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1

Electrochemical characterization of an aqueous lithium rechargeable battery: The effect of CeO 2 additions to the MnO 2 cathode  

Microsoft Academic Search

The effect of CeO2 additions on an aqueous rechargeable lithium battery has been investigated. The CeO2 additions (0, 2, and 5wt.%) were made to the manganese dioxide (MnO2) cathode of a cell comprising zinc as an anode and an aqueous saturated lithium hydroxide solution as the electrolyte. The CeO2 enhances the performance of the cell in terms of capacity and

Manickam Minakshi; Kalaiselvi Nallathamby; David R. G. Mitchell

2009-01-01

2

Mesoporous ?-MnO 2\\/Pd catalyst air electrode for rechargeable lithium–air battery  

Microsoft Academic Search

Rechargeable lithium–air battery is studied using Pd\\/mesoporous ?-MnO2 air composite electrode. In the present work, we have studied the preparation and electrochemical performance of ordered mesoporous ?-MnO2 as a cathode catalyst for rechargeable Li–air batteries. ?-MnO2 was prepared by reduction of KMnO4 solution in acidic aqueous solution followed by successive proton and alkali-ion exchange method. ?-MnO2 with high surface area

Arjun Kumar Thapa; Tatsumi Ishihara

2011-01-01

3

Freestanding MnO2@carbon papers air electrodes for rechargeable Li-O2 batteries  

NASA Astrophysics Data System (ADS)

We have designed the air electrode for rechargeable Li-O2 batteries by adapting conventional current collectors-carbon papers (CPs), as freestanding substrates. The MnO2@CP electrodes are prepared by simply floating CPs on KMnO4 solution at room temperature. CPs act as the reducing agents as well as the freestanding substrates. Birnessite-type MnO2 nanosheets are observed to in situ grow vertically from the surface of CPs, thus building 3D porous architecture. The nanosheets are uniformly distributed and interconnected each other, which contributes to an improved electrical connection among the MnO2 catalyst and CPs. The cycling tests using the electrode as the cathode in rechargeable Li-O2 batteries exhibit high reversibility and superior cycling stability, over 90 cycles with a capacity of more than 1000 mA h (g MnO2)-1 and a high coulombic efficiency of around 100% in the voltage rang of 2.2-4.4 V.

Zhang, Leilei; Zhang, Feifei; Huang, Gang; Wang, Jianwei; Du, Xinchuan; Qin, Yuling; Wang, Limin

2014-09-01

4

Electrode materials for aqueous rechargeable lithium batteries  

Microsoft Academic Search

In this review, we describe briefly the historical development of aqueous rechargeable lithium batteries, the advantages and\\u000a challenges associated with the use of aqueous electrolytes in lithium rechargeable battery with an emphasis on the electrochemical\\u000a performance of various electrode materials. The following materials have been studied as cathode materials: LiMn2O4, MnO2, LiNiO2, LiCoO2, LiMnPO4, LiFePO4, and anatase TiO2. Addition of

H. Manjunatha; G. S. Suresh; T. V. Venkatesha

2011-01-01

5

MnO 2 nanoflakes coated on multi-walled carbon nanotubes for rechargeable lithium-air batteries  

Microsoft Academic Search

Manganese dioxide (MnO2) nanoflakes were uniformly coated on multi-walled carbon nanotubes (MWNTs) by immersing MWNTs into an aqueous KMnO4 solution. Directly using the MnO2\\/MWNT composites (containing 40wt.% MWNTs) as lithium-air battery electrodes enhances kinetics of the oxygen reduction and evolution reactions, thereby effectively improving energy efficiency and reversible capacity.

Jiaxin Li; Ning Wang; Yi Zhao; Yunhai Ding; Lunhui Guan

2011-01-01

6

A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen  

NASA Technical Reports Server (NTRS)

The nickel-hydrogen secondary battery system, developed in the early 1970s, has become the system of choice for geostationary earth orbit (GEO) applications. However, for low earth orbit (LEO) satellites with long expected lifetimes the nickel positive limits performance. This requires derating of the cell to achieve very long cycle life. A new system, rechargeable MnO2-Hydrogen, which does not require derating, is described here. For LEO applications, it promises to have longer cycle life, high rate capability, a higher effective energy density, and much lower self-discharge behavior than those of the nickel-hydrogen system.

Appleby, A. J.; Dhar, H. P.; Kim, Y. J.; Murphy, O. J.

1989-01-01

7

Degradation mechanism of layered MnO 2 cathodes in Zn/ZnSO 4/MnO 2 rechargeable cells  

NASA Astrophysics Data System (ADS)

Layered-type MnO 2 ( ?- or naturally occurring birnessite-related MnO 2) electrodes that suffer capacity degradation during extended cycling in Zn/ZnSO 4/MnO 2 rechargeable cells are investigated. When the composite cathodes consisting of MnO 2 powder, carbon additive and Teflon binder are galvanostatically cycled in the potential range of 1.0-1.9 V (vs. Zn/Zn 2+) where a two-step, two-electron charge/discharge reaction occurs, the cathodes lose their capacities within a few cycles. Such an abrupt capacity loss is found to be caused partly by the formation of basic zinc sulfates (BZS, ZnSO 4·3Zn(OH) 2· nH 2O) on the cathode surface, and also by the Mn losses due to the irreversible nature of the cathodic cell reaction: Mn 2+ ions, once produced during the discharge step, are not fully restored to MnO 2 during the charging period. An addition of 0.1-0.5 M MnSO 4 to 2 M ZnSO 4 electrolyte, however, greatly alleviates these failure modes. With this addition, the Mn losses become insignificant as a result of facilitation in the charging reaction and BZS formation is discouraged. Carbon additives loaded in the composite MnO 2 cathodes also critically affect the cathode cyclabilities by controlling the rate of charging reaction: the cathodes loaded with acetylene blacks display superior cyclabilities to those containing furnace blacks. From one observation whereby the acetylene blacks possess a lesser amount of surface oxygenic species than the furnace blacks and the other whereby the charging reaction more readily occurs in the former cathodes, it is proposed that the charging (deposition) reaction is significantly hindered by the presence of surface oxygenic species on carbon additives. Electron micrographs of cycled MnO 2 cathodes reveal that larger and porous MnO 2 deposits are well-grown on the acetylene-black-loaded cathodes whereas only irregular-shaped smaller deposits are formed on the furnace-black-loaded cathodes.

