the adsorbed O2 as an electron acceptor. As an efficient visible light catalyst, the Ag@Ag2MoO4-AgBr composite exhibited superior photocatalytic activity for the degradation of various organic dyes. The experimental results demonstrated superior photocatalytic rate of Ag@Ag2MoO4-AgBr composite compared to pure AgBr and Ag2MoO4 crystals (37.6% and 348.4% enhancement respectively). The Ag@Ag2MoO4-AgBr composite cloud degraded Rhodamin B, bromophenol blue, and amino black 10b completed in 7min. PMID:26775100

  20. An efficient photocatalyst for degradation of various organic dyes: Ag@Ag2MoO4-AgBr composite.

    PubMed

    Bai, Yu-Yang; Lu, Yi; Liu, Jin-Ku

    2016-04-15

    The Ag2MoO4-AgBr composite was prepared by a facile in-situ anion-exchange method, then the Ag nanoparticles were coated on this composite through photodeposition route to form a novel Ag@Ag2MoO4-AgBr composite. The in-situ Br(-) replacement in a crystal lattice node position of Ag2MoO4 crystal allows for overcoming the resistance of electron transition effectively. Meanwhile silver nano-particles on the surface of Ag@Ag2MoO4-AgBr composite could act as electron traps to intensify the photogeneration electron-hole separation and the subsequent transfer of the trapped electron to the adsorbed O2 as an electron acceptor. As an efficient visible light catalyst, the Ag@Ag2MoO4-AgBr composite exhibited superior photocatalytic activity for the degradation of various organic dyes. The experimental results demonstrated superior photocatalytic rate of Ag@Ag2MoO4-AgBr composite compared to pure AgBr and Ag2MoO4 crystals (37.6% and 348.4% enhancement respectively). The Ag@Ag2MoO4-AgBr composite cloud degraded Rhodamin B, bromophenol blue, and amino black 10b completed in 7min.

  1. AGS 20th anniversary celebration

    SciTech Connect

    Baggett, N.V.

    1980-05-22

    On May 22, 1980, a symposium was held at Brookhaven to celebrate the 20th birthday of the AGS, to recall its beginnings, and to review major discoveries that have been made with its beams. The talks at the symposium are recorded in this volume.

  2. AGS experiments: 1985, 1986, 1987

    SciTech Connect

    Depken, J.C.

    1987-01-01

    This report contains: Experimental areas layout, table of beam parameters and fluxes, experiment schedule ''as run,'' experiment long range schedule, a listing of experiments by number, two-page summaries of each experiment, also ordered by number, and publications of AGS experiments, 1982-1987.

  3. Correcting the AGS depolarizing resonances

    SciTech Connect

    Ratner, L.G.

    1986-01-01

    For the 1986 AGS run, the technique of correcting an imperfection resonance using a beat harmonic instead of the direct harmonic was applied and found to be useful in achieving a 22 GeV/c polarized beam. Both conventional and modified techniques are explained. (LEW)

  4. What Is Ag-Ed?

    ERIC Educational Resources Information Center

    Linley, Judy; Mylne, Lee

    1998-01-01

    Ag-Ed, an agricultural education project for upper elementary students, was held in conjunction with the Toowoomba Show in Queensland, Australia. Agriculture industry representatives provided 20 interactive agricultural presentations for class groups, which were supplemented with a teacher resource-package containing a directory and 13 sections of…

  5. AGS experiments, 1988, 1989, 1990

    SciTech Connect

    Depken, J.C.

    1991-04-01

    This report contains: experimental areas layout; table of beam parameters and fluxes; experiment schedule as run''; experiment long range schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS experiments; and list of experimenters.

  6. Synthesis, structures and properties of Ag+ complexes containing polyphosphine ligands with extended Ag⋯C, N-O⋯π and C-H⋯π interactions

    NASA Astrophysics Data System (ADS)

    Huang, Ting-Hong; Yang, Hu; Yang, Guo; Li, Yanfen; Huang, Li-Li

    2016-08-01

    Based on ligands of N,N-bis((diphenylphosphino)methyl)benzenamine (pba), 4-(4-(bis((diphenylphosphino)methyl)amino)benzyl)-N-((diphenylphosphino)methyl)benzenamine (dptp) and N,N,N‧,N‧-tetrakis((diphenylphosphino)methyl)benzene-1,4-diamine (pbaa), three new silver(I) complexes [Ag(pba)2]ClO4 (1), [Ag2(dptp)2](ClO4)2·2DMF (2) and [Ag4(pbaa)(NO3)4]n (3), have been synthesized and characterized. Structural analysis reveals that all of these complexes contain the 1D infinite chains, with different variations in the weak interactions. Complexes 1 and 2 are interconnected by intermolecular C-H⋯π interactions to form 1D infinite chains and 2D networks, and the ordered-layer-lattic ClO4- and DMF in 2 are between 2D networks. For 3, the pbaa ligand adopts a tetradentate coordination mode to link two adjacent stair-like [Ag4O4] cores resulting in a 1D chain, respectively, with Ag⋯C, N-O⋯π and C-H⋯π interactions. All these show that phosphine ligands play an important role in the construction of interesting topological structures with different types of the weak interactions.

  7. Antibacterial activity and reusability of CNT-Ag and GO-Ag nanocomposites

    NASA Astrophysics Data System (ADS)

    Kim, Ji Dang; Yun, Hyosuk; Kim, Gwui Cheol; Lee, Chul Won; Choi, Hyun Chul

    2013-10-01

    A facile approach to the synthesis of novel CNT-Ag and GO-Ag antibacterial materials, in which thiol groups are utilized as linkers to secure silver (Ag) nanoparticles to the CNT and GO surfaces without agglomeration, is reported. The resulting CNT-Ag and GO-Ag samples were characterized by performing TEM, XRD, Auger, XPS, and Raman measurements, which revealed that in these antibacterial materials size-similar and quasi-spherical Ag nanoparticles are anchored to the CNT and GO surfaces. The Ag nanoparticles in CNT-Ag and GO-Ag have narrow size distributions with average diameters of 2.6 and 3.5 nm respectively. The antibacterial activities of CNT-Ag and GO-Ag against Escherichia coli were assessed with the paper-disk diffusion method and by determining the minimal inhibitory concentrations (MICs). CNT-Ag was found to have higher antibacterial activity than the reference Ag colloid. Moreover, both CNT-Ag and GO-Ag retain more than 50% of their original antibacterial activities after 20 washes with detergent, which indicates their potential as antibacterial materials for laboratory and medical purposes.

  8. Comparative Study of Antimicrobial Activity of AgBr and Ag Nanoparticles (NPs)

    PubMed Central

    Suchomel, Petr; Kvitek, Libor; Panacek, Ales; Prucek, Robert; Hrbac, Jan; Vecerova, Renata; Zboril, Radek

    2015-01-01

    The diverse mechanism of antimicrobial activity of Ag and AgBr nanoparticles against gram-positive and gram-negative bacteria and also against several strains of candida was explored in this study. The AgBr nanoparticles (NPs) were prepared by simple precipitation of silver nitrate by potassium bromide in the presence of stabilizing polymers. The used polymers (PEG, PVP, PVA, and HEC) influence significantly the size of the prepared AgBr NPs dependently on the mode of interaction of polymer with Ag+ ions. Small NPs (diameter of about 60–70 nm) were formed in the presence of the polymer with low interaction as are PEG and HEC, the polymers which interact with Ag+ strongly produce nearly two times bigger NPs (120–130 nm). The prepared AgBr NPs were transformed to Ag NPs by the reduction using NaBH4. The sizes of the produced Ag NPs followed the same trends – the smallest NPs were produced in the presence of PEG and HEC polymers. Prepared AgBr and Ag NPs dispersions were tested for their biological activity. The obtained results of antimicrobial activity of AgBr and Ag NPs are discussed in terms of possible mechanism of the action of these NPs against tested microbial strains. The AgBr NPs are more effective against gram-negative bacteria and tested yeast strains while Ag NPs show the best antibacterial action against gram-positive bacteria strains. PMID:25781988

  9. Active tectonics coupled to fluvial erosion in the NW Himalaya

    NASA Astrophysics Data System (ADS)

    Vannay, J.-C.; Grasemann, B.; Rahn, M.; Frank, W.; Carter, A.

    2003-04-01

    Both syntaxial extremities of the Himalaya show a spatial correlation between active exhumation of deep crustal rocks and the presence of powerful rivers, the Indus and the Tsangpo-Brahmaputra, cutting across the range two of the deepest gorges on Earth. These features strongly suggests that vigorous fluvial erosion can locally enhance isostatic and tectonic uplift, which in turn contributes to heat advection and weakening of the crust, as well as to maintain steep topographic gradients [Zeitler et al., 2001]. In order to test this positive feedback model, we combined structural and geochronological data to constrain the tectono-thermal evolution along the Sutlej (NW India), the third largest river cross-cutting entirely the Himalaya. The Himalayan crystalline core zone exposed along the Sutlej Valley is composed of two gneiss sheets, that were successively underthrusted and tectonically extruded as a consequence of the foreland-directed propagation of deformation in the Indian plate margin. During Early to Middle Miocene, combined thrusting along the Main Central Thrust (MCT) and extension along the Sangla Detachment induced the rapid exhumation and cooling of the amphibolite facies to migmatitic High Himalayan Crystalline Sequence [Vannay &Grasemann, 2001]. Underthrusting beneath the MCT led to the creation of the amphibolite facies Lesser Himalayan Crystalline Sequence (LHCS). The LHCS cooled rapidly from Late Miocene to Pleistocene, as a consequence of tectonic extrusion controlled by thrusting along the Munsiari Thrust, and extension in the MCT hanging wall. This phase is still active, as indicated by: (1) cooling rates in excess of 100^oC/Myr during the past ˜3 Myr in the LHCS; (2) Holocene neo-tectonic activity; (3) present-day hydrothermal activity testifying to elevated near-surface geothermal gradients; and (4) seismic activity along the Munsiari Thrust. Modelling of fluvial erosion in the Himalaya indicate that the Sutlej Valley corresponds to the main

  10. SAR measurements of coastal features in the NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Redondo, Jose M.; Martinez Benjamin, Juan Jose; Diez, Margarita; Lopez Gonzalez-Nieto, Pilar

    2013-04-01

    The Synthetic Aperture Radar (SAR) is a useful tool to study both marine water dynamics and its pollution, this is relevant near the coastline, where river pollution may be also important. Oil spills and natural slicks are detected with SAR [1-3] to reveal river and vessel pollution as well as the complex eddy and current interaction in the ocean surface near the coastline. In the framework of the ESA and European Union contracts, more than 1000 SAR images of the North-west Mediterranean Sea area taken between December 1996 and December 2008 are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, oil spills and tensioactive slicks that eventually allow predicting the behaviour of different tracers and pollutants in the NW Mediterranean Sea. Thanks to different polarization and intensity levels in satellite imagery can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar as a function of spill parameters, environmental conditions and history of both oil release and weather conditions. (Environmental factors determine [4] spreading, drift and weathering of oil on the sea surface - see: Behaviour oil at sea). Detecting the low contrast patches depends also on the speckle noise which always presents in the image. Application of different filters (available for example in several image processing software (Matlab, Envi, IDL) to the radar data decreases noise level and improves the feature detecting in the image [1] Bezerra, M.O., Diez, M., Medeiros, C., Rodriguez, A., Bahia, E., Sanchez-Arcilla, A. and Redondo, J.M. 1998. Study on the influence of waves on coastal diffusion using image analysis. Applied Scientific Research 59, pp.191-204. [2] Carrillo, A., A., Sanchez,, M

  11. Geochemistry and petrology of nephrite from Alamas, Xinjiang, NW China

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Deng, Jun; Shi, Guanghai; Yui, Tzen-Fu; Zhang, Guibin; Abuduwayiti, Maituohuti; Yang, Liqiang; Sun, Xiang

    2011-08-01

    The Hetian nephrite deposit is one of the largest nephrite deposits worldwide. Located within the Hetian deposit, Xinjiang, Northwest China, the Alamas ore body occurs as veins on the contact between the Late Variscan granodiorite and Precambrian dolomitic marble. Petrographic studies and electronic microprobe analyses reveal two possible nephrite formation processes: (1) dolomitic marble → tremolite and (2) dolomitic marble → diopside → tremolite. Nephrite veins show continuous coloration zones, ranging from white and white-green zones to a green zone towards the granodiorite, with increasing concentrations of Cr, FeO and TFe 2O 3. All these nephrite samples have quite low Cr and Ni contents (8.95-178.7 ppm and 0.05-3.95 ppm, respectively) relative to serpentinite-related nephrite (Cr 2O 3, 0.07-0.43 wt.%; NiO, 0.08-0.36 wt.%). Their bulk-rock REE patterns exhibit strong negative Eu anomalies (0.03-0.21) with declined LREE, flat HREE and low ΣREE concentration (2.84-84.81 ppm), similar to those of host dolomitic marble samples with negative Eu anomalies (0.15-0.23), declined LREE, flat HREE and lower ΣREE concentration (8.48-11.1 ppm), indicating a close genetic relationship between them. Homogenization temperatures analyses on the fluid inclusions in tremolite yield a minimum temperature 293 °C for the nephrite formation. Nephrites have oxygen and hydrogen isotope compositions in the range from +3.2 to +6.2 per mil and -83.0 to -94.7 per mil, respectively. The corresponding equilibrated fluids have isotope compositions of δ 18O = +3.1 to +6.1 (293 °C). Combined with field observation, there are at least three possible fluid sources: meteoric water, magmatic water and CO 2 derived from decarbonation of dolomite, and a metasomatic and dolomite-related origin is suggested for the Alamas ore body in the Hetian nephrite deposit, Xinjiang, NW China.

  12. Preparation of the CNC/Ag/beeswax composites for enhancing antibacterial and water resistance properties of paper.

    PubMed

    Liu, Kai; Liang, Hunan; Nasrallah, Joseph; Chen, Lihui; Huang, Liulian; Ni, Yonghao

    2016-05-20

    An effective method of preparing composites containing inorganic (Ag) and organic (beeswax) particles was established in this study. Ag nanoparticles were first immobilized on the cellulose nanocrystals (CNC) during the reduction of AgNO3 in the presence of CNC, then mixed with beeswax by high speed stirring. Scanning transmission electron microscopy (STEM) images indicated that Ag and beeswax particles were uniformly dispersed and stable in the network structure formed by CNC. Upon coating on a paper surface, a layer of beeswax film was evident based on scanning electron microscopy (SEM) images. The dynamic contact angle and antibacterial activity tests indicated that the contact angle of coated paper reached 113.06° and the growth inhibition of Escherichia coli increased to 99.96%, respectively, at a coating amount of 21.53 g/m(2). When applied onto paper surface by coating, the CNC/Ag/beeswax composites can impact paper with antibacterial property and improved water resistance.

  13. Silver nanowire-carbon fiber cloth nanocomposites synthesized by UV curing adhesive for electrochemical point-of-use water disinfection.

    PubMed

    Hong, Xuesen; Wen, Junjie; Xiong, Xuhua; Hu, Yongyou

    2016-07-01

    Novel silver nanowire (AgNW) - carbon fiber cloth (CC) nanocomposites were synthesized by a rapid and facile method. Acting as filter in an electrical gravity filtration device, the AgNW-CC nanocomposites were applied to electrochemical point-of-use water disinfection. AgNW-CC nanocomposites were characterized by FESEM, XRD, and FTIR. Their disinfection performance toward Escherichia coli and bacteriophage MS2 was evaluated by inhibition zone tests, optical density growth curve tests, and flow tests. The results showed that complex 3D AgNW networks with controllable silver release (<100 ppb) were fabricated on CC by using UV curing adhesive. AgNW-CC nanocomposites exhibited excellent intrinsic antibacterial activities against E. coli. The concentration of AgNWs and UV adhesive controlled the released silver and hence led to the change in antibacterial activity. The external electric field significantly enhanced the disinfection efficiency of AgNW-CC nanocomposites. Over 99.999% removal of E. coli and MS2 could be achieved. More complex AgNW networks contributed to higher disinfection efficiency under 10 V and 10(6) CFU (PFU) mL(-1) of microorganism. UV adhesive could keep the disinfection performance from being affected by flow rate. The convenient synthesis and outstanding disinfection performance offer AgNW-CC nanocomposites opportunities in the application of electrochemical point-of-use drinking water disinfection. PMID:27085313

  14. Silver nanowire-carbon fiber cloth nanocomposites synthesized by UV curing adhesive for electrochemical point-of-use water disinfection.

    PubMed

    Hong, Xuesen; Wen, Junjie; Xiong, Xuhua; Hu, Yongyou

    2016-07-01

    Novel silver nanowire (AgNW) - carbon fiber cloth (CC) nanocomposites were synthesized by a rapid and facile method. Acting as filter in an electrical gravity filtration device, the AgNW-CC nanocomposites were applied to electrochemical point-of-use water disinfection. AgNW-CC nanocomposites were characterized by FESEM, XRD, and FTIR. Their disinfection performance toward Escherichia coli and bacteriophage MS2 was evaluated by inhibition zone tests, optical density growth curve tests, and flow tests. The results showed that complex 3D AgNW networks with controllable silver release (<100 ppb) were fabricated on CC by using UV curing adhesive. AgNW-CC nanocomposites exhibited excellent intrinsic antibacterial activities against E. coli. The concentration of AgNWs and UV adhesive controlled the released silver and hence led to the change in antibacterial activity. The external electric field significantly enhanced the disinfection efficiency of AgNW-CC nanocomposites. Over 99.999% removal of E. coli and MS2 could be achieved. More complex AgNW networks contributed to higher disinfection efficiency under 10 V and 10(6) CFU (PFU) mL(-1) of microorganism. UV adhesive could keep the disinfection performance from being affected by flow rate. The convenient synthesis and outstanding disinfection performance offer AgNW-CC nanocomposites opportunities in the application of electrochemical point-of-use drinking water disinfection.

  15. Temporal evolution of surface rupture deduced from coseismic multi-mode secondary fractures: Insights from the October 8, 2005 (Mw 7.6) Kashmir earthquake, NW Himalaya

    NASA Astrophysics Data System (ADS)

    Sayab, Mohammad; Khan, Muhammad Asif

    2010-10-01

    Detailed rupture-fracture analyses of some of the well-studied earthquakes have revealed that the geometrical arrangement of secondary faults and fractures can be used as a geological tool to understand the temporal evolution of slip produced during the mainshock. The October 8, 2005 Mw 7.6 Kashmir earthquake, NW Himalaya, surface rupture provides an opportunity to study a complex network of secondary fractures developed on the hanging wall of the fault scarp. The main fault scarp is clearly thrust-type, rupture length is ~ 75 ± 5 km and the overall trend of the rupture is NW-SE. We present the results of our detailed structural mapping of secondary faults and fractures at 1:100 scale, on the hanging wall of the southern end of the rupture in the vicinity of the Sar Pain. Secondary ruptures can be broadly classified as two main types, 1) normal faults and, (2) right-lateral strike-slip 'Riedel' fractures. The secondary normal faults are NW-SE striking, with a maximum 3.3 meter vertical displacement and 2.5 meter horizontal displacement. Estimated total horizontal extension across the secondary normal faults is 3.1-3.5%. We propose that the bending-moment and coseismic stress relaxation can explain the formation of secondary normal faults on the hanging wall of the thrust fault. The strike-slip 'Riedel' fractures form distinct sets of tension (T) and shear fractures (R', R, Y) with right-lateral displacement. Field observations revealed that the 'Riedel' fractures (T) cut the secondary normal faults. In addition, there is kinematic incompatibility and magnitude mismatch between the secondary normal faults and strike-slip 'Riedel' fractures. The cross-cutting relationship, geometric and magnitude incoherence implies a temporal evolution of slip from dip- to strike-slip during the mainshock faulting. The interpretation is consistent with the thrust fault plane solution with minor right-lateral strike-slip component.

  16. Photostimulated Luminescence and Dynamics of AgI and Ag Nanoclusters in Zeolites

    SciTech Connect

    Chen, Wei; Joly, Alan G.; Roark, Joel

    2002-06-15

    The photoluminescence and photostimulated luminescence of Ag and AgI nanoclusters formed in zeolite-Y are studied using fluorescence spectroscopy. The photoluminescence spectra of AgI nanoclusters show emission from both AgI and Ag nanoclusters, while the in the photostimulated luminescence, only the emission of Ag clusters is observed. While the photoluminescence from both Ag and AgI particles displays both sub-nanosecond and microsecond lifetimes, the emission from photostimulated luminescence shows very short, picosecond lifetimes. A model which ascribes the photostimulated luminescence to recombination of electrons trapped in the zeolite with Ag in close proximity to the trap site is proposed. The appearance of strong photostimulated luminescence with short decays in these systems demonstrates that nanoparticles have potential for digital storage and medical radiology applications.

  17. Chemically-inactive interfaces in thin film Ag/AgI systems for resistive switching memories

    PubMed Central

    Cho, Deok-Yong; Tappertzhofen, Stefan; Waser, Rainer; Valov, Ilia

    2013-01-01

    AgI nanoionics-based resistive switching memories were studied in respect to chemical stability of the Ag/AgI interface using x-ray absorption spectroscopy. The apparent dissolution of Ag films of thickness below some tens of nanometers and the loss of electrode/electrolyte contact was critically addressed. The results evidently show that there are no chemical interactions at the interface despite the high ionic mobility of Ag ions. Simulation results further show that Ag metal clusters can form in the AgI layer with intermediate-range order at least up to next-next nearest neighbors, suggesting that Ag can permeate into the AgI only in an aggregated form of metal crystallite. PMID:23378904

  18. Structural, elastic, electronic, and thermodynamic properties of MgAgSb investigated by density functional theory

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Fei; Fu, Xiao-Nan; Zhang, Xiao-Dong; Wang, Jun-Tao; Li, Xiao-Dong; Jiang, Zhen-Yi

    2016-08-01

    The structural, elastic, electronic, and thermodynamic properties of thermoelectric material MgAgSb in γ,β,α phases are studied with first-principles calculations based on density functional theory. The optimized lattice constants accord well with the experimental data. According to the calculated total energy of the three phases, the phase transition order is determined from α to γ phase with cooling, which is in agreement with the experimental result. The physical properties such as elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and anisotropy factor are also discussed and analyzed, which indicates that the three structures are mechanically stable and each has a ductile feature. The Debye temperature is deduced from the elastic properties. The total density of states (TDOS) and partial density of states (PDOS) of the three phases are investigated. The TDOS results show that the γ phase is most stable with a pseudogap near the Fermi level, and the PDOS analysis indicates that the conduction band of the three phases is composed mostly of Mg-3s, Ag-4d, and Sb-5p. In addition, the changes of the free energy, entropy, specific heat, thermal expansion of γ-MgAgSb with temperature are obtained successfully. The obtained results above are important parameters for further experimental and theoretical tuning of doped MgAgSb as a thermoelectric material at high temperature. Project supported by the National Natural Science Foundation of China (Grant No. 11504088), the Fund from Henan University of Technology, China (Grant Nos. 2014YWQN08 and 2013JCYJ12), the Natural Science Fund from the Henan Provincial Education Department, China (Grant No. 16A140027), the Natural Science Foundation of Shaanxi Province of China (Grant Nos. 2013JQ1018 and 15JK1759), and the Science Foundation of Northwest University of China (Grant No. 14NW23).

  19. Structural, elastic, electronic, and thermodynamic properties of MgAgSb investigated by density functional theory

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Fei; Fu, Xiao-Nan; Zhang, Xiao-Dong; Wang, Jun-Tao; Li, Xiao-Dong; Jiang, Zhen-Yi

    2016-08-01

    The structural, elastic, electronic, and thermodynamic properties of thermoelectric material MgAgSb in γ,β,α phases are studied with first-principles calculations based on density functional theory. The optimized lattice constants accord well with the experimental data. According to the calculated total energy of the three phases, the phase transition order is determined from α to γ phase with cooling, which is in agreement with the experimental result. The physical properties such as elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and anisotropy factor are also discussed and analyzed, which indicates that the three structures are mechanically stable and each has a ductile feature. The Debye temperature is deduced from the elastic properties. The total density of states (TDOS) and partial density of states (PDOS) of the three phases are investigated. The TDOS results show that the γ phase is most stable with a pseudogap near the Fermi level, and the PDOS analysis indicates that the conduction band of the three phases is composed mostly of Mg-3s, Ag-4d, and Sb-5p. In addition, the changes of the free energy, entropy, specific heat, thermal expansion of γ-MgAgSb with temperature are obtained successfully. The obtained results above are important parameters for further experimental and theoretical tuning of doped MgAgSb as a thermoelectric material at high temperature. Project supported by the National Natural Science Foundation of China (Grant No. 11504088), the Fund from Henan University of Technology, China (Grant Nos. 2014YWQN08 and 2013JCYJ12), the Natural Science Fund from the Henan Provincial Education Department, China (Grant No. 16A140027), the Natural Science Foundation of Shaanxi Province of China (Grant Nos. 2013JQ1018 and 15JK1759), and the Science Foundation of Northwest University of China (Grant No. 14NW23).

  20. The new silver borate Ag{sub 3}B{sub 5}O{sub 9}

    SciTech Connect

    Sohr, Gerhard; Falkowski, Viktoria; Huppertz, Hubert

    2015-05-15

    Single crystals of Ag{sub 3}B{sub 5}O{sub 9} were obtained via high-pressure synthesis at 3 GPa and 600 °C, using a Walker-type multianvil high-pressure device. Ag{sub 3}B{sub 5}O{sub 9} crystalizes with a=674.7(2), b=943.5(2), c=1103.5(2) pm, V=0.7025(2) nm{sup 3}, and Z=4 in the noncentrosymmetric space group P2{sub 1}2{sub 1}2{sub 1} (no. 19). The orthorhombic structure was refined from 3740 independent reflections with R1=0.0496 and wR2=0.587 (all data). It is built up from infinite corner-sharing chains of BO{sub 4} tetrahedra along the a axis, which are interconnected by BO{sub 3} groups to form a network. In the structure, three crystallographically independent sites are occupied with Ag{sup +} cations exhibiting argentophillic interactions. The synthetic conditions as well as the results of the single crystal structure analysis are presented. - Graphical abstract: Noncentrosymmetric silver borate: During investigations in the system Ag–B–O, a new noncentrosymmetric silver borate Ag{sub 3}B{sub 5}O{sub 9} was discovered. The new structure type is built up from corner-sharing BO{sub 3} and BO{sub 4} groups, forming a network. Argentophillic interactions are clearly indicated by the Ag{sup +}⋯Ag{sup +} distances present in the structure. - Highlights: • A noncentrosymmetric borate Ag{sub 3}B{sub 5}O{sub 9} is accessible via high-pressure synthesis. • Ag{sub 3}B{sub 5}O{sub 9} is the second high-pressure silver borate. • Ag{sup +}⋯Ag{sup +} distances in Ag3B5O9 clearly indicate the presence of argentophillic interactions.

  1. Ag diffusion in cubic silicon carbide

    NASA Astrophysics Data System (ADS)

    Shrader, David; Khalil, Sarah M.; Gerczak, Tyler; Allen, Todd R.; Heim, Andrew J.; Szlufarska, Izabela; Morgan, Dane

    2011-01-01

    The diffusion of Ag impurities in bulk 3C-SiC is studied using ab initio methods based on density functional theory. This work is motivated by the desire to reduce transport of radioactive Ag isotopes through the SiC boundary layer in the Tristructural-Isotropic (TRISO) fuel pellet, which is a significant concern for the Very High Temperature Reactor (VHTR) nuclear reactor concept. The structure and stability of charged Ag and Ag-vacancy clusters in SiC are calculated. Relevant intrinsic SiC defect energies are also determined. The most stable state for the Ag impurity in SiC is found to be a Ag atom substituting on the Si sub-lattice and bound to a C vacancy. Bulk diffusion coefficients are estimated for different impurity states and values are all found to have very high activation energy. The impurity state with the lowest activation energy for diffusion is found to be the Ag interstitial, with an activation energy of approximately 7.9 eV. The high activation energies for Ag diffusion in bulk 3C-SiC cause Ag transport to be very slow in the bulk and suggests that observed Ag transport in this material is due to an alternative mechanism (e.g., grain boundary diffusion).

  2. Groundwater hydrochemistry evolution in cyclone driven hydrological regimes, NW Australia

    NASA Astrophysics Data System (ADS)

    Skrzypek, G.; Dogramaci, S.; Grierson, P.

    2013-12-01

    Groundwater reserves supply the water needs of many arid regions around the world. Aquifer recharge in these regions is primarily depended on the amount and distribution of rainfall, coupled with exceedingly high rates of evaporation and interactions with both local and regional geomorphology and geology. In semi-arid northwest Australia, the majority of rainfall is delivered by large but infrequent cyclonic events and relatively more frequent but low intensity frontal systems. Changes to rainfall patterns due to global climate change may impact hydrological regimes, recharge rates and groundwater hydrochemistry. These changes may significantly restrict freshwater resources in the future. Between 2008 and 2012, we analysed >400 groundwater, surface and rainwater samples for stable isotope composition (δ2H and δ18O) and major ion chemistry. We then developed conceptual geochemical models of groundwater evolution for the Hamersley Basin (>100,000 km2) and a salt inventory for the Fortescue Marsh (the largest wetland in NW Australia) [1,2]. Fresh groundwater from the alluvium (-8.02 × 0.83‰) and fractured aquifers (-8.22 × 0.70‰) were hydrochemically similar and characterised by a very narrow range of δ18O [1]. In contrast, δ18O of saline and brine groundwater (TDS >10 g L-1) varies in wide range from +2.5 to -7.2‰ [2]. Most of the fresh and brackish groundwater reflects modern recharge and is evaporated by <20% prior to recharge. In contrast, highly saline and brine groundwater reflects mixing between modern rainfall, brackish water and older deep groundwater. The Fortescue Marsh primarily acts as a terminal basin for surface water from the upper Fortescue River catchment [2]. The stable isotope composition of the deep brine groundwater under the Marsh suggests a complex evolution, which cannot be explained by evaporation under current climatic conditions. The observed salinity and δ18O values may result from progressive evaporation from highly saline

  3. Reducing the contact resistance of SiNW devices by employing a heavily doped carrier injection layer.

    PubMed

    Liu, Donghua; Shi, Zhiwen; Zhang, Lianchang; He, Congli; Zhang, Jing; Cheng, Meng; Yang, Rong; Tian, Xuezeng; Bai, Xuedong; Shi, Dongxia; Zhang, Guangyu

    2012-08-01

    Silicon nanowires (SiNWs) are promising building blocks for future electronic devices. In SiNW-based devices, reducing the contact resistance of SiNW-metal as much as possible is critically important. Here we report a simple fabrication approach for SiNW field effect transistors (FETs) with low contact resistances by employing a heavily doped carrier injection layer wrapped around SiNWs at the contact region. Both n- and p-type SiNW-FET devices with carrier injection layers were investigated, the contact resistances were one order smaller than those without carrier injection layers and only contribute less than 14.8% for n-type devices and 11.4% for p-type devices, respectively, to the total resistance. Such low contact resistance guarantees the device characteristics mainly from the channel region of SiNW-based devices.

  4. Au-Ag polymetallic mineralization within tectonically weak zones along the southwestern edge of the Colorado Plateau

    SciTech Connect

    Wenrich, K.J.; Silberman, M.L. )

    1993-04-01

    The Music Mountain mining district lies at the base of the Grand Wash Cliffs, a major fault-line scarp along the Grand Wash fault, which marks the SW margin of the Colorado Plateau. Nearly vertical Au-Ag polymetallic quartz veins parallel, and are in contact with, altered diabase and granite porphyry dikes that cut Proterozoic granite, schist, and gneiss. The gold-bearing veins range in thickness from an inch to several feet and contain significant amounts of sulfide minerals. Diabase dikes and quartz veins in the district and to the north consistently strike N42[degree]W to N57[degree]W, which is one of the most prevalent fracture orientation throughout NW Arizona. In the Gold Basin-Lost Basin districts to the north, the Au occurs in such pegmatite-quartz veins that strike NE. Thirty miles east along Diamond Creek, quartz veins and diabase dikes strike N45[degree]E and are associated with Au and Ag anomalies in stream-sediments and panned concentrates. To the west major Au-Ag polymetallic quartz veins of the Wallapai mining district show consistent strikes from N30[degree] to 60[degree]W. K-Ar ages of hydrothermal alterations of 4 NW oriented diabase dikes that have quartz veins along them, range from 935 [+-] 35 to 755 [+-] 21 Ma. Sericite from altered granite porphyry, adjacent to a mineralized vein, gave a K-Ar age of 72 [+-]2 Ma. All geochemical sites (within a 1,000 mi[sup 2] area) determined to be anomalous in Au lie within 2 mi of either the Grand Wash or Hurricane faults. The Hurricane and Grand Wash faults, major Precambrian fault zones that were reactivated in the Phanerozoic, appear to be good exploration targets for Au-rich quartz veins associated with pegmatite or diabase dikes, many of which may be buried beneath the thick alluvium of Hualapai Valley.

  5. Capacitive deionization of seawater effected by nano Ag and Ag@C on graphene.

    PubMed

    Cai, P-F; Su, C-J; Chang, W-T; Chang, F-C; Peng, C-Y; Sun, I-W; Wei, Y-L; Jou, C-J; Wang, H Paul

    2014-08-30

    Drinking water shortage has become worse in recent decades. A new capacitive deionization (CDI) method for increasing water supplies through the effective desalination of seawater has been developed. Silver as nano Ag and Ag@C which was prepared by carbonization of the Ag(+)-β-cyclodextrin complex at 573 K for 30 min can add the antimicrobial function into the CDI process. The Ag@C and Ag nanoparticles dispersed on reduced graphene oxide (Ag@C/rGO and nano Ag/rGO) were used as the CDI electrodes. The nano Ag/rGO and Ag@C/rGO electrodes can reduce the charging resistant, and enhance the electrosorption capability. Better CDI efficiencies with the nano Ag/rGO and Ag@C/rGO electrodes can therefore be obtained. When reversed the voltage, the electrodes can be recovered up to 90% within 5 min. This work presents the feasibility for the nano Ag and Ag@C on rGO electrodes applied in CDI process to produce drinking water from seawater or saline water.

  6. Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria.

    PubMed

    Hu, Chun; Lan, Yongqing; Qu, Jiuhui; Hu, Xuexiang; Wang, Aimin

    2006-03-01

    Ag/AgBr/TiO2 was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (lambda>420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag0 in the structure of all samples before and after reaction, and Ag0 species scavenged hVB+ and then trapped eCB- in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H2O2 formation revealed that *OH and O2*- were formed in visible light irradiated aqueous Ag/AgBr/TiO2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag0/TiO2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO2 under visible light irradiation are illustrated and discussed. PMID:16509698

  7. Capacitive deionization of seawater effected by nano Ag and Ag@C on graphene.

    PubMed

    Cai, P-F; Su, C-J; Chang, W-T; Chang, F-C; Peng, C-Y; Sun, I-W; Wei, Y-L; Jou, C-J; Wang, H Paul

    2014-08-30

    Drinking water shortage has become worse in recent decades. A new capacitive deionization (CDI) method for increasing water supplies through the effective desalination of seawater has been developed. Silver as nano Ag and Ag@C which was prepared by carbonization of the Ag(+)-β-cyclodextrin complex at 573 K for 30 min can add the antimicrobial function into the CDI process. The Ag@C and Ag nanoparticles dispersed on reduced graphene oxide (Ag@C/rGO and nano Ag/rGO) were used as the CDI electrodes. The nano Ag/rGO and Ag@C/rGO electrodes can reduce the charging resistant, and enhance the electrosorption capability. Better CDI efficiencies with the nano Ag/rGO and Ag@C/rGO electrodes can therefore be obtained. When reversed the voltage, the electrodes can be recovered up to 90% within 5 min. This work presents the feasibility for the nano Ag and Ag@C on rGO electrodes applied in CDI process to produce drinking water from seawater or saline water. PMID:24928455

  8. A multidisciplinary geomatics approach to morphometric and morphotectonic analysis of the Cannobino Basin (Piemonte Region, NW-Italy).

    NASA Astrophysics Data System (ADS)

    Bacenetti, Marco; Ghiraldi, Luca; Giardino, Marco

    2014-05-01

    The paper presents an integrated multidisciplinary approach to the morphometric and morphotectonic characterization of the Cannobino Basin (Piemonte Region, NW-Italy). The basin is drained by the Cannobino river; in its first 8 km, it flows SE to NW along a wide valley characterized by glacial landforms; thereafter it suddenly turns South assuming a W to E direction, by flowing in a deeply entrenched valley to the intermontane basin of the Maggiore Lake. This area belongs to the Lepontine Alps, which from the geological point of view belong to the Southern Alps. His Hercynian basement is divided in two units: Ivrea-Verbano Zone (IVZ) and Serie dei Laghi (SDL). The IVZ outcrops in the northern sector of the basin, while the SDL outcrops in the southern and central sector. They separated by the Cossato-Mergozzo-Brissago (CMB) and Pogallo lines (PL). These major discontinuities and the neoctonic activity of their shear zones possibly control Quaternary evolution of the alpine relief. Detailed studies of the area are needed for understanding possible interactions of neotectonic activity, fluvial/glacial erosional/depositional processes and slope dynamics. Our focus is on drainage basin characteristics and its evolutionary stages in response to local and regional base level changes and to differential rock uplift. GIS methodologies combined with DEMs analyses are among the most common geomatics approaches to geomorphology. Based on this framework, an evaluation of the geomorphometric characteristic of the Cannobino Basin has been carried out by using an aerial LIDAR DEM (5x5 meters, Regione Piemonte, 2009). The workflow followed for calculating the geomorphic indexes can be summarized in different steps: i) drainage network extraction and hierarchization; ii) lineament features digitalization and interpretation; iii) azimuthal distribution of drainage pattern; iv) DEM analysis and evaluation of linear, areal indexes and SWAT profile. The multidisciplinary and innovative

  9. Facile synthesis of S-Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

    2016-06-01

    A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S-Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70-160 nm and lengths of 200-360 nm. X-ray diffraction of the S-Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S-Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S-Ag nanocomposites with diameters of 10-40 nm were obtained. The formation mechanism of the S-Ag nanocomposites was studied by designing a series of experiments using ultraviolet-visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S-Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S-Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

  10. Facile synthesis of S–Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

    2016-06-01

    A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S–Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70–160 nm and lengths of 200–360 nm. X-ray diffraction of the S–Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S–Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S–Ag nanocomposites with diameters of 10–40 nm were obtained. The formation mechanism of the S–Ag nanocomposites was studied by designing a series of experiments using ultraviolet–visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S–Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S–Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

  11. Short Communication: Reassessing the Origin of the HIV-1 CRF02_AG Lineages Circulating in Brazil.

    PubMed

    Delatorre, Edson; Velasco-De-Castro, Carlos A; Pilotto, José H; Couto-Fernandez, José Carlos; Bello, Gonzalo; Morgado, Mariza G

    2015-12-01

    HIV-1 CRF02_AG is responsible for at least 8% of the HIV-1 infections worldwide and is distributed mainly in West Africa. CRF02_AG has recently been reported in countries where it is not native, including Brazil. In a previous study including 10 CRF02_AG Brazilian samples, we found at least four independent introductions and two autochthonous transmission networks of this clade in Brazil. As more CRF02_AG samples have been identified in Brazil, we performed a new phylogeographic analysis using a larger dataset than before. A total of 20 Brazilian (18 from Rio de Janeiro and two from São Paulo) and 1,485 African HIV-1 CRF02_AG pol sequences were analyzed using maximum likelihood (ML). The ML tree showed that the Brazilian sequences were distributed in five different lineages. The Bayesian phylogeographic analysis of the Brazilian and their most closely related African sequences (n = 212) placed the origin of all Brazilian lineages in West Africa, probably Ghana, Senegal, and Nigeria. Two monophyletic clades were identified, comprising only sequences from Rio de Janeiro, and their date of origin was estimated at around 1985 (95% highest posterior density: 1979-1992). These results support the existence of at least five independent introductions of the CRF02_AG lineage from West Africa into Brazil and further indicate that at least two of these lineages have been locally disseminated in the Rio de Janeiro state over the past 30 years.

  12. UV irradiated PVA-Ag nanocomposites for optical applications

    NASA Astrophysics Data System (ADS)

    Chahal, Rishi Pal; Mahendia, Suman; Tomar, A. K.; Kumar, Shyam

    2015-07-01

    The present paper is focused on the in-situ prepared Poly (vinyl alcohol)-Silver (PVA-Ag) nanocomposites and tailoring their optical properties by means of UV irradiation in such a way that these can be used for anti-reflective coatings and bandpass filters. The reflectance from these irradiated nanocomposites has been found to decrease leading to the increase in refractive index (RI), with increasing UV exposure time, in the entire visible region. Decrease in optical energy gap of PVA film from 4.92 to 4.57 eV on doping with Ag nanoparticles has been observed which reduces further to 4.1 eV on exposure to UV radiations for 300 min. This decrease in optical energy gap can be correlated to the formation of charge transfer complexes within the base polymer network on embedding Ag nanoparticles, which further enhances with increasing exposure time. Such complexes may also be responsible for increased molecular density of the composite films which corresponds to decrease in reflectance corroborating the observed results.