Kim, Sa Heum; Oh, Seung Mo

8

Improved performance of rechargeable alkaline batteries via surfactant-mediated electrosynthesis of MnO 2  

NASA Astrophysics Data System (ADS)

An innovative application of surfactant-mediated modifications of electrolytic MnO 2 (EMD), proved to be a major step toward enhancement of the rechargeability in alkaline batteries. Presence of different surfactants in boiling acidic solutions of manganese sulfate, under atmospheric pressure, enhanced a variety of EMD products, with various structural and electrochemical properties. Surfactants employed consisted of: anionic sodium n-dodecylbenzenesulfonate (SDBS), cationic cetyltrimethylammonium bromide (CTAB) and non-ionic t-octyl phenoxy polyethoxyethanol (Triton X-100). Among them, EMDs produced in the presence of CTAB has a slight positive effect on the cycle performances, while SDBS inhibits it. Interestingly, the EMD powders prepared from the micellar solution, in the range of 0.3 wt.% of Triton X-100, exhibited much higher discharge capacities, as well as better cyclabilities in comparison with the commercial EMD sample known as TOSOH™. The superiority of the former EMD was further confirmed through electrochemical cyclic voltammetry and also electrochemical impedance spectroscopy (EIS). Modifications of electrolytic MnO 2, via mediations of different surfactants were perceived through changes in their compositions, crystal structures and morphologies. The characteristics of the produced materials were determined by thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Enhancements of electrochemical properties, observed for Triton X-100 modified EMD, could be attributed to a homogeneous current distribution with unique crystalline structure, based on the modified electrode/solution interface, through adsorbed surfactant layers. Moreover, the observed improvements appear connected to the enhanced film growth, with different degrees of mesoscopic organizations. Higher cycle performances, mechanical stabilities and the ease of production make this method excellent for being employed in a number of industrial applications.

Ghaemi, M.; Khosravi-Fard, L.; Neshati, J.

9

Co3O4 nanoparticle-modified MnO2 nanotube bifunctional oxygen cathode catalysts for rechargeable zinc-air batteries.  

PubMed

We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone. PMID:23608821

Du, Guojun; Liu, Xiaogang; Zong, Yun; Hor, T S Andy; Yu, Aishui; Liu, Zhaolin

2013-06-01

10

?-MnO2 nanostructures directly grown on Ni foam: a cathode catalyst for rechargeable Li-O2 batteries  

NASA Astrophysics Data System (ADS)

A sponge-like ?-MnO2 nanostructure was synthesized by direct growth of ?-MnO2 on Ni foam through a facile electrodeposition route. When applied as a self-supporting, binder-free cathode material for rechargeable nonaqueous lithium-oxygen batteries, the ?-MnO2/Ni electrode exhibits considerable high-rate capability (discharge capacity of ~6300 mA h g-1 at a current density of 500 mA g-1) and enhanced cyclability (exceeding 120 cycles) without controlling the discharge depth. The superior performance is proposed to be associated with the 3D nanoporous structures and abundant oxygen defects as well as the absence of side reactions related to carbon-based conductive additives and binders.A sponge-like ?-MnO2 nanostructure was synthesized by direct growth of ?-MnO2 on Ni foam through a facile electrodeposition route. When applied as a self-supporting, binder-free cathode material for rechargeable nonaqueous lithium-oxygen batteries, the ?-MnO2/Ni electrode exhibits considerable high-rate capability (discharge capacity of ~6300 mA h g-1 at a current density of 500 mA g-1) and enhanced cyclability (exceeding 120 cycles) without controlling the discharge depth. The superior performance is proposed to be associated with the 3D nanoporous structures and abundant oxygen defects as well as the absence of side reactions related to carbon-based conductive additives and binders. Electronic supplementary information (ESI) available: Detailed synthesis procedures and material characterizations, additional SEM, CV, TGA, BET, and electrochemical impedance spectroscopy results. See DOI: 10.1039/c3nr06361e

Hu, Xiaofei; Han, Xiaopeng; Hu, Yuxiang; Cheng, Fangyi; Chen, Jun

2014-03-01

11

Performance of MnO2 Crystallographic Phases in Rechargeable Lithium-Air Oxygen Cathode  

NASA Astrophysics Data System (ADS)

Manganese dioxide (MnO2) has been shown to be effective for improving the efficiency of cathodes in lithium-air cells. Different crystallographic phases including ?-, ?-, and ?-MnO2 nanowires, ?-MnO2 nanospheres, and ?-MnO2 nanowires on carbon ( ?-MnO2/C) were synthesized using the hydrothermal method. Their physical properties were examined using x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, and scanning electron microscopy (SEM) and found to be in agreement with the literature. Electrochemical properties of the synthesized catalyst particles were investigated by fabricating cathodes and testing them in a lithium-air cell with lithium hexafluorophosphate in propylene carbonate (LiPF6/PC) and tetra(ethylene glycol)dimethyl ether (LiTFSi/TEGDME) electrolytes. ?-MnO2 had the highest discharge capacity in the LiTFSi/TEGDME electrolyte (2500 mAh/g), whilst ?-MnO2/C in LiPF6/PC showed a significantly higher discharge capacity of 11,000 mAh/g based on total mass of the catalytic cathode. However, the latter showed poor capacity retention compared with ?-MnO2 nanowires, which was stable for up to 30 cycles. The reported discharge capacity is higher than recorded in previous studies on lithium-air cells.

Oloniyo, Olubukun; Kumar, Senthil; Scott, Keith

2012-05-01

12

Co3O4 nanoparticle-modified MnO2 nanotube bifunctional oxygen cathode catalysts for rechargeable zinc-air batteries  

NASA Astrophysics Data System (ADS)

We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone.We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone. Electronic supplementary information (ESI) available: Zinc-air cell device, XPS survey scan and power density of the cell. See DOI: 10.1039/c3nr00300k

Du, Guojun; Liu, Xiaogang; Zong, Yun; Hor, T. S. Andy; Yu, Aishui; Liu, Zhaolin

2013-05-01

13

A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen  

NASA Technical Reports Server (NTRS)

The nickel-hydrogen secondary battery system is now the one of choice for use in GEO satellites. It offers superior energy density to that of nickel-cadmium, with a lifetime that is at least comparable in terms of both cycle life and overall operating life. While the number of deep cycles required for GEO use is small, LEO satellites with long lifetimes (5 to 10 years) will require secondary battery systems allowing 30,000 to 60,000 useful cycles which are characterized by an approximately 2C charge rate and C average discharge rate. Recent work has shown that birnessite MnO2 doped with bismuth oxide can be cycled at very high rates (6C) over a very large number of cycles (thousands) at depths-of-discharge in the 85 to 90 percent range, based on two electrons, which discharge at the same potential in a flat plateau. The potential is about 0.7 V vs. hydrogen, with a cut-off at 0.6 V. At first sight, this low voltage would seem to be a disadvantage, since the theoretical energy density will be low. However, it permits the use of lightweight materials that are immune from corrosion at the positive. The high utilization and low equivalent weight of the active material, together with the use of teflon-bonded graphite for current collection, result in very light positives, especially when these are compared with those in a derated nickel-hydrogen system. In addition, the weight of the pressure vessel falls somewhat, since the dead volume is lower. Calculations show that a total system will have 2.5 times the Ah capacity of a derated nickel-hydrogen LEO battery, so that the energy density, based on 1.2 V for nickel-hydrogen and 0.7 V for MnO2-hydrogen, will be 45 percent higher for comparable cycling performance.

Appleby, A. John; Dhar, Y. J.; Murphy, O. J.; Srinivasan, Supramaniam

1989-01-01

14

Synthesis of metal-doped todorokite-type MnO 2 and its cathode characteristics for rechargeable lithium batteries  

NASA Astrophysics Data System (ADS)

Todorokite-type MnO 2-doped with Co and Fe has been synthesized by hydrothermal treatment of layered metal-doped manganese oxide, buserite, in water at 120-200 °C. The prepared todorokite products have been characterized by XRD and energy dispersive X-ray spectroscopic (EDX) measurements, TEM observation and thermogravimetric analysis. These measurements showed that the hydrothermal products are the metal-doped todorokite phase having large (3 × 3) tunnel structure, and the chemical compositions are shown to be Mg xM yMn 1- yO 2· zH 2O, where x = 0.08-0.10, y = 0.23-0.29, z = 0.35-0.54 in M = Co and x = 0.13-0.14, y = 0.03-0.16, z = 0.19-0.28 in M = Fe. The preliminary electrochemical characteristics including charge-discharge cyclings of the metal-doped-todorokite electrodes were examined as lithium insertion hosts for cathodes in rechargeable lithium batteries. The metal-doped todorokite exhibited S-shaped discharge behavior and the Co-doped one with x = 0.10, y = 0.29 showed a high discharge capacity of ca. 132 mAh g -1-oxide and cycling capacity of 90-100 mAh g -1.

Kumagai, Naoaki; Komaba, Shinichi; Abe, Kiyoko; Yashiro, Hitoshi

15

Synthesis of metal-doped todorokite-type MnO 2 and its cathode characteristics for rechargeable lithium batteries  

Microsoft Academic Search

Todorokite-type MnO2-doped with Co and Fe has been synthesized by hydrothermal treatment of layered metal-doped manganese oxide, buserite, in water at 120–200°C. The prepared todorokite products have been characterized by XRD and energy dispersive X-ray spectroscopic (EDX) measurements, TEM observation and thermogravimetric analysis. These measurements showed that the hydrothermal products are the metal-doped todorokite phase having large (3×3) tunnel structure,

Naoaki Kumagai; Shinichi Komaba; Kiyoko Abe; Hitoshi Yashiro

2005-01-01

16

Rechargeable batteries with aqueous electrolytes  

Microsoft Academic Search

In recent years, rechargeable batteries (RB’s) have found important new applications in rapidly expanding markets, such as portable computers (laptops), telecommunication equipment (handies), camcorders and tools. The interest in electric vehicles has continued to stimulate research on RB’s having improved specific energy. Attention has been focussed on nonaqueous battery systems, in particular on lithium batteries. Small rechargeable lithium batteries, available

Fritz Beck; Paul Rüetschi

2000-01-01

17

Rechargeable lithium batteries with aqueous electrolytes  

SciTech Connect

Rechargeable lithium-ion batteries that use an aqueous electrolyte have been developed. Cells with LiMn{sub 2}O{sub 4} and VO{sub 2}(B) as electrodes and 5 M LiNO{sub 3} in water as the electrolyte provide a fundamentally safe and cost-effective technology that can compete with nickel-cadmium and lead-acid batteries on the basis of stored energy per unit of weight.14 refs., 4 figs.

Li, Wu; Dahn, J.R. [Simon Fraser Univ., Burnaby, British Columbia (Canada); Wainwright, D.S. [Moli Energy (1990) Limited, Maple Ridge, British Columbia (Canada)

1994-05-20

18

Rechargeable lithium batteries with aqueous electrolytes.  

PubMed

Rechargeable lithium-ion batteries that use an aqueous electrolyte have been developed. Cells with LiMn(2)O(4) and VO(2)(B) as electrodes and 5 M LiNO(3) in water as the electrolyte provide a fundamentally safe and cost-effective technology that can compete with nickelcadmium and lead-acid batteries on the basis of stored energy per unit of weight. PMID:17744893

Li, W; Dahn, J R; Wainwright, D S

1994-05-20

19

Inorganic rechargeable non-aqueous cell  

DOEpatents

A totally inorganic non-aqueous rechargeable cell having an alkali or alkaline earth metal anode such as of lithium, a sulfur dioxide containing electrolyte and a discharging metal halide cathode, such as of CuCl.sub.2, CuBr.sub.2 and the like with said metal halide being substantially totally insoluble in SO.sub.2 and admixed with a conductive carbon material.

Bowden, William L. (Nashua, NH); Dey, Arabinda N. (Needham, MA)

1985-05-07

20

Interconnected Network of MnO2 Nanowires with a "Cocoonlike" Morphology: Redox Couple-Mediated Performance Enhancement in Symmetric Aqueous Supercapacitor.  

PubMed

Low electronic conductivity and slow faradic processes limit the performance of MnO2 as an electrochemical pseudocapacitor with respect to cycling and power density. Herein, we report preparation of single-phase ?-MnO2, composed of an interconnected nanowire network with "cocoonlike" morphology, and its application as electrode in a symmetric aqueous supercapacitor. Increased "effective" surface area, coexistence of micropores and mesopores, and enhanced electron transport in these nanowire networks result in a specific pseudocapacitance (CS) of 775 F·g(-1) in 3 M KOH, derived from cyclic voltammetry in the potential window of -1 to +1 V at a scan rate of 2 mV·s(-1), the highest reported for two-electrode symmetric configuration. Furthermore, introduction of K4Fe(CN)6 as a redox-active additive to KOH results in ?7 times increase in energy density at a power density of ?6000 W·kg(-1). The presence of the Fe(CN)6(4-)/Fe(CN)6(3-) redox couple provides an electron buffer source compensating for the slow faradic reactions. The results demonstrate that this simple approach might be an effective way to enhance the redox kinetics and reversibility of transition metal oxide-based pseudocapacitors. PMID:24930698

Maiti, Sandipan; Pramanik, Atin; Mahanty, Sourindra

2014-07-01

21

Synthesis and Characterization of Lamellar MnO 2 Obtained from Thermal Decomposition of NaMnO 4 for Rechargeable Lithium Cells  

Microsoft Academic Search

Thermal treatment (600-800°C) in air of solid NaMnO4 induces the reduction of Mn(VII), leading to the formation of ternary oxides: ?-Na0.7MnO2 around 500°C and ?-NaMnO2 for higher temperatures (800°C). Sulfuric acid treatment of these compounds leads to the formation of a lamellar phase with a highly preferred orientation: MnO1.86 · n H2O (0.6 ? n ? 0.7). The lithium insertion

S. Bach; J. P. Pereira-Ramos; N. Baffier

1995-01-01

22

Synthesis of Na x MnO 2+ ? by a Reduction of Aqueous Sodium Permanganate with Sodium Iodide  