  13. Ethnoveterinary plant remedies used by Nu people in NW Yunnan of China

    PubMed Central

    2010-01-01

    Background Nu people are the least populous ethnic group in Yunnan Province of China and most are distributed in Gongshan County, NW Yunnan. Animal production plays an important role in Nu livelihoods and the Nu people have abundant traditional knowledge of animal management and ethnoveterinary practices. This study documents the animal diseases, ethnoveterinary plant remedies and related traditional knowledge in three Nu villages of Gongshan County. Methods This study was carried out in three Nu villages of Gongshan County between July 2009 and February 2010. Data was obtained through the use of semi-structured questionnaires, field observation and PRA tools. A total of 60 Nu respondents (34 men and 26 women) provided information on animal ailments and ethnoveterinary plant medicines used for Nu livestock production. Information on traditional ethnoveterinary medicine knowledge and choice of treatment providers was also obtained. Results Thirty-five animal conditions were identified in the surveyed area. The major and most common animal diseases among livestock were skin conditions, diarrhea, heat, fevers, colds, and parasites. Most ailments occurred between June and August. The ethnoveterinary medicinal use of 45 plant species was documented. Most medicinal species (86.7%) were collected from the wild. The most frequently used plant parts were whole plants (35.6%), followed by roots (22.2%). The most important medicinal plant species were Saussurea costus (Falc.) Lipech. (UV = 0.67), Senecio scandens Buch.-Ham.ex D.Don (UV = 0.67), Plantago depressa Willd. (UV = 0.63), Rubus corchorifolius L. f. (UV = 0.62), Bupleurum yunnanense Franch. (UV = 0.60), and Polygonum paleaceum Wall. (UV = 0.60). Animal diseases treated with the highest number of ethnoveterinary plant remedies were diarrhea (16 plant species), heat, fever, colds (11 plant species), retained afterbirth (11 plant species), and skin conditions and sores (11 plant species). Many Nu villagers (52

  14. Geology and geochemistry of the shear-hosted Julie gold deposit, NW Ghana

    NASA Astrophysics Data System (ADS)

    Amponsah, Prince Ofori; Salvi, Stefano; Béziat, Didier; Siebenaller, Luc; Baratoux, Lenka; Jessell, Mark W.

    2015-12-01

    The Leo Man Craton in West Africa is host to numerous economic gold deposits. If some regions, such as the SW of Ghana, are well known for world-class mineralizations and have been extensively studied, gold occurrences elsewhere in the craton have been discovered only in the last half a century or so, and very little is known about them. The Julie gold deposit, located in the Paleoproterozoic Birimian terrane of NW Ghana, is one such case. This deposit is hosted in a series of granitoid intrusives of TTG composition, and consists of a network of deformed, boudinaged quartz lodes (A-type veins) contained within an early DJ1 E-W trending shear zone with dextral characteristics. A conjugate set of veins (C-type) perpendicular to the A-type veins contains low grade mineralization. The main ore zone defines a lenticular corridor about 20-50 m in width and about 3.5 km along strike, trending E-W and dipping between 30 and 60°N. The corridor is strongly altered, by an assemblage of sericite + quartz + ankerite + calcite + tourmaline + pyrite. This is surrounded by a second alteration assemblage, consisting of albite + sericite + calcite + chlorite + pyrite + rutile, which marks a lateral alteration that fades into the unaltered rock. Mass balance calculations show that during alteration overall mass was conserved and elemental transfer is generally consistent with sulfidation, sericitization and carbonatization of the host TTG. Gold is closely associated with pyrite, which occurs as disseminated grains in the veins and in the host rock, within the mineralized corridor. SEM imagery and LA-ICP-MS analyses of pyrites indicate that in A-type veins gold is associated with bismuth, tellurium, lead and silver, while in C-type veins it is mostly associated with silver. Pyrites in A-type veins contain gold as inclusions and as free gold on its edges and fractures, while pyrites from C-type veins contains mostly free gold. Primary and pseudosecondary fluid inclusions from both

  15. Hybridization of granitic magmas in the source: The origin of the Karakoram Batholith, Ladakh, NW India

    NASA Astrophysics Data System (ADS)

    Reichardt, H.; Weinberg, R. F.; Andersson, U. B.; Fanning, C. M.

    2010-05-01

    Many magmatic bodies have a hybrid isotopic signature suggesting that somewhere during genesis, transport and emplacement, magmas assimilated other rocks or mixed with other magmas. Where and how hybridization takes place is seldom documented. Here, we investigate a magmatic system in the Eastern Karakoram, Ladakh, NW India, comprising an anatectic zone, and a network of sheets, stocks and plutons exposed in the Pangong Metamorphic Complex within the Karakoram Shear Zone, as well as the Karakoram Batholith. These granitic rocks have an isotopic signature indicative of a mixture between mantle and crustal sources. In the anatectic region, calc-alkaline granitoids and their meta-sedimentary country rocks underwent water-fluxed partial melting at upper amphibolite facies between 20 and 14 Ma ago. Anatexis gave rise to leucosomes and intrusive rocks that have a range in composition from leucotonalite to leucogranite. Those related to the partial melting of calc-alkaline rocks contain hornblende, whereas those related to Bt-psammites contain two micas ± garnet. Leucosomes rooting in different source rocks merge with each other and homogenize as they link up to form a hierarchy of magma channels, feeding into stocks, plutons and ultimately into the Karakoram Batholith. This interpretation is supported by Sr and Nd isotopes. Initial 87Sr/ 86Sr and ɛNd values are distinct for each of the magma protoliths in the anatectic zone and for the magmatic products. Calc-alkaline granitoids have initial 87Sr/ 86Sr = 0.7042 to 0.7077 and ɛNd = + 0.6 to + 2.4, indicative of a slightly depleted mantle source region. This is in contrast to the meta-sedimentary rocks that yield initial 87Sr/ 86Sr = 0.7115 to 0.7161 and ɛNd = - 10.0 to - 9.6, suggesting a stronger crustal component. Leucogranitic rocks, including a variety of leucosomes in the anatectic zone and samples from the Karakoram Batholith, yield intermediate values of initial 87Sr/ 86Sr = 0.7076 to 0.7121 and ɛNd = - 3.6 to

  16. AgI/Ag{sub 3}PO{sub 4} hybrids with highly efficient visible-light driven photocatalytic activity

    SciTech Connect

    Katsumata, Hideyuki; Hayashi, Takahiro; Taniguchi, Masanao; Suzuki, Tohru; Kaneco, Satoshi

    2015-03-15

    Highlights: • AgI/Ag{sub 3}PO{sub 4} hybrid was prepared via an in situ anion-exchange method. • AgI/Ag{sub 3}PO{sub 4} displays the excellent photocatalytic activity under visible light. • AgI/Ag{sub 3}PO{sub 4} readily transforms to be Ag@AgI/Ag{sub 3}PO{sub 4} system. • h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization over AgI/Ag{sub 3}PO{sub 4}. • The activity enhancement is ascribed to a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI. - Abstract: Highly efficient visible-light-driven AgI/Ag{sub 3}PO{sub 4} hybrid photocatalysts with different mole ratios of AgI were prepared via an in situ anion-exchange method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) technique. Under visible light irradiation (>420 nm), the AgI/Ag{sub 3}PO{sub 4} photocatalysts displayed the higher photocatalytic activity than pure Ag{sub 3}PO{sub 4} and AgI for the decolorization of acid orange 7 (AO 7). Among the hybrid photocatalysts, AgI/Ag{sub 3}PO{sub 4} with 80% of AgI exhibited the highest photocatalytic activity for the decolorization of AO 7. X-ray photoelectron spectroscopy (XPS) results revealed that AgI/Ag{sub 3}PO{sub 4} readily transformed to be Ag@AgI/Ag{sub 3}PO{sub 4} system while the photocatalytic activity of AgI/Ag{sub 3}PO{sub 4} remained after 5 recycling runs. In addition, the quenching effects of different scavengers displayed that the reactive h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization. The photocatalytic activity enhancement of AgI/Ag{sub 3}PO{sub 4} hybrids can be ascribed to the efficient separation of electron–hole pairs through a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI, in which Ag nanoparticles act as the charge separation center.

  17. Fate of zinc and silver engineered nanoparticles in sewerage networks.

    PubMed

    Brunetti, Gianluca; Donner, Erica; Laera, Giuseppe; Sekine, Ryo; Scheckel, Kirk G; Khaksar, Maryam; Vasilev, Krasimir; De Mastro, Giuseppe; Lombi, Enzo

    2015-06-15

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the field using recently developed nanoparticle in situ deployment devices (nIDDs) which were exposed directly to sewerage network conditions by immersing them into a municipal wastewater network trunk sewer and then retrieving them for XAS analysis.

  18. Fate of zinc and silver engineered nanoparticles in sewerage networks.

    PubMed

    Brunetti, Gianluca; Donner, Erica; Laera, Giuseppe; Sekine, Ryo; Scheckel, Kirk G; Khaksar, Maryam; Vasilev, Krasimir; De Mastro, Giuseppe; Lombi, Enzo

    2015-06-15

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the field using recently developed nanoparticle in situ deployment devices (nIDDs) which were exposed directly to sewerage network conditions by immersing them into a municipal wastewater network trunk sewer and then retrieving them for XAS analysis. PMID:25841090

  19. Visible-light-driven photocatalysts Ag/AgCl dispersed on mesoporous Al2O3 with enhanced photocatalytic performance.

    PubMed

    Feng, Zhouzhou; Yu, Jiajie; Sun, Dongping; Wang, Tianhe

    2016-10-15

    In this paper, Ag/AgCl and Ag/AgCl/Al2O3 photocatalysts were synthesized via a precipitation reaction between NaCl and CH3COOAg or Ag(NH3)2NO3, wherein Ag/AgCl was immobilized into mesoporous Al2O3 medium. The Ag/AgCl-based nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra, and so on. The photocatalysts displayed excellent photocatalytic activity for the degradations of methyl orange (MO) and methylene blue (MB) pollutants under visible light irradiation. The Ag/AgCl(CH3COOAg)/Al2O3 sample exhibited the best photocatalytic performance, degrading 99% MO after 9min of irradiation, which was 1.1 times, 1.22 times and 1.65 times higher than that of Ag/AgCl(Ag(NH3)2NO3)/Al2O3, Ag/AgCl(CH3COOAg) and Ag/AgCl(Ag(NH3)2NO3) photocatalyst, respectively. Meanwhile, Ag/AgCl(CH3COOAg)/Al2O3 also showed excellent capability of MB degradation. Compared to the data reported for Ag/AgCl/TiO2, the Ag/AgCl/Al2O3 prepared in this work exhibited a good performance for the degradation of methyl orange (MO). The results suggest that the dispersion of Ag/AgCl on mesoporous Al2O3 strongly affected their photocatalytic activities. O2(-), OH radicals and Cl(0) atoms are main active species during photocatalysis. PMID:27442145

  20. Excitons in AgI-BASED-GLASSES and -

    NASA Astrophysics Data System (ADS)

    Fujishiro, Fumito; Mochizuki, Shosuke

    2007-01-01

    We summarize our recent optical studies on different pristine AgI films, different AgI-based glasses and different AgI-oxide fine particle composites. The exciton spectra of these specimens give useful information about the ionic and electronic structures at the AgI/glass and AgI/oxide particle interfaces.

  1. The cardiovascular response to the AGS

    NASA Technical Reports Server (NTRS)

    Cardus, David; Mctaggart, Wesley G.

    1993-01-01

    This paper reports the preliminary results of experiments on human subjects conducted to study the cardiovascular response to various g-levels and exposure times using an artificial gravity simulator (AGS). The AGS is a short arm centrifuge consisting of a turntable, a traction system, a platform and four beds. Data collection hardware is part of the communication system. The AGS provides a steep acceleration gradient in subjects in the supine position.

  2. 13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW of Amory. St. Louis and San Francisco RR bridge. Steam locomotive and coal train cross bridge on 10 August 1921. Credit: Owned by Jack Donnell, Columbus, Ms., photographer. Copied by Sarcone Photography, Columbus, Ms. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  3. Mineralogical Characteristics of Specimens of a Pseudometeorite ``Fall'' from NW Iran

    NASA Astrophysics Data System (ADS)

    Pourkhorsandi, H.; Mirnejad, H.

    2014-09-01

    In the early hours of October 22, 2011, people of Khameneh town in NW of Iran, noticed sounds of some colliding objects to home roofs and yard floors. Mineralogical investigations revealed the terrestrial and man-made origin of these stony objects.

  4. Neodymium isotope evolution of NW Tethyan upper ocean waters throughout the Cretaceous

    NASA Astrophysics Data System (ADS)

    Pucéat, Emmanuelle; Lécuyer, Christophe; Reisberg, Laurie

    2005-08-01

    Neodymium isotope compositions of twenty-four fish teeth, nineteen from the NW Tethys and five from different locations within the Tethys, are interpreted to reflect the evolution of Tethyan upper ocean water composition during the Cretaceous and used to track changes in erosional inputs to the NW Tethys and in oceanic circulation throughout the Cretaceous. The rather high ɛNd (up to - 7.6) of the NW Tethyan upper ocean waters recorded from the Late Berriasian to the Early Aptian and the absence of negative excursions during this interval support the presence of a permanent westward flowing Tethys Circumglobal Current (TCC). This implies that temperature variations during this time period, inferred from the oxygen isotope analysis of fish tooth enamel, were not driven by changes in surface oceanic currents, but rather by global climatic changes. The results presented here represent a significant advance over previously published Cretaceous seawater Nd isotope records. Our newly acquired data now allow the identification of two stages of low ɛNd values in the NW Tethys, during the Early Albian-Middle Albian interval (down to - 10) and the Santonian-Early Campanian (down to - 11.4), which alternate with two stages of higher ɛNd values (up to - 9) during the Late Albian-Turonian interval and the Maastrichtian. Used in conjunction with the oxygen isotope record, the fluctuations of ɛNd values can be related to major climatic, oceanographic, and tectonic events that appeared in the western Tethyan domain.

  5. 23. Building N9; 3/4 view, looking NW at loading dock. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Building N-9; 3/4 view, looking NW at loading dock. The view also shows the relationship of the blast barricades to the building. (Ryan) - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  6. 4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W WING, SHOWING THE PILASTERS, TERRA COTTA PANELS, AND THE EGYPTIAN MOTIF DECORATIVE CORNICE ELEMENTS; LOOKING ENE. (Harms) - Veterans Administration Medical Center, Building No. 1, Old State Route 13 West, Marion, Williamson County, IL

  7. Airborne radioactivity Survey of part of Saratoga NW quadrangle, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 133 square miles of Saratoga NW quadrangle, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  8. SrAgZn and EuAgZn with KHg{sub 2}-type structure—Structure, magnetic properties, and {sup 151}Eu Mössbauer spectroscopy

    SciTech Connect

    Gerke, Birgit; Rodewald, Ute Ch.; Niehaus, Oliver; Pöttgen, Rainer

    2013-07-15

    Samples of SrAgZn and EuAgZn were synthesized by reaction of the elements in sealed tantalum crucibles. Both structures were refined on the basis of single crystal X-ray diffractometer data: KHg{sub 2}-type, Imma, a=476.7(1), b=780.9(2), c=810.1(2) pm, R{sub 1}/wR{sub 2}=0.0189/0.0119, 381 F² values for SrAg{sub 1.12}Zn{sub 0.88} and a=474.43(9), b=760.8(2), c=799.0(2) pm, R{sub 1}/wR{sub 2}=0.0226/0.0483, 370 F² values for EuAg{sub 1.17}Zn{sub 0.83} with 13 variables per refinement. Silver and zinc are randomly distributed on the Hg position and build up three-dimensional networks. EuAgZn shows ferromagnetic ordering at 29(1) K. In the temperature range from 75 to 300 K the sample shows Curie–Weiss behaviour with μ{sub eff}=7.87(1) μ{sub B}/Eu atom and θ{sub P}=37.1(1) K, indicating divalent europium. {sup 151}Eu Mössbauer spectroscopic measurements confirmed the divalent state with an isomer shift of −9.31 mm/s at 78 K. Temperature dependent {sup 151}Eu data show first magnetic hyperfine field splitting at 25 K and a saturated magnetization of 17 T at 5.2 K. The temperature dependence can be described by an S=7/2 Brillouin function. - Graphical abstract: The near neighbor coordination of the strontium and europium atoms in SrAg{sub 1.12}Zn{sub 0.88}, EuAg{sub 1.17}Zn{sub 0.83}, and EuAuZn. - Highlights: • Synthesis of new intermetallic zinc compounds SrAgZn and EuAgZn. • Ferromagnetic ordering of EuAgZn at 29 K. • Magnetic hyperfine field splitting in the {sup 151}Eu Mössbauer spectrum.

  9. AgRP Neurons Regulate Bone Mass.

    PubMed

    Kim, Jae Geun; Sun, Ben-Hua; Dietrich, Marcelo O; Koch, Marco; Yao, Gang-Qing; Diano, Sabrina; Insogna, Karl; Horvath, Tamas L

    2015-10-01

    The hypothalamus has been implicated in skeletal metabolism. Whether hunger-promoting neurons of the arcuate nucleus impact the bone is not known. We generated multiple lines of mice to affect AgRP neuronal circuit integrity. We found that mice with Ucp2 gene deletion, in which AgRP neuronal function was impaired, were osteopenic. This phenotype was rescued by cell-selective reactivation of Ucp2 in AgRP neurons. When the AgRP circuitry was impaired by early postnatal deletion of AgRP neurons or by cell autonomous deletion of Sirt1 (AgRP-Sirt1(-/-)), mice also developed reduced bone mass. No impact of leptin receptor deletion in AgRP neurons was found on bone homeostasis. Suppression of sympathetic tone in AgRP-Sirt1(-/-) mice reversed osteopenia in transgenic animals. Taken together, these observations establish a significant regulatory role for AgRP neurons in skeletal bone metabolism independent of leptin action. PMID:26411686

  10. Multiple Partial Siberian Snakes in the AGS

    SciTech Connect

    Takano, J.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. J.; Glenn, J. W.; Huang, H.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.; Hattori, T.; Lin, F.

    2007-06-13

    Polarized protons are accelerated up to 24.3 GeV in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). To accelerate the beam with preserving the polarization, two different types of helical dipole partial Siberian snake have been installed to the AGS. One is a superconducting magnet (Cold Snake, CSNK), and the other is a normal conducting one (Warm Snake, WSNK). With these snake magnets, the polarization at the AGS extraction achieved 65%. However, the AGS has spin mismatches at the injection and extraction. This description shows calculated results to have better spin matching with using two or three snakes.

  11. Focal mechanisms of the 2000 swarm in NW-Bohemia/Vogtland anything new in the seismotectonic picture of the area?

    NASA Astrophysics Data System (ADS)

    Horalek, J.; Šílený, J.; Fischer, T.

    2003-04-01

    The Nový Kostel area witnessed the most intensive earthquake swarms of the whole NW-Bohemia/Vogtland swarm region. The Ml = 4.6 swarm of 1985/86, which was the most intensive swarm in the area, showed focal mechanisms compatible with the main fault orientation. By contrast, the recent results of the analysis of the 1997 swarm (Ml = 3) have shown that two types of faulting took place. One of them beards a significant isotropic component in its moment tensors, what may indicate activity of fluids during the rupture process. The events of the most recent 2000 swarm (ML=3.2) lasting for three months were confined to a thin, almost planar, and steeply dipping focal area. The existing, preliminary focal mechanisms of the 2000 swarm show a simple pattern, which is again compatible with the main fault orientation. We made a detailed analysis of swarm seismograms recorded by WEBNET and other local networks in the area to determine precisely the focal mechanisms of all larger events (ML>1.8). We try to find any regularities in the occurrence of different fault mechanisms during the swarm development and across the fault volume. Full moment tensors have been determined for selected events and the rate of shear and non-shear components was critically evaluated. The results are interpreted according to focal mechanisms of the previous swarms occurring in the area and to its seismotectonic regime.

  12. Toxicokinetics of Ag in the terrestrial isopod Porcellionides pruinosus exposed to Ag NPs and AgNO₃ via soil and food.

    PubMed

    Tourinho, Paula S; van Gestel, Cornelis A M; Morgan, A John; Kille, Peter; Svendsen, Claus; Jurkschat, Kerstin; Mosselmans, J Fred W; Soares, Amadeu M V M; Loureiro, Susana

    2016-03-01

    Silver nanoparticles (Ag NPs) have been used in numerous consumer products and may enter the soil through the land application of biosolids. However, little is known about the relationship between Ag NP exposure and their bioavailability for soil organisms. This study aims at comparing the uptake and elimination kinetics of Ag upon exposures to different Ag forms (NPs and ionic Ag (as AgNO3)) in the isopod Porcellionides pruinosus. Isopods were exposed to contaminated Lufa 2.2 soil or alder leaves as food. Uptake and elimination rate constants for soil exposure did not significantly differ between Ag NPs and ionic Ag at 30 and 60 mg Ag/kg. For dietary exposure, the uptake rate constant was up to 5 times higher for Ag NPs than for AgNO3, but this was related to feeding activity and exposure concentrations, while no difference in the elimination rate constants was found. When comparing both routes, dietary exposure resulted in lower Ag uptake rate constants but elimination rate constants did not differ. A fast Ag uptake was observed from both routes and most of the Ag taken up seemed not to be eliminated. Synchrotron X-ray fluorescence showed Ag in the S-cells of the hepatopancreas, thus supporting the observations from the kinetic experiment (i.e. low elimination). In addition, our results show that isopods have an extremely high Ag accumulation capacity, suggesting the presence of an efficient Ag storage compartment. PMID:26581474

  13. Characterization of the intermediate-range order in new superionic conducting AgI-Ag2S-AgPO3 glasses by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Kartini, E.; Kennedy, S. J.; Itoh, K.; Fukunaga, T.; Suminta, S.; Kamiyama, T.

    Superionic conducting glasses are of considerable technological interest because of their use in batteries, sensors, and displays. We have investigated the new ternary systems AgI-Ag2S-AgPO3 where the ratio AgI:Ag2S is 1:1. The system (AgI)x(Ag2S)x(AgPO3)1-2x, for a AgI+Ag2S fraction less than 82mol%, yields glasses. We have used a neutron-diffraction technique to obtain the total scattering structure factor S(Q) of this system at room temperature by using the HIT spectrometer at the High Energy Accelerator (KEK), Tsukuba, Japan. As for AgI-AgPO3 glasses, S(Q) shows a peak at anomalously low Q in the range from 0.6 to 0.9 Å-1. This peak is not observed in the corresponding glass Ag2S-AgPO3 or pure AgPO3. The peak depends strongly on the dopant salt. Its intensity increases as the amount of (AgI+Ag2S) increases and its position shifts to lower Q, while the number density of the glasses decreases with x. This peak can be associated with an intermediate structure of particles lying inside a continuous host with the characteristic length between 5 and 10 Å [1].

  14. Toxicokinetics of Ag in the terrestrial isopod Porcellionides pruinosus exposed to Ag NPs and AgNO₃ via soil and food.

    PubMed

    Tourinho, Paula S; van Gestel, Cornelis A M; Morgan, A John; Kille, Peter; Svendsen, Claus; Jurkschat, Kerstin; Mosselmans, J Fred W; Soares, Amadeu M V M; Loureiro, Susana

    2016-03-01

    Silver nanoparticles (Ag NPs) have been used in numerous consumer products and may enter the soil through the land application of biosolids. However, little is known about the relationship between Ag NP exposure and their bioavailability for soil organisms. This study aims at comparing the uptake and elimination kinetics of Ag upon exposures to different Ag forms (NPs and ionic Ag (as AgNO3)) in the isopod Porcellionides pruinosus. Isopods were exposed to contaminated Lufa 2.2 soil or alder leaves as food. Uptake and elimination rate constants for soil exposure did not significantly differ between Ag NPs and ionic Ag at 30 and 60 mg Ag/kg. For dietary exposure, the uptake rate constant was up to 5 times higher for Ag NPs than for AgNO3, but this was related to feeding activity and exposure concentrations, while no difference in the elimination rate constants was found. When comparing both routes, dietary exposure resulted in lower Ag uptake rate constants but elimination rate constants did not differ. A fast Ag uptake was observed from both routes and most of the Ag taken up seemed not to be eliminated. Synchrotron X-ray fluorescence showed Ag in the S-cells of the hepatopancreas, thus supporting the observations from the kinetic experiment (i.e. low elimination). In addition, our results show that isopods have an extremely high Ag accumulation capacity, suggesting the presence of an efficient Ag storage compartment.

  15. Evidence for surface Ag + complexes as the SERS-active sites on Ag electrodes

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Kawanami, O.; Honda, K.; Pettinger, B.

    1983-12-01

    Evidence is given that SERS-active sites at Ag electrodes are associated with Ag + ions, forming sparingly soluble surface complexes with ligands such as pyridine molecules and halide ions. Such surface Ag + complexes contribute a factor of >800 to the overall (10 7-fold) enhancement, possibly via a resonance Raman effect.

  16. Single step electrochemical synthesis of hydrophilic/hydrophobic Ag5 and Ag6 blue luminescent clusters.

    PubMed

    Santiago González, Beatriz; Blanco, M C; López-Quintela, M Arturo

    2012-12-21

    Well-defined Ag(5) and Ag(6) dodecanethiol/tetrabutyl ammonium-protected clusters were prepared by a one-pot electrochemical method. Ag clusters show bright and photostable emissions. The presence of a dual capping renders the silver clusters soluble in both organic and aqueous solvents.

  17. 78 FR 30965 - AG Valley Railroad, LLC-Operation Exemption-Ag Valley Holdings, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... Surface Transportation Board AG Valley Railroad, LLC--Operation Exemption--Ag Valley Holdings, LLC AG... original and 10 copies of all pleadings, referring to Docket No. FD 35736, must be filed with the Surface.... Board decisions and notices are available on our Web site at www.stb.dot.gov . Decided: May 20, 2013....

  18. A novel three-dimensional AgI coordination polymer based on mixed naphthalene-1,5-disulfonate and aminoacetate ligands.

    PubMed

    Wu, Hua; Lü, Xiao-Li; Lü, Bo; Dong, Chang-Xun; Wu, Mei-Sheng

    2013-08-01

    The three-dimensional coordination polymer poly[[bis(μ₃-2-aminoacetato)di-μ-aqua-μ₃-(naphthalene-1,5-disulfonato)-hexasilver(I)] dihydrate], {[Ag₆(C₁₀H₆O₆S₂)(C₂H₄NO₂)₄(H₂O)₂]·2H₂O}n, based on mixed naphthalene-1,5-disulfonate (L1) and 2-aminoacetate (L2) ligands, contains two Ag(I) centres (Ag1 and Ag4) in general positions, and another two (Ag2 and Ag3) on inversion centres. Ag1 is five-coordinated by three O atoms from one L1 anion, one L2 anion and one water molecule, one N atom from one L2 anion and one AgI cation in a distorted trigonal-bipyramidal coordination geometry. Ag2 is surrounded by four O atoms from two L2 anions and two water molecules, and two AgI cations in a slightly octahedral coordination geometry. Ag3 is four-coordinated by two O atoms from two L2 anions and two AgI cations in a slightly distorted square geometry, while Ag4 is also four-coordinated by two O atoms from one L1 and one L2 ligand, one N atom from another L2 anion, and one AgI cation, exhibiting a distorted tetrahedral coordination geometry. In the crystal structure, there are two one-dimensional chains nearly perpendicular to one another (interchain angle = 87.0°). The chains are connected by water molecules to give a two-dimensional layer, and the layers are further bridged by L1 anions to generate a novel three-dimensional framework. Moreover, hydrogen-bonding interactions consolidate the network.

  19. Progress with the AGS Booster

    SciTech Connect

    Weng, W.T.

    1988-01-01

    Rare K-decay, neutrino and heavy ion physics demands that a rapid- cycling high vacuum and high intensity Booster be built for the AGS at Brookhaven. For each mode of operation there are corresponding accelerator physics and design issues needing special attention. Problems pertinent to any single mode of operation have been encountered and solved before, but putting high intensity proton requirements and high vacuum heavy ion requirements into one machine demands careful design considerations and decisions. The lattice design and magnet characteristics will be briefly reviewed. Major design issues will be discussed and design choices explained. Finally, the construction status and schedule will be presented. 6 refs., 6 figs.

  20. Hypernuclear research at the AGS

    SciTech Connect

    Chrien, R.E.

    1984-01-01

    Although the field of hypernuclear research is over 30 years old, progress in exploring the detailed behavior of hypernuclei has been slow. This fact is due mainly to the technical problems of producing and studying these strange objects. Indeed each step in the improvement of technique has been accompanied by a breakthrough in our understanding of this fascinating subject. In this paper, the aim is to describe the evolution of hypernuclear research, stressing especially the contributions of the program based on the Brookhaven AGS. 23 references, 17 figures, 1 table.

  1. A 300-mV 220-nW event-driven ADC with real-time QRS detection for wearable ECG sensors.

    PubMed

    Zhang, Xiaoyang; Lian, Yong

    2014-12-01

    This paper presents an ultra-low-power event-driven analog-to-digital converter (ADC) with real-time QRS detection for wearable electrocardiogram (ECG) sensors in wireless body sensor network (WBSN) applications. Two QRS detection algorithms, pulse-triggered (PUT) and time-assisted PUT (t-PUT), are proposed based on the level-crossing events generated from the ADC. The PUT detector achieves 97.63% sensitivity and 97.33% positive prediction in simulation on the MIT-BIH Arrhythmia Database. The t-PUT improves the sensitivity and positive prediction to 97.76% and 98.59% respectively. Fabricated in 0.13 μm CMOS technology, the ADC with QRS detector consumes only 220 nW measured under 300 mV power supply, making it the first nanoWatt compact analog-to-information (A2I) converter with embedded QRS detector. PMID:25608283

  2. Synthesis and Optical Responses of Ag@Au/Ag@Au Double Shells

    NASA Astrophysics Data System (ADS)

    Li, Ying-Ying; Liu, Xiao-Li; Yang, Da-Jie; Hao, Zhong-Hua; Wang, Qu-Quan

    2015-02-01

    We synthesize hollow-structured Ag@Au nanoparticles with single porous shell and Ag@Au/Ag@Au double shells by using the galvanic replacement reaction and investigate their linear and nonlinear optical properties. Our results show that the surface plasmon resonance wavelength of the hollow porous nanoparticles could be easily tuned in a wide range in the visible and near infrared region by controlling the volume of HAuCl4. The nonlinear optical refraction of the double-shelled Ag@Au/Ag@Au nanoparticles is prominently enhanced by the plasmon resonance. Our findings may find applications in biosensors and nonlinear optical nanodevices.

  3. Photon emission intensities in the decay of 108mAg and 110mAg.

    PubMed

    Ferreux, L; Lépy, M-C; Bé, M-M; Isnard, H; Lourenço, V

    2014-05-01

    This study focuses on two radioisotopes of silver, (108m)Ag and (110m)Ag, characterized by a complex decay scheme. Each isotope has two disintegration modes, the isomeric transition leading to the daughter isotope ((108)Ag and (110)Ag, respectively) with a short half-life. The radioactive solution was obtained by neutron activation on silver powder enriched in (109)Ag. Gamma-spectrometry was carried out using a calibrated high purity germanium detector. The main relative photon emission intensities for both radionuclides were obtained and compared with previously published values.

  4. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    SciTech Connect

    Singh, Anamika; Dutta, Dimple P.; Ballal, A.; Tyagi, A.K.; Fulekar, M.H.

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  5. Effects of soil and dietary exposures to Ag nanoparticles and AgNO₃ in the terrestrial isopod Porcellionides pruinosus.

    PubMed

    Tourinho, Paula S; van Gestel, Cornelis A M; Jurkschat, Kerstin; Soares, Amadeu M V M; Loureiro, Susana

    2015-10-01

    The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ∼16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils.

  6. Toward a 3:1 frequency divider based on parametric oscillation using AgGaS(2) and PPLN crystals.

    PubMed

    Douillet, A; Zondy, J J; Yelisseyev, A; Lobanov, S; Isaenko, L

    2000-01-01

    Frequency divide-by-two (2:1) and divide-by-three (3:1) optical parametric oscillators (OPOs) are basic devices for the implementation of future accurate optical frequency division chains. We report our latest development toward a phase-locked 3:1 frequency division of a radiation at lambda(p) approximately 843 nm (355.9 THz), using doubly resonant oscillators (DROs) based on silver gallium sulfide (AgGaS(2 ) or AGS) and multigrating periodically poled lithium niobate (PPLN). Although stable single-mode pair operation is achievable without any active cavity length servo with the AGS-DRO, because of a strong passive thermal feedback servo, the PPLN-DRO requires an active intensity side-of-fringe locking servo to maintain long-term, single-mode pair operation. To overcome the limited idler output power (<1 mW) due to the weak mirror transmissivity at 2.53 mum, a CaF (2) Brewster-oriented plate was inserted in a longer-cavity PPLN-DRO as a variable output coupler. About 3 mW of idler wave is thus coupled outside the cavity, yielding 15 nW of doubled-idler. We obtained a 30 dB signal-to-noise ratio beatnote in a 100 kHz resolution bandwidth of a spectrum analyser. This beat signal will be used to phase-lock the divider. PMID:18238651

  7. Large incised channels on the Chukchi Shelf provide new constraints on onshore drainage: Implications for tectonic and climatic evolution of NW Alaska

    NASA Astrophysics Data System (ADS)

    Hill, J. C.; Driscoll, N. W.; Brigham-Grette, J.; Lundeen, Z.

    2003-12-01

    High resolution Chirp seismic data acquired onboard the USCGC Healy in September 2002 imaged large, incised channels across the Chukchi Shelf, offshore NW Alaska. The channels range from several meters to tens of kilometers in width and trend roughly NNW across the margin. Subbottom profiles across many of the channels display evidence for a marine transgression, with stratal geometries that suggest fluvial infill as well as marine. Piston cores taken within the channels show relatively coarse, well-sorted sand overlain by open marine muds. The level of discharge required to excavate the observed offshore channels is not consistent with the discharge observed from modern streams and rivers on the NW Alaskan margin. This appears to indicate that the offshore channels are misfit with the present day drainage. There are several ways to reconcile the very low, modern discharge and the huge offshore drainage networks observed in the Chirp data. One possibility is that there has been much greater climate variability than previously recognized, such that past discharge levels were much higher than the modern. Higher discharge levels require an increased moisture supply, either in the form of increased precipitation rates or released from storage in regional ice cover. Alternatively, several tectonic explanations may be invoked. Previous researchers have indicated that any channels on the Chukchi shelf should be related to modern drainage from the Hope Valley region. This would require the formation of Herald Bank, a bathymetric high that effectively acts as a modern drainage divide between Hope Valley and the outer Chukchi shelf, to post-date the channel incision. However, the stratal geometry observed in the Chirp subbottom profiles indicates that the underlying, Cretaceous, northward dipping strata were tilted prior to channel incision. Our preferred explanation is that tectonic deformation has altered onshore drainage patterns rather than offshore. In this scenario

  8. Long term monitoring system integrated in an elevational gradient in NW Argentina

    NASA Astrophysics Data System (ADS)

    Carilla, J.; Malizia, A.; Osinaga, O.; Blundo, C.; Grau, R.; Malizia, L.; Aráoz, E.

    2013-05-01

    Ecological trends and ranges of variability are poorly known in the tropical and subtropical Andes. Long term studies are powerful tools to detect the response of vegetation dynamics, biodiversity and hydrological cycle to these trends. We present a long term monitoring system in NW Argentinean mountains, including forest permanent plots at different elevations and high elevation grasslands, encompassing more than 3.000 m elevation range. Long term studies include: 1) 66 ha of mountain forest permanent plots along the Yungas elevational gradient from c. 400 to 2500 masl , and latitudinal gradient (22-28S) with 45 plots in mature forests and 28 in secondary forests originated in grazing, agriculture and selective logging. Some of these permanent plots have achieved 20 years of monitoring and all of them are included in the "Red de Bosques Andinos" a network created recently, together with c. 10 institutions and more than 130 (c. 120 ha) forest permanent plots from Argentina to Colombia Andes. 2) Two GLORIA (Global Observation Research Initiative in Alpine Environments) sites, above 4000 masl with more than 170 species recorded, including one re-measurement. This system is included in GLORIA network (www.gloria.ac.at) and in GLORIA Andes (http://www.condesan.org/gloria), and 3) more than 15 satellite monitored high Andean lakes and a wide extension of vegas (75800 ha in Argentinean puna). A digital database is being implemented to organize and provide access to the information generated by these three systems coordinated by the Instituto de Ecología Regional (http://www.iecologia.com.ar). These monitoring data are analyzed together with instrumental and dendrochronological data to describe the dynamics of these ecosystems over an area of 20 million hectares distributed between 22 and 28°S. Some of the most significant results to date include: 1) secondary mountain forests are expanding over grasslands and agriculture lands, and tend to converge toward mature forest

  9. Tribological properties of ag-based amphiphiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most ag-based materials are amphiphilic because they comprise polar and non-polar groups within the same molecule. One of the major categories of amphiphilic ag-based materials are seed oils, which are actively investigated as substitutes for petroleum in a wide variety of consumer and industrial a...

  10. AgRISTARS documents tracking list report

    NASA Technical Reports Server (NTRS)

    Hawkins, J. L.

    1983-01-01

    A quarterly listing of documents issued and placed in the AgRISTARS tracking system is provided. The technical publications are arranged by type of documents. The reference AgRISTARS document number, title and date of publication, the issuing organization, and the National Technical Information Service reference number is given.

  11. The AGS synchrotron with four helical magnets

    SciTech Connect

    Tsoupas N.; Huang, H.; Roser, T.; MacKay, W.W.; Trbojevic, D.

    2012-05-20

    The idea of using two partial helical magnets was applied successfully to the AGS synchrotron to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. The placement of four helical magnets in the AGS ring provides many advantages over the present setup of the AGS which uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides for a larger 'spin tune gap', which allows the vertical and horizontal tunes to be placed, and prevent the horizontal and vertical intrinsic spin resonances of the AGS to occur during the acceleration cycle. Although the same spin gap can be obtained with a single or two partial helices, the required high field strength of a single helix makes its use impractical, and that of the double helix rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare these results with the present setup of the AGS that uses two partial helical magnets.

  12. Recent hypernuclear research at the Brookhaven AGS

    SciTech Connect

    Chrien, R.E.

    1985-01-01

    Recent AGS experiments contributing to our knowledge of hypernuclei are reviewed. These experiments have suggested new areas of research on hypernuclei. With the proper beam line facilities, the AGS will be able to perform experiments in these areas and provide a transition to the future era of ''kaon factories''. 20 refs., 14 figs.

  13. Manipulation resolves non-trivial structure of corrole monolayer on Ag(111)

    NASA Astrophysics Data System (ADS)

    Tebi, Stefano; Aldahhak, Hazem; Serrano, Giulia; Schöfberger, Wolfgang; Rauls, Eva; Gero Schmidt, Wolf; Koch, Reinhold; Müllegger, Stefan

    2016-01-01

    Non-trivial arrangement of molecules within a molecular network complicates structure determination due to interdigitation, partial overlap, or stacking. We demonstrate that combined imaging and lateral manipulation with a scanning tunneling microscope resolves the intricate structure of a molecular network in two-dimensions in a straightforward manner. The network, formed by a monolayer of 5,10,15-tris(pentafluorophenyl)-corrole molecules on Ag(111), is manipulated for the first time with single-molecule precision. Our results reveal a shingle-like packing of partially overlapping corrole molecules. Density functional theory calculations support our findings.

  14. The Structure and Electrical Properties of the Ag2Se + Ga2Se3 + GeSe2 Glass System

    NASA Astrophysics Data System (ADS)

    Marple, Maxwell Adam Thomas

    Silver containing homogeneous chalcogenide glasses in the ternary system Ag2Se-Ga2Se3-GeSe2 (AGGS) are synthesized and their atomic structure-property relationships are investigated. Structural studies are carried out using Raman, 77Se, 71Ga, 69Ga, and 109Ag nuclear magnetic resonance (NMR) spectroscopy. The structure of these glasses consists primarily of a network of corner sharing (Ga/Ge)Se4/2 tetrahedra with a small fraction of homopolar Se-Se bonds. Compositional modification of the atomic structure follows the charge compensated network model developed in the literature for aluminosilicate glasses. Ag2Se acts as a network modifier, forming non-bridging Se in glasses with Ag/Ga >1, while Ga 2Se3 plays the role of a network intermediate similar to Al2O3 in oxide glasses. The network favors the formation of homopolar Ge-Ge bonding in glasses with Ag/Ga <1, to accommodate the Se deficiency brought by the incorporation of Ga2Se3 with Ga being tetrahedrally coordinated to Se. This structural model is consistent with the variation in the glass transition temperatures and molar volume. Electrical Impedance Spectroscopy (EIS) reveals the ionic conductivity of the AGGS glasses to be quite high at ambient temperature, reaching up to 10 --4 S/cm for glasses with the highest Ag content. Increasing Se deficiency with respect to stoichiometry can enhance the conductivity further to ˜3x10--4 S/cm . Transference number measurements using the electromotive force (EMF) method as well as variable temperature 109Ag NMR line shape studies indicate that the conductivity is predominantly ionic in nature and results from fast hopping dynamics of Ag ions. The high ionic conductivity can be related to a heavily modified structural network that results in a potential energy landscape with many suitable hopping sites for the Ag ions. These structural characteristics and electrical properties of the glasses in the AGGS system may guide in the development of next generation fast ion

  15. Label-Free Detection of Ag+ Based on Gold Nanoparticles and Ag+-Specific DNA.

    PubMed

    Pu, Wendan; Zhao, Zhao; Wu, Liping; Liu, Yue; Zhao, Huawen

    2015-08-01

    A sensitive label-free method was presented for the determination of silver ion (Ag+) in this paper. Cytosine-rich DNA (C-DNA) was used as Ag+ specific DNA. Without Ag+ in the solution, fluorescence of fluorescein (FAM) is quenched by C-DNA stabilized gold nanoparticles (AuNPs) in high salt environment. When Ag+ is present in the solution, however, Ag+-mediated cytosine-Ag+-cytosine (C-Ag+-C) base pairs induced the C-DNA folding into a hairpin structure, which can not stabilize AuNPs in high salt environment, thus causing AuNPs aggregation. After centrifugation to remove the aggregated AuNPs, the quenching ability of the supernatant for FAM is decreased and the fluorescence intensity of solution increases with increasing the Ag+ concentration. Due to the highly specific interaction of the C-DNA towards Ag+ and the strong fluorescent quenching ability of AuNPs for FAM, the method has high selectivity and sensitivity for Ag+. Under the optimal conditions, the fluorescence intensity at 515 nm increased linearly with the concentration of Ag+ ranging from 15 nM to 700 nM, and the detection limit was determined as 6 nM based on 3 σ/slope. This method is simple, sensitive, and may be applied to other detection systems by selecting the appropriate DNA sequences. PMID:26369112

  16. Raman scattering enhanced within the plasmonic gap between an isolated Ag triangular nanoplate and Ag film

    NASA Astrophysics Data System (ADS)

    Li, Kuanguo; Jiang, Kang; Zhang, Lan; Wang, Yong; Mao, Lei; Zeng, Jie; Lu, Yonghua; Wang, Pei

    2016-04-01

    Enhanced electromagnetic field in the tiny gaps between metallic nanostructures holds great promise in optical applications. Herein, we report novel out-of-plane nanogaps composed of micrometer-sized Ag triangular nanoplates (AgTN) on Ag films. Notably, the new coupled plasmonic structure can dramatically enhance the surface-enhanced Raman scattering (SERS) by visible laser excitation, although the micrometer-sized AgTN has localized plasmon resonance at infrared wavelength. This enhancement is derived from the gap plasmon polariton between the AgTN and Ag film, which is excited via the antenna effect of the corner and edge of the AgTN. Systematic SERS studies indicated that the plasmon enhancement was on the order of corner > edge > face. These results were further verified by theoretical simulations. Our device paves the way for rational design of sensitive SERS substrates by judiciously choosing appropriate nanoparticles and optimizing the gap distance.

  17. Atomic-level observation of Ag-ion hopping motion in AgI

    NASA Astrophysics Data System (ADS)

    Sato, W.; Komatsuda, S.; Mizuuchi, R.; Irioka, N.; Kawata, S.; Ohkubo, Y.

    2015-04-01

    Applicability of the 111mCd(→111Cd) and 111In(→111Cd) probes to the study of dynamics in polycrystalline silver iodide (AgI) was examined by means of the time-differential perturbed angular correlation technique. It was found that the 111mCd(→111Cd) probe occupies a unique site in γ-AgI and exhibits nuclear relaxation caused by dynamic perturbation arising from Ag + hopping motion in α-AgI; while the residential sites of 111In(→111Cd) vary, suggesting that 111In ions can not settle themselves in a fixed site in the AgI crystal structure. We here demonstrate that 111mCd(→111Cd) can be a potential nucleus to probe the Ag +-ion dynamic motion in α-AgI.

  18. AgPO2F2 and Ag9(PO2F2)14: the first Ag(i) and Ag(i)/Ag(ii) difluorophosphates with complex crystal structures.

    PubMed

    Malinowski, Przemysław J; Kurzydłowski, Dominik; Grochala, Wojciech

    2015-12-01

    The reaction of AgF2 with P2O3F4 yields a mixed valence Ag(I)/Ag(II) difluorophosphate salt with AgAg(PO2F2)14 stoichiometry - the first Ag(ii)-PO2F2 system known. This highly moisture sensitive brown solid is thermally stable up to 120 °C, which points at further feasible extension of the chemistry of Ag(ii)-PO2F2 systems. The crystal structure shows a very complex bonding pattern, comprising of polymeric Ag(PO2F2)14(4-) anions and two types of Ag(I) cations. One particular Ag(II) site present in the crystal structure of Ag9(PO2F2)14 is the first known example of square pyramidal penta-coordinated Ag(ii) in an oxo-ligand environment. Ag(i)PO2F2 - the product of the thermal decomposition of Ag9(PO2F2)14 - has also been characterized by thermal analysis, IR spectroscopy and X-ray powder diffraction. It has a complicated crystal structure as well, which consists of infinite 1D [Ag(I)O4/2] chains which are linked to more complex 3D structures via OPO bridges. The PO2F2(-) anions bind to cations in both compounds as bidentate oxo-ligands. The terminal F atoms tend to point inside the van der Waals cavities in the crystal structure of both compounds. All important structural details of both title compounds were corroborated by DFT calculations. PMID:26200921

  19. Nanoscale current spreading analysis in solution-processed graphene oxide/silver nanowire transparent electrodes via conductive atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Shaw, Joseph E.; Perumal, Ajay; Bradley, Donal D. C.; Stavrinou, Paul N.; Anthopoulos, Thomas D.

    2016-05-01

    We use conductive atomic force microscopy (CAFM) to study the origin of long-range conductivity in model transparent conductive electrodes composed of networks of reduced graphene oxide (rGOX) and silver nanowires (AgNWs), with nanoscale spatial resolution. Pristine networks of rGOX (1-3 monolayers-thick) and AgNWs exhibit sheet resistances of ˜100-1000 kΩ/□ and 100-900 Ω/□, respectively. When the materials are deposited sequentially to form bilayer rGOX/AgNW electrodes and thermally annealed at 200 °C, the sheet resistance reduces by up to 36% as compared to pristine AgNW networks. CAFM was used to analyze the current spreading in both systems in order to identify the nanoscale phenomena responsible for this effect. For rGOX networks, the low intra-flake conductivity and the inter-flake contact resistance is found to dominate the macroscopic sheet resistance, while for AgNW networks the latter is determined by the density of the inter-AgNW junctions and their associated resistance. In the case of the bilayer rGOX/AgNWs' networks, rGOX flakes are found to form conductive "bridges" between AgNWs. We show that these additional nanoscopic electrical connections are responsible for the enhanced macroscopic conductivity of the bilayer rGOX/AgNW electrodes. Finally, the critical role of thermal annealing on the formation of these nanoscopic connections is discussed.

  20. Agricultural terraces and slope instability at Cinque Terre (NW Italy)

    NASA Astrophysics Data System (ADS)

    Brandolini, Pierluigi; Cevasco, Andrea

    2015-04-01

    Cinque Terre, located in the eastern Liguria, are one of the most representative examples of terraced coastal landscape within the Mediterranean region. They are the result of a century-old agricultural practice and constitute an outstanding example of human integration with the natural landscape. For this highly unusual man-made coastal landscape, the Cinque Terre have been recognized as a World Heritage Site by UNESCO since 1997 and became National Park in 1999. The complex network of retaining dry stone walls and drainage networks ensured through times the control of shallow water erosion and therefore, indirectly, favoured debris cover stability. The lack of maintenance of terracing due to farmer abandonment since the 1950s led to widespread slope erosion phenomena. The effects of such phenomena culminated during the 25 October 2011 storm rainfall event, when slope debris materials charged by streams gave rise to debris floods affecting both Monterosso and Vernazza villages. As the analysis of the relationships between geo-hydrological processes and land use in the Vernazza catchment highlighted, abandoned and not well maintained terraces were the most susceptible areas to shallow landsliding and erosion triggered by intense rainfall. As a consequence, the thousands of kilometres of dry stone walls retaining millions of cubic metres of debris cover at Cinque Terre currently constitute a potential menace for both villages, that are mainly located at the floor of deep cut valleys, and tourists. Given the increasing human pressure due to tourist activities, geo-hydrological risk mitigation measures are urgently needed. At the same time, restoration policies are necessary to preserve this extraordinary example of terraced coastal landscape. In this framework, the detailed knowledge of the response of terraced areas to intense rainfall in terms of slope instability is a topic issue in order to identify adequate land planning strategies as well as the areas where

  1. Antibacterial biodegradable Mg-Ag alloys.

    PubMed

    Tie, D; Feyerabend, F; Müller, W D; Schade, R; Liefeith, K; Kainer, K U; Willumeit, R

    2013-06-16

    The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4) and aging (T6) heat treatment. The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH)₂ and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7), revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231) and Staphylococcus epidermidis (DSMZ 3269), and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  2. AgRP Neural Circuits Mediate Adaptive Behaviors in the Starved State

    PubMed Central

    Padilla, Stephanie L.; Qiu, Jian; Soden, Marta E.; Sanz, Elisenda; Nestor, Casey C; Barker, Forrest D.; Quintana, Albert; Zweifel, Larry S.; Rønnekleiv, Oline K.; Kelly, Martin J.; Palmiter, Richard D.

    2016-01-01

    In the face of starvation animals will engage in high-risk behaviors that would normally be considered maladaptive. Starving rodents for example will forage in areas that are more susceptible to predators and will also modulate aggressive behavior within a territory of limited or depleted nutrients. The neural basis of these adaptive behaviors likely involves circuits that link innate feeding, aggression, and fear. Hypothalamic AgRP neurons are critically important for driving feeding and project axons to brain regions implicated in aggression and fear. Using circuit-mapping techniques, we define a disynaptic network originating from a subset of AgRP neurons that project to the medial nucleus of the amygdala and then to the principle bed nucleus of the stria terminalis, which plays a role in suppressing territorial aggression and reducing contextual fear. We propose that AgRP neurons serve as a master switch capable of coordinating behavioral decisions relative to internal state and environmental cues. PMID:27019015

  3. Synthesis and Overall Photophysical Characterization of SiO2:(Ag/SiO2) Nanostructured Sonogel Hybrid Glasses

    NASA Astrophysics Data System (ADS)

    Morales-Saavedra, Omar G.; Zanella, Rodolfo

    2014-08-01

    Bulk SiO2-based inorganic-inorganic sonogel (SG) hybrid glasses were fabricated with Ag/SiO2 supported metal nanoparticles (MNPs). The catalyst-free SG route was implemented to produce these optically active nanostructured composites by doping the liquid sol-phase with Ag/SiO2 synthesized according to the deposition-precipitation method. As prepared Ag/SiO2-MNPs exhibited particle diameters below 10 nm and homogeneous size distribution. The easy and homogeneous Ag/SiO2 loading within the micro/mesoporous SiO2-SG network has evidenced the guest-host chemical affinity of these systems. This fact allowed us to fabricate outstanding chemically, photo-physically and mechanically stable bulk hybrid monoliths with controllable geometry and doping rates, suitable for linear and nonlinear optical (NLO)-spectroscopic characterizations. Indeed, the hosting SG matrix provided an elevated thermal and mechanical stability protecting the reactive Ag nanoparticles from environment conditions, diminishing their tendency to from aggregates and, above all, preserving their pristine photophysical properties. Comprehensive morphological, structural, spectroscopic and NLO characterizations were performed on the obtained SiO2:(Ag/SiO2) hybrid composites. Results have shown that the nanocrystalline (NC) properties, multipolar nature and small sizes of the implemented Ag/SiO2-nanoparticles, together with the bulk guest-host mechanical interactions, play a crucial role for the observation of outstanding spectroscopic and quadratic NLO properties of the developed hybrid systems.

  4. Indium Tin Oxide Nanowire Networks as Effective UV/Vis Photodetection Platforms

    PubMed Central

    2015-01-01

    We demonstrate that indium tin oxide nanowires (ITO NWs) and cationic polymer-modified ITO NWs configured in a network format can be used as high performing UV/vis photodetectors. The photovoltage response of ITO NWs is much higher than similarly constructed devices made from tin oxide, zinc tin oxide, and zinc oxide nanostructures. The ITO NW mesh-based devices exhibit a substantial photovoltage (31–100 mV under illumination with a 1.14 mW 543 nm laser) and photocurrent (225–325 μA at 3 V). The response time of the devices is fast with a rise time of 20–30 μs and a decay time of 1.5–3.7 ms when probed with a 355 nm pulsed laser. The photoresponsivity of the ITO NW devices ranges from 0.07 to 0.2 A/W at a 3 V bias, whose values are in the performance range of most commercial UV/vis photodetectors. Such useful photodetector characteristics from our ITO NW mesh devices are attained straightforwardly without the need for complicated fabrication procedures involving highly specialized lithographic tools. Therefore, our approach of ITO NW network-based photodetectors can serve as a convenient alternative to commercial or single NW-based devices. PMID:26167237

  5. Si/Ag composite with bimodal micro-nano porous structure as a high-performance anode for Li-ion batteries.

    PubMed

    Hao, Qin; Zhao, Dianyun; Duan, Huimei; Zhou, Qiuxia; Xu, Caixia

    2015-03-12

    A one-step dealloying method is employed to conveniently fabricate a bimodal porous (BP) Si/Ag composite in high throughput under mild conditions. Upon dealloying the carefully designed SiAgAl ternary alloy in HCl solution at room temperature, the obtained Si/Ag composite has a uniform bicontinuous porous structure in three dimensions with micro-nano bimodal pore size distribution. Compared with the traditional preparation methods for porous Si and Si-based composites, this dealloying route is easily operated and environmentally benign. More importantly, it is convenient to realize the controllable components and uniform distribution of Si and Ag in the product. Owing to the rich porosity of the unique BP structure and the incorporation of highly conductive Ag, the as-made Si/Ag composite possesses the improved conductivity and alleviated volume changes of the Si network during repeated charging and discharging. As expected, the BP Si/Ag anode exhibits high capacity, excellent cycling reversibility, long cycling life and good rate capability for lithium storage. When the current rate is up to 1 A g(-1), BP Si/Ag can deliver a stable reversible capacity above 1000 mA h g(-1), and exhibits a capacity retention of up to 89.2% against the highest capacity after 200 cycles. With the advantages of unique performance and easy preparation, the BP Si/Ag composite holds great application potential as an advanced anode material for Li-ion batteries.

  6. Flexible membranes of Ag-nanosheet-grafted polyamide-nanofibers as effective 3D SERS substrates

    NASA Astrophysics Data System (ADS)

    Qian, Yiwu; Meng, Guowen; Huang, Qing; Zhu, Chuhong; Huang, Zhulin; Sun, Kexi; Chen, Bin

    2014-04-01

    We report on a synthetic approach to produce self-supported flexible surface-enhanced Raman scattering (SERS) active membranes consisting of polyamide (PA) nanofibers grafted with vertical Ag-nanosheets, via a combinatorial process of electrospinning PA-nanofiber membranes, assembling Au-nanoparticles on the PA-nanofibers as seeds for subsequent growth of Ag-nanosheets, and electrodepositing Ag-nanosheets on the electrospun PA-nanofibers. As a high density of Ag-nanosheets are vertically grown around each PA-nanofiber in the three-dimensional (3D) networked PA-nanofiber membranes, homogeneous nano-scaled gaps between the neighboring Ag-nanosheets are formed, leading to a high density of 3D SERS ``hot spots'' within the Ag-nanosheet-grafted PA-nanofiber membranes. The Ag-nanosheet-grafted PA-nanofiber membranes demonstrate high SERS activity with excellent Raman signal reproducibility for rhodamine 6G over the whole membrane. For a SERS-based trial analysis of polychlorinated biphenyls (PCBs, a kind of global environmental hazard), the 3D SERS substrate membranes are modified with mono-6-β-cychlodextrin to effectively capture PCB molecules. As a result, not only a low concentration down to 10-6 M is reached, but also two congeners of PCBs in their mixed solution are identified, showing promising potential in SERS-based rapid detection of trace organic pollutants such as PCBs in the environment.We report on a synthetic approach to produce self-supported flexible surface-enhanced Raman scattering (SERS) active membranes consisting of polyamide (PA) nanofibers grafted with vertical Ag-nanosheets, via a combinatorial process of electrospinning PA-nanofiber membranes, assembling Au-nanoparticles on the PA-nanofibers as seeds for subsequent growth of Ag-nanosheets, and electrodepositing Ag-nanosheets on the electrospun PA-nanofibers. As a high density of Ag-nanosheets are vertically grown around each PA-nanofiber in the three-dimensional (3D) networked PA

  7. Monitoring of Landslides using Repeated Kinematics GPS Observables in Sevketiye Town, Biga Peninsula, Çanakkale, NW Turkey

    NASA Astrophysics Data System (ADS)

    Cuneyt Erenoglu, Ramazan; Akcay, Ozgun; Karaca, Zeki; Erenoglu, Oya; Sengul Uluocak, Ebru; Yucel, Mehmet Ali

    2014-05-01

    through the Biga Peninsula. This pipeline has been damaged due to a landslide occurred in February 2006. It is essential to temporal monitoring of urban areas, transportation and infrastructure facilities against the possibility of landslides. Landslide hazards are evaluated in the earthquake and heavy rainfall processes that are the most important factors triggering landslide, and as a result the size of the hazards is estimated lower than the fact. In Çanakkale, the climate prevails in transition climates of the Mediterranean and Black Sea. So the main source of water in the project areas is meteoric water that is the most important component of the hydrological cycle. Moreover a big earthquake can trigger landslides when the ground is saturated by water in the period of between December and April. There are many landslides depending on the region's high sloping topography. It should be paid attention to aspect of movements of these landslides that could threaten residential areas the long-distance transport network and infrastructure. Conventionally, landslides are monitored by sampling of soil, rock, slope, land cover, underground water level, geology in the field and so on. The purpose of this study is to analyze the spatial and temporal behavior of the landslide located in Şevketiye Town, Çanakkale, NW Turkey. A network consisting of 16 sites has been designed surveyed three times from 2013 to 2014 using GPS. The deformation analysis has been performed in order to model the parameters of movements for the landslides based on the GPS sites using three epochs. The rates of determined deformation are summarized by strains, velocities and also displacements. Thereby, all the landslide region can be easily characterized using the GPS sites of the network. Individual GPS sites showed various statistical properties due to their relative movements. Keywords: Landslide, GPS, Deformation, Monitoring, Strain

  8. Ag(I)-binding to phytochelatins.

    PubMed

    Mehra, R K; Tran, K; Scott, G W; Mulchandani, P; Saini, S S

    1996-02-01

    Phytochelatins (PCs) are glutathione-derived peptides with the general structure (gamma-Glu-Cys)nGly, where n varies from 2 to 11. A variety of metal ions such as Cu(II), Cd(II), Pb(II), Zn(II), and Ag(I) induce PC synthesis in plants and some yeasts. It has generally been assumed that the inducer metals also bind PCs. However, very little information is available on the binding of metals other than Cu(I) and Cd(II) to PCs. In this paper, we describe the Ag(I)-binding characteristics of PCs with the structure (gamma-Glu-Cys)2Gly, (gamma-Glu-Cys)3Gly, and (gamma-Glu-Cys)4Gly. The Ag(I)-binding stoichiometries of these three peptides were determined by (i) UV/VIS spectrophotometry, (ii) luminescence spectroscopy at 77 K, and (iii) reverse-phase HPLC. The three techniques yielded similar results. ApoPCs exhibit featureless absorption in the 220-340 nm range. The binding of Ag(I) to PCs induced the appearance of specific absorption shoulders. The titration end point was indicated by the flattening of the characteristic absorption shoulders. Similarly, luminescence at 77 K due to Ag(I)-thiolate clusters increased with the addition of graded Ag(I) equivalents. The luminescence declined when Ag(I) equivalents in excess of the saturating amounts were added to the peptides. At neutral pH, (gamma-Glu-Cys)2Gly, (gamma-Glu-Cys)3Gly, and (gamma-Glu-Cys)4Gly bind 1.0, 1.5, and 4.0 equivalents of Ag(I), respectively. The Ag(I)-binding capacity of (gamma-Glu-Cys)2Gly and (gamma-Glu-Cys)3Gly was increased at pH 5.0 and below so that Ag(I)/-SH ratio approached 1.0. A similar pH-dependent binding of Ag(I) to glutathione was also observed. The increased Ag(I)-binding to PCs at lower pH is of physiological significance as these peptides accumulate in acidic vacuoles. We also report lifetime data on Ag(I)-PCs. The relatively long decay-times (approximately 0.1-0.3 msec) accompanied with a large Stokes shift in the emission band are indicative of spin-forbidden phosphorescence. PMID

  9. Selected species of the family Diastylidae (Cumacea, Peracarida, Crustacea) from the deep-sea of the NW Pacific.

    PubMed

    Mühlenhardt-Siegel, Ute; Lavrenteva, Anna V

    2015-05-11

    New species of the genera Diastylis, Divacuma and Leptostylis are described. Also a new species of the genus Pseudoleptostyloides, known from the Atlantic, is described for the NW Pacific. Additional information is given on Leptostyloides quadridentata.

  10. Preliminary Feasibility Assessment of Integrating CCHP with NW Food Processing Plant #1: Modeling Documentation

    SciTech Connect

    Hoffman, Michael G.; Srivastava, Viraj; Wagner, Anne W.; Makhmalbaf, Atefe; Thornton, John

    2014-01-01

    The Pacific Northwest National Laboratory (PNNL) has launched a project funded by the Bonneville Power Association (BPA) to identify strategies for increasing industrial energy efficiency and reducing energy costs of Northwest Food Processors Association (NWFPA) plants through deployment of novel combinations and designs of variable-output combined heat and power (CHP) distributed generation (DG), combined cooling, heating and electric power (CCHP) DG and energy storage systems. Detailed evaluations and recommendations of CHP and CCHP DG systems will be performed for several Northwest (NW) food processing sites. The objective is to reduce the overall energy use intensity of NW food processors by 25% by 2020 and by 50% by 2030, as well as reducing emissions and understanding potential congestion reduction impacts on the transmission system in the Pacific Northwest.

  11. Marine sedimentary record of Meltwater Pulse 1a along the NW Barents Sea continental margin

    NASA Astrophysics Data System (ADS)

    Giulia Lucchi, Renata; Sagnotti, Leonardo; Camerlenghi, Angelo; Macrì, Patrizia; Rebesco, Michele; Pedrosa, Maria Teresa; Giorgetti, Giovanna

    2016-04-01

    The upper continental slope of the Storfjorden-Kveithola Trough Mouth Fans (NW Barents Sea) contains a several m-thick late Pleistocene sequence of plumites composed of laminated mud interbedded with sand/silt layers. Radiocarbon ages revealed that deposition occurred during about 130 years at a very high sedimentation rate of 3.4 cm a-1, at about 7 km from the present shelf break. Palaeomagnetic and rock magnetic analyses confirm the existence of a prominent, short-living sedimentary event. The plumites appear laterally continuous and were correlated with the sedimentary sequences described west of Svalbard and neighbouring glacial depositional systems representing a major event at regional scale appointed to correspond to the deep-sea sedimentary record of Meltwater Pulse-1a. We also present new sedimentological and geochemical insights, and multi-beam data adding information on the palaeoenvironmental characteristics during MWP-1a and ice sheet decay in the NW Barents Sea.

  12. Spectroscopic Study on Eu3+ Doped Borate Glasses Containing Ag Nanoparticles and Ag Aggregates.

    PubMed

    Fu, Shaobo; Zheng, Hui; Zhang, Jinsu; Li, Xiangping; Sun, Jiashi; Hua, Ruinian; Dong, Bin; Xia, Haiping; Chen, Baojiu

    2015-01-01

    Transparent Eu(3+)-doped borate glasses containing Ag nanoparticles and Ag aggregates with composition (40 - x) CaO-59.5B2O3-0.5Eu2O3-xAgNO3 were prepared by a simple one-step melt-quenching technique. The X-ray diffraction (XRD) patterns of the glasses reveal amorphous structural properties and no diffraction peaks belonging to metal Ag particles. Ag particles and Ag aggregates were observed from the absorption spectra. Effective energy transfers from the Ag aggregates to the Eu3+ ions were observed in the excitation spectra from monitoring the intrinsic emission of Eu3+x .5D0 --> 7F2. The glasses with higher Ag content can be effectively excited by light in a wide wavelength region, indicating that these glasses have potential application in the solid state lighting driven by semiconductor light emitting diodes (LEDs). The emission spectra of the samples with higher Ag contents exhibit plenteous spectral components covering the full visible region from violet to red, thus indicating that these glass materials possess an excellent and tunable color rendering index. The color coordinates for all the glass samples were calculated by using the intensity-corrected emission spectra and the standard data issued by the CIE (Commission International de l' Eclairage) in 1931. It was found that the color coordinates for most samples with higher Ag contents fall into the white region in the color space. PMID:26328363

  13. Study of antibacterial activity of Ag and Ag2CO3 nanoparticles stabilized over montmorillonite

    NASA Astrophysics Data System (ADS)

    Sohrabnezhad, Sh.; Pourahmad, A.; Mehdipour Moghaddam, M. J.; Sadeghi, A.

    2015-02-01

    Silver carbonate and silver nanoparticles (NPs) over of stabilizer montmorillonite (MMT) have been synthesized in aqueous and polyol solvent, respectively. Dispersions of silver nanoparticles have been prepared by the reduction of silver nitrate over of MMT in presence and absence of Na2CO3 compound in ethylene glycol. It was observed that montmorillonite was capable of stabilizing formed Ag nanoparticles through the reduction of Ag+ ions in ethylene glycol. Na2CO3 was used as carbonate source in synthesis of Ag2CO3 NPs in water solvent and also for controlling of Ag nanoparticles size in ethylene glycol medium. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The TEM images showed that Ag NPs size in presence Na2CO3 salts was smaller than without that. The results indicated intercalation of Ag and Ag2CO3 nanoparticles into the montmorillonite clay layers. The diffuse reflectance spectra exhibited a strong surface plasmon resonance (SPR) adsorption peak in the visible region, resulting from Ag nanoparticles. The antibacterial testing results showed that the Ag2CO3-MMT nanocomposite exhibited an antibacterial activity higher than Ag-MMT sample against Escherichia coli.

  14. Evaluation of two new automated assays for hepatitis B virus surface antigen (HBsAg) detection: IMMULITE HBsAg and IMMULITE 2000 HBsAg.

    PubMed

    Weber, Bernard; Dengler, Thomas; Berger, Annemarie; Doerr, Hans Wilhelm; Rabenau, Holger

    2003-01-01

    In recent years the diagnostic industry has developed new automated immunoassays for the qualitative detection of hepatitis B virus (HBV) surface antigen (HBsAg) in serum and plasma samples that are performed on analyzers that permit a high-speed throughput, random access, and primary tube sampling. The aim of the present study was the evaluation of two new automated HBsAg screening assays, IMMULITE HBsAg and IMMULITE 2000 HBsAg, from Diagnostic Products Corporation. The new HBsAg assays were compared to well-established tests (Auszyme Monoclonal [overnight incubation, version B], IMx HBsAg, AxSYM HBsAg, and Prism HBsAg [all from Abbott] and Elecsys HBsAg [Roche Diagnostics]). In the evaluation were included seroconversion panels, sera from the acute and chronic phases of infection, dilution series of various HBsAg standards, HBV subtypes and S gene mutants. To challenge the specificity of the new assays, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. IMMULITE HBsAg and IMMULITE 2000 HBsAg, although not as sensitive as the Elecsys HBsAg assay, were equivalent to the AxSYM HBsAg assay and showed a higher sensitivity than the Auszyme Monoclonal B and IMx HBsAg systems for detection of acute infection in seroconversion panels. The specificities (100%) of both IMMULITE assays on unselected blood donors and potentially interfering samples were comparable to those of the alternative assays after repeated testing. In conclusion, the new IMMULITE HBsAg and IMMULITE 2000 HBsAg assays show a good sensitivity for HBsAg detection compared to other well-established tests. The specificity on repeatedly tested samples was equivalent to that of the alternative assays. The rapid turnaround time, primary tube sampling, and on-board dilution make it an interesting assay system for clinical laboratory diagnosis.

  15. 3D graphene network@WO3 nanowire composites: a multifunctional colorimetric and electrochemical biosensing platform.

    PubMed

    Ma, Ye; Zhao, Minggang; Cai, Bin; Wang, Wei; Ye, Zhizhen; Huang, Jingyun

    2014-10-01

    A three dimensional graphene network (3DGN)@WO3 nanowire (NW) sensor is proposed which can perform colorimetric and electrochemical sensing techniques to detect H2O2, ascorbic acid and dopamine. The 3DGN provides three functions: anchoring, separating, conducting, while the WO3 NWs maximize surface area and catalyse reactions.

  16. Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Hanson, M.; Beaulieu, S.; Tunnicliffe, V.; Chadwick, W.; Breuer, E. R.

    2015-12-01

    In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 through 2010 and ceased as of 2014. In late 2009, NW Rota-1 experienced a massive landslide decimating the habitat on the southern side of the volcano. This presented an enormous natural disturbance to the community. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching specifically for larvae which have the potential to recolonize the sea floor after such a major disturbance. We focused on samples for which profiles with a MAPR sensor indicated hydrothermal plumes in the water column. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument also can act as sources for these planktonic, recolonizing larvae. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both

  17. Hydrological cycles and trends in the NW Argentine Andes since 1940

    NASA Astrophysics Data System (ADS)

    Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred

    2016-04-01

    Strong spatiotemporal variability characterizes the hydrometeorological pattern in the NW Argentine Andes, draining parts of the most populated and economically important areas of South America. During the summer monsoon season (DJF), the eastern flanks of the central Andes are characterized by deep convection, exposing them to extreme hydrometeorological events. These often result in floods and landslides with disastrous effects on the local populations. Here, we analyze river discharge to explore long-term hydrological variability in NW Argentine Andes and the linked climate controlling processes. We rely on 13 daily river discharge time series relevant to drainage basins spanning several size orders (102-104 km2) starting in 1914 and define different hydro-climate indices both for the mean and the extreme hydrological events. We apply quantile regression to investigate long-term trends and spectral analysis associated with cross-correlation with SST-based climate indices to identify links to large-scale climate variability modes. River discharge presents a pronounced and coherent variability signal in South America, particularly for wide drainage basins, such as the Amazon and Paraná/La Plata rivers, strongly associated to Pacific and Atlantic Oceans Sea Surface Temperature (SST) anomalies (i.e. ENSO, PDO, AMO). Our analysis evidences that in the NW Argentine Andes, mean discharge values are characterized by statistically significant, mostly positive, long-term trends since 1940, whereas the extreme events present a more non-unidirectional trend pattern. Also, coherent multi-annual to multi-decadal cycles characterizing the discharge pattern have been identified, suggesting that processes linked to SST anomaly-modes strongly control the hydrometeorology variability in the NW Argentina Andes.

  18. Double-gated Si NW FET sensors: Low-frequency noise and photoelectric properties

    NASA Astrophysics Data System (ADS)

    Gasparyan, F.; Khondkaryan, H.; Arakelyan, A.; Zadorozhnyi, I.; Pud, S.; Vitusevich, S.

    2016-08-01

    The transport, noise, and photosensitivity properties of an array of silicon nanowire (NW) p+-p-p+ field-effect transistors (FETs) are investigated. The peculiarities of photosensitivity and detectivity are analyzed over a wide spectrum range. The absorbance of p-Si NW shifts to the short wavelength region compared with bulk Si. The photocurrent and photosensitivity reach increased values in the UV range of the spectrum at 300 K. It is shown that sensitivity values can be tuned by the drain-source voltage and may reach record values of up to 2-4 A/W at a wavelength of 300 nm at room temperature. Low-frequency noise studies allow calculating the photodetectivity values, which increase with decreasing wavelength down to 300 nm. We show that the drain current of Si NW biochemical sensors substantially depends on pH value and the signal-to-noise ratio reaches the high value of 105. Increasing pH sensitivity with gate voltage is revealed for certain source-drain currents of pH-sensors based on Si NW FETs. The noise characteristic index decreases from 1.1 to 0.7 with the growth of the liquid gate voltage. Noise behavior is successfully explained in the framework of the correlated number-mobility unified fluctuation model. pH sensitivity increases as a result of the increase in liquid gate voltage, thus giving the opportunity to measure very low proton concentrations in the electrolyte medium at certain values of the liquid gate voltage.

  19. Airborne radioactivity survey of parts of Savery NW and Savery NE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 266 square miles of Savery NW and Savery NE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  20. Neurons in the amygdala play an important role in the neuronal network mediating a clonic form of audiogenic seizures both before and after audiogenic kindling.

    PubMed

    Raisinghani, Manish; Faingold, Carl L

    2005-01-25

    Previous studies showed that neuronal network nuclei for behaviorally different forms of audiogenic seizure (AGS) exhibit similarities and important differences. The amygdala is involved differentially in tonic AGS as compared to clonic AGS networks. The role of the lateral amygdala (LAMG) undergoes major changes after AGS repetition (AGS kindling) in tonic forms of AGS. The present study examined the role of LAMG in a clonic form of AGS [genetically epilepsy-prone rats (GEPR-3s)] before and after AGS kindling using bilateral microinjection and chronic neuronal recordings. AGS kindling in GEPR-3s results in facial and forelimb (F&F) clonus, and this behavior could be blocked following bilateral microinjection of a NMDA antagonist (2-amino-7-phosphonoheptanoate) without affecting generalized clonus. Higher AP7 doses blocked both generalized clonus and F&F clonus. LAMG neurons in GEPR-3s exhibited only onset type neuronal responses both before and after AGS kindling, unlike LAMG neurons in normal rats and a tonic form of AGS. A significantly greater LAMG neuronal firing rate occurred after AGS kindling at high acoustic intensities. The latency of LAMG neuronal firing increased significantly after AGS kindling. Burst firing occurred during wild running and generalized clonic behaviors before and after AGS kindling. Burst firing also occurred during F&F clonus after AGS kindling. These findings indicate that LAMG neurons play a critical role in the neuronal network for generalized clonus as well as F&F clonus in GEPR-3s, both before and after AGS kindling, which contrasts markedly with the role of LAMG in tonic AGS.

  1. Demonstration and partial characterization of 22-nm HBsAg and Dane particles of subtype HBsAg/ady.

    PubMed

    Hess, G; Shih, J W; Arnold, W; Gerin, J L; zum Büschenfelde, K H

    1979-09-01

    The present paper describes the demonstration of d, y, w, and r HBsAg determinants in one serum. It was shown that there are two populations of HBsAg particles: HBsAg/ad and HBsAg/ady. All complete Dane particles were of subtype HBsAg/ady. Further characterization of HBsAg/ady particles did not reveal morphologic differences when they were compared with HBsAg/ad and HBsAg/ay particles. An HBsAg/ady phenotype may be the result of a double infection with hepatitis B viruses or exchanges of DNA sequences that determine HBsAg/ay and HBsAg/ad to form a new genotype. PMID:89163

  2. Demonstration and partial characterization of 22-nm HBsAg and Dane particles of subtype HBsAg/ady.

    PubMed

    Hess, G; Shih, J W; Arnold, W; Gerin, J L; zum Büschenfelde, K H

    1979-09-01

    The present paper describes the demonstration of d, y, w, and r HBsAg determinants in one serum. It was shown that there are two populations of HBsAg particles: HBsAg/ad and HBsAg/ady. All complete Dane particles were of subtype HBsAg/ady. Further characterization of HBsAg/ady particles did not reveal morphologic differences when they were compared with HBsAg/ad and HBsAg/ay particles. An HBsAg/ady phenotype may be the result of a double infection with hepatitis B viruses or exchanges of DNA sequences that determine HBsAg/ay and HBsAg/ad to form a new genotype.

  3. Time and Space Variations of Local Seismic Signals in the NW-Bohemia/Vogtland Swarm Region

    NASA Astrophysics Data System (ADS)

    Bouskova, A.; Horalek, J.; Fischer, T.; Hudova, Z.

    2003-04-01

    Local WEBNET stations in the NW-Bohemia/Vogtland earthquake swarm region provide high quality data, which make possible a detailed analysis of converted phases contained in the seismograms. Seismograms of local earthquakes display pronounced reflections or splitting of P- and S-waves. Some of the reflections could origin from the presence of fluids or a molten material at a short distance from the earthquake hypocentres, the other reflect the complex geological structure of the region. The existence of split phases can verify the anisotropy of earth crust in this area. The occurrence of secondary phases, similarly to the other attributes of seismic wave propagation (velocity ratio of P- and S- waves, wave back-azimuth), varies in time and space. This contribution presents the space and time changes of some of observed secondary phases in the local NW-Bohemia seismograms and also gives some possible interpretations of these phenomena. Consequently, we discuss the processes acting during earthquake swarms in the NW- Bohemia/Vogtland region and in the time intervals between swarm activity.

  4. New Early Paleozoic Paleomagnetic Poles From NW Argentina: a Reappraisal of Tectonic Models

    NASA Astrophysics Data System (ADS)

    Spagnuolo, C. M.; Rapalini, A. E.; Astini, R. A.

    2007-05-01

    A paleomagnetic study carried out on Early Ordovician volcanic units in the Famatina Ranges of NW Argentina yielded a pre-tectonic paleomagnetic pole at 32.7°S, 4.3°E, (5.6°/ 8.6°, N=14 sites) that is consistent with four previous Early Ordovician poles from the Famatina - Eastern Puna Eruptive Belt of NW Argentina. However, these five poles are rotated around 50° clockwise respect to the coeval reference pole of Gondwana. Our new results seem to confirm previous models of this belt as a paraauthocthonous rotated terrane on the southwestern margin of Gondwana. However, a recent paleomagnetic pole from the Late Cambrian Mesón Group, at the Eastern Cordillera of NW Argentina, corresponding to the Gondwana foreland (4.5°S, 359.0°E, dp=5.5°, dm=8.8°, n=26 samples) and preliminary paleopoles obtained from the same unit and the latest Cambrian - Early Ordovician Santa Victoria Group at other three localities in the same region, also indicate an anomalous pole position rotated some 40° clockwise respect to the reference pole for Gondwana. These results suggest that the postulated model of a rotated terrane for the Famatina-Eastern Puna belt must be reconsidered. Different alternative scenarios including the possibility of an Early Paleozoic displacement of the whole basement of the Eastern Sierras Pampeanas of Argentina ("Pampia") will be explored.

  5. Evidence for an Ancient Buried Landscape on the NW Rim of Hellas Basin, Mars

    NASA Technical Reports Server (NTRS)

    Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.; Mustard, John F.; Vincendon, Mathieu

    2010-01-01

    Hellas basin is the largest (2000+ km across) well-preserved impact structure on Mars and its deepest depositional sink [e.g., 1]. The Hellas rim and adjacent highlands are of special interest given the possibility of paleolakes on the basin floor [2-4], recent studies of potential localized fluvial/lacustrine systems [2, 5-17], and evidence for phyllosilicates around and within impact craters north of the basin [18-26]. We are producing a 1:1.5M-scale geologic map of eight MTM quadrangles (-25312, -25307, -25302, -25297, -30312, -30307, -30302, -30297) along Hellas NW rim. The map region (22.5-32.5degS, 45- 65degE) includes a transect across the cratered highlands of Terra Sabaea, the degraded NW rim of Hellas, and basin interior deposits of NW Hellas Planitia. No previous mapping studies have focused on this region, although it has been included in earlier global and regional maps [27-29].