Microsoft Academic Search

Reduction of sodium permanganate with sodium iodide in aqueous solutions has been investigated systematically. The products formed have been characterized by X-ray diffraction, wet-chemical analysis, and surface area and magnetic susceptibility measurements after firing at various temperatures. The results reveal that the sodium content x in the reduction products NaxMnO2+? depends strongly on the reaction pH and mildly on the

Y. U. Jeong; A. Manthiram

2001-01-01

23

Characteristics of an aqueous rechargeable lithium battery (ARLB)  

Microsoft Academic Search

Electrochemical performance of an aqueous rechargeable lithium battery (ARLB) containing a LiV3O8 (negative electrode) and LiCoO2 (positive electrode) in saturated LiNO3 aqueous electrolyte was studied. These two electrode materials are stable in the aqueous solution and intercalation\\/deintercalation of lithium ions occurs within the window of electrochemical stability of water. The obtained capacity of this cell system is about 55mAh\\/g based

G. J. Wang; N. H. Zhao; L. C. Yang; Y. P. Wu; H. Q. Wu; R. Holze

2007-01-01

24

Structural and electrochemical studies of ?-manganese dioxide ( ?-MnO 2)  

NASA Astrophysics Data System (ADS)

The structural and electrochemical properties of ?-MnO 2, prepared by acid digestion of Mn 2O 3, and its lithiated derivatives xLi 2O · MnO 2 (0 ? x ? 0.25) have been investigated as insertion compounds in the search for new and viable cathode materials for rechargeable 3 V batteries. The ?-MnO 2 product fabricated by this technique contains water within the large (2 × 2) channels of the structure; the water can be removed from the ?-MnO 2 framework without degradation of the structure, and then at least partially replaced by Li 2O (lithium oxide). The Li 2O-doped ?-MnO 2 electrodes, described generically as xLi 2O · MnO 2, stabilize the structure and provide higher capacities on cycling than the parent material. The structures of these ?-MnO 2-type electrode materials are described, and electrochemical data are presented for both liquid electrolyte and polymer electrolyte Li/ ?-MnO 2 and Li/ xLi 2O · MnO 2 cells.

Johnson, C. S.; Dees, D. W.; Mansuetto, M. F.; Thackeray, M. M.; Vissers, D. R.; Argyriou, D.; Loong, C.-K.; Christensen, L.

25

Electrolyte for Lithium-Inorganic Non-Aqueous Rechargeable Cell System and Rechargeable Cell System Including Said Electrolyte.  

National Technical Information Service (NTIS)

The general object of this invention is to provide an improved high energy lithium inorganic non-aqueous rechargeable cell system. A more particular object of the invention is to provide such an improved system wherein the lithium dithionite discharge pro...

R. J. Mammone M. Binder

1985-01-01

26

Nanostructured cathode materials for alkaline and lithium rechargeable batteries  

Microsoft Academic Search

US Nanocorp, Inc. is pioneering the synthesis of nanostructured active battery materials by a novel aqueous solution reaction (ASR) process that is inherently low cost and scalable to volume production. Strategies for the production of high energy content battery electrodes are discussed. Focus areas include Ni(OH)2, both pure and Al-doped and ?-MnO2 for rechargeable alkaline batteries as well as the

D. E. Reisner; Jinxiang Daib; Rongde Gea; Meidong Wanga; Hui Yea; D. Xiao; A. J. Salkind

1999-01-01

27

Preparation of mesoporous MnO2/C catalyst for n-hexyl acetate synthesis  

NASA Astrophysics Data System (ADS)

A mesoporous MnO2/C composite was prepared by impregnating self-made porous carbon spheres with manganese nitrate aqueous solution and subsequently reacting with KMnO4 aqueous solution. It was characterized with X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), the Brunauer-Emmett-Teller (BET) surface area and the Barrett-Joyner-Halenda (BJH) pore size distribution. The as-prepared mesoporous MnO2/C composite was used as catalyst for the synthesis of n-hexyl acetate, and the effects of MnO2 loading and esterification reaction parameters on the esterification rate were investigated. The results prove that MnO2 loading has a significant effect on the catalytic activity and that the mesoporous MnO2/C composite exhibits high catalytic activity with an esterification rate of 96.42% under the conditions below: MnO2 loading (73.09 wt%), catalyst dosage (0.1% in total weight), acetic acid/n-hexanol molar ratio (2:1), reaction temperature (130 °C) and reaction time (5 h).

Yang, Zeheng; Pan, Yanmei; Mei, Zhousheng; Zhang, Weixin

2012-03-01

28

Structural and optical properties of ?-MnO2 nanowires and ?-MnO2 nanorods  

NASA Astrophysics Data System (ADS)

One-dimensional (1D) ?-MnO2 nanowires (NWs) and ?-MnO2 nanorods (NRs) were synthesized by hydrothermal method. The effects of reactant concentration on the phase and morphology of the products have been investigated. The structural and optical properties were investigated by XRD, SEM, EDS and UV-vis, FTIR spectroscopy. The absorption spectra of ?-MnO2 NWs and ?-MnO2 NRs exhibit a band gap of 5.49 and 5.37 eV, which are blue shifted from bulk. Fourier transform infrared (FTIR) spectroscopy confirmed the Mn-O bond.

Rajamanickam, N.; Ganesan, P.; Rajashabala, S.; Ramachandran, K.

2014-04-01

29

Synthesis and characterization of olivine LiNiPO 4 for aqueous rechargeable battery  

Microsoft Academic Search

LiNiPO4 belongs to a family of olivine type compounds, with members LiMPO4 where M=Fe, Mn, Co or Ni are transition metals. The lithium nickel phosphate was prepared and characterized in order to evaluate a new potential cathode material for our ongoing research in aqueous rechargeable batteries. Annealing the final product is critical in obtaining the stoichiometric LiNiPO4 pure phase; conventional

Manickam Minakshi; Pritam Singh; Dominique Appadoo; Danielle E. Martin

2011-01-01

30

Structure and Manufacturing Process of MnO2 Counter Electrode in Niobium Suboxide Capacitors  

NASA Astrophysics Data System (ADS)

The influence of iterative heat treatment of impregnated aqueous Mn(NO3)2 solution on the microstructure of the produced MnO2 has been investigated in the fabrication process for niobium suboxide capacitors. We separate the whole process into two stages: At the early stage of impregnations in Mn(NO3)2 solution (with specific density less than 1.35 g/cm3), the produced MnO2 grains with equiaxed nanocrystalline morphology are mainly located in the inner space and pores, avoiding the performance deterioration due to the electrical conductivity anisotropy of columnar texture in NbO capacitors. For impregnation in Mn(NO3)2 solutions with specific density greater than 1.35 g/cm3, MnO2 grains in the inner space and pores continue to grow and present a hexagonal pyramid shape. At this stage, MnO2 starts to be produced on the outer surface of pellets and exhibits a cluster morphology that consists of MnO2 grains with size between 30 nm and 80 nm. The electrical performance of NbO capacitors has been optimized by adjusting the impregnation times and sequence. By alternately impregnating in Mn(NO3)2 solutions with specific densities of 1.23 g/cm3 and 1.35 g/cm3, MnO2 grains are better combined and the internal space of the pellets is fully filled. Impregnation in Mn(NO3)2 solutions with low specific densities (1.10 g/cm3 and 1.23 g/cm3) in dry atmosphere produces a denser MnO2 layer in the internal space, leading to improved capacitor performance.

Chen, Liqin; Li, Bo; Qi, Zhaoxiong; Guo, Hai; Zhou, Ji; Li, Longtu

2013-10-01

31

The reversible anomalous high lithium capacity of MnO2 nanowires.  

PubMed

MnO2 as a material for supercapacitors is generally predicted to insert only one cation per unit cell. However, it is shown here to reversibly insert more than one cation in an organic electrolyte; however, in an aqueous electrolyte, the insertion ion is actually shown to be a combination of protons and cations. PMID:24871137

Song, Jaehee; Duay, Jonathon; Gillette, Eleanor; Lee, Sang Bok

2014-06-12

32

Growth of One-Dimensional MnO2 Nanostructure  

NASA Astrophysics Data System (ADS)

Large scale MnO2 nanorods were controllably synthesized from the inexpensive precursors (e.g., manganese acetate, ammonium persulfate) via a facile one-step low temperature hydrothermal strategy. The crystal phase and microscopic morphology of the as-prepared MnO2 nanorods were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM). Through investigating the morphology evolution of MnO2 products in the whole synthesis process, a novel growth mechanism of these MnO2 nanorods was proposed, which may be efficiently extended to other material systems as a general approach towards one-dimensional nanostructures. The obtained MnO2 nanorods may have potential applications in Li-ion batteries and supercapacitors.

Lu, Pai; Xue, Dongfeng

33

Rechargeable aqueous lithium-air batteries with an auxiliary electrode for the oxygen evolution  

NASA Astrophysics Data System (ADS)

A rechargeable aqueous lithium-air cell with a third auxiliary electrode for the oxygen evolution reaction was developed. The cell consists of a lithium metal anode, a lithium conducting solid electrolyte of Li1+x+yAlx(Ti,Ge)2-xSiyP3-yO12, a carbon black oxygen reduction air electrode, a RuO2 oxygen evolution electrode, and a saturated aqueous solution of LiOH with 10 M LiCl. The cell was successfully operated for several cycles at 0.64 mA cm-2 and 25 °C under air, where the capacity of air electrode was 2000 mAh gcathod-1. The cell performance was degraded gradually by cycling under open air. The degradation was reduced under CO2-free air and pure oxygen. The specific energy density was calculated to be 810 Wh kg-1 from the weight of water, lithium, oxygen, and carbon in the air electrode.

Sunahiro, S.; Matsui, M.; Takeda, Y.; Yamamoto, O.; Imanishi, N.

2014-09-01

34

An aqueous rechargeable lithium battery using coated Li metal as anode.  

PubMed

New energy industry including electric vehicles and large-scale energy storage in smart grids requires energy storage systems of good safety, high reliability, high energy density and low cost. Here a coated Li metal is used as anode for an aqueous rechargeable lithium battery (ARLB) combining LiMn2O4 as cathode and 0.5?mol l(-1) Li2SO4 aqueous solution as electrolyte. Due to the "cross-over" effect of Li(+) ions in the coating, this ARLB delivers an output voltage of about 4.0?V, a big breakthrough of the theoretic stable window of water, 1.229?V. Its cycling is very excellent with Coulomb efficiency of 100% except in the first cycle. Its energy density can be 446?Wh kg(-1), about 80% higher than that for traditional lithium ion battery. Its power efficiency can be above 95%. Furthermore, its cost is low and safety is much reliable. It provides another chemistry for post lithium ion batteries. PMID:23466633

Wang, Xujiong; Hou, Yuyang; Zhu, Yusong; Wu, Yuping; Holze, Rudolf

2013-01-01

35

Impact of environmental conditions on the sorption behavior of radionuclide 63 Ni(II) onto hierarchically structured ?-MnO 2  

Microsoft Academic Search

A novel hierarchically structured ?-MnO2 has been synthesized using a simple chemical reaction between MnSO4 and KMnO4 in aqueous solution without using any templates, surfactants, catalysts, calcination and hydrothermal processes. As an example\\u000a of potential applications, hierarchically structured ?-MnO2 was used as adsorbent in radionuclide 63Ni(II) treatment, and showed an excellent ability. The effects of pH, ionic strength, temperature, humic

Juan Mou; Guoju Wang; Wenxian Shi; Shouwei Zhang

36

An aqueous rechargeable lithium battery of high energy density based on coated Li metal and LiCoO2.  

PubMed

Using a coated Li metal as an anode and LiCoO2 as a cathode, an aqueous rechargeable battery is built up, whose average discharge voltage is 3.70 V. This high voltage stability is due to the "cross-over" effect of Li(+) ions, which is different from the traditional ways of increasing overpotentials. The total energy density can be 465 W h kg(-1). PMID:23732678

Wang, Xujiong; Qu, Qunting; Hou, Yuyang; Wang, Faxing; Wu, Yuping

2013-07-14

37

Glucose ENFET doped with MnO 2 powder  

Microsoft Academic Search

In this study, a glucose-sensitive enzyme field-effect transistor (ENFET) coimmobilized with glucose oxidase (GOD) and manganese dioxide (MnO2) have been investigated. The biomembrane of the ENFET was immobilized on the amorphous tin oxide\\/indium tin oxide glass structure extended sensitive gate, which used as a disposable transducer of a glucose biosensor. MnO2 was used as a catalyst which can catalyze the

Li-Te Yin; Jung-Chuan Chou; Wen-Yaw Chung; Tai-Ping Sun; Kuang-Pin Hsiung; Shen-Kan Hsiung

2001-01-01

38

Morphologies Controlled Synthesis of MnO2 Nanostructures  

Microsoft Academic Search

Spherical MnO2 nanosheet aggregates have been synthesized by the reaction between MnSO4 and KMnO4 at room temperature. After the resulting products are treated under hydrothermal conditions, MnO2 nanorods and tower?like crystals have been prepared in the absence\\/presence of cetyltrimethylammonium bromide, respectively. The products are characterized by field?emission scanning electron microscopy and x?ray diffractometer, respectively.

Hongtao Pang; Li Jiang; Guicun Li; Hongrui Peng; Zhikun Zhang

2006-01-01

39

High-voltage and high-rate symmetric supercapacitor based on MnO2-polypyrrole hybrid nanofilm.  