  6. Mercury content and their risk assessment in farmed shrimp Litopenaeus vannamei from NW Mexico.

    PubMed

    Delgado-Alvarez, C G; Ruelas-Inzunza, J; Osuna-López, J I; Voltolina, D; Frías-Espericueta, M G

    2015-01-01

    The main objective of this study was to evaluate the total mercury content in hepatopancreas and edible muscle of the whiteleg shrimp Litopenaeus vannamei cultured along the NW coast of Mexico, and to evaluate the potential human health risk due to their consumption. Samples were obtained between May and June 2010 in 26 shrimp farms from the three most important shrimp-producing states of NW Mexico, and total Hg was analyzed after reduction with SnCl2 in a mercury analyzer. The ranges of Hg concentrations of the hepatopancreas were 0.101±0.03-0.184±0.13 μg g(-1) in Sonora, 0.077±0.055-0.813±0.363 μg g(-1) in Sinaloa and 0.139±0.037-0.791±0.33 μg g(-1) in Nayarit. In the muscle, values were from 0.078±0.02 to 0.539±0.09 μg g(-1) in Sonora, 0.154±0.03-0.861±0.423 μg g(-1) in Sinaloa and 0.121±0.041-1.48±0.44 μg g(-1) in Nayarit. Considering the concentrations of Hg in the muscle and the national consumption rate, shrimp farmed in NW Mexico does not represent a risk for human health (HQ<1).

  7. A solution-processed molybdenum oxide treated silver nanowire network: a highly conductive transparent conducting electrode with superior mechanical and hole injection properties

    NASA Astrophysics Data System (ADS)

    Chang, Jung-Hao; Chiang, Kai-Ming; Kang, Hao-Wei; Chi, Wei-Jung; Chang, Jung-Hung; Wu, Chih-I.; Lin, Hao-Wu

    2015-02-01

    We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 °C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq-1, a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole injection in optoelectronic applications. By utilizing these s-MoOx-treated AgNW TCEs as the anode in ITO-free organic light emitting diodes, promising performance of 29.2 lm W-1 and 10.3% external quantum efficiency are demonstrated. The versatile, multi-functional s-MoOx treatment presented here paves the way for the use of low-temperature, solution-processed MoOx as both a nanowire linker and a hole injection interfacial layer for future flexible optoelectronic devices.We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 °C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq-1, a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole

  8. Height reversal of Si micro dot and well patterns during Si nanowire formation by Ag-assisted chemical etching

    NASA Astrophysics Data System (ADS)

    Yamaura, Daichi; Takeuchi, Koji; Lu, Zhiqiang; Arai, Yuki; Ogino, Toshio

    2015-05-01

    The Si nanowire (Si-NW) formation process has been studied to develop a new anode material for lithium ion batteries. Si-NWs were prepared by a combination of electroless metal deposition (EMD) of Ag and metal-assisted chemical etching (Mac etching) on Si substrates that have micro dot and well patterns with respect to their height. During the fabrication of Si-NWs, height reversal occurred in the micro dot and well patterns, and Si micro- and nano-hybrid systems were fabricated. We also observed structural changes of the Si micro- and nano-hybrid structures during the electrochemical charge/discharge process of lithium ions, and showed that this hybrid system is robust for the volume change accompanied with the lithiation/delithiation reaction.

  9. Agent planning in AgScala

    NASA Astrophysics Data System (ADS)

    Tošić, Saša; Mitrović, Dejan; Ivanović, Mirjana

    2013-10-01

    Agent-oriented programming languages are designed to simplify the development of software agents, especially those that exhibit complex, intelligent behavior. This paper presents recent improvements of AgScala, an agent-oriented programming language based on Scala. AgScala includes declarative constructs for managing beliefs, actions and goals of intelligent agents. Combined with object-oriented and functional programming paradigms offered by Scala, it aims to be an efficient framework for developing both purely reactive, and more complex, deliberate agents. Instead of the Prolog back-end used initially, the new version of AgScala relies on Agent Planning Package, a more advanced system for automated planning and reasoning.

  10. A FLYING WIRE SYSTEM IN THE AGS.

    SciTech Connect

    HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

    1999-03-29

    As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

  11. Crystallization kinetics of {alpha}-AgI in AgI-based silver orthoborate glasses

    SciTech Connect

    Taniguchi, Akihiro; Tatsumisago, Masahiro; Minami, Tsutomu

    1995-02-01

    Kinetics for nucleation and growth of {alpha}-AgI crystals in AgI-based silver orthoborate glasses, in which only {alpha}-AgI crystals were found to crystallize in the heating process of the glasses, were studied by isothermal and nonisothermal measurements using differential scanning calorimetry and by observations of the microstructure of the glasses using scanning electron microscopy. The values of both n and m, dependent on the crystallization mechanism, were found to be 3, indicating that a constant number of nuclei of {alpha}-AgI precipitated in a glass matrix grew three-dimensionally. The preannealing of the glasses at temperatures between glass transition and crystallization did not affect the DSC isothermal curves in the crystal growth process, which suggested that the number of {alpha}-AgI nuclei would have been saturated in the glass when the glasses were prepared by quenching the AgI-based melts.

  12. Extranuclear dynamics of 111Ag(→111Cd) doped in AgI nanoparticles

    NASA Astrophysics Data System (ADS)

    Sato, W.; Mizuuchi, R.; Irioka, N.; Komatsuda, S.; Kawata, S.; Taoka, A.; Ohkubo, Y.

    2014-08-01

    Dynamic behavior of the extranuclear field relative to the 111Ag(→111Cd) probe nucleus introduced in a superionic conductor silver iodide (AgI) was investigated by means of the time-differential perturbed angular correlation technique. For poly-N-vinyl-2-pyrrolidone (PVP)-coated AgI nanoparticles, we observed nuclear spin relaxation of the probe at room temperature. This result signifies that Ag+ ions in the polymer-coated sample make hopping motion from site to site at this low temperature. The activation energy for the dynamic motion was successfully estimated to be 46(10) meV. The first atomic-level observation of the temperature-dependent dynamic behavior of Ag+ ions in the polymer-coated AgI is reported.

  13. Ag induced electromagnetic interference shielding of Ag-graphite/PVDF flexible nanocomposites thinfilms

    NASA Astrophysics Data System (ADS)

    Kumaran, R.; Alagar, M.; Dinesh Kumar, S.; Subramanian, V.; Dinakaran, K.

    2015-09-01

    We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70 S/cm at 1 MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt. % graphite in PVDF.

  14. Permeability enhancement during gold mineralization: Evidences from Kestanelik epithermal vein system, NW Turkey

    NASA Astrophysics Data System (ADS)

    Gulyuz, Nilay; Shipton, Zoe; Kuscu, Ilkay; Lord, Richard A.; Gladwell, David R.; Kaymakci, Nuretdin

    2016-04-01

    The most favourable and principal mineral deposition mechanism in low sulphidation epithermal systems is boiling. Mineralization in these systems occurs dominantly as veins and stockworks; therefore, structures play major role in the localization of epithermal fluid flow. Epithermal fluids rise from depth along structural conduits at high temperatures under enough pressure to prevent boiling. When the pressure drops suddenly (for instance, through faulting or any fracturing), boiling occurs, and CO2 and H2S are released to the vapour phase. Change in fluid chemistry due to the boiling causes first the base metals, and then the ore and gangue minerals to deposit in a well-recognized temporal and vertical sequence until all open spaces are filled. Vein infill in epithermal deposits indicate that mineralization is multiphase and associated with repeated and episodic fluid flow rather than a steady-state process. How can permeability enhancement be achieved after deposition of minerals in fractures and faults chokes permeable pathways and restrict fluid flow? Although geochemical aspects of LS epithermal systems are well known, limited studies exist on the permeability enhancement mechanisms in LS epithermal veins. The main aim of the study is to understand the permeability enhancement mechanisms in epithermal gold deposits by focussing on the structures and quartz textures of a well-preserved low sulphidation epithermal quartz vein/breccia system in Lapseki, NW Turkey. We revealed the kinematics of the structure-vein network by mapping the geometries of epithermal quartz veins and associated structures and collecting detailed structural data from them. In addition, we determined the different phases of fluid flow and mineralization with the cross-cutting and structural relationships among them by examining the quartz textures and breccias and mapping their spatial distribution on vein outcrops and in drill cores with the help of thin section analyses. On-going work

  15. Identification of flood events inside karst cavities: Fria Cave (Asturias - NW Spain)

    NASA Astrophysics Data System (ADS)

    Gonzalez Lemos, Saul; Stoll, Heather

    2013-04-01

    Fluvial records may be well preserved in subterranean karst drainage networks and fluvial deposits cemented in speleothems may provide good chronology of past flood events. In several karst systems in Asturias (NW. Spain), moments of extreme precipitation events produce deposits from flood events in the bed and walls of caves which we propose are also recorded in the calcium carbonate stalagmites growing in the cave. The final stretch of the studied cave (Fria Cave), with a development of 360 m in length, intersects a small perennial stream which in our observation has maintained a minimum discharge of about 0.022 m3/s but periodically overflows into the vadose cave passage. Immediately after a flood overflow event, water marks and foam detritus are visible at various levels on the cave walls and corresponding to heights of bottlenecks in overflow drainage through the cave passage. Flood events deposit sand on terraces on the cave wall and move large volumes of sand in the cave bed. These extreme events leave a long-term record in i) wall coloration or water marks on the cave walls; and ii) detrital particles preserved as inclusions inside the stalagmites. Throughout this cave, it is possible to recognize chromatic changes in the walls, such as manganese oxide stains, which coincide with one of the water marks left during a recent flood event. The most salient manganese oxide on the walls rises up to 1.5 m measured from the thalweg and we interpreted it as the result of a frequent process of wetting - drying related to frequent flooding of the cave. Since 3-4 ka, drapery flowstone has been deposited over this oxide coating in some parts of the cave and the drapery remains free of oxide coating. We interpret this as indicating a reduction in the frequency and/or duration of flooding to this height, coincident with a regional drying trend in late Holocene. Stalagmites growing in the bed of the cave appear to trap fluvial sediments like sand or silts particles, which

  16. Margin Shape Response to Changes in Submarine Turbiditic Systems Along the NE Iberian Margin, NW Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Amblas, D.; Gerber, T.; Canals, M.; Urgeles, R.; Lastras, G.

    2006-12-01

    Submarine canyons can efficiently drain continental margins just as river systems drain subaerial catchments. Highly detailed seafloor topography acquired by state-of-the-art multibeam echosounders provides the opportunity to compare submarine and subaerial morphologies at a similar resolution. New bathymetric data show geomorphic similarities between fluvial and turbiditic systems, including: a) long-profile channel concavity, b) tributary branching, c) tributary confluences at converging elevations, and d) knickpoints. Recent models explaining these features are formulated using morphodynamic and hydrologic relations developed to study subaerial systems. Here we apply these models using multibeam, seismic reflection, sidescan sonar and core data from the NE Iberian margin (Catalano-Balearic Sea, NW Mediterranean). The margin is drained by the Valencia deep-sea channel, which collects sediment from canyon-channel systems and unconfined mass-wasting events along most of its length before debouching onto the Valencia Fan. The Valencia Channel has been active since the late Miocene, evolving in response to Plio-Quaternary episodes of erosion and deposition. Seismic records from beneath the modern Valencia Channel show that mass-failure deposits have periodically filled the channel through this period. Observations from the modern seafloor suggest that the most recent major failure, dated at 11,500 yr B.P., perturbed the Valencia Channel long profile and may have caused readjustment of the entire submarine drainage network. The modern Valencia Channel shows no major discontinuities at junctions with canyon-channel tributaries, indicating that all the channels have been active with similar time-averaged erosion rates at these locations (analogous to Playfair's Law for fluvial systems). However, several tributaries contain knickpoints and evidence for retrogradation of canyon heads. These tributaries join the Valencia Channel downstream from a major change in its long

  17. Chandra and Spitzer Observations of the NW Filament of SN 1006

    NASA Astrophysics Data System (ADS)

    Williams, Brian J.; Winkler, P. F.; Katsuda, S.; Blair, W. P.; Borkowski, K. J.; Ghavamian, P.; Long, K. S.; Petre, R.; Raymond, J. C.; Reynolds, S. P.

    2013-01-01

    We present results from Chandra and Spitzer observations of the NW region of SN1006. Deep X-ray observations from Chandra (companion paper by Winkler et al.) allow us to study the variation in shock velocity around the shell and elucidate the physics of diffusive shock acceleration, and both non-thermal and thermal X-ray emission, in unprecedented detail. Along the thermally-dominated NW limb, X-ray proper motions over an 11-yr baseline indicate a shock velocity of about 3000 km/s, consistent with measurements from optical studies. But even in the NW we find a few regions dominated by non-thermal emission, and proper motions of these small filaments show a velocity of 5000 km/s, virtually identical to that seen along the synchrotron-dominated NE limb. Higher shock speeds in the non-thermal regions than in thermal ones are consistent with the theoretical view of diffusive shock acceleration that faster shocks can enhance synchrotron X-ray emission. The existence of thermal and non-thermal regions, with strongly contrasting X-ray spectra and proper motions, in close proximity to one another indicates that interstellar density inhomogeneities exist on pc scales, even at the location of SN 1006, 550 pc above the Galactic plane. Spitzer IR imaging and spectroscopic observations also indicate an inhomogeneous ISM surrounding SN1006, where the shock has recently encountered a denser region to the NW. The 24 micron image from MIPS clearly shows faint filamentary emission just interior to the NW Balmer filaments that delineate the present position of the expanding shock. This is the first detection of IR radiation from SN 1006 and clearly indicates an origin in shock-heated interstellar dust grains. The spectrum confirms a warm dust origin for the IR emission, and a model of the dust spectrum is consistent with the pre-shock density of 1 cm^-3 derived from optical and X-ray studies. The dust-to-gas mass ratio in the pre-shock ambient medium is a factor of several lower than

  18. Control and performance of the AGS and AGS Booster Main Magnet Power Supplies

    SciTech Connect

    Reece, R.K.; Casella, R.; Culwick, B.; Geller, J.; Marneris, I.; Sandberg, J.; Soukas, A.; Zhang, S.Y.

    1993-01-01

    Techniques for precision control of the main magnet power supplies for the AGS and AGS Booster synchrotron will be discussed. Both synchrotrons are designed to operate in a Pulse-to-Pulse Modulation (PPM) environment with a Supercycle Generator defining and distributing global timing events for the AGS Facility. Details of modelling, real-time feedback and feedforward systems, generation and distribution of real time field data, operational parameters and an overview of performance for both machines are included.

  19. Control and performance of the AGS and AGS Booster Main Magnet Power Supplies

    SciTech Connect

    Reece, R.K.; Casella, R.; Culwick, B.; Geller, J.; Marneris, I.; Sandberg, J.; Soukas, A.; Zhang, S.Y.

    1993-06-01

    Techniques for precision control of the main magnet power supplies for the AGS and AGS Booster synchrotron will be discussed. Both synchrotrons are designed to operate in a Pulse-to-Pulse Modulation (PPM) environment with a Supercycle Generator defining and distributing global timing events for the AGS Facility. Details of modelling, real-time feedback and feedforward systems, generation and distribution of real time field data, operational parameters and an overview of performance for both machines are included.

  20. Structure and vibrational modes of AgI-doped AsSe glasses: Raman scattering and ab initio calculations

    SciTech Connect

    Kostadinova, O.; Chrissanthopoulos, A.; Petkova, T.; Petkov, P.; Yannopoulos, S.N.

    2011-02-15

    We report an investigation of the structure and vibrational modes of (AgI){sub x} (AsSe){sub 100-x}, bulk glasses using Raman spectroscopy and first principles calculations. The short- and medium-range structural order of the glasses was elucidated by analyzing the reduced Raman spectra, recorded at off-resonance conditions. Three distinct local environments were revealed for the AsSe glass including stoichiometric-like and As-rich network sub-structures, and cage-like molecules (As{sub 4}Se{sub n}, n=3, 4) decoupled from the network. To facilitate the interpretation of the Raman spectra ab initio calculations are employed to study the geometric and vibrational properties of As{sub 4}Se{sub n} molecular units that are parts of the glass structure. The incorporation of AgI causes appreciable structural changes into the glass structure. AgI is responsible for the population reduction of molecular units and for the degradation of the As-rich network-like sub-structure via the introduction of As-I terminal bonds. Ab initio calculations of mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} provided useful information augmenting the interpretation of the Raman spectra. -- Graphical abstract: Raman scattering and ab initio calculations are employed to study the structure of AgI-AsSe superionic glasses. The role of mixed chalcohalide pyramidal units as illustrated in the figure is elucidated. Display Omitted Research highlights: {yields} Doping binary As-Se glasses with AgI cause dramatic changes in glass structure. {yields} Raman scattering and ab initio calculations determine changes in short- and medium-range order. {yields} Three local environments exist in AsSe glass including a network sub-structure and cage-like molecules. {yields} Mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} dominate the AgI-doped glass structure.

  1. Structural analysis of Nalagarh lobe, NW Himalaya: implication of thrusting across tectonic edge of NW limb of Nahan salient, Himachal Pradesh, India

    NASA Astrophysics Data System (ADS)

    Bhakuni, S. S.; Philip, G.; Suresh, N.

    2016-08-01

    The Main Boundary Fault (MBF), convex towards southwest, forms the leading edge of the Nahan salient. Near the southern end of an oblique ramp, a lobe-shaped physiographic front, named in this work as Nalagarh lobe, has developed across NW limb of salient. The lobe has formed across the MBF that separates the hanging wall Lower Tertiary Dharmsala rocks from the foot wall Upper Tertiary Siwalik rocks and overlying Quaternaries. In front of lobe Dharmsala, thrust fault splays (Splay-1 and Splay-2) and associated tectonic fabrics have developed within the Late Pleistocene fan deposit. Structural elements developed across the front of Nalagarh lobe are analysed with reference to evolution of lobe. With reference to the evolution of lobe, an unweathered ~15-m-high hanging wall or wedge top forms the uplifted and rejuvenated bedrock fault scarp of the MBF. Below the MBF, the fan deposit has underthrust along Splay-1. Later the Splay-2 formed within fan deposit near south of Splay-1. Geometry of the overturned limb of tight to isoclinal fault propagation fold, formed on Splay-2 plane, suggests that the fold formed by normal drag, produced by intermittent fault-slips along Splay-2. The displacement along Splay-2 offset the marker bed to ~1 m by which some clasts rotated parallel to the traces of brittle axial planes of fold. The variable fold geometry and style of deformation are analysed along length of thrust splays for 5 km. It is revealed that the lobe is bounded by transverse thrust faults along its NW and SE margins. The geometry of salient and oblique ramp suggests that the transverse thrust faults and associated transverse folds formed by right-lateral displacement along the NW limb of the salient. Marking the northern margin of the intermontane piggyback basin of Pinjaur dun, the MBF is interpreted to be an out-of-sequence thrust that has brought up the Lower Tertiary Dharmsala rocks over the Late Pleistocene fan deposit. The geometry of lobe and its bounding

  2. Nanoporous Ag prepared from the melt-spun Cu-Ag alloys

    NASA Astrophysics Data System (ADS)

    Li, Guijing; Song, Xiaoping; Sun, Zhanbo; Yang, Shengchun; Ding, Bingjun; Yang, Sen; Yang, Zhimao; Wang, Fei

    2011-07-01

    Nanoporous Ag ribbons with different morphology and porosity were achieved by the electrochemical corrosion of the melt-spun Cu-Ag alloys. The Cu-rich phase in the alloys was removed, resulting in the formation of the nanopores distributed across the whole ribbon. It is found that the structures, morphology and porosity of the nanoporous Ag ribbons were dependent on the microstructures of the parent alloys. The most of ligaments presented a rod-like shape due to the formation of pseudoeutectic microstructure in the melt-spun Cu 55Ag 45 and Cu 70Ag 30 alloys. For nanoporous Ag prepared from Cu 85Ag 15 alloys, the ligaments were camber-like because of the appearance of the divorced microstructures. Especially, a novel bamboo-grove-like structure could be observed at the cross-section of the nanoporous Ag ribbons. The experiment reveals that nanoporous Ag ribbons exhibited excellent enhancement of surface-enhanced Raman scattering (SERS) effect, but a slight difference existed due to the discrepancy of their morphology.

  3. Near-infrared emitting AgInTe2 and Zn-Ag-In-Te colloidal nanocrystals

    NASA Astrophysics Data System (ADS)

    Langevin, Marc-Antoine; Pons, Thomas; Ritcey, Anna M.; Nì. Allen, Claudine

    2015-06-01

    The synthesis of AgInTe2 nanocrystals emitting between 1095 nm and 1160 nm is presented. Evolution of the Ag:In:Te ratio shows progressive incorporation of In3+ in Ag2Te, leading to the formation of orthorhombic AgInTe2. When zinc is added to the synthesis, the photoluminescence quantum yield reaches 3.4 %.

  4. Redetermination of AgPO3

    PubMed Central

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  5. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  6. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure. PMID:21522230

  7. Exposure-dependent Ag+ release from silver nanoparticles and its complexation in AgS2 sites in primary murine macrophages

    NASA Astrophysics Data System (ADS)

    Veronesi, G.; Aude-Garcia, C.; Kieffer, I.; Gallon, T.; Delangle, P.; Herlin-Boime, N.; Rabilloud, T.; Carrière, M.

    2015-04-01

    Silver nanoparticle (AgNP) toxicity is related to their dissolution in biological environments and to the binding of the released Ag+ ions in cellulo; the chemical environment of recombined Ag+ ions is responsible for their toxicological outcome, moreover it is indicative of the cellular response to AgNP exposure, and can therefore shed light on the mechanisms governing AgNP toxicity. This study probes the chemistry of Ag species in primary murine macrophages exposed to AgNPs by making use of X-ray Absorption Fine Structure spectroscopy under cryogenic conditions: the linear combination analysis of the near-edge region of the spectra provides the fraction of Ag+ ions released from the AgNPs under a given exposure condition and highlights their complexation with thiolate groups; the ab initio modelling of the extended spectra allows measuring the Ag-S bond length in cellulo. Dissolution rates depend on the exposure scenario, chronicity leading to higher Ag+ release than acute exposure; Ag-S bond lengths are 2.41 +/- 0.03 Å and 2.38 +/- 0.01 Å in acute and chronic exposure respectively, compatible with digonal AgS2 coordination. Glutathione is identified as the most likely putative ligand for Ag+. The proposed method offers a scope for the investigation of metallic nanoparticle dissolution and recombination in cellular models.Silver nanoparticle (AgNP) toxicity is related to their dissolution in biological environments and to the binding of the released Ag+ ions in cellulo; the chemical environment of recombined Ag+ ions is responsible for their toxicological outcome, moreover it is indicative of the cellular response to AgNP exposure, and can therefore shed light on the mechanisms governing AgNP toxicity. This study probes the chemistry of Ag species in primary murine macrophages exposed to AgNPs by making use of X-ray Absorption Fine Structure spectroscopy under cryogenic conditions: the linear combination analysis of the near-edge region of the spectra provides

  8. Evidence for rapid epithermal mineralization and coeval bimodal volcanism, Bruner Au-Ag property, NV USA

    NASA Astrophysics Data System (ADS)

    Baldwin, Dylan

    -ore hydrothermal system is overprinted by Au-Ag stage alteration consisting of proximal quartz + Fe-sericite + pyrite +/- adularia and distal illite-montmorillonite-chlorite (after biotite). The distribution of steam-heated alteration zones and vitrophyre units, along with prominent chemical and textural zonation of veins, suggest that a 400 m vertical section of the epithermal system is now exposed at surface. 40Ar/39Ar geochronology of 3 adularia and 4 volcanic samples identified a rhyolite unit that slightly predates ~16.34 Ma Au-Ag mineralization and mafic magmatism. The proposed timeline for deposit formation is: 21-20 Ma, eruption of locally derived rhyolitic flows; 16.62 Ma, development of new rhyolite flow-dome complex and meteoric-dominated geothermal circulation along N-S structural fabric driven by heat from rhyolite domes; ~16.34 Ma, emplacement of NW trending basalt dikes, followed by violent hydrothermal eruptions, eruption of tuffisite breccia dikes, and Au-Ag mineralization; <16.34 Ma, post-mineral rhyolitic volcanism and normal faulting; and <16 Ma to present, continued faulting and dismemberment of the mineral system. The close spatial and temporal association of veining with coeval volcanic units suggests that Au-Ag-S traveled along similar structure and may have been supplied from the same magma chamber. Deposition of Au and Ag from HS- complexes by boiling appears to have occurred rapidly following closely spaced violent magmatic/hydrothermal eruption events. On a deposit scale, a complex interplay of depth, proximity to dikes, and structural dilatency during Au-Ag stage fluid pulses controlled localization of economic mineralization, which can be highly variable over meter-scale distances. Bruner appears to belong to a small subset of mid-Miocene epithermal deposits in Nevada with low base metal contents and low to no Se, related to calc- alkaline rhyolite flow-dome complexes. Multiple lines of evidence document decoupled sourcing of Al-Si-K-O from Au-Ag

  9. Morphometric age estimate of the last phase of accelerated uplift in the Kazdag area (Biga Peninsula, NW Turkey)

    NASA Astrophysics Data System (ADS)

    Demoulin, A.; Altin, T. Bayer; Beckers, A.

    2013-11-01

    While the Plio-Quaternary uplift of the Kazdag mountain range (Biga Peninsula, NW Turkey) is generally acknowledged, little is known about its detailed timing. Partly because of this lack of data, the cause of this uplift phase is also debated, being associated either to back-arc extension in the rear of the Hellenic subduction zone, to transpression along the northern edge of the west-moving Anatolian microplate, or to extension driven by gravitational collapse. Here, we perform a morphometric study of the fluvial landscape at the scale of the Biga Peninsula, coupling the recently developed R/SR analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes. While the dependence of profile concavity on basin size confirms that the landscape of the peninsula is still in a transient state, the spatial distribution of profile steepness values characterized by higher values for streams flowing down from the Kazdag massif shows that the latter undergoes higher uplift rates than the rest of the peninsula. We obtain a SR value of 0.324 ± 0.035 that, according to the relation established by Demoulin (2012), yields an age range of 0.5-1.3 Ma and a most probable value of 0.8 Ma for the time of the last tectonic perturbation in the region. In agreement with the analysis of knickpoint migration in a subset of rivers, this suggests that a pulse of uplift occurred at that time and, corroborated by sparse published observations in the Bayramiç and Çanakkale depressions, that the peninsula was uplifted as a whole from that time. This uplift pulse might have been caused by transient compressive conditions in the Anatolian plate when the Eratosthenes seamount came to subduct beneath the Cyprus arc around the early-to-mid Pleistocene transition (Schattner, 2010).

  10. Variations and origin of the atmospheric pollen of Cannabis detected in the province of Tetouan (NW Morocco): 2008-2010.

    PubMed

    Aboulaich, Nadia; Trigo, M Mar; Bouziane, Hassan; Cabezudo, Baltasar; Recio, Marta; El Kadiri, Mohamed; Ater, Mohammed

    2013-01-15

    Cannabis, also called marihuana or hemp, is a wind-pollinated plant that produces hundreds of flowers on large inflorescences. It is also one of the oldest psychoactive plants known to humanity. Morocco has become one of the main producers of Cannabis resin (hashish), primarily supplying the European market. The aim of this paper is to ascertain whether the atmospheric monitoring of Cannabis pollen can play a role, from a criminological point of view, in the surveillance of Cannabis cultivation in the area of Tetouan (NW Morocco) as well as to estimate pollen emission so that the sensitive population can be warned about the allergic diseases that its pollen can cause. Aerobiological samplings were made with the aid of a Hirst type volumetric trap (Hirst, 1952), which worked uninterruptedly during a 3-year period (2008-2010) according to the methodology proposed by the Spanish Aerobiology Network, the REA. Cannabis pollen was present in the atmosphere of Tetouan mainly from early April to late August, a period in which about 95% of the annual counts were registered. The highest levels were detected in June and July, with concentrations more or less evenly distributed throughout the day with slight increases of 5% between 12:00 and 16:00 h. The strong association between skin test reactivity, respiratory symptoms, and pollination period found by other authors, together with the levels registered, suggests that Cannabis pollen could be a clinically important aeroallergen for sensitive patients. On the other hand, the data obtained could serve as an indicator of the cultivation activity of this species and should be taken into account by the state authorities since they provide strong evidence of the existence of Cannabis crops in the region of Tetouan.

  11. Assessment of bedload equations using data obtained with tracers in two coarse-bed mountain streams (Narcea River basin, NW Spain)

    NASA Astrophysics Data System (ADS)

    Vázquez-Tarrío, Daniel; Menéndez-Duarte, Rosana

    2015-06-01

    This paper evaluates the predictive power of nine bedload equations, comparing the results provided by the equations with the bedload rates obtained in a previous field-based tracer experiment accomplished in River Pigüeña and River Coto, two coarse bed streams from NW Spain. Rivers from NW Spain draining the northern watershed of the Cantabrian Mountain range flow into the Bay of Biscay in a short path (50-60 km). In this region, they are developed forested catchments featured by fluvial networks with relatively steep slopes, single-thread sinuous channels, and where bed sediment is typically coarse (cobble and gravel). Tagged stones were used to trace bed sediment movement during flood events in River Pigüeña and River Coto, the two main tributaries of the Narcea River basin. With the tracer results, bedload transport rates between 0.2 and 4.0 kg/s were estimated for six flood episodes. The tracer-based bedload discharges were compared with the bedload rates estimated with the bedload formulae (DuBoys-Straub, Schoklitsch, Meyer Peter-Müller, Bagbold, Einstein, Parker-Klingeman-McLean, Parker-Klingeman, Parker and Wilcock-Crowe). Our assessment shows that all of the bedload equations tend to overestimate when compared with the tracer-based results, with the Wilcock and Crowe (2003) equation the only exception in River Pigüeña. We linked these results to the particular geomorphology of coarse-bed rivers in humid and forested mountain environments. Within these rivers, armored textures and structural arrangements in the bed are ubiquitous; these features, together with a low sediment supply coming from upstream forested reaches, define a supply-limited condition for these channels limiting the potential use of bedload equations. The Wilcock and Crowe (2003) equation introduces complex corrections into the 'hiding function', and this could explain why it performs better.

  12. Insights on high-grade deformation in quartzo-feldspathic gneisses during the early Variscan exhumation of the Cabo Ortegal nappe, NW Iberia

    NASA Astrophysics Data System (ADS)

    José Fernández, Francisco; Llana-Fúnez, Sergio; Valverde-Vaquero, Pablo; Marcos, Alberto; Castiñeiras, Pedro

    2016-04-01

    High-grade, highly deformed gneisses crop out continuously along the Masanteo peninsula and constitute the upper part of the lower crustal section in the Cabo Ortegal nappe (NW Spain). The rock sequence formed by migmatitic quartzo-feldspathic (qz-fsp) gneisses and mafic rocks records the early Ordovician (ca. 480-488 Ma) injection of felsic dioritic/granodioritic dykes at the base of the qz-fsp gneisses, and Devonian eclogitization (ca. 390.4 ± 1.2 Ma), prior to its exhumation. A SE-vergent ductile thrust constitutes the base of quartzo-feldspathic gneissic unit, incorporating mafic eclogite blocks within migmatitic gneisses. A NW-vergent detachment displaced metasedimentary qz-fsp gneisses over the migmatites. A difference in metamorphic pressure of ca. 0.5 GPa is estimated between both gneissic units. The tectono-metamorphic relationships of the basal ductile thrust and the normal detachment bounding the top of the migmatites indicate that both discrete mechanical contacts were active before the recumbent folding affecting the sequence of gneisses during their final emplacement. The progressive tectonic exhumation from eclogite to greenschist facies conditions occurred over ca. 10 Ma and involved bulk thinning of the high-grade rock sequence in the high pressure and high temperature (HP-HT) Cabo Ortegal nappe. The necessary strain was accommodated by the development of a widespread main foliation, dominated by flattening, that subsequently localized to a network of anastomosing shear bands that evolved to planar shear zones. Qz-fsp gneisses and neighbouring mafic granulites were exhumed at > 3 mm yr-1, and the exhumation path involved a cooling of ˜ 20 °C/100 MPa, These figures are comparable to currently active subduction zones, although exhumation P-T trajectory and ascent rates are at the hotter and slower end in comparison with currently active similar settings, suggesting an extremely ductile deformation environment during the exhumation of qz

  13. AgRISTARS documents tracking list report

    NASA Technical Reports Server (NTRS)

    Hawkins, J. L.

    1982-01-01

    A quarterly listing of those documents and related publications that have been issued and placed in the AgRISTARS tracking system is presented. The Tracking List Report provides a catalog, by project, of technical publications arranged by type of document and gives the reference AgRISTARS document numbers, title and date of publication, the issuing organization, and the National Technical Information Service reference number.

  14. 20% PARTIAL SIBERIAN SNAKE IN THE AGS.

    SciTech Connect

    Huang, H; Bai, M; Brown, K A; Glenn, W; Luccio, A U; Mackay, W W; Montag, C; Ptitsyn, V; Roser, T; Tsoupas, N; Zeno, K; Ranjbar, V; Spinka, H; Underwood, D

    2002-11-06

    An 11.4% partial Siberian snake was used to successfully accelerate polarized proton through a strong intrinsic depolarizing spin resonance in the AGS. No noticeable depolarization was observed. This opens up the possibility of using a 20% to 30% partial Siberian snake in the AGS to overcome all weak and strong depolarizing spin resonances. Some design and operation issues of the new partial Siberian snake are discussed.

  15. Three-dimensional Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O heterostructures for improving photocatalytic activity

    SciTech Connect

    He, Xiaoyu; Hu, Chenguo; Xi, Yi; Zhang, Kaiyou; Hua, Hao

    2014-02-01

    Highlights: • Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O 3D network heterostructures are prepared via a simple precipitatation method. • Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O networks exhibit much enhanced photocatalytic activity. • High photocatalytic activity is attributed to its heterostructure and 3D architectures. - Abstract: Three-dimensional Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O heterostructures were fabricated by loading Ag{sub 2}O nanoparticles on WO{sub 3}·0.33H{sub 2}O 3D networks via a simple chemical precipitation method. The Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O heterostructures exhibited much enhanced photocatalytic activity for the degradation of methylene blue (MB) under simulated solar light irradiation. The optimal molar ratio of Ag{sub 2}O and WO{sub 3}·0.33H{sub 2}O is 1:2. The outstanding photocatalytic activity of the Ag{sub 2}O/WO{sub 3}·0.33H{sub 2}O can be attributed to its large surface area of the three-dimensional networks, the enhanced sunlight absorption and the prevention of electrons–holes combination from the heterostructures. The experiment result demonstrates that wide band gap semiconductor (WO{sub 3}·0.33H{sub 2}O) modified by narrow band gap metal oxide (Ag{sub 2}O) with 3D architecture will be an effective route to enhance its photocatalytic activity.

  16. Acceleration of polarized protons in the AGS

    SciTech Connect

    Tsoupas, N.; Ahrens, L.; Bai, M.; Brown, K.; Courant, E.; Glenn, J.W.; Huang, H.; Luccio, A.; MacKay, W.W.; Roser, T.; Schoefer, V.; Zeno, K.

    2010-02-25

    The high energy (s{sup 1/2} = 500 GeV) polarized proton beam experiments performed in RHIC, require high polarization of the proton beam. With the AGS used as the pre-injector to RHIC, one of the main tasks is to preserve the polarization of the proton beam, during the beam acceleration in the AGS. The polarization preservation is accomplished by the two partial helical magnets [1,2,3,4,5,6,7] which have been installed in AGS, and help overcome the imperfection and the intrinsic spin resonances which occur during the acceleration of protons. This elimination of the intrinsic resonances is accomplished by placing the vertical tune Q{sub y} at a value close to 8.98, within the spin-tune stop-band created by the snake. At this near integer tune the perturbations caused by the partial helical magnets is large resulting in large beta and dispersion waves. To mitigate the adverse effect of the partial helices on the optics of the AGS, we have introduced compensation quads[2] in the AGS. In this paper we present the beam optics of the AGS which ameliorates this effect of the partial helices.

  17. A visible-light-driven core-shell like Ag2S@Ag2CO3 composite photocatalyst with high performance in pollutants degradation.

    PubMed

    Yu, Changlin; Wei, Longfu; Zhou, Wanqin; Dionysiou, Dionysios D; Zhu, Lihua; Shu, Qing; Liu, Hong

    2016-08-01

    A series of Ag2S-Ag2CO3 (4%, 8%, 16%, 32% and 40% Ag2S), Ag2CO3@Ag2S (32%Ag2S) and Ag2S@Ag2CO3 (32%Ag2S) composite photocatalysts were fabricated by coprecipitation or successive precipitation reaction. The obtained catalysts were analyzed by N2 physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photocurrent test. Under visible light irradiation, the influences of Ag2S content and core-shell property on photocatalytic activity and stability were evaluated in studies focused on the degradation of methyl orange (MO) dye, phenol, and bisphenol A. Results showed that excellent photocatalytic performance was obtained over Ag2S/Ag2CO3 composite photocatalysts with respect to Ag2S and Ag2CO3. With optimal content of Ag2S (32 wt%), the Ag2S-Ag2CO3 showed the highest photocatalytic degradation efficiency. Moreover, the structured property of Ag2S/Ag2CO3 greatly influenced the activity. Compared with Ag2S-Ag2CO3 and Ag2CO3@Ag2S, core-shell like Ag2S@Ag2CO3 demonstrated the highest activity and stability. The main reason for the boosting of photocatalytic performance was due to the formation of Ag2S/Ag2CO3 well contacted interface and unique electron structures. Ag2S/Ag2CO3 interface could significantly increase the separation efficiency of the photo-generated electrons (e(-)) and holes (h(+)), and production of OH radicals. More importantly, the low solubility of Ag2S shell could effectively protect the core of Ag2CO3, which further guarantees the stability of Ag2CO3. PMID:27236845

  18. Crystallization and preliminary X-ray analysis of a monomeric mutant of Azami-Green (mAG), an Aequorea victoria green fluorescent protein-like green-emitting fluorescent protein from the stony coral Galaxea fascicularis.

    PubMed

    Ebisawa, Tatsuki; Yamamura, Akihiro; Kameda, Yasuhiro; Hayakawa, Kou; Nagata, Koji; Tanokura, Masaru

    2009-12-01

    Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first monomeric green-emitting fluorescent protein that is not a derivative of Aequorea victoria green fluorescent protein (avGFP). mAG and avGFP are 27% identical in amino-acid sequence. Diffraction-quality crystals of recombinant mAG were obtained by the sitting-drop vapour-diffusion method using PEG 3350 as the precipitant. The mAG crystal diffracted X-rays to 2.20 A resolution on beamline AR-NW12A at the Photon Factory (Tsukuba, Japan). The crystal belonged to space group P1, with unit-cell parameters a = 41.78, b = 51.72, c = 52.89 A, alpha = 90.96, beta = 103.41, gamma = 101.79 degrees. The Matthews coefficient (V(M) = 2.10 A(3) Da(-1)) indicated that the crystal contained two mAG molecules per asymmetric unit.

  19. Investigation of the structure of a Ag/Pd/Ag( 1 1 1 ) trilayer by means of electronic spectroscopies

    NASA Astrophysics Data System (ADS)

    Dumont, J.; Ghijsen, J.; Sporken, R.

    2002-06-01

    The growth of the Ag/Pd/Ag system has been studied by X-ray photoelectron spectroscopy and low energy electron diffraction. No chemical reaction or interdiffusion was observed between the Pd and Ag layers. The growth of the Pd interlayer follows the Frank Van der Merwe mode but is not pseudomorphic on the Ag(1 1 1) substrate. The growth of the top Ag layer on the Pd interlayer is pseudomorphic and layer by layer but contains around 12% of voids.

  20. Gate modulation of anodically etched gallium arsenide nanowire random network

    NASA Astrophysics Data System (ADS)

    Aikawa, Shinya; Yamada, Kohei; Asoh, Hidetaka; Ono, Sachiko

    2016-06-01

    Gallium arsenide nanowires (GaAs NWs) formed by anodic etching show an electrically semi-insulating behavior because of charge carrier depletion caused by high interface state density. Here, we demonstrate the gate modulation of an anodically etched GaAs NW random network. By applying a reverse bias voltage after anodic etching of bulk GaAs, hydrogen ion exposure of the depleted NW region occurs, and then the interface state density is possibly decreased owing to the reduction in the amount of excess As generated at the interface between the amorphous Ga2O3 and GaAs layers. Consequently, the drain current of the thin-film transistor (TFT) with the GaAs NW random network was increased and was changed by the gate voltage. In contrast, the random network film remained in the insulator in the absence of reverse electrolysis treatment. The TFT performance is still insufficient but may be improved by optimizing the hydrogen ion exposure conditions.

  1. Facile synthesis of sunlight-driven AgCI:Ag plasmonic nanophotocatalyst.

    SciTech Connect

    An, C.; Peng, S.; Sun, Y.; Center for Nanoscale Materials; Univ. of Illinois

    2010-06-18

    Highly efficient plasmonic photocatalysts of AgCl:Ag hybrid nanoparticles are successfully synthesized via a one-pot synthetic approach involving a precipitation reaction followed by polyol reduction. The as-synthesized nanoparticles exhibit high catalytic performance under visible light and sunlight for decomposing organics, such as methylene blue.

  2. Beet Juice-Induced Green Fabrication of Plasmonic AgCl/Ag Nanoparticles

    EPA Science Inventory

    A simple, green, and fast approach (complete within 5 min) was explored for the fabrication of hybrid AgCl/Ag plasmonic nanoparticles under microwave (MW) irradiation. In this method, beet juice served as a reducing reagent, which is an abundant sugar-rich agricultural produce. I...

  3. Ultra-Fast Synthesis for Ag2Se and CuAgSe Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    DUAN, H. Z.; LI, Y. L.; ZHAO, K. P.; QIU, P. F.; SHI, X.; CHEN, L. D.

    2016-10-01

    Ag2Se and CuAgSe have been recently reported as promising thermoelectric materials at room temperature. The traditional melting-annealing-sintering processes are used to grow Ag2Se and CuAgSe materials with the disadvantages of high costs of energy and time. In this work, phase-pure polycrystalline Ag2Se and CuAgSe compounds were synthesized from raw elemental powders directly by manual mixing followed by spark plasma sintering (MM-SPS) in a few minutes. The influence of SPS heating rate on the phase composition, microstructure, and thermoelectric properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity, were investigated. The zTs of 0.8 at 390 K and 0.6 at 450 K are obtained for Ag2Se and CuAgSe, respectively, which is comparable with the values in the materials prepared by the traditional method. Furthermore, this ultrafast sample synthesis can significantly save material synthesis time and thus has the obvious advantage for large-scale production.

  4. EXAFS Studies of Bimetallic Ag-Pt and Ag-Pd Nanorods

    SciTech Connect

    Lahiri, D.; Chattopadhyay, S.; Bunker, B.A.; Doudna, C.M.; Bertino, M.F.; Blum, F.; Tokuhiro, A.; Terry, J.

    2008-10-30

    Nanoparticles of Ag-Pt and Ag-Pd with high aspect ratios were synthesized using a radiolysis method. Gamma rays at dose rates below 0.5 kGy/h were used for irradiation. The nanoparticles were characterized by transmission electron microscopy (TEM), optical absorption spectroscopy and x-ray Absorption Fine Structure (XAFS) spectroscopy. Bright field micrographs show that Ag-Pt nanowires are composed of large particles with diameters ranging from 20-30 nm and joined by filaments of diameter between 2-5 nm. The Ag-Pd nanowires have diameters of 20-25 nm and lengths of 1.5 {micro}m. For XAFS measurements, the Pt L3 edge (11.564 keV), Ag K-edge (25.514 keV) and Pd K-edge (24.350 keV) were excited to determine the local structure around the respective atoms in the cluster. The Ag-Pt particles were found to possess a distinct core-shell structure with Pt in the core surrounded by Ag shell, with no indication of alloy formation. However, nanorods of Ag-Pd have formed an alloy for all the alloy compositions.

  5. Ultra-Fast Synthesis for Ag2Se and CuAgSe Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    DUAN, H. Z.; LI, Y. L.; ZHAO, K. P.; QIU, P. F.; SHI, X.; CHEN, L. D.

    2016-06-01

    Ag2Se and CuAgSe have been recently reported as promising thermoelectric materials at room temperature. The traditional melting-annealing-sintering processes are used to grow Ag2Se and CuAgSe materials with the disadvantages of high costs of energy and time. In this work, phase-pure polycrystalline Ag2Se and CuAgSe compounds were synthesized from raw elemental powders directly by manual mixing followed by spark plasma sintering (MM-SPS) in a few minutes. The influence of SPS heating rate on the phase composition, microstructure, and thermoelectric properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity, were investigated. The zTs of 0.8 at 390 K and 0.6 at 450 K are obtained for Ag2Se and CuAgSe, respectively, which is comparable with the values in the materials prepared by the traditional method. Furthermore, this ultrafast sample synthesis can significantly save material synthesis time and thus has the obvious advantage for large-scale production.

  6. Ultra-sensitive detection of Ag+ ions based on Ag+-assisted isothermal exponential degradation reaction.

    PubMed

    Zhao, Jing; Fan, Qi; Zhu, Sha; Duan, Aiping; Yin, Yongmei; Li, Genxi

    2013-01-15

    Ag(+) ions are greatly toxic to a lot of algae, fungi, viruses and bacteria, which can also induce harmful side-effects to environments and human health. Herein we report an ultra-sensitive method for the selective detection of Ag(+) ions with electrochemical technique based on Ag(+)-assisted isothermal exponential degradation reaction. In the presence of Ag(+), mismatched trigger DNA can transiently bind to template DNA immobilized on an electrode surface through the formation of C-Ag(+)-C base pair, which then initiates the isothermal exponential degradation reaction. As a result, the mismatched trigger DNA may melt off the cleaved template DNA to trigger rounds of elongation and cutting. After the cyclic degradation reactions, removal of the template DNA immobilized on the electrode surface can be efficiently monitored by using electrochemical technique to show the status of the electrode surface, which can be then used to determine the presence of Ag(+). Further studies reveal that the proposed method can be ultra-sensitive to detect Ag(+) at a picomolar level. The selectivity of the detection can also be satisfactory, thus the proposed method for the Ag(+) ions detection may be potentially useful in the future. PMID:22921090

  7. Ag on Si(111) from basic science to application

    SciTech Connect

    Belianinov, Aleksey

    2012-01-01

    In our work we revisit Ag and Au adsorbates on Si(111)-7x7, as well as experiment with a ternary system of Pentacene, Ag and Si(111). Of particular interest to us is the Si(111)-(√3x√3)R30°}–Ag (Ag-Si-√3 hereafter). In this thesis I systematically explore effects of Ag deposition on the Ag-Si-√3 at different temperatures, film thicknesses and deposition fluxes. The generated insight of the Ag system on the Si(111) is then applied to generate novel methods of nanostructuring and nanowire growth. I then extend our expertise to the Au system on the Ag-Si(111) to gain insight into Au-Si eutectic silicide formation. Finally we explore behavior and growth modes of an organic molecule on the Ag-Si interface.

  8. Enhanced thermoelectric performance of CdO : Ag nanocomposites.

    PubMed

    Gao, Linjie; Wang, Shufang; Liu, Ran; Zha, Xinyu; Sun, Niefeng; Wang, Shujie; Wang, Jianglong; Fu, Guangsheng

    2016-07-26

    CdO : Ag nanocomposites with metallic Ag nanoparticles embedded in the polycrystalline CdO matrix were synthesized by the solid-state reaction method. The addition of Ag led to increased grain boundaries of CdO and created numerous CdO/Ag interfaces. By incorporating Ag into the CdO matrix, the power factor was increased which was probably due to the carrier energy filtering effect induced by the enhanced energy-dependent scattering of electrons. In addition, reduced thermal conductivity was also achieved by stronger phonon scattering from grain boundaries, CdO/Ag interfaces and Ag nanoparticles. These concomitant effects resulted in enhanced ZT values for all CdO : Ag nanocomposites, demonstrating that the strategy of introducing metallic Ag nanoparticles into the CdO host was very effective in optimizing the thermoelectric performance. PMID:27411573

  9. Digital geologic map of the Thirsty Canyon NW quadrangle, Nye County, Nevada

    USGS Publications Warehouse

    Minor, S.A.; Orkild, P.P.; Sargent, K.A.; Warren, R.G.; Sawyer, D.A.; Workman, J.B.

    1998-01-01

    This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern Nevada. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic and tectonic interest. The Thirsty Canyon NW quadrangle is located in southern Nye County about 20 km west of the Nevada Test Site (NTS) and 30 km north of the town of Beatty. The map area is underlain by extensive layers of Neogene (about 14 to 4.5 million years old [Ma]) mafic and silicic volcanic rocks that are temporally and spatially associated with transtensional tectonic deformation. Mapped volcanic features include part of a late Miocene (about 9.2 Ma) collapse caldera, a Pliocene (about 4.5 Ma) shield volcano, and two Pleistocene (about 0.3 Ma) cinder cones. Also documented are numerous normal, oblique-slip, and strike-slip faults that reflect regional transtensional deformation along the southern part of the Walker Lane belt. The Thirsty Canyon NW map provides new geologic information for modeling groundwater flow paths that may enter the map area from underground nuclear testing areas located in the NTS about 25 km to the east. The geologic map database comprises six component ArcINFO map coverages that can be accessed after decompressing and unbundling the data archive file (tcnw.tar.gz). These six coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt) are formatted here in ArcINFO EXPORT format. Bundled with this database are two PDF files for readily viewing and printing the map, accessory graphics, and a description of map units and compilation methods.

  10. Crust-mantle accommodation of Africa-Eurasia convergence in the NW-Moroccan margin

    NASA Astrophysics Data System (ADS)

    Zlotnik, S.; Jimenez-Munt, I.; Fernandez, M.

    2011-12-01

    Recent studies carried out in NW-Africa indicate prominent variations of the lithosphere-asthenosphere boundary (LAB) depth. The studies combine gravity, geoid, surface heat flow, elevation and seismic data along a profile running from the Tagus Abyssal Plain to the Sahara Platform and crossing the Gorringe Bank, the NW Moroccan Margin and the Atlas Mountains. The resulting mantle density anomalies show a prominent lithospheric mantle thickening beneath the margin (LAB >200 km-depth) followed by thinning beneath the Atlas Mountains (LAB ~90 km-depth). A combination of mantle underthrusting due to oblique convergence together with a viscous dripping fed by lateral mantle dragging can explain the imaged lithospheric structure. The model is consistent with a strong decoupled crustal-mantle mechanical response to the Africa-Eurasia convergence and results in positive/negative dynamic topography in regions with thickened/thinned crust. In this work we go a step further analysing, by means of dynamic numerical simulations, the viscous dragging and the Rayleigh-Taylor-like process. Our goal is to understand the initial lithospheric mantle structure suitable to produce the inferred dynamic process. In addition, we study the key factors controlling the deformation of the lithospheric mantle when submitted to convergence. Using the numerical framework Underworld to carry out the simulations we found the key factors controlling the process. Chief among these factors are lithospheric/mantle viscosity ratio and initial mantle and crustal structure. Nevertheless, the process is not very sensitive to the usual power law parameters for mantle rocks (activation energy and volume, power law exponent, etc.), indicating the importance of the rheology of the upper half of the lithosphere, where the power law is not active. These results allow us to speculate on the past and future evolution of the NW-Moroccan margin which could show the appropriated conditions for subduction initiation.

  11. Anomalous evolution of interfaces in Fe/Ag magnetic multilayer

    NASA Astrophysics Data System (ADS)

    Sharma, Gagan; Gupta, Ranjeeta; Kumar, Dileep; Gupta, Ajay

    2013-12-01

    Interfaces greatly influence the magnetic properties of multilayer nanostructures. In the present work, the x-ray standing wave (XSW) technique along with conversion electron Mössbauer spectroscopy have been used to study the evolution of interfaces in Fe/Ag system as a function of thermal annealing. The XSW technique has sufficient depth resolution so as to determine the concentration profiles of Fe across the two interfaces, namely Fe-on-Ag and Ag-on-Fe independently. In as-deposited Ag/Fe/Ag trilayer, Fe-on-Ag interface has a substantially higher roughness of 1.3 nm as compared to 0.9 nm of Ag-on-Fe interface. It is shown that the observed difference in the roughness of the two interfaces is due to a substantial intermixing between Fe and Ag occurring preferentially at Fe-on-Ag interface. With thermal annealing, the two interfaces exhibit opposite behaviour; while Fe-on-Ag interface exhibits an initial sharpening, Ag-on-Fe interface exhibits a monotonous broadening. Two competing processes occur at the interfaces, (i) interface sharpening as a result of de-mixing, driven by a large positive heat of mixing between Fe and Ag and (ii) increase in topological roughness due to increased thermal agitation. This results in a non-monotonous variation in the roughness of Fe-on-Ag interface. At sufficiently high temperature the layered structure is completely destroyed, leading to formation of Fe and Ag nanoparticles.

  12. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum

    NASA Astrophysics Data System (ADS)

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-01

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10-5 Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

  13. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum

    NASA Astrophysics Data System (ADS)

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-01

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10‑5 Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

  14. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum.

    PubMed

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-16

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10(-5) Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

  15. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum.

    PubMed

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-16

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10(-5) Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains. PMID:27487089

  16. Direct Observations of Explosive Eruptive Activity at a Submarine Volcano, NW Rota-1, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Deardorff, N.; Matsumoto, H.; Cashman, K. V.; Dziak, R. P.; Merle, S. G.

    2006-12-01

    In April 2006, a series of extraordinary observations of a deep-sea volcanic eruption were made at NW Rota-1, located at 14^{circ}36'N in the Mariana arc, western Pacific. This is a conical, basaltic-andesite submarine volcano with a summit depth of 517 m. Explosive eruptive activity at NW Rota-1 was discovered in 2004 and was witnessed again in 2005, but the activity in 2006 was especially vigorous and well documented. During six dives with the remotely operated vehicle Jason II over a period of 7 days, video observations made at close range documented a diverse and increasingly energetic range of volcanic activity that culminated in explosive bursts with flashes of glowing red lava propelled by violently expanding gases. Other notable activity included discreet degassing events, extrusion of sluggish lava flows, explosions that formed dilute density currents and/or expelled rocks and ash tens of meters from the vent, and rapid pressure oscillations apparently caused by the repeated formation and condensation of steam. During the last dive when the highest extrusion rates were observed, quasi-periodic bursts from the vent, each lasting 1-10 minutes, were separated by pauses lasting 10 seconds to a few minutes. Each burst started as a plug of crusted-over lava rose in the vent and was blown apart by expanding gases, producing large lava bombs with distinctly flat, disc-like shapes. A remarkable aspect of these observations was how close Jason II could be to the vent during the eruptions. This was because the pressure of the overlying seawater dampened the energy of the explosions and slowed the velocity of volcanic ejecta. Also, lava degassing could be visualized with great clarity underwater as either clear bubbles (CO2) or opaque yellow clouds (dominated by SO2 and H2S). A portable hydrophone with a 30-hour recording capacity was deployed twice by Jason II at the summit of NW Rota-1 during the 2006 dive series. The hydrophone data extends the visual observations

  17. The Neo-Tethyan subduction zone(s,?) in Azerbaijan, NW Iran: preliminary results

    NASA Astrophysics Data System (ADS)

    Lechmann, Anna; Burg, Jean-Pierre; Faridi, Mohammad

    2015-04-01

    Azerbaijan in NW Iran, and in particular the Khoy ophiolitic complex, require more detailed documentation to integrate them as elements of the Alpine-Himalayan orogenic belt. They are attributed to multiple accretion and collision after subduction and closure of the Tethys Ocean and related seaways. We are interested in the pre- to syn-collisional relationships between the ophiolitic, arc and other magmatic units. This work investigates to what extent single or multiple collisions and orogeny have shaped the NW Iranian Plateau. In particular, we want to understand the changes in deformation style within the collision zone and the effects of several possibly coeval events such as closure of two suture zones separated by an arc and possibly followed by slab break-off(s). Fieldwork focused on sampling the different magmatic rock units to specify the structural record and the structural relationships between the various lithological units. Cretaceous to Quaternary, regionally distributed magmatic rocks were collected to have good resolution of their changes in space and time. Petrological, geochemical and isotope studies will characterize magmatic rocks and their sources. Major and trace element geochemistry of mantle and crustal suites of the Khoy ophiolitic complex help to constrain the tectonic setting. Two complexes were defined on the basis of K-Ar dating (Khalatbari-Jafari et al., 2004). An older, probably subducted ophiolite of Triassic-Jurassic age and a younger non-metamorphic ophiolite of Late Cretaceous age. Fossil-bearing sediments provide stratigraphic ages of important contacts. Preliminary results are present in form of bulk rock and trace element chemistry of ultramafic and mafic rocks of the Khoy ophiolite(s, ?) and offer a first possibility to compare the data with already existing publications. Additionally, petrological studies of various magmatic rocks present first products for a starting discussion on the geodynamic evolution of the NW part of

  18. Pollen loads of eucalypt and other pollen types in birds in NW Spain.

    PubMed

    Calviño-Cancela, María; Neumann, Max

    2015-12-01

    Here we present the amount of pollen of eucalypt and pollen of other types for birds captured in two bird ringing stations for 14 months (March 2014 to April 2015) in NW Spain. Common and latin names of all birds species captured, together with the number of captured individuals (N), prevalence of eucalypt pollen (percentage of individuals with eucalypt pollen) and of pollen of other types and average pollen loads per individual for eucalypt and other pollen types is presented. See [1] for further information and discussion.

  19. Three new species of Pruvotinidae (Mollusca: Solenogastres) from Antarctica and NW Spain

    NASA Astrophysics Data System (ADS)

    Zamarro, Maria; García-Álvarez, Oscar; Urgorri, Victoriano

    2013-09-01

    The family Pruvotinidae (Solenogastres, Cavibelonia) includes thirty species of fifteen genera grouped in five subfamilies. These subfamilies are defined by the combination of the presence or absence of hollow hook-shaped sclerites, the presence or absence of a dorsopharyngeal gland and the type of ventrolateral foregut glandular organs: type A, type C or circumpharyngeal. In this paper, three new species of the family Pruvotinidae are described: Pruvotina artabra n. sp. and Gephyroherpia impar n. sp. from NW Spain, and Pruvotina manifesta n. sp. from Antarctic Peninsula. These new descriptions increase the global knowledge of Solenogastres biodiversity.

  20. Crystal structure and properties of tetragonal EuAg{sub 4}In{sub 8} grown by metal flux technique

    SciTech Connect

    Subbarao, Udumula; Sarkar, Sumanta; Peter, Sebastian C.

    2015-03-15

    The compound EuAg{sub 4}In{sub 8} has been obtained as single crystals in high yield from reactions run in liquid indium. X-ray diffraction on single crystals suggests that EuAg{sub 4}In{sub 8} crystallizes in the CeMn{sub 4}Al{sub 8} structure type, tetragonal space group I4/mmm with lattice constants a=b=9.7937(2) Å and c=5.7492(2) Å. Crystal structure of EuAg{sub 4}In{sub 8} is composed of pseudo Frank–Kasper cages occupied by one europium atom in each ring, which are shared through the corner along the ab plane resulting in a three dimensional network. The magnetic susceptibility of EuAg{sub 4}In{sub 8} was measured in the temperature range 2–300 K, which obeyed Curie–Weiss law above 50 K. Magnetic moment value calculated from the fitting indicates the presence of divalent europium, which was confirmed by X-ray absorption near edge spectroscopy. Electrical resistivity measurements suggest that EuAg{sub 4}In{sub 8} is metallic in nature with a probable Fermi liquid behavior at low temperature. - Graphical abstract: The tetragonal EuAg{sub 4}In{sub 8} has been grown as single crystals from reactions run in liquid indium. Magnetic and XANES measurements suggest divalent nature of Eu and resistivity measurements suggest metallic nature. - Highlights: • EuAg{sub 4}In{sub 8} phase having tetragonal phase is grown by metal flux technique. • Magnetic and XANES measurements exhibit divalent nature of Eu in EuAg{sub 4}In{sub 8}. • Resistivity measurement suggests metallic nature and probable Fermi liquid behavior.

  1. Synthesis, characterization and antimycobacterial activity of Ag(I)-aspartame, Ag(I)-saccharin and Ag(I)-cyclamate complexes.

    PubMed

    Cavicchioli, Maurício; Leite, Clarice Q F; Sato, Daisy N; Massabni, Antonio C

    2007-10-01

    The present work describes the synthesis and antimycobacterial activity of three Ag(I)-complexes with the sweeteners aspartame, saccharin, and cyclamate as ligands, with the aim of finding new candidate substances for fighting tuberculosis and other mycobacterial infections. The minimal inhibitory concentration of these three complexes was investigated in order to determine their in-vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium malmoense, and Mycobacterium kansasii. The MIC values were determined using the Microplate Alamar Blue Assay. The best MIC values found for the complexes were 9.75 microM for Ag(I)-aspartame against M. kansasii and 15.7 microM for Ag(I)-cyclamate against M. tuberculosis.

  2. Groundwater composition near the nickel—copper smelting industry on the Kola Peninsula, central Barents Region (NW Russia and NE Norway)

    NASA Astrophysics Data System (ADS)

    de Caritat, Patrice; Danilova, Svetlana; Jæger, Øystein; Reimann, Clemens; Storrø, Gaute

    1998-07-01

    The chemical composition of 185 groundwater samples collected from two catchments in the extreme NE Norway and NW Russia over the period April 1994 to November 1995 is reported in terms of Ag, Al, As, B, Ba, Be, Bi, Br, Ca, Cd, Cl, Co, Cr, Cu, F, Fe, K, Li, Mg, Mn, Mo, Na, Ni, NO 3, P, Pb, PO 4,Rb, S, Sb, Se, Si, SO 4, Sr, Th, Ti, Tl, U, V and Zn concentrations (as determined by ICP-MS, ICP-AES and IC), pH and electrical conductance. One catchment (C2) is located in Russia 5 km downwind of the nickel—copper ore smelting industry in Monchegorsk, which is a major SO 2 and trace metal emission source, the other (C5) is located in Norway 30 km off-wind from the nickel-copper ore smelter in Nikel and 52 km off-wind from the nickel—copper ore roasting plant of Zapoljarniy, which are also significant emitters of inorganic atmospheric pollutants. Groundwater chemistry mostly reflects the mineralogical composition of the gabbro aquifer in C2 and the Quaternary deposits in C5, although groundwater in C2 also shows signs of incipient contamination from surface waters (heavy metals, sulphate, chloride). Groundwater in C2 appears to have been acidified by S-compounds emitted from Monchegorsk, but the groundwater's capacity to neutralise incoming acidity has not been exhausted. In C5, groundwater has not been acidified to any extent and has a high acid neutralising capacity. This study demonstrates that the geological substrate of a catchment is a fundamental control on how groundwater responds to atmospheric pollution, even if the latter is severe.

  3. Spin coating of Ag nanoparticles: Effect of reduction

    SciTech Connect

    Ansari, A. A. Sartale, S. D.

    2014-04-24

    A surfactant free method for the growth of Ag nanoparticles on glass substrate by spin coating of Ag ions solution followed by chemical reduction in aqueous hydrazine hydrate (HyH) solution has been presented. Appearance of surface plasmon resonance confirms the formation of Ag nanoparticles. Morphology and absorbance spectra of Ag nanoparticles films are used to examine effect of hydrazine concentration on the growth of Ag nanoparticles. SEM images show uniformly distributed Ag nanoparticles. Rate constant was found to be dependent on HyH concentration as a consequence influence particle size.

  4. Template synthesis of Ag/AgCl microrods and their efficient visible light-driven photocatalytic performance

    SciTech Connect

    Chen, Hua; Xiao, Liang; Huang, Jianhua

    2014-09-15

    Highlights: • Preparation ofAg/AgCl microrods by reaction of Ag{sub 2}WO{sub 4} microrods with NaCl solution. • Generation of metallic Ag is induced by the ambient light in the synthesis process. • Ag/AgCl shows excellent visible light-driven photodegradation of organic dyes. - Abstract: Ag/AgCl microrods, aggregated by nanoparticles with a diameter ranging from 100 nm to 2 μm, were prepared by an ion-exchange reaction at 80 °C between Ag{sub 2}WO{sub 4} template and NaCl solution. The existence of metallic Ag species was confirmed by XRD, DRS and XPS measurements. Ag/AgCl microrods showed excellent photocatalytic activity for the degradation of rhodamine B and methylene blue under visible light irradiation. The degradation rate constants of rhodamine B and methylene blue are 0.176 and 0.114 min{sup −1}, respectively. The cycling photodegradation experiments suggest that Ag/AgCl microds could be employed as stable plasmonic photocatalysts for the degradation of organic dyes under visible light irradiation.

  5. Size distributions of chemically synthesized Ag nanocrystals

    NASA Astrophysics Data System (ADS)

    Thøgersen, Annett; Bonsak, Jack; Fosli, Carl Huseby; Muntingh, Georg

    2011-08-01

    Silver nanocrystals made by a chemical reduction of silver salts (AgNO3) by sodium borohydride (NaBH4) were studied using transmission electron microscopy and light scattering simulations. For various AgNO3/NaBH4 molar ratios, the size distributions of the nanocrystals were found to be approximately log-normal. In addition, a linear relation was found between the mean nanocrystal size and the molar ratio. In order to relate the size distribution of Ag nanocrystals of the various molar ratios to the scattering properties of Ag nanocrystals in solar cell devices, light scattering simulations of Ag nanocrystals in Si, SiO2, SiN, and Al2O3 matrices were carried out using MiePlot. These light scattering spectra for the individual nanocrystal sizes were combined into light scattering spectra for the fitted size distributions. The evolution of these scattering spectra with respect to an increasing mean nanocrystal size was then studied. From these findings, it is possible to find the molar ratio for which the corresponding nanocrystal size distribution has maximum scattering at a particular wavelength in the desired matrix.

  6. Mussel-inspired green synthesis of polydopamine-Ag-AgCl composites with efficient visible-light-driven photocatalytic activity.

    PubMed

    Cai, Aijun; Wang, Xiuping; Guo, Aiying; Chang, Yongfang

    2016-09-01

    Polydopamine-Ag-AgCl composites (PDA-Ag-AgCl) were synthesized using a mussel-inspired method at room temperature, where PDA acts as a reducing agent to obtain the noble Ag nanoparticles from a precursor. The morphologies and structures of the as-prepared PDA-Ag-AgCl were characterized by several techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (SEM), Raman spectra, and X-Ray photoelectron spectrum (XPS). The morphological observation depicts formation of nanoparticles with various micrometer size diameters and surface XPS analysis shows presence of various elements including Ag, N, Cl, and O. The enhanced absorbance of the PDA-Ag-AgCl particles in the visible light region is confirmed through UV-Vis diffuse reflectance spectra (DRS), and the charge transfer is demonstrated by photoluminescence (PL) and photocurrent response. The synthesized PDA-Ag-AgCl composites could be used as visible-light-driven photocatalysts for the degradation of Rhodamine B. The elevated photocatalytic activity is ascribed to the effective charge transfer from plasmon-excited Ag to AgCl that can improve the efficiency of the charge separation during the photocatalytic reaction. Furthermore, differences in the photocatalytic performance among the different PDA-Ag-AgCl composites are noticed that could be attributed to the Brunauer-Emmett-Teller (BET) specific surface area, which benefits to capture the visible light efficiently. The PDA-Ag-AgCl exhibits excellent stability without a significant loss in activity after 5cycles. The proposed method is low-cost and environmentally friendly, hence a promising new way to fabricate plasmon photocatalysts. PMID:27450302

  7. Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

    USGS Publications Warehouse

    Luoma, Samuel N.; Tasha Stoiber,; Croteau, Marie-Noele; Isabelle Romer,; Ruth Merrifeild,; Jamie Lead,

    2016-01-01

    Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

  8. Mussel-inspired green synthesis of polydopamine-Ag-AgCl composites with efficient visible-light-driven photocatalytic activity.

    PubMed

    Cai, Aijun; Wang, Xiuping; Guo, Aiying; Chang, Yongfang

    2016-09-01

    Polydopamine-Ag-AgCl composites (PDA-Ag-AgCl) were synthesized using a mussel-inspired method at room temperature, where PDA acts as a reducing agent to obtain the noble Ag nanoparticles from a precursor. The morphologies and structures of the as-prepared PDA-Ag-AgCl were characterized by several techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (SEM), Raman spectra, and X-Ray photoelectron spectrum (XPS). The morphological observation depicts formation of nanoparticles with various micrometer size diameters and surface XPS analysis shows presence of various elements including Ag, N, Cl, and O. The enhanced absorbance of the PDA-Ag-AgCl particles in the visible light region is confirmed through UV-Vis diffuse reflectance spectra (DRS), and the charge transfer is demonstrated by photoluminescence (PL) and photocurrent response. The synthesized PDA-Ag-AgCl composites could be used as visible-light-driven photocatalysts for the degradation of Rhodamine B. The elevated photocatalytic activity is ascribed to the effective charge transfer from plasmon-excited Ag to AgCl that can improve the efficiency of the charge separation during the photocatalytic reaction. Furthermore, differences in the photocatalytic performance among the different PDA-Ag-AgCl composites are noticed that could be attributed to the Brunauer-Emmett-Teller (BET) specific surface area, which benefits to capture the visible light efficiently. The PDA-Ag-AgCl exhibits excellent stability without a significant loss in activity after 5cycles. The proposed method is low-cost and environmentally friendly, hence a promising new way to fabricate plasmon photocatalysts.

  9. Three new Ag(I) coordination architectures based on mixed ligands: Syntheses, structures and photoluminescent properties

    SciTech Connect

    Li, Yamin; Xiao, Changyu; Li, Shu; Chen, Qi; Li, Beibei; Liao, Qian; Niu, Jingyang

    2013-04-15

    Three new silver (I) coordination complexes, [Ag{sub 2}(1,2-bdc)(phdat)]{sub n} (1), [Ag{sub 2}(NO{sub 2}-bdc)(phdat)]{sub n} (2), [Ag{sub 4}(nta){sub 3}(phdat)NO{sub 3}]{sub n} (3) (1,2-bdc=phthalic acid dianion, NO{sub 2}-bdc=5-nitro-1,3-benzenedicarboxylic acid dianion, nta=nicotinic acid anion, phdat=2,4-diamine-6-phenyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of silver nitrate and phdat with the homologous ligands 1,2-H{sub 2}bdc, NO{sub 2}-H{sub 2}bdc, and Hnta, respectively, and characterized by single-crystal X-ray diffractions, IR spectra, elemental analyses thermogravimetric analyses (TGA). The compound 1 exhibits a chiral 3D network with cbs/CrB self-dual topological net, which contains two kinds of single helical chains. For compound 2, the 3D network is comprised of two kinds of similar 2D sheets with the topological symbol of sql-type packed in AABBAA mode by Ag–N/O weakly contacts. And compound 3 has 2D double layer architecture, consisting of the 2D plane with hcb-type topological symbol connected by Ag–O weakly coordinations. The photoluminescent properties associated with the crystal structures of three compounds have also been measured. - Graphical abstract: Three new silver(I) coordination complexes 1–3 have been synthesized and characterized by single-crystal X-ray diffractions, IR spectra, elemental analyses, thermogravimetric analyses (TGA) and photoluminescent spectra. Highlights: ► The compound 1 exhibits a novel chiral 3D network with two kinds of single helical chains. ► 3D or 2D new Ag coordination complexes. ► The photoluminescent properties have been measured.

  10. Electrical conductivity of a system of Ag2SO4:AgI eutectic added to 30Li2SO4:70Ag2SO4

    NASA Astrophysics Data System (ADS)

    Chandrayan, V. R.; Tejpal, A.; Singh, K.

    1989-10-01

    The electrical conductivity of rapidly quenched specimens of 48Ag2SO4:52AgI eutectic added to 30Li2SO4:70Ag2SO4 has been measured as a function of frequency and temperature. The results show a significant enhancement in the conductivity of the 30Li2SO4:70Ag2SO4 system with a maximum value at 12.5 mol. pct eutectic. This phenomenon is explained in terms of the dispersive nature of the fine eutectic crystallites in the crystalline matrix of the Li2SO4:Ag2SO4 system.

  11. A Fabrication Method for Highly Stretchable Conductors with Silver Nanowires.

    PubMed

    Chang, Chia-Wei; Chen, Shih-Pin; Liao, Ying-Chih

    2016-01-01

    Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of stretchable electronic devices is the preparation of stretchable conductors with great mechanical stability. In this study, we developed a simple fabrication method to chemically solder the contact points between silver nanowire (AgNW) networks. AgNW nanomesh was first deposited on a glass slide via spray coating method. A reactive ink composed of silver nanoparticle (AgNPs) precursors was applied over the spray coated AgNW thin films. After heating for 40 min, AgNPs were preferentially generated over the nanowire junctions to solder the AgNW nanomesh, and reinforced the conducting network. The chemically modified AgNW thin film was then transferred to polyurethane (PU) substrates by casting method. The soldered AgNW thin films on PU exhibited no obvious change in electrical conductivity under stretching or rolling process with elongation strains up to 120%. PMID:26862843

  12. Photocurrent enhancement of SiNW-FETs by integrating protein-shelled CdSe quantum dots.

    PubMed

    Moh, Sang Hyun; Kulkarni, Atul; San, Boi Hoa; Lee, Jeong Hun; Kim, Doyoun; Park, Kwang Su; Lee, Min Ho; Kim, Taesung; Kim, Kyeong Kyu

    2016-01-28

    We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 10(6), the highest value compared to other SiNW-based devices in the visible light range. PMID:26755346

  13. One-pot synthesis of ternary Ag₂CO₃/Ag/AgCl photocatalyst in natural geothermal water with enhanced photocatalytic activity under visible light irradiation.

    PubMed

    Yao, Xiaxi; Liu, Xiaoheng

    2014-09-15

    Geothermal water is a clean, cheap and renewable resource and it is widely distributed all over the world. In this work, ternary Ag2CO3/Ag/AgCl photocatalyst has been successfully synthesized via a one-pot precipitation method in natural geothermal water at room temperature, wherein the geothermal water serves as the source of chlorine and carbonate. The results suggest that the Ag/AgCl nanoparticles are anchored on the surface of Ag2CO3 and Ag2CO3/Ag/AgCl composite shows strong absorption ability in the visible light region. The evaluation of the photocatalytic activity indicates that the as-synthesized Ag2CO3/Ag/AgCl photocatalyst exhibits higher photocatalytic performance for the degradation of methylene blue (MB) aqueous solution under visible light irradiation than one-component (Ag2CO3), two-component (Ag/AgCl, Ag2CO3/AgCl) and the mechanical mixture of Ag2CO3 and Ag/AgCl. The trapping experiments confirmed that holes (h(+)) and (•)O2(-) were the two main active species in the photocatalytic process. Finally, a possible Z-scheme photocatalytic mechanism of the charge transfer was proposed for the enhanced photocatalytic performance. This work may open up new insights into the application of cheap geothermal water resources in the word and provide new opportunities for facile fabrication of Ag/AgCl-based photocatalysts.

  14. Bipolar Ag-Zn battery

    NASA Technical Reports Server (NTRS)

    Giltner, L. John

    1994-01-01

    The silver-zinc (AgZn) battery system has been unique in its ability to safely satisfy high power demand applications with low mass and volume. However, a new generation of defense, aerospace, and commercial applications will impose even higher power demands. These new power demands can be satisfied by the development of a bipolar battery design. In this configuration the power consuming, interelectrode current conductors are eliminated while the current is then conducted via the large cross-section electrode substrate. Negative and positive active materials are applied to opposite sides of a solid silver foil substrate. In addition to reducing the weight and volume required for a specified power level, the output voltage performance is also improved as follows. Reduced weight through: elimination of the plastic cell container; elimination of plate leads and intercell connector; and elimination of internal plate current collector. Increased voltage through: elimination of resistance of current collector; elimination of resistance of plate lead; and elimination of resistance of intercell connector. EPI worked previously on development of a secondary bipolar silver zinc battery. This development demonstrated the electrical capability of the system and manufacturing techniques. One difficulty with this development was mechanical problems with the seals. However, recent improvements in plastics and adhesives should eliminate the major problem of maintaining a seal around the periphery of the bipolar module. The seal problem is not as significant for a primary battery application or for a requirement for only a few discharge cycles. A second difficulty encountered was with activation (introducing electrolyte into the cell) and with venting gas from the cell without loss of electrolyte. During previous work, the following projections for energy density were made from test data for a high power system which demonstrated in excess of 50 discharge/charge cycles. Projected

  15. AG Channel Measurement and Modeling Results for Over-Water and Hilly Terrain Conditions

    NASA Technical Reports Server (NTRS)

    Matolak, David W.; Sun, Ruoyu

    2015-01-01

    This report describes work completed over the past year on our project, entitled "Unmanned Aircraft Systems (UAS) Research: The AG Channel, Robust Waveforms, and Aeronautical Network Simulations." This project is funded under the NASA project "Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS)." In this report we provide the following: an update on project progress; a description of the over-freshwater and hilly terrain initial results on path loss, delay spread, small-scale fading, and correlations; complete path loss models for the over-water AG channels; analysis for obtaining parameter statistics required for development of accurate wideband AG channel models; and analysis of an atypical AG channel in which the aircraft flies out of the ground site antenna main beam. We have modeled the small-scale fading of these channels with Ricean statistics, and have quantified the behavior of the Ricean K-factor. We also provide some results for correlations of signal components, both intra-band and inter-band. An updated literature review, and a summary that also describes future work, are also included.

  16. New isomeric state in {sup 116}Ag

    SciTech Connect

    Batchelder, J.C.; Carter, H.K.; Spejewski, E.H.; Bingham, C.R.; Fong, D.; Hamilton, J.H.; Hwang, J.K.; Ramayya, A.V.; Garrett, P.E.; Hartley, D.J.; Krolas, W.; Kulp, W.D.; Wood, J.L.; Larochelle, Y.; Tantawy, M.N.; Piechaczek, A.

    2005-10-01

    A new isomer in {sup 116}Ag with a half-life of 20(1) s has been discovered through the use of conversion electron, {beta}, and {gamma} spectroscopy of on-line mass-separated radioactivities at the Holifield Radioactive Ion Beam Facility at ORNL. The observed electron peaks at 22.5, 44.42, and 47.33 keV were interpreted as the K,L, and M conversion electron lines resulting from a 47.9-keV E3 transition associated with the decay of a second isomeric level in {sup 116}Ag. A new level structure of {sup 116}Ag is proposed, with the levels identified as the 0{sup -} ground-state and isomers at 47.9 and 128.8 keV having spin/parities of 3{sup +} and 6{sup -} respectively.

  17. Adsorption of sulfur on Ag(100)

    SciTech Connect

    Russell, Selena M.; Shen, Mingmin; Liu, Da-Jiang; Thiel, Patricia A.

    2010-12-17

    We have used scanning tunneling microscopy and density Functional theory to investigate the structures formed by sulfur on Ag(100). As indicated by previous low-energy electron diffraction studies, the main phases have unit cells of p(2 x 2) and ({radical}17 x {radical}17)R14{sup o}. We show that the latter is a reconstruction. The favored structural model is one in which 5 Ag atoms are missing from the (100) surface plane per unit cell. The ejected Ag atoms combine with sulfur to form islands of the reconstructed phase on the terraces. The ({radical}17 x {radical}17)R14{sup o} phase coexists with the p(2 x 2), at sulfur coverages slightly above 0.25 monolayers. In addition, chain-like structures are observed in STM, both at room temperature (where they are dynamic) and below (where they are not). These results are compared with relevant literature for copper surfaces.

  18. Nonequilibrium microstructures for Ag-Ni nanowires.

    PubMed

    Rai, Rajesh K; Srivastava, Chandan

    2015-04-01

    This work illustrates that a variety of nanowire microstructures can be obtained either by controlling the nanowire formation kinetics or by suitable thermal processing of as-deposited nanowires with nonequilibrium metastable microstructure. In the present work, 200-nm diameter Ag-Ni nanowires with similar compositions, but with significantly different microstructures, were electrodeposited. A 15 mA deposition current produced nanowires in which Ag-rich crystalline nanoparticles were embedded in a Ni-rich amorphous matrix. A 3 mA deposition current produced nanowires in which an Ag-rich crystalline phase formed a backbone-like configuration in the axial region of the nanowire, whereas the peripheral region contained Ni-rich nanocrystalline and amorphous phases. Isothermal annealing of the nanowires illustrated a phase evolution pathway that was extremely sensitive to the initial nanowire microstructure.

  19. Spectrophotometry of the shell around AG Carinae

    NASA Technical Reports Server (NTRS)

    Mitra, P. Mila; Dufour, Reginald J.

    1990-01-01

    Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances and ionization structure are calculated and compared with other types of planetary nebulae and shells around other luminous stars. It is found that the N/O and N/S ratios of Ag Car are high compared to solar neighborhood ISM values. The O/H depletion found for the AG Car shell approaches that found in the condensations of the Eta Car system.