PubMed

A manganese oxide (MnO2) nanosheet film, hybridized with a conducting polymer polypyrrole (PPy), was prepared through the direct reaction of a carbon cloth with potassium permanganate (KMnO4) and through the subsequent chemical polymerization; this type of prepared nanosheet has been used as an electrode for symmetric supercapacitors. The influence of the reaction time in the KMnO4 solution on the capacitive property of the MnO2 film was systematically investigated. Further experimentation revealed that the PPy with the high electrical conductivity had promoted the charge transfer in the MnO2 nanofilm and had played an important role in enhancing the electrode performance (?45.6 mF cm(-2)). An areal capacitance of 25.9 mF cm(-2) and an excellent rate performance (?50.08% of the initial capacitance when the scan rate increases 100 times from 2.5 to 250 mV s(-1)) can be achieved for an aqueous symmetric supercapacitor that is assembled from the MnO2-PPy nanofilm. In particular, an operating voltage of 1.2 V can be delivered by choosing an appropriate electrolyte; this voltage level is much larger than that of traditional aqueous symmetric supercapacitors (?1.0 V) and contributes to a high energy density (?3.5 ?Wh cm(-2)). Under such a high output voltage, the device can still maintain ?86.21% of the initial capacitance, even after 2000 cycles. PMID:25008287

Wang, Chong; Zhan, Yang; Wu, Lingxia; Li, Yuanyuan; Liu, Jinping

2014-08-01

40

High-performance rechargeable lithium-iodine batteries using triiodide/iodide redox couples in an aqueous cathode.  

PubMed

Development of promising battery systems is being intensified to fulfil the needs of long-driving-ranged electric vehicles. The successful candidates for new generation batteries should have higher energy densities than those of currently used batteries and reasonable rechargeability. Here we report that aqueous lithium-iodine batteries based on the triiodide/iodide redox reaction show a high battery performance. By using iodine transformed to triiodide in an aqueous iodide, an aqueous cathode involving the triiodide/iodide redox reaction in a stable potential window avoiding water electrolysis is demonstrated for lithium-iodine batteries. The high solubility of triiodide/iodide redox couples results in an energy density of ~ 0.33?kWh?kg(-1), approximately twice that of lithium-ion batteries. The reversible redox reaction without the formation of resistive solid products promotes rechargeability, demonstrating 100 cycles with negligible capacity fading. A low cost, non-flammable and heavy-metal-free aqueous cathode can contribute to the feasibility of scale-up of lithium-iodine batteries for practical energy storage. PMID:23695690

Zhao, Yu; Wang, Lina; Byon, Hye Ryung

2013-01-01

41

Manganese dioxide rechargeability in aqueous media. The combination of oxygen-regeneration with electrochemical regeneration  

SciTech Connect

The common manganese dioxides IC2 and Tekkosha are rechargeable only for 18 and 10 cycles, respectively, when the depth of discharge is {approximately}0.5 e/Mn. This low cycle life is due to the production of Mn{sub 3}O{sub 4} during cycling. When the oxygen evolution is combined with electrochemical oxidation, these samples become rechargeable for 60--70 cycles. The increase in the cycle life is due to the oxidation of Mn{sub 3}O{sub 4} to the initial MnO{sub 2} by oxidizing species generated near the Mn{sub 3}O{sub 4} sites during oxygen evolution by overcharging. The overrecharging has a positive effect when the duration of the recharge stage does not exceed {approximately}50% of that of the discharge stage. Beyond this value the cycle life decreases.

Ouboumour, H.; Cachet, C.; Bode, M.; Yu, L.T. [UMR28 CNRS-Univ. Paris Val-de-Marne, Thiais (France)

1995-04-01

42

Facile synthesis of ultra-long ?-MnO 2 nanowires and their microwave absorption properties  

Microsoft Academic Search

Well crystallized ?-MnO2 nanowires (NWs) with an average diameter of about 40nm and an average length of about 30?m were successfully synthesized by hydrothermal method. The complex permittivity and permeability of ?-MnO2 NWs\\/paraffin composites with 20vol.% ?-MnO2 NWs were measured in a frequency region from 0.1 to 13GHz. The value of maximum reflection loss of the composites with 20vol.% ?-MnO2

Xinghui Wang; Shibing Ni; Guo Zhou; Xiaolei Sun; Feng Yang; Junming Wang; Deyan He

2010-01-01

43

New-concept batteries based on aqueous Li+/Na+ mixed-ion electrolytes.  

PubMed

Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li(+)/Na(+) mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. One involves Li(+) insertion/extraction reaction, and the other mainly relates to Na(+) extraction/insertion reaction. Two batteries exhibit specific energy of 17 Wh kg(-1) and 25 Wh kg(-1) based on the total weight of active electrode materials, respectively. As well, aqueous LiMn2O4/Na0.22MnO2 battery is capable of separating Li(+) and Na(+) due to its specific mechanism unlike the traditional "rocking-chair" lithium-ion batteries. Hence, the Li(+)/Na(+) mixed-ion batteries offer promising applications in energy storage and Li(+)/Na(+) separation. PMID:23736113

Chen, Liang; Gu, Qingwen; Zhou, Xufeng; Lee, Saixi; Xia, Yonggao; Liu, Zhaoping

2013-01-01

44

New-concept Batteries Based on Aqueous Li+/Na+ Mixed-ion Electrolytes  

PubMed Central

Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li+/Na+ mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. One involves Li+ insertion/extraction reaction, and the other mainly relates to Na+ extraction/insertion reaction. Two batteries exhibit specific energy of 17?Wh kg?1 and 25?Wh kg?1 based on the total weight of active electrode materials, respectively. As well, aqueous LiMn2O4/Na0.22MnO2 battery is capable of separating Li+ and Na+ due to its specific mechanism unlike the traditional “rocking-chair” lithium-ion batteries. Hence, the Li+/Na+ mixed-ion batteries offer promising applications in energy storage and Li+/Na+ separation.

Chen, Liang; Gu, Qingwen; Zhou, Xufeng; Lee, Saixi; Xia, Yonggao; Liu, Zhaoping

2013-01-01

45

New-concept Batteries Based on Aqueous Li+/Na+ Mixed-ion Electrolytes  

NASA Astrophysics Data System (ADS)

Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li+/Na+ mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. One involves Li+ insertion/extraction reaction, and the other mainly relates to Na+ extraction/insertion reaction. Two batteries exhibit specific energy of 17 Wh kg-1 and 25 Wh kg-1 based on the total weight of active electrode materials, respectively. As well, aqueous LiMn2O4/Na0.22MnO2 battery is capable of separating Li+ and Na+ due to its specific mechanism unlike the traditional ``rocking-chair'' lithium-ion batteries. Hence, the Li+/Na+ mixed-ion batteries offer promising applications in energy storage and Li+/Na+ separation.