  20. Is global change a real threat for conservation of the NW Mediterranean marine biodiversity?

    NASA Astrophysics Data System (ADS)

    Garrabou, J.; Dimar Team

    2003-04-01

    An increasing body of evidence is demonstrating that global change is already affecting terrestrial and marine ecosystems. Coastal marine habitats are a main subject of attention because they harbour a high biological diversity, are among the most productive systems of the world and present high anthropogenic interaction levels. Most studies on the effects of global change on marine ecosystems have focused on tropical habitats but effects on marine habitats at higher latitudes have been increasingly reported during the last decades. We examined the case of the NW Mediterranean sublittoral habitats for which a warming trend in water temperature has already been detected. The actual and potential responses of different taxonomic groups have been examined. We found a clear trend in northward range shifts for a number of species and an increase in disease and mass mortalities events during the last two decades. Therefore, significant modifications of diversity are expected in the next decades in the NW Mediterranean (at least at local scale), through species' immigrations, extinctions or shifts, and potential subsequent cascade effects. These modifications could ultimately disrupt ecosystem functions. Since the Mediterranean, with only 0.82 % of oceans' surface, harbours 4 to 18 % of total marine biodiversity, potential effects of global change in this area could have dramatic consequences for the conservation of the marine diversity, world-wide.

  1. Paleomagnetic investigation of the Early Permian Panjal Traps of NW India; regional tectonic implications

    NASA Astrophysics Data System (ADS)

    Stojanovic, Denis; Aitchison, Jonathan C.; Ali, Jason R.; Ahmad, Talat; Dar, Reyaz Ahmad

    2016-01-01

    The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafic suites (Abor, Sikkim etc.) that were erupted onto northern India (present-day coordinates) around the same time as separation of the Cimmerian blocks of Qiangtang and Sibumasu. We report new data from only the second paleomagnetic investigation of this unit. Standard alternating field and thermal demagnetization methods were used to isolate characteristic magnetizations from seven outcrops at three locations within the Kashmir Valley, NW India. Analysis of four sections (14 individual cooling units) from close to Srinagar, that together form a tectonically coherent sequence spanning ∼3 km of stratigraphy, yield a single-component, primary magnetization with a mean direction of Dec: 134.8°, Inc: 55.3° (α95 = 8.9°, k = 21.0). An inclination-only mean of 52.5° (α95 = 8.9°, k = 47.2) gives a paleolatitude of ∼33°S (±5°). A paleopole of 110.5°E 8.4°S (A95 = 10.7) is also calculated. Assuming the magnetization records a portion of the reverse polarity Kiaman Superchron, the new result indicates extrusion of the Panjal Traps basalts at mid-latitudes in the southern hemisphere. By inference this constrains the location of central Gondwana, and informs debates related to Cimmeria's detachment from Gondwana.

  2. A mid-Holocene candidate tsunami deposit from the NW Cape (Western Australia)

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Falvard, Simon; Norpoth, Maike; Pint, Anna; Brill, Dominik; Engel, Max; Scheffers, Anja; Dierick, Manuel; Paris, Raphaël; Squire, Peter; Brückner, Helmut

    2016-03-01

    Although extreme-wave events are frequent along the northwestern coast of Western Australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally, robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking. Based on the analyses of X-ray computed microtomography (μCT) of oriented sediment cores, multi-proxy sediment and microfaunal analyses, optically stimulated luminescence (OSL) and 14C-AMS dating, this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back-barrier depression on the NW Cape Range peninsula. The event layer consists of material from the adjacent beach and dune, fines and thins inland, and was traced up to ~ 400 m onshore. Although a cyclone-induced origin cannot entirely be ruled out, the particular architecture and fabric of the sediment, rip-up clasts and three subunits point to deposition by a tsunami. As such, it represents the first stratigraphical evidence of a prehistoric, mid-Holocene tsunami in NW Western Australia. It was OSL-dated to 5400-4300 years ago, thus postdating the regional mid-Holocene sea-level highstand.

  3. Kashmir Basin Fault and its tectonic significance in NW Himalaya, Jammu and Kashmir, India

    NASA Astrophysics Data System (ADS)

    Shah, A. A.

    2015-10-01

    The Kashmir Basin Fault is located in the Jammu and Kashmir region of Kashmir Basin in NW Himalaya, India. It is a classic example of an out-of-sequence thrust faulting and is tectonically active as observed from multiple geological evidences. Its geomorphology, structure and lateral extent indicate significant accommodation of stress since long, which is further supported by the absence of a large earthquake in this region. It seems this fault is actively accommodating some portion of the total India-Eurasia convergence, apart from two well-recognised active structures the Medlicott-Wadia Thrust and the Main Frontal Thrust, which are referred in Vassallo et al. (Earth Planet Sci Lett 411:241-252, 2015). This requires its quantification and inclusion into slip distribution scheme of NW Himalaya. Therefore, it should be explored extensively because this internal out-of-sequence thrust could serve major seismic hazard in KB, repeating a situation similar to Muzaffarabad earthquake of Northern Pakistan in 2005.

  4. New Insight Into The Crustal Structure of The Continental Margin Off NW Sabah/borneo

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Franke, D.; Behain, D.; Meyer, H.

    The continental margin offshore NW Sabah/Borneo (Malaysia) has been investigated with reflection and refraction seismics, magnetics, and gravity during the recent cruise BGR01-POPSCOMS. A total of 4000 km of geophysical profiles has been acquired, thereof 2900 km with reflection seismics. Like in major parts of the South China Sea, the area seaward of the Sabah Trough consists of extended continental lithosphere. We found evidence that the continental crust also underlies the continental slope land- ward of the Trough, a fact that raises many questions about the tectonic history and development of this margin. The characteristic pattern of rotated fault blocks and half grabens and the carbon- ates which are observed all over the Dangerous Grounds can be traced a long way landward of the Sabah Trough beneath the sedimentary succession of the upper plate. The magnetic anomalies which are dominated by the magnetic signatures of relatively young volcanic features also continue under the continental slope. The sedimentary rocks of the upper plate, in contrast, seem to generate hardly any magnetic anoma- lies. We suspect that the volcanic activity coincided with the collision of Borneo and the Dangerous Grounds in middle or late Miocene time. The emplacement of an al- lochtonous terrane on top of the extended continental lithosphere could be explained by overthrusting as a result of the collision or it could be related to gravity sliding following a broad uplift of NW Borneo at the same time.

  5. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao )

    1996-01-01

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  6. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao

    1996-12-31

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil & gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  7. Feeding and production of zooplankton in the Catalan Sea (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Saiz, Enric; Calbet, Albert; Atienza, Dacha; Alcaraz, Miquel

    2007-08-01

    Zooplankton are key components of the structure and functioning of marine planktonic food webs. They are the main link of planktonic primary production towards top pelagic consumer levels (fish), and play a relevant role on the nutrient recycling in the water column and on the export of particulate matter out of the photic zone. In this paper, we review the present knowledge on the feeding and production of zooplankton in the Catalan Sea (NW Mediterranean), with special emphasis on copepods. Feeding of zooplankton in the Catalan Sea appears typically food limited, with average daily rations on a yearly basis in the order of 48% body C d -1. Heterotrophic prey constitute a relevant fraction of their diet, as an alternative to the scarce phytoplankton in the area. From a structural point of view, the trophic impact and control of their prey populations are low on standing stocks but, at certain times, zooplankton can exert a meaningful effect on their prey production. Regarding zooplankton production, the available estimates of growth rates in the area are based on the egg production rate of copepods. Egg production rates appear to be limited, especially in summer. Tentative estimates of copepod production in the area are in the order of 20-40 mg C m -2 d -1. In conclusion, this review confirms that the oligotrophic character of the NW Mediterranean constrains the feeding activity and production of zooplankton.

  8. Organic micropollutants in coastal waters from NW Mediterranean Sea: sources distribution and potential risk.

    PubMed

    Sánchez-Avila, Juan; Tauler, Romà; Lacorte, Silvia

    2012-10-01

    This study provides a first estimation on the sources, distribution and risk of organic micropollutants (OMPs) in coastal waters from NW Mediterranean Sea. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, phthalates and alkylphenols were analyzed by solid phase extraction and gas chromatography coupled to tandem mass spectrometry (SPE-GC-EI-MS/MS). River waters and wastewater treatment plant effluents discharging to the sea were identified as the main sources of OMPs to coastal waters, with an estimated input amount of around of 25,800 g d(-1). The concentration of ΣOMPs in coastal areas ranged from 17.4 to 8442 ng L(-1), and was the highest in port waters, followed by coastal and river mouth seawaters. A summarized overview of the patterns and sources of OMP contamination on the investigated coastal sea waters of NW Mediterranean Sea, as well as of their geographical distribution was obtained by Principal Component Analysis of the complete data set after its adequate pretreatment. Alkylphenols, bisphenol A and phthalates were the main contributors to ΣOMPs and produced an estimated significant pollution risk for fish, algae and the sensitive mysid shrimp organisms in seawater samples. The combination of GC-MS/MS, chemometrics and risk analysis is proven to be useful for a better control and management of OMP discharges. PMID:22706016

  9. Substantial Improvement of Short Wavelength Response in n-SiNW/PEDOT:PSS Solar Cell

    NASA Astrophysics Data System (ADS)

    Ge, Zhaoyun; Xu, Ling; Cao, Yunqing; Wu, Tao; Song, Hucheng; Ma, Zhongyuan; Xu, Jun; Chen, Kunji

    2015-08-01

    We report herein on the effects of silicon nanowire with different morphology on the device performance of n-SiNW/PEDOT:PSS hybrid solar cells. The power conversion efficiency (PCE) and external quantum efficiency (EQE) of the SiNW/PEDOT:PSS hybrid solar cells can be optimized by varying the length of the silicon nanowires. The optimal length of silicon nanowires is 0.23 μm, and the hybrid solar cell with the optimal length has the V oc of 569 mV, J sc of 30.1 mA/cm2, and PCE of 9.3 %. We fabricated more isolated silicon nanowires with the diluted etching solution. And the J sc of the hybrid solar cell with more isolated nanowires has a significant enhancement, from 30.1 to 33.2 mA/cm2. The remarkable EQE in the wavelength region of 300 and 600 nm was also obtained, which are in excess of 80 %. Our work provides a simple method to substantially improve the EQE of hybrid solar cell in the short wavelength region.

  10. Photocurrent enhancement of SiNW-FETs by integrating protein-shelled CdSe quantum dots

    NASA Astrophysics Data System (ADS)

    Moh, Sang Hyun; Kulkarni, Atul; San, Boi Hoa; Lee, Jeong Hun; Kim, Doyoun; Park, Kwang Su; Lee, Min Ho; Kim, Taesung; Kim, Kyeong Kyu

    2016-01-01

    We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 106, the highest value compared to other SiNW-based devices in the visible light range.We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 106, the highest value compared to other SiNW-based devices in the visible light range. Electronic supplementary information (ESI) available: Materials and methods. See DOI: 10.1039/c5nr07901b

  11. Direct Cross-Linking of Au/Ag Alloy Nanoparticles into Monolithic Aerogels for Application in Surface-Enhanced Raman Scattering.

    PubMed

    Gao, Xiaonan; Esteves, Richard J Alan; Nahar, Lamia; Nowaczyk, Jordan; Arachchige, Indika U

    2016-05-25

    The direct cross-linking of Au/Ag alloy nanoparticles (NPs) into high surface area, mesoporous Au/Ag aerogels via chemical oxidation of the surface ligands is reported. The precursor alloy NPs with composition-tunable morphologies were produced by galvanic replacement of the preformed Ag hollow NPs. The effect of Au:Ag molar ratio on the NP morphology and surface plasmon resonance has been thoroughly investigated and resulted in smaller Au/Ag alloy NPs (4-8 nm), larger Au/Ag alloy hollow NPs (40-45 nm), and Au/Ag alloy hollow particles decorated with smaller Au NPs (2-5 nm). The oxidative removal of surfactant ligands, followed by supercritical drying, is utilized to construct large (centimeter to millimeter) self-supported Au/Ag alloy aerogels. The resultant assemblies exhibit high surface areas (67-73 m(2)/g), extremely low densities (0.051-0.055 g/cm(3)), and interconnected mesoporous (2-50 nm) networks, making them of great interest for a number of new technologies. The influence of mesoporous gel morphology on surface-enhanced Raman scattering (SERS) has been studied using Rhodamine 101 (Rd 101) as the probe molecule. The alloy aerogels exhibit SERS signal intensities that are 10-42 times higher than those achieved from the precursor Au/Ag alloy NPs. The Au/Ag alloy aerogel III exhibits SERS sensing capability down to 1 nM level. The increased signal intensities attained for alloy aerogels are attributed to highly porous gel morphology and enhanced surface roughness that can potentially generate a large number of plasmonic hot spots, creating efficient SERS substrates for future applications. PMID:27142886

  12. Photocatalytic activity of undoped and Ag-doped TiO{sub 2}-supported zeolite for humic acid degradation and mineralization

    SciTech Connect

    Lazau, C.; Ratiu, C.; Orha, C.; Pode, R.; Manea, F.

    2011-11-15

    Highlights: {yields} Hybrid materials based on natural zeolite and TiO{sub 2} obtained by solid-state reaction. {yields} XRD proved the presence of anatase form of undoped and Ag-doped TiO{sub 2} onto zeolite. {yields} FT-IR spectra evidenced the presence on TiO{sub 2} bounded at the zeolite network. {yields} Ag-doped TiO{sub 2} onto zeolitic matrix exhibited an enhanced photocatalytic activity. -- Abstract: The hybrid materials based on natural zeolite and undoped and Ag-doped TiO{sub 2}, i.e., Z-Na-TiO{sub 2} and Z-Na-TiO{sub 2}-Ag, were successfully synthesized by solid-state reaction in microwave-assisted hydrothermal conditions. Undoped TiO{sub 2} and Ag-doped TiO{sub 2} nanocrystals were previously synthesized by sol-gel method. The surface characterization of undoped TiO{sub 2}/Ag-doped TiO{sub 2} and natural zeolite hybrid materials has been investigated by X-ray diffraction, DRUV-VIS spectroscopy, FT-IR spectroscopy, BET analysis, SEM microscopy and EDX analysis. The results indicated that anatase TiO{sub 2} is the dominant crystalline type as spherical form onto zeolitic matrix. The presence of Ag into Z-Na-TiO{sub 2}-Ag was confirmed by EDX analysis. The DRUV-VIS spectra showed that Z-Na-TiO{sub 2}-Ag exhibited absorption within the range of 400-500 nm in comparison with Z-Na-TiO{sub 2} catalyst. The enhanced photocatalytic activity of Z-Na-TiO{sub 2}-Ag catalyst is proved through the degradation and mineralization of humic acid under ultraviolet and visible irradiation.

  13. The axisymmetric stellar wind of AG Carinae

    NASA Technical Reports Server (NTRS)

    Schulte-Ladbeck, Regina E.; Clayton, Geoffrey C.; Hillier, D. John; Harries, Tim J.; Howarth, Ian D.

    1994-01-01

    We present optical linear spectropolarimetry of the Luminous Blue Variable AG Carinae obtained after a recent visual brightness increase. The absence of He II lambda 4686 emission, together with the weakening of the He I spectrum and the appearance of Fe lines in the region around 5300 A, confirm that AG Car has started a new excursion across the HR diagram. The H alpha line profile exhibits very extended line wings that are polarized differently in both amount and position angle from either the continuum or the line core. The polarization changes across H alpha, together with variable continuum polarization, indicate the presence of intrinsic polarization. Coexistence of the line-wing polarization with extended flux-line wings evidences that both are formed by electron scattering in a dense wind. The position angle rotates across the line profiles, in a way that presently available models suggest is due to rotation and expansion of the scattering material. AG Car displays very large variations of its linear polarization with time, Delta P approximately 1.2%, indicating significant variations in envelope opacity. We find that the polarization varies along a preferred position angle of approximately 145 deg (with a scatter of +/- 10 deg) which we interpret as a symmetry axis of the stellar wind (with an ambiguity of 90 deg). This position angle is co-aligned with the major axis of the AG Car ring nebula and perpendicular to the AG Car jet. Our observations thus suggest that the axisymmetric geometry seen in the resolved circumstellar environment at various distances already exists within a few stellar radii of AG Car. From the H alpha polarization profile we deduce an interstellar polarization of Q = 0.31%, U = -1.15% at H alpha. The inferred interstellar polarization implies that the intrinsic polarization is not always of the same sign. This indicates either significant temporal changes in the envelope geometry, or it may arise from effects of multiple scattering

  14. Along and across arc geochemical variations in NW Central America: Evidence for involvement of lithospheric pyroxenite

    NASA Astrophysics Data System (ADS)

    Heydolph, Ken; Hoernle, Kaj; Hauff, Folkmar; Bogaard, Paul van den; Portnyagin, Maxim; Bindeman, Ilya; Garbe-Schönberg, Dieter

    2012-05-01

    The Central American Volcanic Arc (CAVA) has been the subject of intensive research over the past few years, leading to a variety of distinct models for the origin of CAVA lavas with various source components. We present a new model for the NW Central American Volcanic Arc based on a comprehensive new geochemical data set (major and trace element and Sr-Nd-Pb-Hf-O isotope ratios) of mafic volcanic front (VF), behind the volcanic front (BVF) and back-arc (BA) lava and tephra samples from NW Nicaragua, Honduras, El Salvador and Guatemala. Additionally we present data on subducting Cocos Plate sediments (from DSDP Leg 67 Sites 495 and 499) and igneous oceanic crust (from DSDP Leg 67 Site 495), and Guatemalan (Chortis Block) granitic and metamorphic continental basement. We observe systematic variations in trace element and isotopic compositions both along and across the arc. The data require at least three different endmembers for the volcanism in NW Central America. (1) The NW Nicaragua VF lavas require an endmember with very high Ba/(La, Th) and U/Th, relatively radiogenic Sr, Nd and Hf but unradiogenic Pb and low δ18O, reflecting a largely serpentinite-derived fluid/hydrous melt flux from the subducting slab into a depleted N-MORB type of mantle wedge. (2) The Guatemala VF and BVF mafic lavas require an enriched endmember with low Ba/(La, Th), U/Th, high δ18O and radiogenic Sr and Pb but unradiogenic Nd and Hf isotope ratios. Correlations of Hf with both Nd and Pb isotopic compositions are not consistent with this endmember being subducted sediments. Granitic samples from the Chiquimula Plutonic Complex in Guatemala have the appropriate isotopic composition to serve as this endmember, but the large amounts of assimilation required to explain the isotope data are not consistent with the basaltic compositions of the volcanic rocks. In addition, mixing regressions on Nd vs. Hf and the Sr and O isotope plots do not go through the data. Therefore, we propose that this

  15. Facile synthesis of ternary Ag/AgBr-Ag2CO3 hybrids with enhanced photocatalytic removal of elemental mercury driven by visible light.

    PubMed

    Zhang, Anchao; Zhang, Lixiang; Lu, Hao; Chen, Guoyan; Liu, Zhichao; Xiang, Jun; Sun, Lushi

    2016-08-15

    A novel technique for photocatalytic removal of elemental mercury (Hg(0)) using visible-light-driven Ag/AgBr-Ag2CO3 hybrids was proposed. The ternary Ag/AgBr-Ag2CO3 hybrids were synthesized by a simple modified co-precipitation method and characterized by N2 adsorption-desorption, scanning electron microscope (SEM), X-ray diffraction (XRD), UV-vis diffused reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) techniques. The effects of AgBr content, fluorescent lamp (FSL) irradiation, solution temperature, SO2 and NO on Hg(0) removal were investigated in detail. Furthermore, a possible reaction mechanism for higher Hg(0) removal was proposed, and the simultaneous removal of Hg(0), SO2 and NO was studied. The results showed that a high efficiency of Hg(0) removal was obtained by using Ag/AgBr-Ag2CO3 hybrids under fluorescent lamp irradiation. The AgBr content, FSL irradiation, solution temperature, and SO2 all exhibited significant effects on Hg(0) removal, while NO had slight effect on Hg(0) removal. The addition of Ca(OH)2 demonstrated a little impact on Hg(0) removal and could significantly improve the SO2-resistance performance of Ag/AgBr(0.7)-Ag2CO3 hybrid. The characterization results exhibited that hydroxyl radical (OH), superoxide radical (O2(-)), hole (h(+)), and Br(0), were reactive species responsible for removing Hg(0), and the h(+) played a key role in Hg(0) removal. PMID:27135702

  16. Polarized proton acceleration program at the AGS

    SciTech Connect

    Lee, Y.Y.

    1981-01-01

    The unexpected importance of high energy spin effects and the success of the ZGS in correcting many intrinsic and imperfection depolarizing resonances led us to attempt to accelerate polarized protons in the AGS. A multi-university/laboratory collaborative effort involving Argonne, Brookhaven, Michigan, Rice and Yale is underway to improve and modify to accelerate polarized protons. From the experience at the ZGS and careful studies made us confident of the feasibility of achieving a polarization of over 60 percent up to 26 GeV/c with an intensity of 10/sup 11/ approx. 10/sup 12/ per pulse. The first polarized proton acceleration at the AGS is expected in 1983.

  17. RESONANT EXTRACTION PARAMETERS FOR THE AGS BOOSTER.

    SciTech Connect

    BROWN,K.A.; CULLEN,J.; GLENN,J.W.; MAPES,M.; MARNERIS,I.; TSOUPAS,N.; SNYDSTRUP,L.; VAN ASSELT,W.

    2001-06-18

    Brookhaven's AGS Booster is the injector for the AGS. It is being modified to send resonant extracted heavy ions to a new beam line, the Booster Applications Facility (BAF). The design of the resonant extraction system for BAF was described in [1]. This note will give a more detailed description of the system and describe the predicted resonant beam time structure. We will describe tune space manipulations necessary to extract the resonant beam at the maximum Booster rigidity, schemes for performing resonant extraction, and describe the modifications required to perform bunched beam extraction to the BAF facility.

  18. Reducing Strength Prevailing at Root Surface of Plants Promotes Reduction of Ag+ and Generation of Ag0/Ag2O Nanoparticles Exogenously in Aqueous Phase

    PubMed Central

    Pardha-Saradhi, Peddisetty; Yamal, Gupta; Peddisetty, Tanuj; Sharmila, Peddisetty; Nagar, Shilpi; Singh, Jyoti; Nagarajan, Rajamani; Rao, Kottapalli S.

    2014-01-01

    Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP) to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs) from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5–50 nm containing Ag. Selected area electron diffraction and powder X-ray diffraction patterns of the silver NPs showed Bragg reflections, characteristic of crystalline face-centered cubic structure of Ag0 and cubic structure of Ag2O. Root system of intact plants raised under sterile conditions also generated Ag0/Ag2O-NPs under strict sterile conditions in a manner similar to that recorded under non-sterile conditions. This revealed the inbuilt potential of root system to generate Ag0/Ag2O-NPs independent of any microorganism. Roots of intact plants reduced triphenyltetrazolium to triphenylformazon and impermeable ferricyanide to ferrocyanide, suggesting involvement of plasma membrane bound dehydrogenases in reduction of Ag+ and formation of Ag0/Ag2O-NPs. Root enzyme extract reduced triphenyltetrazolium to triphenylformazon and Ag+ to Ag0 in presence of NADH, clearly establishing potential of dehydrogenases to reduce Ag+ to Ag0, which generate Ag0/Ag2O-NPs. Findings presented in this manuscript put forth a novel, simple

  19. Facile synthesis of novel Ag/AgI/BiOI composites with highly enhanced visible light photocatalytic performances

    SciTech Connect

    Cao, Jing; Zhao, Yijie; Lin, Haili; Xu, Benyan; Chen, Shifu

    2013-10-15

    Novel Ag/AgI/BiOI composites were controllably synthesized via a facile ion-exchange followed by photoreduction strategy by using hierarchical BiOI microflower as substrate. The as-prepared Ag/AgI/BiOI composites were studied by X-ray powder diffractometer (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analyzer and UV–vis diffuse reflectance spectroscopy (DRS). Under visible light (λ>420 nm), Ag/AgI/BiOI displayed highly enhanced photocatalytic activities for degradation of methyl orange (MO) compared to the pure hierarchical BiOI, which was mainly ascribed to the highly efficient separation of electrons and holes through the closely contacted interfaces in the Ag/AgI/BiOI ternary system. - Graphical abstract: Ag/AgI/BiOI displayed excellent photocatalytic activities for methyl orange degradation under visible light, which was mainly ascribed to the highly efficient separation of electrons and holes through Z-scheme pathway. Display Omitted - Highlights: • Novel Ag/AgI/BiOI composites were successfully synthesized. • Ag/AgI/BiOI displayed higher visible light activities than those of pure BiOI and AgI. • ·O{sub 2}{sup −} and h{sup +}, especially ·O{sub 2}{sup −}, dominated the photodegradation process of MO. • A Z-scheme pattern was adopted for Ag/AgI/BiOI activity enhancement.

  20. The AGS (alternating gradient synchrotron): Performance and potential

    SciTech Connect

    Ratner, L.G.

    1989-01-01

    This report discusses the following topics on the Brookhaven AGS: basic parameters, description of the accelerator complex and proton operation; operation with heavy ions and polarized protons; AGS upgrades and expanded potential. (LSP)

  1. Highly Effective Electromagnetic Interference Shielding Materials based on Silver Nanowire/Cellulose Papers.

    PubMed

    Lee, Tae-Won; Lee, Sang-Eui; Jeong, Young Gyu

    2016-05-25

    We fabricated silver nanowire (AgNW)-coated cellulose papers with a hierarchical structure by an efficient and facile dip-coating process, and investigated their microstructures, electrical conductivity and electromagnetic interference (EMI) shielding effectiveness. SEM images confirm that AgNWs are coated dominantly on the paper surfaces, although they exist partially in the inner parts of the cellulose papers, which demonstrates that the AgNW density gradually decreases in thickness direction of the AgNW/cellulose papers. This result is supported by the anisotropic apparent electrical conductivity of the AgNW/cellulose papers depending on in-plane or thickness direction. Even for a AgNW/cellulose paper obtained by a single dip-coating cycle, the apparent electrical conductivity in the in-plane direction of 0.34 S/cm is achieved, which is far higher than the neat cellulose paper with ∼10(-11) S/cm. In addition, the apparent electrical conductivity of the papers in the in-plane direction increases significantly from 0.34 to 67.51 S/cm with increasing the number of dip-coating cycle. Moreover, although the AgNW/cellulose paper with 67.51 S/cm possesses 0.53 vol % AgNW only, it exhibits high EMI shielding performance of ∼48.6 dB at 1 GHz. This indicates that the cellulose paper structure is highly effective to form a conductive AgNW network. Overall, it can be concluded that the AgNW/cellulose papers with high flexibility and low density can be used as electrically conductive components and EMI shielding elements in advanced application areas.

  2. Study of structural modification of PVA by incorporating Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Saini, Isha; Sharma, Annu; Rozra, Jyoti; Aggarwal, Sanjeev; Dhiman, Rajnish; Sharma, Pawan K.

    2016-05-01

    Nanocomposites of PVA with Ag nanoparticles dispersed in it were synthesized using solution casting method. The morphology and size distribution of Ag nanoparticles embedded in PVA matrix were obtained by transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FE-SEM). Raman spectroscopy was used to examine structural changes taking place inside polyvinyl alcohol (PVA) matrix due to incorporation of Ag nanoparticle. Raman analysis indicates that Ag nanoparticles interact with PVA through H-bonding.

  3. A multi-wire beam profile monitor in the AGS

    SciTech Connect

    Huang, H.; Buxton, W.; Castillo, V.; Glenn, J.W.

    1997-07-01

    A multi-wire beam profile monitor which can be used to directly monitor and control the optical matching between the Booster and AGS rings has been installed and tested in the AGS. Placement of a multi-wire monitor directly in the AGS provides profile measurements taken upon injection and the first two or more revolutions of the beam. The data from such measurements can be used to determine the optical properties of the beam transport line leading into the AGS.

  4. Free-Standing Copper Nanowire Network Current Collector for Improving Lithium Anode Performance.

    PubMed

    Lu, Lei-Lei; Ge, Jin; Yang, Jun-Nan; Chen, Si-Ming; Yao, Hong-Bin; Zhou, Fei; Yu, Shu-Hong

    2016-07-13

    Lithium metal is one of the most attractive anode materials for next-generation lithium batteries due to its high specific capacity and low electrochemical potential. However, the poor cycling performance and serious safety hazards, caused by the growth of dendritic and mossy lithium, has long hindered the application of lithium metal based batteries. Herein, we reported a rational design of free-standing Cu nanowire (CuNW) network to suppress the growth of dendritic lithium via accommodating the lithium metal in three-dimensional (3D) nanostructures. We demonstrated that as high as 7.5 mA h cm(-2) of lithium can be plated into the free-standing copper nanowire (CuNW) current collector without the growth of dendritic lithium. The lithium metal anode based on the CuNW exhibited high Coulombic efficiency (average 98.6% during 200 cycles) and outstanding rate performance owing to the suppression of lithium dendrite growth and high conductivity of CuNW network. Our results demonstrate that the rational nanostructural design of current collector could be a promising strategy to improve the performance of lithium metal anode enabling its application in next-generation lithium-metal based batteries. PMID:27253417

  5. A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics.

    PubMed

    Selzer, Franz; Weiss, Nelli; Kneppe, David; Bormann, Ludwig; Sachse, Christoph; Gaponik, Nikolai; Eychmüller, Alexander; Leo, Karl; Müller-Meskamp, Lars

    2015-02-14

    We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 Ω □(-1) at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode.

  6. Effect of Solder-Joint Geometry on the Low-Cycle Fatigue Behavior of Sn-xAg-0.7Cu

    NASA Astrophysics Data System (ADS)

    Lee, Hwa-Teng; Huang, Kuo-Chen

    2016-07-01

    Low-cycle fatigue tests of Sn-Ag-Cu (SAC) Pb-free solder joints under fixed displacement were performed to evaluate the influence of Ag content (0-3 wt.%) and solder-joint geometry (barrel and hourglass types) on solder-joint fatigue behavior and reliability. The solder joints were composed of fine particles of Ag3Sn and Cu6Sn5, which aggregated as an eutectic constituent at grain boundaries of the primary β-Sn phase and formed a dense network structure. A decrease in the Ag content resulted in coarsening of the β-Sn and eutectic phases, which, in turn, decreased the strength of the joint and caused earlier failure. Solder joints in the hourglass form exhibited better fatigue performance with longer life than barrel-type joints. The sharp contact angle formed between the solder and the Cu substrate by the barrel-type joints concentrated stress, which compromised fatigue reliability. The addition of Ag to the solder, however, enhanced fatigue performance because of strengthening caused by Ag3Sn formation. The cracks of the barrel-type SAC solder joints originated mostly at the contact corner and propagated along the interfacial layer between the interfacial intermetallic compound (IMC) and solder matrix. Hourglass-type solder joints, however, demonstrated both crack initiation and propagation in the solder matrix (solder mode). The addition of 1.5-2.0 wt.% Ag to SAC solder appears to enhance the fatigue performance of solder joints while maintaining sufficient strength.

  7. Development of a Rhizoctonia solani AG1-IB Specific Gene Model Enables Comparative Genome Analyses between Phytopathogenic R. solani AG1-IA, AG1-IB, AG3 and AG8 Isolates.

    PubMed

    Wibberg, Daniel; Rupp, Oliver; Blom, Jochen; Jelonek, Lukas; Kröber, Magdalena; Verwaaijen, Bart; Goesmann, Alexander; Albaum, Stefan; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2015-01-01

    Rhizoctonia solani, a soil-born plant pathogenic basidiomycetous fungus, affects various economically important agricultural and horticultural crops. The draft genome sequence for the R. solani AG1-IB isolate 7/3/14 as well as a corresponding transcriptome dataset (Expressed Sequence Tags--ESTs) were established previously. Development of a specific R. solani AG1-IB gene model based on GMAP transcript mapping within the eukaryotic gene prediction platform AUGUSTUS allowed detection of new genes and provided insights into the gene structure of this fungus. In total, 12,616 genes were recognized in the genome of the AG1-IB isolate. Analysis of predicted genes by means of different bioinformatics tools revealed new genes whose products potentially are involved in degradation of plant cell wall components, melanin formation and synthesis of secondary metabolites. Comparative genome analyses between members of different R. solani anastomosis groups, namely AG1-IA, AG3 and AG8 and the newly annotated R. solani AG1-IB genome were performed within the comparative genomics platform EDGAR. It appeared that only 21 to 28% of all genes encoded in the draft genomes of the different strains were identified as core genes. Based on Average Nucleotide Identity (ANI) and Average Amino-acid Identity (AAI) analyses, considerable sequence differences between isolates representing different anastomosis groups were identified. However, R. solani isolates form a distinct cluster in relation to other fungi of the phylum Basidiomycota. The isolate representing AG1-IB encodes significant more genes featuring predictable functions in secondary metabolite production compared to other completely sequenced R. solani strains. The newly established R. solani AG1-IB 7/3/14 gene layout now provides a reliable basis for post-genomics studies.

  8. The electron paramagnetic resonance spectrum of Ag2 3

    NASA Astrophysics Data System (ADS)

    van der Pol, A.; Reijersen, E. J.; de Boer, E.; Wasowicz, T.; Michalik, J.

    A highly resolved EPR spectrum of the silver trimer 109Ag2+3, present in 109Ag1-NaA zeolite, has been measured. The spectrum is characterized by an axially symmetric spin Hamiltonian having and for each of the 109Ag nuclei tMPH0037_images.

  9. AGS experiments -- 1996, 1997, 1998, 1999. Fifteenth edition

    SciTech Connect

    Lo Presti, P.

    1999-03-01

    This report is a compilation of two-page summaries for AGS experiments for FY 1996, FY 1997, FY 1998, FY 1999. The bulk of the experiments are for high energy physics and nuclear physics programs. Also included are the run schedules for the AGS for each of those years and a listing of publications of AGS experiments for 1982--1999.

  10. Effect of Ag+ and PO43‑ ratios on the microstructure and photocatalytic activity of Ag3PO4

    NASA Astrophysics Data System (ADS)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Song, Aijun; Zhang, Bing; Rajendran, Saravanan; Ma, Mingzhen; Liu, Riping

    2016-09-01

    In this work, the catalyst silver phosphate (Ag3PO4) with different initial ratios of Ag+ and PO43‑ in aqueous solution was synthesized by a simple precipitation method from AgNO3 and NH4H2PO4 which were used as the precursor. After that, the prepared samples were characterized by different techniques such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-DRS) and decomposition evolution of rhodamine B (RhB) solution. The results indicate that the initial ratios of Ag+/PO43‑ in aqueous solution can modify the morphology and also it can significantly affect the photocatalytic performance. During photocatalytic process, the rich Ag+ ion Ag3PO4 can form the surface plasmon resonance (SPR) of Ag nanoparticles, which inhibit the reduction of Ag3PO4 resulting in higher photocatalytic activity and stability.

  11. Fabrication of Sn-3.5Ag Eutectic Alloy Powder by Annealing Sub-Micrometer Sn@Ag Powder Prepared by Citric Acid-Assisted Ag Immersion Plating.

    PubMed

    Chee, Sang-Soo; Choi, Eun Byeol; Lee, Jong-Hyun

    2015-11-01

    A Sn-3.5Ag eutectic alloy powder has been developed by chemically synthesizing sub-micrometer Sn@Ag powder at room temperature. This synthesis was achieved by first obtaining a sub-micrometer Sn powder for the core using a modified variant of the polyol method, and then coating this with a uniformly thin and continuous Ag layer through immersion plating in 5.20 mM citric acid. The citric acid was found to play multiple roles in the Ag coating process, acting as a chelating agent, a reducing agent and a stabilizer to ensure coating uniformity; and as such, the amount used has an immense influence on the coating quality of the Ag shells. It was later verified by transmission electron microscopy and X-ray diffraction analysis that the coated Ag layer transfers to the Sn core via diffusion to form an Ag3Sn phase at room temperature. Differential scanning calorimetry also revealed that the synthesized Sn@Ag powder is nearly transformed into Sn-3.5Ag eutectic alloy powder upon annealing three times at a temperature of up to 250 degrees C, as evidenced by a single melting peak at 220.5 degrees C. It was inferred from this that Sn-3.5Ag eutectic alloy powder can be successfully prepared through the synthesis of core Sn powders by a modified polyol method, immersion plating using citric acid, and annealing, in that order.

  12. Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

    NASA Astrophysics Data System (ADS)

    Manninen, N. K.; Calderon, S.; Carvalho, I.; Henriques, M.; Cavaleiro, A.; Carvalho, S.

    2016-07-01

    Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano-galvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against Staphylococcus epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive OCP value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag+ due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 h, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

  13. Communication: Kinetics of chemical ordering in Ag-Au and Ag-Ni nanoalloys

    NASA Astrophysics Data System (ADS)

    Calvo, F.; Fortunelli, A.; Negreiros, F.; Wales, D. J.

    2013-09-01

    The energy landscape and kinetics of medium-sized Ag-Au and Ag-Ni nanoalloy particles are explored via a discrete path sampling approach, focusing on rearrangements connecting regions differing in chemical order. The highly miscible Ag27Au28 supports a large number of nearly degenerate icosahedral homotops. The transformation from reverse core-shell to core-shell involves large displacements away from the icosahedron through elementary steps corresponding to surface diffusion and vacancy formation. The immiscible Ag42Ni13 naturally forms an asymmetric core-shell structure, and about 10 eV is required to extrude the nickel core to the surface. The corresponding transformation occurs via a long and smooth sequence of surface displacements. For both systems the rearrangement kinetics exhibit Arrhenius behavior. These results are discussed in the light of experimental observations.

  14. Geometry optimization and structural distribution of silver clusters from Ag 170 to Ag 310

    NASA Astrophysics Data System (ADS)

    Shao, Xueguang; Yang, Xiaoli; Cai, Wensheng

    2008-07-01

    Silver clusters in the size range of 170-310 were optimized with a modified dynamic lattice search (DLS) method. Considering the computational complexity, only 21 clusters of several tens and magic numbers of atoms were investigated. The interaction of silver atoms is modeled by the Gupta potential. Results show that, between the 21 clusters, nine fcc and twelve m-Dh structures are obtained. Compared with the structures adopted by Ag 13 to Ag 160, the main motif is still m-Dh in the range of Ag 170-Ag 310, but the ratio of fcc structures obviously increases. It can, therefore, be deduced that the fcc motif is more stable for larger size silver clusters.

  15. Accuracy Assessment for AG500, Electromagnetic Articulograph

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Mefferd, Antje

    2009-01-01

    Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…

  16. High Resolution PDF Measurements on Ag Nanoparticles

    SciTech Connect

    Rocha, Tulio C. R.; Martin, Chris; Kycia, Stefan; Zanchet, Daniela

    2009-01-29

    The quantitative analysis of structural defects in Ag nanoparticles was addressed in this work. We performed atomic scale structural characterization by a combination of x-ray diffraction (XRD) using the Pair Distribution Function analysis (PDF) and High Resolution Transmission Electron Microscopy (HRTEM). The XRD measurements were performed using an innovative instrumentation setup to provide high resolution PDF patterns.

  17. Middle Miocene coralline algal facies from the NW Transylvanian Basin (Romania)

    NASA Astrophysics Data System (ADS)

    Chelaru, Ramona; Bucur, Ioan I.; Sǎsǎran, Emanoil; Bǎlc, Ramona; Tǎmas, Tudor

    2016-04-01

    The current study focus on the coralline algae from the Middle Miocene limestones in NW Transylvania to provide an outline for their systematics and palaeoecology. The investigated samples were collected from three carbonate outcrops: Vǎlenii Șomcutei, Ciolt 1 and Ciolt 2, named after the respective localities situated in the vicinity of the Țicǎu-Preluca Mountains (NW Romania). The microfacies analysis suggest shallowing upward tendency in middle to proximal shelf environments. The coralline algae are present in the carbonate successions as detritus, branches, crusts and rhodoliths. The Vǎlenii Șomcutei section shows a depositional model where large and spheroidal rhodoliths develop in high energy conditions, most probably generated by storm waves. The sections from the Ciolt area are distinguished by the presence of green algae in association with the encrusting and geniculate coralline specimens. The identified species belong to Ord. Corallinales (Hydrolithon, Spongites, Lithophyllum, Jania), Hapalidales (Lithothamnion and Mesophyllum) and Sporolithales (Sporolithon). In the taxonomic identification of coralline red algae we used as many diagnostic features as possible, known from the description of present - day species, such as: shape of epithallial cells and roof morphology for melobesioids; presence/absence of a layer of elongated cells below sporangial compartments and number of cells in paraphyses for sporolithoids. The identified coralline algal assemblages are discussed according to different paleoenvironmental conditions (paleo-depth, hydrodynamic energy) and then compared with similar fossil assemblages and recent analogs like modern maërl and rhodolith pavements. The study of the calcareous nannoplankton assemblages from the Vǎlenii Șomcutei section [1] and the presence of previously dated tuffite intercalations of Dej Tuff [2] in the two sections near the Ciolt village confirm the Badenian age (NN5) of these deposits. [1] Chelaru R., S

  18. Rapid hydrological response to central Andean Plateau uplift, NW-Argentina

    NASA Astrophysics Data System (ADS)

    Rohrmann, Alexander; Sachse, Dirk; Strecker, Manfred R.; Mulch, Andreas; Pingel, Heiko; Alonso, Ricardo N.

    2015-04-01

    The response of the regional and global hydrological cycle, vegetation and erosion to tectonic surface uplift and topographic growth of the world's largest orogenic plateaus and their flanking ranges is subject to ongoing debate. During the last decade reconstructions of paleo-environmental conditions and the topographic evolution of mountain belts have increasingly relied on stable isotope proxies retaining the oxygen (δ18O) or hydrogen (δD) isotopic composition of ancient meteoric waters or carbon (δ13C) of vegetation. Intermontane basin sediments along the Puna of NW Argentina, the southern extension of the Altiplano-Puna Plateau and the world's second largest plateau, record the eastward-directed lateral growth of the central Andes and the spatiotemporal impact of tectonism on hydrologic, sedimentary, and ecological changes through time. Here we reconstructed paleo-hydrological changes during a phase of major Andean uplift and orographic barrier formation (10-2 Ma) along the eastern flank of the Puna Plateau from a sedimentary sequence within the intermontane Angastaco basin of NW Argentina (25°45 S, 66 W). We use a unique array of stable water-isotope proxies in leafwaxes, pedogenic carbonates and hydrated volcanic glass. In addition we use vegetation-cover proxies based on stable C isotopes obtained from leaf-waxes and pedogenic carbonates. Lipid biomarker leafwax δD values range between -95 and -160 ‰ (VSMOW), and δ13C values from -23 to -36 ‰ (PDB). Pedogenic carbonate δ18O values range from 18 to 31 ‰ (VSMOW) and δ13C values vary between -4 to -17 ‰ (PDB), whereas volcanic glass δD values range from -71 to -95 ‰ (VSMOW). In combination, these proxies provide a precipitation - evapotranspiration record, which reveals the onset of the South American Low Level-Jet in NW Argentina at ~ 9 Ma and the presence of seasonally humid foreland conditions until 7 Ma, followed by orographic barrier formation upwind of the basin and rapid creation of

  19. Cave-dwelling invertebrates of the NW Mediterranean: silent victims of global warming?

    NASA Astrophysics Data System (ADS)

    Lejeusne, C.; Chevaldonné, P.

    2003-04-01

    Dark submarine caves constitute an extreme and fragmented habitat of the littoral zone. They present environmental conditions characterised by a complete absence of light and a strong oligotrophy, and then are inhabited by endemic and specialised species. However, the extremely fragmented and poorly resilient characteristics of these communities imply that they are more sensitive than any other littoral community to large-scale perturbations such as global warming. Global change induces a long term increase in water temperatures, but also shorter and more acute events such as those recorded in the NW Mediterranean during summers 1997 and 1999. During these two thermal anomalies, water temperatures of up to 24^oC reached 40m depth and below, during several weeks. Many sessile invertebrate species such as sponges, cnidarians and bivalves, were heavily affected. Consequences on NW Mediterranean caves were studied through mysids (Crustacea: Peracarida), especially Hemimysis genus. Since its discover, Hemimysis speluncola Ledoyer, 1963 had been the dominant endemic mysid in those caves, where it formed large and high-density swarms. However, consequently to the thermal anomalies, swarm density declined rapidly, leading to an almost complete disappearance of the species. This phenomenon was first recorded in the Marseille (France) area, but we show that it happened in most other NW Mediterranean regions. At the same time, another mysid Hemimysis margalefi Alcaraz, Riera &Gili, 1986 replaced H. speluncola in the caves. Comparative thermotolerance experiments between the two species revealed more eurythermal characteristics in H. margalefi and a better resistance to acute thermal stress. Because of the Mediterranean geography, the endemic H. speluncola, with distant fragmented populations and a low thermal tolerance cannot migrate to northern (colder) regions. It may therefore be doomed to disappear in the context of global change, with replacement by the more thermophile

  20. New Insight Into the Crustal Structure of the Continental Margin offshore NW Sabah/Borneo

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Franke, D.; Behain, D.; Meyer, H.

    2002-12-01

    The continental margin offshore NW Sabah/Borneo (Malaysia) has been investigated with reflection and refraction seismics, magnetics, and gravity during the recent cruise BGR01-POPSCOMS. A total of 4000 km of geophysical profiles has been acquired, thereof 2900 km with reflection seismics. The focus of investigations was on the deep water areas. The margin looks like a typical accretionary margin and was presumably formed during the subduction of a proto South China Sea. Presently, no horizontal movements between the two plates are being observed. Like in major parts of the South China Sea, the area seaward of the Sabah Trough consists of extended continental lithosphere which is characterised by a pattern of rotated fault blocks and half grabens and a carbonate platform of Early Oligocene to Early Miocene age. We found evidence that the continental crust also underlies the Sabah Trough and the adjacent continental slope, a fact that raises many questions about the tectonic history and development of this margin. The tectonic pattern of the Dangerous Grounds' extended continental crust can be traced a long way landward of the Sabah Trough beneath the sedimentary succession of the upper plate. The magnetic anomalies which are dominated by the magnetic signatures of relatively young volcanic features also continue under the continental slope. The sedimentary rocks of the upper plate, in contrast, seem to generate hardly any magnetic anomalies. Based on the new data we propose the following scenario for the development of the NW Sabah continental margin: Seafloor spreading in the present South China Sea started at about 30 Ma in the Late Oligocene. The spreading process separated the Dangerous Grounds area from the SE Asian continent and ceased in late Early Miocene when the oceanic crust of the proto South China Sea was fully subducted in eastward direction along the Borneo-Palawan Trough. During Lower and/or Middle Miocene, Borneo rotated counterclockwise and was

  1. GPR Surveys for Archaeological Investigation in a Bronze Age site from NW Portugal

    NASA Astrophysics Data System (ADS)

    Gonçalves, L.; Sampaio, H. A.; Bettencourt, A. M. S.; Alves, M. I. C.

    2012-04-01

    This work describes the use of Ground-penetrating Radar (GPR) surveys in the identification and mapping of subtle cultural remains, from Pego Late Bronze Age settlement, located near the city of Braga, in NW Portugal. Bronze Age settlements from NW Portugal are characterized by the presence archaeological structures such as storage pits, postholes and trenches. These subtle structures have a very low dielectric contrast, making them quite difficult to detect in GPR surveys. In the case of Pego Site, previous investigations using conventional archaeological techniques, during a rescue excavation, partially revealed a residential area, a necropolis, and a stockade foundation trench that encircle the whole settlement. Different GPR prospection approaches were performed using GSSI Sir 3000 System, with 400 MHz antennae, with the objective of identify and define the borders between the different areas of human occupation inside the settlement. For the GPR survey, a grid-based approach with closely spaced parallels transects was defined, covering different areas inside the site. A first survey was conducted with a pseudo-3D methodology, with 50 cm profile separation, followed by a second survey with a dense data acquisition methodology, with 10 cm profile separation. Processed two-dimensional GPR profiles and constructed amplituded-slice maps were produced and analysed. Wave velocities were determined by reflected wave methods and by Hyperbola-Fitting method. The background analysis of the archaeological and geological features of the site, integrated with the preliminary interpretation of GPR data (profiles and amplitude slice-maps) suggest the presence of flat graves, in the west part of the site, and storage pits, post holes and some small trenches, in the centre and north area of the settlement. This interpretation indicates that the settlement is individualized in two different areas, a necropolis and a residential area, such as the first archaeological study

  2. Structural Setting of Western Monferrato (Alps-Apennines Junction Zone, NW Italy)

    NASA Astrophysics Data System (ADS)

    Piana, Fabrizio

    2000-10-01

    New data on the structural setting of the Torino Hill and Western Monferrato domains provide a clearer picture of the kinematic evolution of the Alps-Apennines junction zone. In the Alps-Apennines junction, left-lateral underthrusting of Ligurian units below Alpine crust has often been invoked to explain the underthrusting of the Insubric domain and the NW-ward movement of the Adriatic indenter. A transpressive fault system (Rio Freddo Fault Zone) developed in the Monferrato epi-Ligurian succession is here understood as the surficial expression of a deep-seated thrust along which the Alpine metamorphic basement of the Torino Hill has overridden the Apenninic Ligurian nappes since the Paleogene up to Burdigalian. In the Western Monferrato the regional sinistral transpression differentiated separated crustal blocks during the Oligocene-early Miocene, and kilometer-thick successions were steepened by NNW-SSE faults that acted as reverse and/or left-lateral faults. Double-vergent (SE-NW) low-angle shear zones then cut the Rio Freddo Fault Zone in post-Langhian times. They have been here related with the eastward tectonic transport of the Torino Hill and relative Alpine crust toward the Monferrato domain, which occurred before the seismic line scale middle Miocene unconformity was established. This poses the problem of the exact age of this regional unconformity, which in our case should be at least Serravallian. Finally, the Monferrato and Torino Hill domains were coupled, and both were NW-ward translated by the Padan Thrust Front in the Pliocene. The youngest strike-slip and reverse faults of the Western Monferrato may be tear or compartmental faults that partitioned the Padan Thrust motion, whose propagation could be controlled by pre-middle-Miocene tectonic structures. The structural complexity of the study area is here understood as the inheritance of deep crosscutting regional structures that forced the convergent structural units of the Alpine and Insubric

  3. Linking the field to the stream: soil erosion and sediment yield in a rural catchment, NW Spain

    NASA Astrophysics Data System (ADS)

    Rodriguez-Blanco, M. L.; Taboada-Castro, M. M.; Palleiro-Suarez, L.; Taboada-Castro, M. T.

    2009-04-01

    Quantifying the linkages between field erosion, fluvial response and catchment sediment yield remains problematic, among other reasons, because of the re-deposition of eroded sediment within the catchment, which is controlled by the spatial organization of the land use and the connectivity between sediment sources and the stream network. This paper presents the results of an integrated study that considered the relationship between erosion and stream sediment yield in an agroforestry catchment (16 km2) in NW Spain. The geology consists of basic metamorphic schist. The relieve of the area is steeper, the mean slope is approximately 19%. Main soil types are classified as Umbrisol and Cambisol. Soils are acidic and rich in organic matter. The soil texture is silt and silt-loam. Land cover consists of a mixture of forest (65%) and agricultural fields (mainly grassland, pasture and maize). The study combined measurements of soil erosion by concentrate flow and sediment deposition at field scale with sediment yield measured at the catchment outlet. The hydrological data and water samples were obtained at the catchment outlet. Stream water level was monitored continuously and converted to discharge using a rating curve. The sampling for suspended sediments was supplemented by an automatic sampler. Suspended sediment load was calculated from the suspended sediment concentrations and discharge data. Eroded volume was calculated from cross-sections (measured at specific points, where the section changed abruptly) and length of the channel segments. The total sediment delivered to stream was determined as the difference between all erosion features (rills and gullies) and the sediment volumes that were deposited on the fields. The results showed that in the catchment during the period winter 2007/08 soil erosion by concentrate flow, i.e. rills and ephemeral gullies, occurred on unprotected crop field. Erosion by concentrate flow was highly discontinuous within the catchment

  4. Evolution of Extensional Structures Within the Internal Parts of the Higher Himalaya (Sutlej River Region, NW India)

    NASA Astrophysics Data System (ADS)

    Hintersberger, E.; Thiede, R. C.; Strecker, M. R.

    2006-12-01

    One of the most challenging problems in understanding the tectonics of active mountain belts is the presence of normal faults in the overall compressive settings. Consistent observations in the Andes, the Alps, as well as in the Himalaya record the presence of upper crustal structures with normal displacement contemporaneously with shortening and thrusting at lower crustal levels and elevations. Within the internal and high elevation sectors of the Himalayan orogen, active N-S striking normal fault systems are well documented. Crosscutting relationships indicate that these closely spaced faults cut all pre-existing compressional structures and are the youngest structural features in this region. However, their mode of propagation in time and space, as well as their origin remain largely unknown. For example, in the Sutlej River region (NW Himalaya, India), it is unclear whether these fault systems either are a local phenomenon and related to ongoing exhumation of the Leo Pargil metamorphic dome or, alternatively, are an integral part of the structural framework in the Himalaya and thus of regional importance. To better understand which processes constrain N-S striking normal faulting in the evolution of the Higher Himalaya, we have mapped the young extensional sectors in the greater Sutlej River area. In addition, we combine seismological data with the spacial and temporal distribution of brittle normal faulting to better understand the interaction between the ongoing normal and thrust faulting in the orogen. Using globally recorded seismicity data we observed ongoing extension in a N-S striking band extending from to the Leo Pargil extensional dome southward to the main thrust belts along the Himalayan front. Further installation of a seismic network in this region will provide the level of resolution needed to analyze the detailed pattern of local seismicity of the Sutlej-Spiti River region. Our preliminary structural geological field work reveals that the

  5. Combining double difference and amplitude ratio approaches for Q estimates at the NW Bohemia earthquake swarm region

    NASA Astrophysics Data System (ADS)

    Kriegerowski, Marius; Cesca, Simone; Krüger, Frank; Dahm, Torsten; Horálek, Josef

    2016-04-01

    Aside from the propagation velocity of seismic waves, their attenuation can provide a direct measure of rock properties in the sampled subspace. We present a new attenuation tomography approach exploiting relative amplitude spectral ratios of earthquake pairs. We focus our investigation on North West Bohemia - a region characterized by intense earthquake swarm activity in a confined source region. The inter-event distances are small compared to the epicentral distances to the receivers meeting a fundamental requirement of the method. Due to the similar event locations also the ray paths are very similar. Consequently, the relative spectral ratio is affected mostly by rock properties along the path of the vector distance and thus representative of the focal region. In order to exclude effects of the seismic source spectra, only the high frequency content beyond the corner frequency is taken into consideration. This requires high quality as well as high sampling records. Future improvements in that respect can be expected from the ICDP proposal "Eger rift", which includes plans to install borehole monitoring in the investigated region. 1D and 3D synthetic tests show the feasibility of the presented method. Furthermore, we demonstrate influences of perturbations in source locations and travel time estimates on the determination of Q. Errors in Q scale linearly with errors in the differential travel times. These sources of errors can be attributed to the complex velocity structure of the investigated region. A critical aspect is the signal-to-noise ratio, which imposes a strong limitation and emphasizes the demand for high quality recordings. Hence, the presented method is expected to benefit from bore hole installations. Since we focus our analysis on the NW Bohemia case study example, a synthetic earthquake catalog incorporating source characteristics deduced from preceding moment tensor inversions coupled with a realistic velocity model provides us with a realistic

  6. Normal-incidence steering effect in crystal growth: Ag/Ag(100)

    SciTech Connect

    Montalenti, F.; Voter, A. F.

    2001-08-15

    During crystal growth by vapor deposition, normal incident atoms are deflected toward three-dimensional surface structures. The effect becomes strong when the atoms are deposited with a low initial kinetic energy. At low T this steering effect induces an instability in the growth process, causing a perfectly flat surface to become rough after a few monolayers are deposited. Quantitative results for the initial stages of growth of Ag/Ag(100) at T{approx}0 K are presented.

  7. Surface-enhanced Raman scattering from AgNP-graphene-AgNP sandwiched nanostructures

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Xu, Yijun; Xu, Pengyu; Pan, Zhenghui; Chen, Sheng; Shen, Qishen; Zhan, Li; Zhang, Yuegang; Ni, Weihai

    2015-10-01

    We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials.We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials. Electronic supplementary information (ESI) available: Additional SEM images, electric field enhancement profiles, Raman scattering spectra, and structure-dependent peak ratios. See DOI: 10.1039/c5nr04500b

  8. A dry method to synthesize dendritic Ag2Se nanostructures utilizing CdSe quantum dots and Ag thin films.

    PubMed

    Hu, Lian; Zhang, Bingpo; Xu, Tianning; Li, Ruifeng; Wu, Huizhen

    2015-01-01

    Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates. PMID:25483981

  9. A dry method to synthesize dendritic Ag2Se nanostructures utilizing CdSe quantum dots and Ag thin films

    NASA Astrophysics Data System (ADS)

    Hu, Lian; Zhang, Bingpo; Xu, Tianning; Li, Ruifeng; Wu, Huizhen

    2015-01-01

    Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates.

  10. New insight into daylight photocatalysis of AgBr@Ag: synergistic effect between semiconductor photocatalysis and plasmonic photocatalysis.

    PubMed

    Jiang, Jing; Li, Hao; Zhang, Lizhi

    2012-05-14

    Noble metal nanoparticles (NPs) are often used as electron scavengers in conventional semiconductor photocatalysis to suppress electron-hole (e(-)-h(+) ) recombination and promote interfacial charge transfer, and thus enhance photocatalytic activity of semiconductors. In this contribution, it is demonstrated that noble metal NPs such as Ag NPs function as visible-light harvesting and electron-generating centers during the daylight photocatalysis of AgBr@Ag. Novel Ag plasmonic photocatalysis could cooperate with the conventional AgBr semiconductor photocatalysis to enhance the overall daylight activity of AgBr@Ag greatly because of an interesting synergistic effect. After a systematic investigation of the daylight photocatalysis mechanism of AgBr@Ag, the synergistic effect was attributed to surface plasmon resonance induced local electric field enhancement on Ag, which can accelerate the generation of e(-)-h(+) pairs in AgBr, so that more electrons are produced in the conduction band of AgBr under daylight irradiation. This study provides new insight into the photocatalytic mechanism of noble metal/semiconductor systems as well as the design and fabrication of novel plasmonic photocatalysts.

  11. A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

    SciTech Connect

    Sinha, Sumona Mukherjee, M.

    2015-10-15

    The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL) was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

  12. Enhancement of ferromagnetism by Ag doping in Ni-Mn-In-Ag Heusler alloys

    NASA Astrophysics Data System (ADS)

    Pandey, Sudip; Quetz, Abdiel; Aryal, Anil; Dubenko, Igor; Mazumdar, Dipanjan; Stadler, Shane; Ali, Naushad

    The effect of Ag on the structural, magnetocaloric, and thermomagnetic properties of Ni50Mn35In15-xAgx (x = 0.1, 0.2, 0.5, and 1) Heusler alloys was studied. The magnitude of the magnetization change at martensitic transition temperature (TM) decreases with increasing Ag concentration A smaller magnetic entropy changes (ΔSM) for the alloys with higher Ag concentration is observed. A shift of TM by about 25 K to a higher temperature was detected for P = 6.6 kbar with respect to ambient pressure. Large drop of resistivity is observed with the increase of Ag concentration. The magnetoresistance is dramatically suppressed with increasing Ag concentration due to the weakening of the antiferromagnetic interactions in the martensitic phase. The experimental results demonstrate that Ag substitution in Ni50Mn35In15-xAgx Heusler alloys suppresses the AFM interactions and enhances the FM interactions in the alloys. The possible mechanisms responsible for the observed behavior are discussed. Acknowledgement: This work was supported by the Office of Basic Energy Sciences, Material Science Division of the U.S. Department of Energy (DOE Grant No. DE-FG02-06ER46291 and DE-FG02-13ER46946).

  13. The Effect of Ag and Ag+N Ion Implantation on Cell Attachment Properties

    SciTech Connect

    Urkac, Emel Sokullu; Oztarhan, Ahmet; Gurhan, Ismet Deliloglu; Iz, Sultan Gulce; Tihminlioglu, Funda; Oks, Efim; Nikolaev, Alexey; Ila, Daryush

    2009-03-10

    Implanted biomedical prosthetic devices are intended to perform safely, reliably and effectively in the human body thus the materials used for orthopedic devices should have good biocompatibility. Ultra High Molecular Weight Poly Ethylene (UHMWPE) has been commonly used for total hip joint replacement because of its very good properties. In this work, UHMWPE samples were Ag and Ag+N ion implanted by using the Metal-Vapor Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with a fluency of 1017 ion/cm2 and extraction voltage of 30 kV. Rutherford Backscattering Spectrometry (RBS) was used for surface studies. RBS showed the presence of Ag and N on the surface. Cell attachment properties investigated with model cell lines (L929 mouse fibroblasts) to demonstrate that the effect of Ag and Ag+N ion implantation can favorably influence the surface of UHMWPE for biomedical applications. Scanning electron microscopy (SEM) was used to demonstrate the cell attachment on the surface. Study has shown that Ag+N ion implantation represents more effective cell attachment properties on the UHMWPE surfaces.

  14. Ag induced electromagnetic interference shielding of Ag-graphite/PVDF flexible nanocomposites thinfilms

    SciTech Connect

    Kumaran, R.; Alagar, M.; Dinesh Kumar, S.; Subramanian, V.; Dinakaran, K.

    2015-09-14

    We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70 S/cm at 1 MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt. % graphite in PVDF.

  15. The Effect of Ag and Ag+N Ion Implantation on Cell Attachment Properties

    NASA Astrophysics Data System (ADS)

    Urkac, Emel Sokullu; Oztarhan, Ahmet; Tihminlioglu, Funda; Gurhan, Ismet Deliloglu; Iz, Sultan Gulce; Oks, Efim; Nikolaev, Alexey; Ila, Daryush

    2009-03-01

    Implanted biomedical prosthetic devices are intended to perform safely, reliably and effectively in the human body thus the materials used for orthopedic devices should have good biocompatibility. Ultra High Molecular Weight Poly Ethylene (UHMWPE) has been commonly used for total hip joint replacement because of its very good properties. In this work, UHMWPE samples were Ag and Ag+N ion implanted by using the Metal-Vapor Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with a fluency of 1017 ion/cm2 and extraction voltage of 30 kV. Rutherford Backscattering Spectrometry (RBS) was used for surface studies. RBS showed the presence of Ag and N on the surface. Cell attachment properties investigated with model cell lines (L929 mouse fibroblasts) to demonstrate that the effect of Ag and Ag+N ion implantation can favorably influence the surface of UHMWPE for biomedical applications. Scanning electron microscopy (SEM) was used to demonstrate the cell attachment on the surface. Study has shown that Ag+N ion implantation represents more effective cell attachment properties on the UHMWPE surfaces.

  16. A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

    NASA Astrophysics Data System (ADS)

    Sinha, Sumona; Mukherjee, M.

    2015-10-01

    The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL) was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

  17. Preparation of the CNC/Ag/beeswax composites for enhancing antibacterial and water resistance properties of paper.

    PubMed

    Liu, Kai; Liang, Hunan; Nasrallah, Joseph; Chen, Lihui; Huang, Liulian; Ni, Yonghao

    2016-05-20

    An effective method of preparing composites containing inorganic (Ag) and organic (beeswax) particles was established in this study. Ag nanoparticles were first immobilized on the cellulose nanocrystals (CNC) during the reduction of AgNO3 in the presence of CNC, then mixed with beeswax by high speed stirring. Scanning transmission electron microscopy (STEM) images indicated that Ag and beeswax particles were uniformly dispersed and stable in the network structure formed by CNC. Upon coating on a paper surface, a layer of beeswax film was evident based on scanning electron microscopy (SEM) images. The dynamic contact angle and antibacterial activity tests indicated that the contact angle of coated paper reached 113.06° and the growth inhibition of Escherichia coli increased to 99.96%, respectively, at a coating amount of 21.53 g/m(2). When applied onto paper surface by coating, the CNC/Ag/beeswax composites can impact paper with antibacterial property and improved water resistance. PMID:26917389

  18. Si/Ag composite with bimodal micro-nano porous structure as a high-performance anode for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Hao, Qin; Zhao, Dianyun; Duan, Huimei; Zhou, Qiuxia; Xu, Caixia

    2015-03-01

    A one-step dealloying method is employed to conveniently fabricate a bimodal porous (BP) Si/Ag composite in high throughput under mild conditions. Upon dealloying the carefully designed SiAgAl ternary alloy in HCl solution at room temperature, the obtained Si/Ag composite has a uniform bicontinuous porous structure in three dimensions with micro-nano bimodal pore size distribution. Compared with the traditional preparation methods for porous Si and Si-based composites, this dealloying route is easily operated and environmentally benign. More importantly, it is convenient to realize the controllable components and uniform distribution of Si and Ag in the product. Owing to the rich porosity of the unique BP structure and the incorporation of highly conductive Ag, the as-made Si/Ag composite possesses the improved conductivity and alleviated volume changes of the Si network during repeated charging and discharging. As expected, the BP Si/Ag anode exhibits high capacity, excellent cycling reversibility, long cycling life and good rate capability for lithium storage. When the current rate is up to 1 A g-1, BP Si/Ag can deliver a stable reversible capacity above 1000 mA h g-1, and exhibits a capacity retention of up to 89.2% against the highest capacity after 200 cycles. With the advantages of unique performance and easy preparation, the BP Si/Ag composite holds great application potential as an advanced anode material for Li-ion batteries.A one-step dealloying method is employed to conveniently fabricate a bimodal porous (BP) Si/Ag composite in high throughput under mild conditions. Upon dealloying the carefully designed SiAgAl ternary alloy in HCl solution at room temperature, the obtained Si/Ag composite has a uniform bicontinuous porous structure in three dimensions with micro-nano bimodal pore size distribution. Compared with the traditional preparation methods for porous Si and Si-based composites, this dealloying route is easily operated and environmentally benign

  19. Enhanced thermal stability of Ag nanorods through capping

    SciTech Connect

    Bachenheimer, Lou; Elliott, Paul; Stagon, Stephen; Huang, Hanchen

    2014-11-24

    Ag nanorods may serve as sensors in the detection of trace amounts of chemical agents, even single molecules, through surface enhanced Raman spectroscopy (SERS). However, thermal coarsening of Ag nanorods near room temperature limits their applications. This letter proposes the use of a thin oxide capping layer to enhance the thermal stability of Ag nanorods beyond 100 °C. Using electron microscopy characterization and SERS tests, the authors show that the proposed method is effective in stabilizing both morphology and sensitivity of Ag nanorods. The results of this work extend the applicability of Ag nanorods as chemical sensors to higher temperatures.

  20. High intensity proton operation at the Brookhaven AGS accelerator complex

    SciTech Connect

    Ahrens, L.A.; Blaskiewicz, M.; Bleser, E.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Onillon, E.; Reece, R.K.; Roser, T.; Soukas, A.

    1994-08-01

    With the completion of the AGS rf upgrade, and the implementation of a transition {open_quotes}jump{close_quotes}, all of accelerator systems were in place in 1994 to allow acceleration of the proton intensity available from the AGS Booster injector to AGS extraction energy and delivery to the high energy users. Beam commissioning results with these new systems are presented. Progress in identifying and overcoming other obstacles to higher intensity are given. These include a careful exploration of the stopband strengths present on the AGS injection magnetic porch, and implementation of the AGS single bunch transverse dampers throughout the acceleration cycle.

  1. Actual and future trends of extreme values of temperature for the NW Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Taboada, J.; Brands, S.; Lorenzo, N.

    2009-09-01

    It is now very well established that yearly averaged temperatures are increasing due to anthropogenic climate change. In the area of Galicia (NW Spain) this trend has also been determined. The main objective of this work is to assess actual and future trends of different extreme indices of temperature, which are of curcial importance for many impact studies. Station data for the study was provided by the CLIMA database of the regional government of Galicia (NW Spain). As direct GCM-output significantly underestimates the variance of daily surface temperature variables in NW Spain, these variables are obtained by applying a statistical downscaling technique (analog method), using 850hPa temperature and mean sea level pressure as combined predictors. The predictor fields have been extracted from three GCMs participating in the IPCC AR4 under A1, A1B and A2 scenarios. The definitions of the extreme indices have been taken from the joint CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI) This group has defined a set of standard extreme values to simplify intercomparisons of data from different regions of the world. For the temperatures in the period 1960-2006, results show a significant increase of the number of days with maximum temperatures above the 90th percentile. Furthermore, a significant decrease of the days with maximum temperatures below the 10th percentile has been found. The tendencies of minimum temperatures are reverse: less nights with minimum temperatures below 10th percentile, and more with minimum temperatures above 90th percentile. Those tendencies can be observed all over the year, but are more pronounced in summer. We have also calculated the relationship between the above mentioned extreme values and different teleconnection patterns appearing in the North Atlantic area. Results show that local tendencies are associated with trends of EA (Eastern Atlantic) and SCA (Scandinavian) patterns. NAO (North Atlantic

  2. Total Mercury in Mugil spp and Eugerres axillaris of a Subtropical Lagoon of NW Mexico.

    PubMed

    Frías-Espericueta, M G; Vargas-Jiménez, A; Ruelas-Inzunza, J; Osuna-López, J I; Aguilar-Juárez, M; Bautista-Covarrubias, J C; Voltolina, D

    2016-08-01

    The mercury content of mullets and black mojarras of Urías lagoon (NW Mexico) were determined every second month from November 2012 to September 2013, to determine differences related to season or to trophic levels. The Hg contents of the muscle were significantly higher in mojarras, confirming that Hg contents tend to increase along the food chain, while the levels in liver were higher in mullets, suggesting different Hg storage strategies of these species. In mullets, the content of muscles did not vary seasonally and was significantly lower than in the liver. In black mojarras there were no significant differences between muscle and liver, and the lowest mean values were in May in both tissues. Given the low Hg contents, both species are safe for human consumption, but care should be taken in traditional fishing communities. PMID:27178545

  3. Petrography and physicomechanical properties of rocks from the Ambela granitic complex, NW Pakistan.

    PubMed

    Arif, Mohammad; Bukhari, S Wajid Hanif; Muhammad, Noor; Sajid, Muhammad

    2013-01-01

    Petrography and physicomechanical properties of alkali granites, alkali quartz syenite, and nepheline syenite from Ambela, NW Pakistan, have been investigated. Whereas the alkali quartz syenite and most of the alkali granites are megaporphyritic, the nepheline syenite and some of the alkali granites are microporphyritic. Their phenocryst shape and size and abundance of groundmass are also different. The values of unconfined compressive strength (UCS) are the lowest and highest for megaporphyritic alkali granite and alkali quartz syenite, respectively. However, all the four rock types are moderately strong. Correspondingly, their specific gravity and water absorption values are within the permissible range for use as construction material. The UCS for the alkali quartz syenite is the highest, most probably because (i) it has roughly equal amounts of phenocryst and groundmass, (ii) it displays maximum size contrast between phenocryst and groundmass, (iii) its phenocrysts are highly irregular, and (iv) it contains substantial amounts of quartz. PMID:23861654

  4. Petrography and Physicomechanical Properties of Rocks from the Ambela Granitic Complex, NW Pakistan

    PubMed Central

    Arif, Mohammad; Bukhari, S. Wajid Hanif; Muhammad, Noor; Sajid, Muhammad

    2013-01-01

    Petrography and physicomechanical properties of alkali granites, alkali quartz syenite, and nepheline syenite from Ambela, NW Pakistan, have been investigated. Whereas the alkali quartz syenite and most of the alkali granites are megaporphyritic, the nepheline syenite and some of the alkali granites are microporphyritic. Their phenocryst shape and size and abundance of groundmass are also different. The values of unconfined compressive strength (UCS) are the lowest and highest for megaporphyritic alkali granite and alkali quartz syenite, respectively. However, all the four rock types are moderately strong. Correspondingly, their specific gravity and water absorption values are within the permissible range for use as construction material. The UCS for the alkali quartz syenite is the highest, most probably because (i) it has roughly equal amounts of phenocryst and groundmass, (ii) it displays maximum size contrast between phenocryst and groundmass, (iii) its phenocrysts are highly irregular, and (iv) it contains substantial amounts of quartz. PMID:23861654

  5. Early late Visean ammonoid faunas from the Jadar Block (NW Serbia)

    NASA Astrophysics Data System (ADS)

    Korn, Dieter; Jovanović, Divna; Novak, Matevž; Sudar, Milan N.

    2010-10-01

    The outcrop at Milivojevića Kamenjar in Družetić (Jadar Block, Vardar Zone, NW Serbia), which exposes a fossiliferous limestone olistolith, is one of the key sites for Carboniferous stratigraphy and paleogeography in the Balkan Peninsula. Its age has been debated several times, and re-examination of the succession was required. Based on ammonoids and conodonts, an interval spanning from the latest Devonian to the basal Serpukhovian is represented. From the early late Visean portion of the section, the new ammonoid genus and species Ubites filipovici gen. nov. et sp. nov. is described. Entogonites tetragonus (Kullmann, 1962), a formerly misinterpreted ammonoid species, is revised.

  6. Banderas Rift Zone: A plausible NW limit of the Jalisco Block

    NASA Astrophysics Data System (ADS)

    Alvarez, Román

    2002-10-01

    Echo soundings recently made in Bahía de Banderas show that this region is a graben with steeply dipping walls and several basins; it is the offshore continuation of the Valle de Banderas graben, and of a branching rift (Río Ameca rift) originating in the Tepic-Zacoalco rift zone. The general trend of the three structures is ENE with some NE trending offsets, and they have a total length of 150 km; this Banderas Rift Zone is proposed as the NW limit of the Jalisco block. The existence of this limit suggests that there is another platelet, or block, between the Jalisco block and a portion of the Rivera plate, probably bounded by the Tres Marías escarpment, the Jalisco block and the North America plate.

  7. Petrography and physicomechanical properties of rocks from the Ambela granitic complex, NW Pakistan.

    PubMed

    Arif, Mohammad; Bukhari, S Wajid Hanif; Muhammad, Noor; Sajid, Muhammad

    2013-01-01

    Petrography and physicomechanical properties of alkali granites, alkali quartz syenite, and nepheline syenite from Ambela, NW Pakistan, have been investigated. Whereas the alkali quartz syenite and most of the alkali granites are megaporphyritic, the nepheline syenite and some of the alkali granites are microporphyritic. Their phenocryst shape and size and abundance of groundmass are also different. The values of unconfined compressive strength (UCS) are the lowest and highest for megaporphyritic alkali granite and alkali quartz syenite, respectively. However, all the four rock types are moderately strong. Correspondingly, their specific gravity and water absorption values are within the permissible range for use as construction material. The UCS for the alkali quartz syenite is the highest, most probably because (i) it has roughly equal amounts of phenocryst and groundmass, (ii) it displays maximum size contrast between phenocryst and groundmass, (iii) its phenocrysts are highly irregular, and (iv) it contains substantial amounts of quartz.

  8. New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods.

    PubMed

    Canale, Juan I; Scanferla, Carlos A; Agnolin, Federico L; Novas, Fernando E

    2009-03-01

    A nearly complete skeleton of the new abelisaurid Skorpiovenator bustingorryi is reported here. The holotype was found in Late Cenomanian-Early Turonian outcrops of NW Patagonia, Argentina. This new taxon is deeply nested within a new clade of South American abelisaurids, named Brachyrostra. Within brachyrostrans, the skull shortening and hyperossification of the skull roof appear to be correlated with a progressive enclosure of the orbit, a set of features possibly related to shock-absorbing capabilities. Moreover, the development of horn-like structures and differential cranial thickening appear to be convergently acquired within Abelisauridae. Based on the similarities between Skorpiovenator and carcharodontosaurid tooth morphology, we suggest that isolated teeth originally referred as post-Cenomanian Carcharodontosauridae most probably belong to abelisaurids.

  9. Effect of brine discharge from a desalination plant on macrobenthic communities in the NW Mediterranean.

    PubMed

    Raventos, N; Macpherson, E; García-Rubiés, A

    2006-07-01

    This paper examines the possible effects of discharges from a desalination plant on the macrobenthic community inhabiting the sandy substratum off the coast of Blanes in Spain (NW Mediterranean) using multivariate and univariate analyses. Two controls and one putatively impacted location were selected and visual censuses were carried out 12 times before and 12 times after the plant had begun operating. No significant variations attributable to the brine discharges from the desalination plant were found. The failure to record any impact may be explained by the high natural variability that is a characteristic feature of bottoms of this type and also by the rapid dilution undergone by the hypersaline brine upon leaving the discharge pipe.

  10. Geology and energy resources of the Sand Butte Rim NW Quadrangle, Sweetwater County, Wyoming

    USGS Publications Warehouse

    Roehler, Henry W.

    1979-01-01

    The Sand Butte Rim NW 71-minute quadrangle occupies 56 square miles of an arid, windy, sparsely vegetated area of ridges and valleys on the east flank of the Rock Springs uplift in southwest Wyoming. The area is underlain by a succession of sedimentary rocks, about 20,000 feet thick, that includes 28 formations ranging in age from Cambrian to Tertiary. Upper Cretaceous and lower Tertiary formations crop out and dip 3?-6? southeast. They are unfaulted and generally homoclinal, but a minor anticlinal nose is present. Older rocks in the subsurface are faulted and folded. Coal resources are estimated to be nearly I billion short tons of subbituminous coal, in beds more than 2.5 feet thick, under less than 3,000 feet of overburden, in the Fort Union Formation of Paleocene age and the Lance and Almond Formations of Cretaceous age.

  11. New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods.

    PubMed

    Canale, Juan I; Scanferla, Carlos A; Agnolin, Federico L; Novas, Fernando E

    2009-03-01

    A nearly complete skeleton of the new abelisaurid Skorpiovenator bustingorryi is reported here. The holotype was found in Late Cenomanian-Early Turonian outcrops of NW Patagonia, Argentina. This new taxon is deeply nested within a new clade of South American abelisaurids, named Brachyrostra. Within brachyrostrans, the skull shortening and hyperossification of the skull roof appear to be correlated with a progressive enclosure of the orbit, a set of features possibly related to shock-absorbing capabilities. Moreover, the development of horn-like structures and differential cranial thickening appear to be convergently acquired within Abelisauridae. Based on the similarities between Skorpiovenator and carcharodontosaurid tooth morphology, we suggest that isolated teeth originally referred as post-Cenomanian Carcharodontosauridae most probably belong to abelisaurids. PMID:19057888

  12. Changes in metal contents in shrimp cultured in NW Mexico (2000-2010).

    PubMed

    Frías-Espericueta, M G; Osuna-López, J I; Delgado-Alvarez, C G; Muy-Rangel, M D; López-López, G; Izaguirre-Fierro, G; Jaimes-Bustamante, F; Zazueta-Padilla, H M; Aguilar-Juárez, M; Rubio-Carrasco, W; Voltolina, D

    2015-05-01

    This study shows the concentrations of Cd, Cu, Pb, and Zn in the muscle and hepatopancreas of Pacific white shrimps, Litopenaeus vannamei, cultured during 2010 in 26 commercial farms of the three main producer states of the Mexican NW, Sonora, Sinaloa, and Nayarit and compares the results to those obtained in 2000 using samples collected in16 farms of the same states. No significant changes were detected in Cd concentrations, but the 2010 Zn levels were significantly higher in all states in the hepatopancreas and in Sinaloa in the case of the muscle. Cu showed a tendency to higher hepatopancreas values in 2010, but differences were significant only in Sonora and for the global mean value. In contrast, Pb was one order of magnitude lower in both organs in 2010, possibly because of the almost 15 years since leaded gasoline was discontinued in Mexico.

  13. Total Mercury in Mugil spp and Eugerres axillaris of a Subtropical Lagoon of NW Mexico.

    PubMed

    Frías-Espericueta, M G; Vargas-Jiménez, A; Ruelas-Inzunza, J; Osuna-López, J I; Aguilar-Juárez, M; Bautista-Covarrubias, J C; Voltolina, D

    2016-08-01

    The mercury content of mullets and black mojarras of Urías lagoon (NW Mexico) were determined every second month from November 2012 to September 2013, to determine differences related to season or to trophic levels. The Hg contents of the muscle were significantly higher in mojarras, confirming that Hg contents tend to increase along the food chain, while the levels in liver were higher in mullets, suggesting different Hg storage strategies of these species. In mullets, the content of muscles did not vary seasonally and was significantly lower than in the liver. In black mojarras there were no significant differences between muscle and liver, and the lowest mean values were in May in both tissues. Given the low Hg contents, both species are safe for human consumption, but care should be taken in traditional fishing communities.

  14. Causal Interrogation of Neuronal Networks and Behavior through Virally Transduced Ivermectin Receptors

    PubMed Central

    Obenhaus, Horst A.; Rozov, Andrei; Bertocchi, Ilaria; Tang, Wannan; Kirsch, Joachim; Betz, Heinrich; Sprengel, Rolf

    2016-01-01

    The causal interrogation of neuronal networks involved in specific behaviors requires the spatially and temporally controlled modulation of neuronal activity. For long-term manipulation of neuronal activity, chemogenetic tools provide a reasonable alternative to short-term optogenetic approaches. Here we show that virus mediated gene transfer of the ivermectin (IVM) activated glycine receptor mutant GlyRα1AG can be used for the selective and reversible silencing of specific neuronal networks in mice. In the striatum, dorsal hippocampus, and olfactory bulb, GlyRα1AG promoted IVM dependent effects in representative behavioral assays. Moreover, GlyRα1AG mediated silencing had a strong and reversible impact on neuronal ensemble activity and c-Fos activation in the olfactory bulb. Together our results demonstrate that long-term, reversible and re-inducible neuronal silencing via GlyRα1AG is a promising tool for the interrogation of network mechanisms underlying the control of behavior and memory formation.