Chen, Liang; Gu, Qingwen; Zhou, Xufeng; Lee, Saixi; Xia, Yonggao; Liu, Zhaoping

2013-06-01

46

Rechargeable alkaline manganese dioxide/zinc batteries  

NASA Astrophysics Data System (ADS)

The rechargeable alkaline manganese dioxide/zinc MnO 2/Zn) system, long established commercial as a primay battery, has reached a high level of performance as a secondary battery system. The operating principles are presented and the technological achievements are surveyed by referencing the recent publications and patent literature. A review is also given of the improvements obtained with newly formulated cathodes and anodes and specially designed batteries. Supported by modelling of the cathode and anode processes and by statistical evidence during cycling of parallel/series-connected modules, the envisioned performance of the next generation of these batteries is described. The possibility of extending the practical use of the improved rechargeable MnO 2/Zn system beyond the field of small electronics into the area of power tools, and even to kW-sized power sources, is demonstrated. Finally, the commercial development in comparison with other rechargeable battery systems is examined.

Kordesh, K.; Weissenbacher, M.

47

Key scientific challenges in current rechargeable non-aqueous Li-O2 batteries: experiment and theory.  

PubMed

Rechargeable Li-air (henceforth referred to as Li-O2) batteries provide theoretical capacities that are ten times higher than that of current Li-ion batteries, which could enable the driving range of an electric vehicle to be comparable to that of gasoline vehicles. These high energy densities in Li-O2 batteries result from the atypical battery architecture which consists of an air (O2) cathode and a pure lithium metal anode. However, hurdles to their widespread use abound with issues at the cathode (relating to electrocatalysis and cathode decomposition), lithium metal anode (high reactivity towards moisture) and due to electrolyte decomposition. This review focuses on the key scientific challenges in the development of rechargeable non-aqueous Li-O2 batteries from both experimental and theoretical findings. This dual approach allows insight into future research directions to be provided and highlights the importance of combining theoretical and experimental approaches in the optimization of Li-O2 battery systems. PMID:24833409

Bhatt, Mahesh Datt; Geaney, Hugh; Nolan, Michael; O'Dwyer, Colm

2014-05-28

48

The structure and ordering of ?-MnO 2  

NASA Astrophysics Data System (ADS)

The presence of ?-MnO 2 as a major component of electrolytic manganese dioxide (EMD) has been demonstrated by a combined X-ray diffraction/transmission electron microscopy (TEM) study. ?-MnO 2 usually has a partially ordered defect NiAs structure containing 50% cation vacancies; these vacancies can be fully ordered by a low temperature (200 °C) heat treatment to form a pseudohexagonal but monoclinic superlattice. Numerous fine-scale anti-phase domain boundaries are present in ordered ?-MnO 2 and cause extensive peak broadening and a massive shift of a very intense, 0.37 nm superlattice peak. This suggests a radically different explanation of the ubiquitous, very broad ˜0.42 nm peak (˜21-22° 2 ?, Cu K? radiation) in EMDs, which heretofore has been attributed to Ramsdellite containing numerous planar defects. This work confirms the multi-phase model of equiaxed EMDs proposed by Heuer et al. [ITE Lett. 1(6) (2000) B50; Proc. Seventh Int. Symp. Adv. Phys. Fields 92 (2001)], rather than the defective single-phase model of Chabre and Pannetier [Prog. Solid State Chem. 23 (1995) 1] and Bowden et al. [ITE Lett. 4(1) (2003) B1].

Kim, Chang-Hoon; Akase, Zentaro; Zhang, Lichun; Heuer, Arthur H.; Newman, Aron E.; Hughes, Paula J.

2006-03-01

49

Investigation of the Rechargeability of Li-O2 Batteries in Non-aqueous Electrolyte  

SciTech Connect

In order to understand the nature of the limited cycle life and poor energy efficiency associated with the secondary Li-O¬2 batteries the discharge products of primary Li-O2 cells at different depth of discharge (DOD) are systematically analyzed in this work. It is revealed that if discharged to 2.0 V a small amount of Li2O2 coexist with Li2CO3 and RO-(C=O)-OLi) in alkyl carbonate-based electrolyte. Further discharging the air electrodes to below 2.0 V the amount of Li2CO3 and LiRCO3 increases significantly due to the severe electrolyte decomposition. There is no Li2O detected in this alkyl carbonate electrolyte regardless of DOD. It is also found that the alkyl carbonate based electrolyte begins to decompose at 4.0 V during charging under the combined influences from the high surface area carbon, the nickel metal current collector and the oxygen atmosphere. Accordingly the impedance of the Li-O2 cell continues to increase after each discharge and recharge process indicating a repeated plating of insoluble lithium salts on the carbon surface. Therefore the whole carbon electrode becomes completely insulated only after a few cycles and loses the function of providing active tri-phase regions for the Li-oxygen batteries.

Xiao, Jie; Hu, Jian Z.; Wang, Deyu; Hu, Dehong; Xu, Wu; Graff, Gordon L.; Nie, Zimin; Liu, Jun; Zhang, Jiguang

2011-07-01

50

Modification of MnO2 nanoparticles with rutin synthesized by Triton X-100 aggregations' template  

NASA Astrophysics Data System (ADS)

Manganese dioxide (MnO2) nanoparticles have been prepared through the redox reaction between KMnO4 and the nonionic surfactant Triton X-100 with the aid of rod-like micelles, hexagonal liquid crystals and reverse micelle templates, in which Triton X-100 acts both as template and reductant. MnO2 nanorods (20 50 nm in diameter) can be obtained in rod-like micelles and hexagonal liquid crystals, whereas MnO2 nanospheres (about 85 nm in diameter) are formed in reverse micelles. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to characterize the products. Modification of MnO2 nanoparticles by rutin has been discussed using fluorescence spectra and UV vis spectra, and the free radical eliminating investigations of surface-modified MnO2 nanoparticles with rutin show that MnO2 nanoparticles can improve the free-radical-scavenging activity of rutin.

Wang, Yi; Zhu, Jun; Han, Jie; Guo, Rong

2008-10-01

51

?-MnO 2/polyaniline composites: Preparation, characterization, and applications in microwave absorption  

NASA Astrophysics Data System (ADS)

MnO 2/doped polyaniline (PANI) is prepared by an in situ polymerization method using ?-MnO 2 as the addition agent and hydrochloric acid as the doping agent. Products are characterized by FT-IR, UV-vis, XRD, and TEM. Conductivity, electromagnetic properties, and microwave absorption properties are first discussed on the basis of structural characterization. The as-prepared products of MnO 2/PANI are partially crystalline in nature and spherical in pattern with grain sizes of 50-70 nm. MnO 2 particles are successfully decorated with doped PANI. MnO 2/PANI displays moderate electric conduction, excellent dielectric losses, and microwave absorption capabilities. Compared to pure MnO 2, the dielectric and reflection loss properties of MnO 2/PANI composites exhibit significant improvements, with an effective absorption band at 5 GHz under -10 dB and maximum reflection loss of -21 dB at 13.56 GHz. Pure MnO 2 shows an effective absorption band of 3 GHz under -10 dB and a maximum reflection loss of -14.20 dB at 11.5 GHz. Thus, MnO 2/PANI composites are found to be a promising microwave absorption material.