  15. Causal Interrogation of Neuronal Networks and Behavior through Virally Transduced Ivermectin Receptors.

    PubMed

    Obenhaus, Horst A; Rozov, Andrei; Bertocchi, Ilaria; Tang, Wannan; Kirsch, Joachim; Betz, Heinrich; Sprengel, Rolf

    2016-01-01

    The causal interrogation of neuronal networks involved in specific behaviors requires the spatially and temporally controlled modulation of neuronal activity. For long-term manipulation of neuronal activity, chemogenetic tools provide a reasonable alternative to short-term optogenetic approaches. Here we show that virus mediated gene transfer of the ivermectin (IVM) activated glycine receptor mutant GlyRα1 (AG) can be used for the selective and reversible silencing of specific neuronal networks in mice. In the striatum, dorsal hippocampus, and olfactory bulb, GlyRα1 (AG) promoted IVM dependent effects in representative behavioral assays. Moreover, GlyRα1 (AG) mediated silencing had a strong and reversible impact on neuronal ensemble activity and c-Fos activation in the olfactory bulb. Together our results demonstrate that long-term, reversible and re-inducible neuronal silencing via GlyRα1 (AG) is a promising tool for the interrogation of network mechanisms underlying the control of behavior and memory formation.

  16. Functional subdivisions in the left angular gyrus where the semantic system meets and diverges from the default network

    PubMed Central

    Seghier, Mohamed L; Fagan, Elizabeth; Price, Cathy J

    2011-01-01

    The left angular gyrus (AG) is reliably activated across a wide range of semantic tasks, and is also a consistently reported component of the so-called default network that it is deactivated during all goal-directed tasks. We show here that there is only partial overlap between the semantic system and the default network in left AG and the overlap defines a reliable functional landmark that can be used to segregate functional subdivisions within AG. In 94 healthy human subjects, we collected fMRI data during fixation and eight goal directed tasks that involved semantic matching, perceptual matching or speech production in response to familiar or unfamilair stimuli presented in either verbal (letters) or nonverbal (pictures) formats. Our results segregated three different left AG regions that were all activated by semantic relative to perceptual matching: (i) a mid-region (mAG) that overlapped with the default network because it was deactivated during all tasks relative to fixation; (ii) a dorso-mesial region (dAG) that was more activated by all tasks relative to fixation; and (iii) a ventro-lateral region (vAG) that was only activated above fixation during semantic matching. By examining the effects of task and stimuli in each AG subdivision, we propose that mAG is involved in semantic associations irrespective of the presence or absence of a stimulus; dAG is involved in searching for semantics in all visual stimuli, and vAG is involved in the conceptual identification of visual inputs. Our findings provide a framework for reporting and interpreting AG activations with greater definition. PMID:21159952

  17. A Probabilistic Assessment of Earthquake Hazard Parameters in NW Himalaya and the Adjoining Regions

    NASA Astrophysics Data System (ADS)

    Yadav, R. B. S.; Bayrak, Yusuf; Tripathi, J. N.; Chopra, S.; Singh, A. P.; Bayrak, Erdem

    2012-09-01

    The maximum likelihood estimation method is applied to study the geographical distribution of earthquake hazard parameters and seismicity in 28 seismogenic source zones of NW Himalaya and the adjoining regions. For this purpose, we have prepared a reliable, homogeneous and complete earthquake catalogue during the period 1500-2010. The technique used here allows the data to contain either historical or instrumental era or even a combination of the both. In this study, the earthquake hazard parameters, which include maximum regional magnitude ( M max), mean seismic activity rate ( λ), the parameter b (or β = b/log e) of Gutenberg-Richter (G-R) frequency-magnitude relationship, the return periods of earthquakes with a certain threshold magnitude along with their probabilities of occurrences have been calculated using only instrumental earthquake data during the period 1900-2010. The uncertainties in magnitude have been also taken into consideration during the calculation of hazard parameters. The earthquake hazard in the whole NW Himalaya region has been calculated in 28 seismogenic source zones delineated on the basis of seismicity level, tectonics and focal mechanism. The annual probability of exceedance of earthquake (activity rate) of certain magnitude is also calculated for all seismogenic source zones. The obtained earthquake hazard parameters were geographically distributed in all 28 seismogenic source zones to analyze the spatial variation of localized seismicity parameters. It is observed that seismic hazard level is high in Quetta-Kirthar-Sulaiman region in Pakistan, Hindukush-Pamir Himalaya region and Uttarkashi-Chamoli region in Himalayan Frontal Thrust belt. The source zones that are expected to have maximum regional magnitude ( M max) of more than 8.0 are Quetta, southern Pamir, Caucasus and Kashmir-Himanchal Pradesh which have experienced such magnitude of earthquakes in the past. It is observed that seismic hazard level varies spatially from one zone

  18. Geochemistry of natural gases from mud volcanoes and surface gas seeps in NW-Columbia

    SciTech Connect

    Beeunas, M.A. ); Schoell, M. ); Beroiz, C. )

    1991-03-01

    Mud volcanoes and natural gas seeps are common in the southwest-northeast-trending Sinu Atlantico basin (SAB) and San Jacinto Fold Belt (SJFB) of NW-Colombia. The structural subunits are part of a highly complex active continental margin where the sediments become increasingly younger to the west from Late Cretaceous to Early Tertiary in the SJFB to Late Tertiary in the SAB. Some of the mud volcanoes are permanently active and form huge structures and are often aligned along major faults. Both seep and mud volcano gases are with low C{sub 2}-C{sub 4} and CO{sub 2} contents. Carbon and hydrogen isotope concentrations allow the subdivision into four groups of gas. These gases can be divided into four genetic based on their carbon and hydrocarbon isotope compositions. The isotopic variability of the different groups attests to the fact that very different gas-forming processes are or have been operating in the subsurface ranging from low-temperature thermogenesis. The various groups show, with few exceptions, a distinct regional distribution: Mud volcanoes and seeps with bacterial gases are restricted to the southern part of the SAB where the greatest thickness of young sediments is observed; gases of mixed thermogenic and bacterial origin are found in the coastal areas of the northern SAB; gases of thermogenic origin are predominantly observed in the SJFB; the thermogenic gases of Group 3 are restricted to two locations in the north of the SJFB. This regional association of genetic gas types with specific geotectonic units reflects different thermal histories of the respective tectonic areas and allowed the authors to delineate prospective areas for oil in NW-Colombia.

  19. Responding to Change in NW Alaska: Ethnographic Film and the Voices of the People

    NASA Astrophysics Data System (ADS)

    Betcher, S. R.; Gerlach, S. C.; Atkinson, D. E.; Loring, P. A.

    2014-12-01

    Communities in the NW arctic rely on subsistence activities such as hunting, fishing and gathering to ensure their food security and to maintain a cultural identity but climate change is altering the timing and distribution of plants and animals. Arctic Alaskan villages are only accessible by air or watercraft thus limiting the options of goods and services and increasing the cost due to vast distances traveled. Additionally, these goods and services must be transported during winter months, which include some of the most extreme temperatures and landscapes people permanently occupy. Many rural community members mitigate these high food prices by maintaining their traditional lifestyle of hunting fishing and gathering of marine mammals, fish, greens and berries. These essential subsistence activities are impacted by a warming arctic as reduced sea ice extent, permafrost thaw, increased storm severity and shifting seasonality alters plant and animal patterns that people in the region have knowledge about for thousands of years. Now with increased weather variability and a changing climate the people in the region are adapting and responding to these changes. Local traditional knowledge (LTK) of active hunters, fishers, and gatherers can provide a deeper and more comprehensive understanding to western science of how climate change is impacting the Arctic. This documentary film captures footage from the summer and fall of 2013 of activities of hunters fishers and gatherers and recorded their sentiments of how climate changes has impacted their subsistence way of life, and how arctic residence are responding to both climate and extreme weather events. Video is taken from the land, sea and air in and around Kotzebue, Kivalina, Point Hope, Noatak, Ambler, Buckland and Deering. The presenters will discuss how the film shows responses to change and how the film was made in close collaboration with NW arctic residents.

  20. Direct video and hydrophone observations of submarine explosive eruptions at NW Rota-1 volcano, Mariana arc

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Cashman, K. V.; Embley, R. W.; Matsumoto, H.; Dziak, R. P.; de Ronde, C. E. J.; Lau, T. K.; Deardorff, N. D.; Merle, S. G.

    2008-08-01

    Extraordinary video and hydrophone observations of a submarine explosive eruption were made with a remotely operated vehicle in April 2006 at a depth of 550-560 m on NW Rota-1 volcano in the Mariana arc. The observed eruption evolved from effusive to explosive, while the eruption rate increased from near zero to 10-100 m3/h. During the peak in activity, cyclic explosive bursts 2-6 min long were separated by shorter non-eruptive pauses lasting 10-100 s. The size of the ejecta increased with the vigor of the explosions. A portable hydrophone deployed near the vent recorded sounds correlated with the explosive bursts; the highest amplitudes were ˜50 dB higher than ambient noise at frequencies between 10 and 50 Hz. The acoustic data allow us to quantify the durations, amplitudes, and evolution of the eruptive events over time. The low eruption rate, high gas/lava ratio, and rhythmic eruptive behavior at NW Rota-1 are most consistent with a Strombolian eruptive style. We interpret that the eruption was primarily driven by the venting of magmatic gases, which was also the primary source of the sound recorded during the explosive bursts. The rhythmic nature of the bursts can be explained by partial gas segregation in the conduit and upward migration in a transitional regime between bubbly flow and fully developed slug flow. The strongest explosive bursts were accompanied by flashes of red glow and oscillating eruption plumes in the vent, apparently caused by magma-seawater interaction and rapid steam formation and condensation. This is the first time submarine explosive eruptions have been witnessed with simultaneous near-field acoustic recordings.

  1. Geomorphological analysis of the drainage system on the active convergent system in Azerbaijan, NW Iran

    NASA Astrophysics Data System (ADS)

    Kaveh Firouz, Amaneh; Burg, Jean-Pierre; Giachetta, Emanuele

    2016-04-01

    Rivers are important landforms to reconstruct recent tectonic history because they are sensitive to surface movements, especially uplift and tilting. The most important drainage basins of NW Iran are, from north to south, the Arax River, the Urmia Lake and the Ghezel Ozan River catchment. The morphology of the two adjacent catchments draining into the Caspian Sea, the Arax and Ghezel Ozan were studied to better understand the active tectonics and the effect of fault activity on morphology and erosion rate of NW Iran. We performed a quantitative analysis of channel steepness and concavity, from slope-area plots calculated from digital elevation model. This information has been combined with GPS velocity vectors and seismicity. Both catchments developed under uniform climate conditions. Results show that the two rivers are in morphological disequilibrium; they exhibit profiles with prominent convexities and knickpoints. The Arax River shows higher channel steepness and concavity index in downstream part of the profile. Distribution of knickpoints show scattered elevation between 700m and 3000m. GPS rates display shortening 10 ± 2 mma‑1 and 14 ± 2 mma‑1 in upstream and downstream, respectively. The river profiles of Ghezel Ozan River and its tributaries reveal more disequilibrium downstream where channel steepness and concavity index are higher than upstream. Most knickpoints occur between 1000m and 2000m. The amount of shortening by GPS measurement changes from upstream 13 ± 2 mma‑1to downstream 14 ± 2 mma‑1. Recorded earthquakes, such as Rudbar earthquake (Mw=7.3, 1990), are more frequent downstream. The Urmia Lake is surrounded by many small and large catchments. Only major catchments were considered for the analysis. One of the most active faults, the north Tabriz fault, corresponds to a major knickpoints on the Talkhe rud River. Concordance between river profile analysis, GPS and seismotectonic records suggests that the characteristics of the river

  2. To what extent did changes in July temperature influence Lateglacial vegetation patterns in NW Europe?

    NASA Astrophysics Data System (ADS)

    Birks, Hilary H.; Birks, H. John B.

    2014-12-01

    What was the impact of July temperature changes on vegetation patterns during the Lateglacial period in north-west Europe? Chironomid-inferred mean July air temperature estimates (C-Tjul) are proxy temperature records independent of terrestrial vegetation. The relationships between Lateglacial vegetation inferred from pollen percentages and these temperature estimates are explored using data synthesised geographically from 15 sites where both pollen percentages and C-Tjul are published to assess the influence of temperature and of temperature changes on regional vegetation. Direct impacts of temperature on a species involve passing the range limits or realised niche of that species. The Bølling warming allowed vegetation to develop. The Younger Dryas cooling had direct impacts on species and vegetation types that were at a critical ecotone and thus sensitive to change. Precipitation is extremely important and its interaction with temperature controlled most of the vegetation patterns inferred from these NW European pollen data. High precipitation was important in W Norway, whereas aridity in the YD was a controlling factor in N Norway, the Netherlands, and NE Germany. Under constant climate, ecological processes occurred such as immigration, succession, and soil development that resulted in vegetation changes. Biotic interactions were also important, such as the impact of grazing by mega-herbivores during Allerød time in Ireland that may have restricted the development of birch woodland. At the coarse scale of this synthesis, July temperature alone is seen not to be a good predictor of the patterns of pollen percentages and hence of vegetation through the Lateglacial. Rather, it is the interactions of temperature and precipitation, combined with ecological processes that appear to be the major factors influencing Lateglacial palynological and vegetation patterns in NW Europe.

  3. Characterisation of bio-aerosols during dust storm period in N-NW India

    NASA Astrophysics Data System (ADS)

    Yadav, Sudesh; Chauhan, M. S.; Sharma, Anupam

    Bio-investigations for pollen and spores were performed on dry free-fall dust and PM 10 aerosol samples, collected from three different locations separated by a distance of 600 km, situated in dust storm hit region of N-NW India. Presence of pollen of trees namely Prosopis ( Prosopis juliflora and Prosopis cinearia), Acacia, Syzygium, Pinus, Cedrus, Holoptelea and shrubs namely Ziziphus, Ricinus, Ephedra and members of Fabaceae, Oleaceae families was recorded but with varying proportions in the samples of different locations. Poaceae, Chenopodiaceae/Amaranthaceae, Caryophyllaceae, Brassicaceae and Cyperaceae (sedges) were some of the herb pollen identified in the samples. Among the fungal spores Nigrospora was seen in almost all samples. Nigrospora is a well known allergen and causes health problems. The concentration of trees and shrubs increases in the windward direction just as the climate changes from hot arid to semiarid. The higher frequency of grasses (Poaceae) or herbs could either be a result of the presence of these herbs in the sampling area and hence the higher production of pollen/spores or due to the resuspension from the exposed surface by the high-intensity winds. But we cannot ascertain the exact process at this stage. The overall similarity in the pollen and spore assemblage in our dust samples indicates a common connection or source(s) to the dust in this region. Presence of the pollen of the species of Himalayan origin in our entire samples strongly point towards a Himalayan connection, could be direct or indirect, to the bioaerosols and hence dust in N-NW India. In order to understand the transport path and processes involved therein, present study needs further extension with more number of samples and with reference to meteorological parameters.

  4. Fractionation of 210Po and 210Pb in coastal waters of the NW Mediterranean continental margin

    NASA Astrophysics Data System (ADS)

    Tateda, Yutaka; Carvalho, Fernando P.; Fowler, Scott W.; Miquel, Juan-Carlos

    2003-03-01

    The natural radionuclides 210Po and 210Pb were analyzed in samples of surface sea water, rain and dry fallout, and river water collected along the NW Mediterranean coast as well as from a sediment trap moored 3 km south of Monaco. Using a box model calculation, the balances and fluxes of 210Po and 210Pb in the coastal waters of the NW Mediterranean were estimated. Atmospheric inputs of 210Po and 210Pb to Monaco coastal waters varied seasonally and were maximal in winter when storms and strong winds transfered continental 222Rn-rich air and aerosols of top soil particles to coastal surface waters, which in turn enhanced the 210Po and 210Pb input to these waters. The balance estimation using all fluxes in surface waters indicated that 210Pb was removed from surface water with residence times of 2.1, 0.40, and 2.7 years for dissolved, particulate, and total 210Pb, respectively. In the bottom water and surface sediments, additional excess 210Pb sinking and sedimentation fluxes were observed, suggesting a substantial down slope transport of sediment particles. Similarly, the residence times of 210Po in surface water were 1.2, 0.38, and 0.77 years for dissolved, particulate, and total 210Po, respectively; however, a deficit in the 210Po sinking flux in the bottom layer, compared to removal flux from the surface waters, suggested rapid degradation of 210Po-bearing biogenic particles during sinking following periods of low biological productivity.

  5. A 3D model of crustal magnetization at the Pinacate Volcanic Field, NW Sonora, Mexico

    NASA Astrophysics Data System (ADS)

    García-Abdeslem, Juan; Calmus, Thierry

    2015-08-01

    The Pinacate Volcanic Field (PVF) is located near the western border of the southern Basin and Range province, in the State of Sonora NW Mexico, and within the Gulf of California Extensional Province. This volcanic field contains the shield volcano Santa Clara, which mainly consists of basaltic to trachytic volcanic rocks, and reaches an altitude of ~ 1200 m. The PVF disrupts a series of discontinuous ranges of low topographic relief aligned in a NW direction, which consist mainly of Proterozoic metamorphic rocks and Proterozoic through Paleogene granitoids. The PVF covers an area of approximately 60 by 55 km, and includes more than 400 well-preserved cinder cones and vents and eight maar craters. It was active from about 1.7 Ma until about 13 ka. We have used the ages and magnetic polarities of the volcanic rocks, along with mapped magnetic anomalies and their inverse modeling to determine that the Pinacate Volcanic Field was formed during two volcanic episodes. The oldest one built the Santa Clara shield volcano of basaltic and trachytic composition, and occurred during the geomagnetic Matuyama Chron of reverse polarity, which also includes the normal polarity Jaramillo and Olduvai Subchrons, thus imprinting both normal and reverse magnetization in the volcanic products. The younger Pinacate series of basaltic composition represents monogenetic volcanic activity that extends all around the PVF and occurred during the subsequent geomagnetic Brunhes Chron of normal polarity. Magnetic anomalies toward the north of the Santa Clara volcano are the most intense in the PVF, and their inverse modeling indicates the presence of a large subsurface body magnetized in the present direction of the geomagnetic field. This suggests that the magma chambers at depth cooled below the Curie temperature during the Brunhes Chron.

  6. Zooplankton diel vertical migration and contribution to deep active carbon flux in the NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Isla, Alejandro; Scharek, Renate; Latasa, Mikel

    2015-03-01

    The diel vertical migration (DVM) of zooplankton contributes to the biological pump transporting material from surface to deep waters. We examined the DVM of the zooplankton community in different size fractions (53-200 μm, 200-500 μm, 500-1000 μm, 1000-2000 μm and > 2000 μm) during three cruises carried out in the open NW Mediterranean Sea. We assessed their metabolic rates from empirical published relationships and estimated the active fluxes of dissolved carbon to the mesopelagic zone driven by migrant zooplankton. Within the predominantly oligotrophic Mediterranean Sea, the NW region is one of the most productive ones, with a seasonal cycle characterized by a prominent spring bloom. The study area was visited at three different phases of the seasonal cycle: during the spring bloom, the post-bloom, and strongly stratified oligotrophic conditions. We found seasonal differences in DVM, less evident during the bloom. Changes in DVM intensity were related to the composition of the zooplanktonic assemblage, which also varied between cruises. Euphausiids appeared as the most active migrants in all seasons, and their life cycle conditioned the observed pattern. Immature stages, which are unable to perform large diel vertical movements, dominated during the bloom, in contrast to the higher relative importance of migrating adults in the other two sampling periods. The amount of dissolved carbon exported was determined by the migrant zooplankton biomass, being highest during the post-bloom (2.2 mmol C respired m- 2 d- 1, and up to 3.1 mmol C exported m- 2 d- 1 when DOC release estimations are added). The active transport by diel migrants represented a substantial contribution to total carbon export to deep waters, especially under stratified oligotrophic conditions, revealing the importance of zooplankton in the biological pump operating in the study area.

  7. Mineralogy and geochemistry of base-metal deposits at Halilar area, NW Turkey

    NASA Astrophysics Data System (ADS)

    Kiran Yildirim, D.; Abdelnasser, A.; Doner, Z.; Kumral, M.

    2015-12-01

    This study focuses on the base-metal deposits at Halilar area (NW Turkey) by reporting new data obtained from mineralogical, petrographical and geochemical investigation of this deposit. It is to determine key features of the host rocks, mineralogical changes and alteration zones related to this mineralization. Halilar area is located about 25-30 km NE of Edremit in Balikseir district (NW Turkey). This area contains Halilar group that overlies pre-Late Triassic metamorphic rocks and Permian limestone in the surrounding areas. This Halilar group consists of Bagcagiz and Sakarkaya Formations; later intruded by Duztarla granitic rocks. The base metal deposits at study area represent locally Cu-Pb with some Zn vein type deposits. These deposits restricted to fault gouge zone directed NE-SW as well as occurred at the lower boundary of Bagcagiz and Duztarla granite. It also closely associated with intense hydrothermal alteration within brecciation, and quartz stockwork veining. The mineral assemblage includes chalcopyrite, galena, and some sphalerite, with covellite, and goethite in an abundant gangue of quartz and pyrite. Paragenetic relationships reveal three stages of mineralization; pre-ore, ore, and supergene. Wall-rock hydrothermal alteration includes pervasive silicification, sulfidation, carbonatization, and selective chloritization, sericitization and muscovitization. The geochemical studies refer to the altered samples have high CIA relative to the least altered rocks. The relationship between Na2O and K2O with the Ishikawa alteration index refers to the data plot close to chlorite/sericite. Also, based on alteration box plotting (Ishikawa alteration index vs. chlorite-carbonate-pyrite index), they mostly plotted in the field of the hydrothermal alteration close to chlorite and pyrite minerals with more hydrothermal trends; Intense sericite-chlorite ± pyrite alteration, chlorite ± sericite ± pyrite alteration, and sericite-carbonate alteration.

  8. Geomorphological analysis of the drainage system on the active convergent system in Azerbaijan, NW Iran

    NASA Astrophysics Data System (ADS)

    Kaveh Firouz, Amaneh; Burg, Jean-Pierre; Giachetta, Emanuele

    2016-04-01

    Rivers are important landforms to reconstruct recent tectonic history because they are sensitive to surface movements, especially uplift and tilting. The most important drainage basins of NW Iran are, from north to south, the Arax River, the Urmia Lake and the Ghezel Ozan River catchment. The morphology of the two adjacent catchments draining into the Caspian Sea, the Arax and Ghezel Ozan were studied to better understand the active tectonics and the effect of fault activity on morphology and erosion rate of NW Iran. We performed a quantitative analysis of channel steepness and concavity, from slope-area plots calculated from digital elevation model. This information has been combined with GPS velocity vectors and seismicity. Both catchments developed under uniform climate conditions. Results show that the two rivers are in morphological disequilibrium; they exhibit profiles with prominent convexities and knickpoints. The Arax River shows higher channel steepness and concavity index in downstream part of the profile. Distribution of knickpoints show scattered elevation between 700m and 3000m. GPS rates display shortening 10 ± 2 mma-1 and 14 ± 2 mma-1 in upstream and downstream, respectively. The river profiles of Ghezel Ozan River and its tributaries reveal more disequilibrium downstream where channel steepness and concavity index are higher than upstream. Most knickpoints occur between 1000m and 2000m. The amount of shortening by GPS measurement changes from upstream 13 ± 2 mma-1to downstream 14 ± 2 mma-1. Recorded earthquakes, such as Rudbar earthquake (Mw=7.3, 1990), are more frequent downstream. The Urmia Lake is surrounded by many small and large catchments. Only major catchments were considered for the analysis. One of the most active faults, the north Tabriz fault, corresponds to a major knickpoints on the Talkhe rud River. Concordance between river profile analysis, GPS and seismotectonic records suggests that the characteristics of the river profiles

  9. Ag@Ag8W4O16 nanoroasted rice beads with photocatalytic, antibacterial and anticancer activity.

    PubMed

    Selvamani, Muthamizh; Krishnamoorthy, Giribabu; Ramadoss, Manigandan; Sivakumar, Praveen Kumar; Settu, Munusamy; Ranganathan, Suresh; Vengidusamy, Narayanan

    2016-03-01

    Increasing resistance of pathogens and cancer cell line towards antibiotics and anticancer agents has caused serious health problems in the past decades. Due to these problems in recent years, researchers have tried to combine nanotechnology with material science to have intrinsic antimicrobial and anticancer activity. The metals and metal oxides were investigated with respect to their antimicrobial and anticancer effects towards bacteria and cancer cell line. In the present work metal@metal tungstate (Ag@Ag8W4O16 nanoroasted rice beads) is investigated for antibacterial activity against Escherichia coli and Staphylococcus aureus using Mueller-Hinton broth and the anticancer activity against B16F10 cell line was studied. Silver decorated silver tungstate (Ag@Ag8W4O16) was synthesized by the microwave irradiation method using Cetyl Trimethyl Ammonium Bromide (CTAB). Ag@Ag8W4O16 was characterized by using various spectroscopic techniques. The phase and crystalline nature were analyzed by using XRD. The morphological analysis was carried out using Field Emission Scanning Electron Microscopy (FE-SEM), and High Resolution Transmission Electron Microscopy (HR-TEM). Further, Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectral analysis were carried out in order to ascertain the presence of functional groups in Ag@Ag8W4O16. The optical property was investigated using Diffuse Reflectance Ultraviolet-Visible Spectroscopy (DRS-UV-Vis) and the band gap was found to be 3.08eV. Surface area of the synthesized Ag@Ag8W4O16 wasanalyzed by BET analysis and Ag@Ag8W4O16 was utilized for the degradation of organic dyes methylene blue and rhodamine B. The morphology of the Ag@Ag8W4O16 resembles roasted rice beads with breath and length in nm range. The oxidation state of tungsten (W) and silver (Ag) was investigated using X-ray photoelectron spectroscopy (XPS).

  10. Temperature dependent effects during Ag deposition on Cu(110)

    SciTech Connect

    Taylor, T.N.; Muenchausen, R.E.; Hoffbauer, M.A.; Denier van der Gon, A.W.; van der Veen, J.F.; FOM-Instituut voor Atoom-en Molecuulfysica, Amsterdam )

    1989-01-01

    The composition, structure, and morphology of ultrathin films grown by Ag deposition on Cu(110) were monitored as a function of temperature using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and medium energy ion scattering (MEIS). Aligned backscattering measurements with 150 keV He ions indicate that the Ag resides on top of the Cu and there is no significant surface compound formation. Measurements with LEED show that the Ag is initially confined to the substrate troughs. Further deposition forces the Ag out of the troughs and results in a split c(2 {times} 4) LEED pattern, which is characteristic of a distorted Ag(111) monolayer template. As verified by both AES and MEIS measurements, postmonolayer deposition of Ag on Cu(110) at 300K leads to a pronounced 3-dimensional clustering. Ion blocking analysis of the Ag clusters show that the crystallites have a (110)-like growth orientation, implying that the Ag monolayer template undergoes a rearrangement. These data are confirmed by low temperature LEED results in the absence of clusters, which indicate that Ag multilayers grow from a Ag--Cu interface where the Ag is captured in the troughs. Changes observed in the film structure and morphology are consistent with a film growth mechanism that is driven by overlayer strain response to the substrate corrugation. 16 refs., 4 figs.

  11. Ag(+)-mediated assembly of 5'-guanosine monophosphate.

    PubMed

    Loo, Kristine; Degtyareva, Natalya; Park, Jihae; Sengupta, Bidisha; Reddish, Michaeal; Rogers, Christopher C; Bryant, Andrea; Petty, Jeffrey T

    2010-04-01

    Polymorphic forms of nucleic acids provide platforms for new nanomaterials, and transition metal cations give access to alternative arrangements of nucleobases by coordinating with electron-rich functional groups. Interaction of Ag(+) with 5'-guanosine monophosphate (5'-GMP) is considered in this work. Ag(+) promotes nucleotide stacking and aggregation, as indicated by the increased viscosity of 5'-GMP solutions with Ag(+), magnification of the circular dichroism response of guanine by Ag(+), and exothermic reactions between Ag(+) and guanine derivatives. Isothermal titration calorimetry studies show that the reaction is favored starting at 10 microM 5'-GMP. Utilizing the exothermic heat change associated with reaction of Ag(+) with 5'-GMP, local structure within the aggregate was assessed. On the basis of the salt dependence of the reaction and comparison with the corresponding nucleoside, the dianionic phosphate of 5'-GMP is one binding site for Ag(+), although this electrostatic interaction is not a dominant contribution to the overall heat change. Another binding site is the N7 on the nucleobase, as determined via studies with 7-deazaguanosine. Besides this binding site, Ag(+) also associates with the O6, as earlier studies deduced from the shift in the carbonyl stretching frequency associated with adduct formation. With these two binding sites on the nucleobase, the empirical stoichiometry of approximately 1 Ag(+):nucleobase derived from the calorimetry studies indicates that Ag(+) coordinates two nucleobases. The proposed structural model is a Ag(+)-mediated guanine dimer within a base stacked aggregate. PMID:20205377

  12. Metallurgical characterization of experimental Ag-based soldering alloys

    PubMed Central

    Ntasi, Argyro; Al Jabbari, Youssef S.; Silikas, Nick; Al Taweel, Sara M.; Zinelis, Spiros

    2014-01-01

    Aim To characterize microstructure, hardness and thermal properties of experimental Ag-based soldering alloys for dental applications. Materials and methods Ag12Ga (AgGa) and Ag10Ga5Sn (AgGaSn) were fabricated by induction melting. Six samples were prepared for each alloy and microstructure, hardness and their melting range were determined by, scanning electron microscopy, energy dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), Vickers hardness testing and differential scanning calorimetry (DSC). Results Both alloys demonstrated a gross dendritic microstructure while according to XRD results both materials consisted predominately of a Ag-rich face centered cubic phase The hardness of AgGa (61 ± 2) was statistically lower than that of AgGaSn (84 ± 2) while the alloys tested showed similar melting range of 627–762 °C for AgGa and 631–756 °C for AgGaSn. Conclusion The experimental alloys tested demonstrated similar microstructures and melting ranges. Ga and Sn might be used as alternative to Cu and Zn to modify the selected properties of Ag based soldering alloys. PMID:25382945

  13. RRR and thermal conductivity of Ag and Ag-0.2 wt.%Mg alloy in Ag/Bi-2212 wires

    NASA Astrophysics Data System (ADS)

    Li, P.; Ye, L.; Jiang, J.; Shen, T.

    2015-12-01

    Residual resistivity ratio (RRR) and thermal conductivity of metal matrix in metal/superconductor composite wires are important parameters for designing superconducting magnets. However, the resistivity of silver in reacted Ag/Bi-2212 wires has yet to be determined over temperature range from 4.2 K to 80 K because Bi-2212 filaments have a critical transition temperature Tc of ∼ 80 K, and because it is unknown whether the RRR of Ag/Bi-2212 degrades with Cu diffusing from Bi-2212 filaments into silver sheathes at elevated temperatures and to what degree it varies with heat treatment. We measured the resistivity of stand-alone Ag and AgMg (Ag-0.2 wt.% Mg) wires as well as the resistivity of Ag and Ag-0.2 wt.% Mg in Ag/Bi- 2212 round wires reacted in 1 bar oxygen at 890 °C for 1, 8, 24 and 48 hours and quickly cooled to room temperature. The heat treatment was designed to reduce the critical current Ic of Bi- 2212 wires to nearly zero while allowing Cu loss to fully manifest itself. We determined that pure silver exhibits a RRR of ∼ 220 while the oxide-dispersion strengthened Ag-Mg exhibits a RRR of ∼ 5 in stand-alone samples. A surprising result is that the RRR of silver in the composite round wires doesn't degrade with extended time at 890 °C for up to 48 hours. This surprising result may be explained by our observation that the Cu that diffuses into silver tends to form Cu2O precipitates in oxidizing atmosphere, instead of forming Ag-Cu solution alloy. We also measured the thermal conductivity and the magneto-resistivity of pure Ag and Ag-0.2 wt. % Mg from 4.2 K to 300 K in magnetic fields up to 14.8 T and summarized them using a Kohler plot.

  14. Post-Synthetic Decoupling of On-Surface-Synthesized Covalent Nanostructures from Ag(111).

    PubMed

    Rastgoo-Lahrood, Atena; Björk, Jonas; Lischka, Matthias; Eichhorn, Johanna; Kloft, Stephan; Fritton, Massimo; Strunskus, Thomas; Samanta, Debabrata; Schmittel, Michael; Heckl, Wolfgang M; Lackinger, Markus

    2016-06-27

    The on-surface synthesis of covalent organic nanosheets driven by reactive metal surfaces leads to strongly adsorbed organic nanostructures, which conceals their intrinsic properties. Hence, reducing the electronic coupling between the organic networks and commonly used metal surfaces is an important step towards characterization of the true material. We demonstrate that post-synthetic exposure to iodine vapor leads to the intercalation of an iodine monolayer between covalent polyphenylene networks and Ag(111) surfaces. The experimentally observed changes from surface-bound to detached nanosheets are reproduced by DFT simulations. These findings suggest that the intercalation of iodine provides a material that shows geometric and electronic properties substantially closer to those of the freestanding network.

  15. Fluoride-induced reduction of Ag(I) cation leading to formation of silver mirrors and luminescent Ag-nanoparticles.

    PubMed

    Maity, Krishnendu; Panda, Dillip K; Lochner, Eric; Saha, Sourav

    2015-03-01

    In aprotic solvents, Lewis basic F(-) anion reduces Lewis acidic Ag(I) cation to Ag(0), forming metallic silver mirrors on the inner surfaces of reaction vessels and luminescent Ag-nanoparticles (AgNPs) in supernatant solutions, which emit blue light upon UV irradiation. The F(-)-induced formation of silver mirrors and AgNPs was confirmed through X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), fluorescence spectroscopy, and mass spectrometry, whereas the Ag(I)-induced oxidation of F(-) to Ḟ radical, followed by its conversion to HF2(-) via H-abstraction and H-bonding, was evident from (19)F NMR spectroscopy. This redox reaction is deactivated in water, as the reducing power of hydrated F(-) diminishes drastically. Less Lewis basic Cl(-), Br(-), and I(-) ions do not reduce Ag(I) to Ag(0), instead they can only form Ag(I) halide precipitates irrespective of protic or aprotic solvents. The Ag-coated surfaces, luminescent AgNPs, and Ḟ radicals produced by this unprecedented redox reaction could be exploited as electrodes, light-emitting materials, and radical initiators, respectively.

  16. New frontiers in water purification: highly stable amphopolycarboxyglycinate-stabilized Ag-AgCl nanocomposite and its newly discovered potential

    NASA Astrophysics Data System (ADS)

    Krutyakov, Yurii A.; Zherebin, Pavel M.; Kudrinskiy, Alexey A.; Zubavichus, Yan V.; Presniakov, Mikhail Yu; Yapryntsev, Alexey D.; Karabtseva, Anastasia V.; Mikhaylov, Dmitry M.; Lisichkin, Georgii V.

    2016-09-01

    A simple synthetic procedure for high-stable dispersions of porous composite Ag/AgCl nanoparticles stabilized with amphoteric surfactant sodium tallow amphopolycarboxyglycinate has been proposed for the first time. The prepared samples were characterized by UV-vis spectroscopy, x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy, small area electron diffraction (SAED), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and electron probe micro-analysis. In addition, measurements (carried out at the Kurchatov synchrotron radiation source stations) of the Ag K-edge extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) spectra and XRD of the prepared nanoparticles have been performed. The obtained results suggest that small-sized Ag clusters are homogeneously distributed in the mass of the AgCl nanoparticle (~80 nm) formed during the synthesis. The Ag/AgCl dispersion demonstrates photocatalytic activity (with respect to methyl orange) and high bactericidal activity against E. coli. This activity is superior to the activity of both Ag and AgCl nanoparticles stabilized by the same surfactant. Thus, porous composite Ag/AgCl nanoparticles can be used as a multifunctional agent that is able to remove both pollutants and bacterium from water.

  17. High-Quality AgGaTe2 Layers on Si Substrates with Ag2Te Buffer Layers

    NASA Astrophysics Data System (ADS)

    Uruno, Aya; Kobayashi, Masakazu

    2016-09-01

    AgGaTe2 layers were successfully grown on Si substrates by the close-spaced sublimation method. The Si substrates were confirmed to be etched during AgGaTe2 layer growth when the layer was grown directly on the substrate. To eliminate melt-back etching, a buffer layer of Ag2Te was introduced. It was found that the Ag2Te buffer layer changed into the AgGaTe2 layer during the growth process, and a uniform AgGaTe2 layer with an abrupt interface was formed. Both the diffusion of Ga into Ag2Te and the growth of AgGaTe2 occurred simultaneously. It was confirmed that uniform AgGaTe2 layers could be formed without any traces of the Ag2Te layer or melt-back etching by tuning the growth parameters. A solar cell was also fabricated using the p-AgGaTe2/n-Si heterojunction. This solar cell showed conversion efficiency of approximately 3%.

  18. Superionic behavior in the xAgI-(1-x)CsAg2I3 polycrystalline system

    NASA Astrophysics Data System (ADS)

    Rodríguez, L. A.; Zapata, J.; Vargas, R. A.; Peña Lara, D.; Diosa, J. E.

    2016-06-01

    A superionic phase behavior (with DC ionic conductivities higher than 0.01 S/cm) has been observed in xAgI-(1-x)CsAg2I3 (x≈0.67) polycrystalline system grown by slow evaporation using AgI and CsI powders (molar ratio Cs/Ag=0.25) as starting salts and an aqueous solution of HI as solvent. The transition from the normal-to- the superionic state is first-order with a hysteretic behavior in temperature centered at about 116 °C as reflected by thermal (DSC) and electrical conductivity measurements. This mixture is composed of CsAg2I3 and AgI crystalline phases and an additional amorphous AgI phase that explains the glassy-type behavior observed in the superionic phase transition.

  19. Synthesis, characterization and optical properties of low nuclearity liganded silver clusters: Ag31(SG)19 and Ag15(SG)11.

    PubMed

    Bertorelle, Franck; Hamouda, Ramzi; Rayane, Driss; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Gell, Lars; Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta

    2013-06-21

    We report a simple synthesis of silver:glutathione (Ag:SG) clusters using a cyclic reduction under oxidative conditions. Two syntheses are described which lead to solutions containing well-defined Ag31(SG)19 and Ag15(SG)11 clusters that have been characterized by mass spectrometry. The optical properties of silver:glutathione (Ag:SG) cluster solutions have been investigated experimentally. In particular, the solution containing Ag15(SG)11 clusters shows a bright and photostable emission. For Ag31(SG)19 and Ag15(SG)11 clusters, the comparison of experimental findings with DFT and TDDFT calculations allowed us to reveal the structural and electronic properties of such low nuclearity liganded silver clusters.

  20. Effect of Ag/Au bilayer assisted etching on the strongly enhanced photoluminescence and visible light photocatalysis by Si nanowire arrays.

    PubMed

    Ghosh, Ramesh; Imakita, Kenji; Fujii, Minoru; Giri, P K

    2016-03-21

    We report on the strongly enhanced photoluminescence (PL) and visible light photocatalysis by arrays of vertically aligned single crystalline Si nanowires (NWs) grown by Ag/Au bilayer assisted etching. High resolution FESEM and TEM imaging reveals that the Si NWs are decorated with ultra-small size arbitrary shaped Si nanocrystals (NCs) due to the lateral etching of the NWs. A strong broad band and tunable visible to near-infrared (NIR) photoluminescence (PL) in the range 1.3-2.4 eV are observed for these Si NWs/NCs at room temperature, depending on the etching conditions. Our studies reveal that the visible-NIR PL intensity is about two orders of magnitude higher and it exhibits faster decay dynamics in the bilayer assisted etching case as compared to the Ag or Au single layer etching case. The enhanced PL in the bimetal case is attributed to the longer length and higher density of the Si NWs/NCs, surface plasmon resonance enhanced absorption by residual bimetal NPs and the enhanced radiative recombination rate. Studies on the time evolution of PL spectral features with laser exposure under ambient conditions and laser power dependence reveal that both the quantum confinement of carriers in Si NCs and the nonbridging oxygen hole defects in the SiOx layer contribute to the tunable PL. Interestingly, Si NWs grown by Ag/Au bilayer assisted etching exhibit enhanced photocatalytic degradation of methylene blue in comparison to Si NWs grown by single layer Ag or Au assisted etching. The Schottky barrier present between bimetallic NPs and nanoporous Si NWs with Si-H bonds facilitates the photocatalytic activity by efficient separation of photogenerated e-h pairs. Our results demonstrate the superiority of the Si NW array grown by bilayer assisted etching for their cutting edge applications in optoelectronics and environmental cleaning.