Jianjun, Hu; Yuping, Duan; Jia, Zhang; Hui, Jing; Shunhua, Liu; Weiping, Li

2011-05-01

52

High-conducting polyaniline via oxidative polymerization of aniline by MnO 2, PbO 2 and NH 4VO 3  

Microsoft Academic Search

Chemical oxidative polymerization of aniline (ANI) by MnO2, PbO2 and NNH4VO3 in aqueous acidic medium led to the formation of polyaniline (PANI). Various acids were used with different strength during the course of polymerization of ANI. FTIR spectral studies confirmed the formation of PANI in each of the polymerization systems. Thermogravimetric analyses (TG\\/DTA) matched with the reported data for PANI

Nirmalya Ballav

2004-01-01

53

A new rechargeable dialysis pore water sampler for monitoring sub-aqueous in-situ sediment caps  

Microsoft Academic Search

A new rechargeable dialysis pore water sampler is proposed that is adapted to the requirements of monitoring in-situ sediment remediation techniques, in particular in-situ capping. Sampling and recharging of the sampler can be carried out from a boat or a pontoon by means of separate tubing and a peristaltic pump. The possibility of repeated sampling permits a temporal as well

Patrick H Jacobs

2002-01-01

54

One-pot synthesis of hierarchical MnO2-modified diatomites for electrochemical capacitor electrodes  

NASA Astrophysics Data System (ADS)

The hierarchical and porous MnO2-modified diatomite structures are prepared for the first time by a one-pot hydrothermal method. The morphology and structure of MnO2-modified diatomite hierarchical structures are examined by focus ion beam scanning electron microscopy (FIB/SEM) and X-ray diffraction spectroscopy (XRD). The results show that Birnessite-type MnO2 nanosheets are observed to grow vertically on the purified diatomite, thus building hierarchical architecture. Furthermore, the electrochemical properties of the MnO2-modified diatomite electrodes are elucidated by cyclic voltammograms, galvanostatic charge/discharge tests and electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte. The electrochemical results demonstrate that the MnO2-modified diatomite electrode exhibits highly reversible features and good rate abilities, respectively. Significantly, it exhibits the specific capacitance of 202.6 F g-1 for the MnO2-modified diatomite and 297.8 F g-1 for the MnO2 nanostructures after etching the diatomite. The capacitance retention of 95.92% over 5000 cycles further indicates the suitability of the low-cost MnO2-modified diatomite structure as a potential electrode material for supercapacitors.

Zhang, Yu Xin; Huang, Ming; Li, Fei; Wang, Xue Li; Wen, Zhong Quan

55

Study of electrochemical reduced graphene oxide and MnO2 heterostructure for supercapacitor application  

NASA Astrophysics Data System (ADS)

In this paper we have shown enhanced supercapacitive property of electrochemically reduced graphene oxide (ERGO) and manganese dioxide (MnO2) based heterostructure over single MnO2 thin film grown by electrochemical deposition on indium tin oxide (ITO). ERGO improves the electrical conduction leading to decrease of the internal resistance of the heterostructure.

Jana, S. K.; Rao, V. P.; Banerjee, S.

2013-02-01

56

MnO 2\\/polyimide hybrid materials prepared with a convenient ultraviolet irradiation technique  

Microsoft Academic Search

A novel ultraviolet irradiation technique was developed to synthesize manganese dioxide-polyimide hybrids. The hybrids were characterized by FTIR, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). It was found that the MnO2 particles were of nanometric scale and well dispersed in the MnO2\\/polyimide hybrids prepared by this method.

Jun-chao Huang; Zi-kang Zhu; Xue-feng Qian; Jie Yin

2000-01-01

57

A redox-hydrothermal route to ?-MnO 2 hollow octahedra  

NASA Astrophysics Data System (ADS)

Beta-Manganese dioxides' (?-MnO 2) hollow octahedra have been prepared by a synergetic redox reaction using cuprous chloride (CuCl) and hydrochloric acid (HCl) as reductants and potassium permanganate (KMnO 4) as oxidant through a hydrothermal route. During the process, the self-generated chlorine (Cl 2) gas bubbles and HCl's etching appear to be necessary for the formation of MnO 2 hollow structure. The catalytic efficiency of the prepared ?-MnO 2 hollow octahedra was high which has been demonstrated by the catalytic oxidation of methylene blue (MB) dye in the presence of hydrogen peroxide (H 2O 2) under natural light.

Zhang, Yange; Chen, Liyong; Zheng, Zhi; Yang, Fengling

2009-07-01

58

Preparation of ?-MnO 2with an Open Tunnel  

NASA Astrophysics Data System (ADS)

A single-phase ?-MnO 2without any large stabilizing cations was successfully prepared by starting from hollandite-type (NH 4) xMn 8O 16and quenching from 440°C during heating in flowing Ar. The unit-cell dimension was determined by XRD analysis to be a=10.308(2) Å and c=2.854(1) Å. In comparison with that of the starting material ( a=9.896(1) Å and c= 2.859(1) Å), the adimension increased while the cdimension changed little. No presence of ammonium ions in the structure of this specimen was shown by IR spectroscopy, the Kjeldahl analysis, or temperature-programmed-desorption (TPD) measurement. The structural change from the hollandite phase to Mn 2O 3was observed at 540°C. TPD analysis indicates the presence of nitrogen other than ammonium ions in the hollandite material we prepared, and also suggests that this nitrogen might have a strong chemical interaction to the hollandite structure.

Muraoka, Yuji; Chiba, Hiroshi; Atou, Toshiyuki; Kikuchi, Masae; Hiraga, Kenji; Syono, Yasuhiko; Sugiyama, Shoko; Yamamoto, Sadaaki; Grenier, Jean-Claude

1999-04-01

59

?-MnO 2 for Li batteries . Part I. ?-MnO 2: Relationships between synthesis conditions, material characteristics and performances in lithium batteries  

NASA Astrophysics Data System (ADS)

With the use of various electrodeposition conditions (concentration and pH of the bulk MnSO 4 solution, temperature, synthetic mode) and thermal treatments, ?-MnO 2 materials exhibiting rather different physico-chemical and structural characteristics were prepared. Relationships were established between synthesis conditions and such characteristics, showing that to some extent, these physico-chemical and structural parameters can be tuned. The electrochemical behavior of lithiated phases obtained upon the first Li insertion into these ?-MnO 2 materials has been investigated. It is shown that the maximum Li reversible intercalation capacity strongly depends on the structural parameters (concentration of De Wolff defects and degree of microtwinning) of the starting ?-MnO 2 samples.

Sarciaux, S.; Le Gal La Salle, A.; Verbaere, A.; Piffard, Y.; Guyomard, D.

60

Hybrid MnO2/carbon nanotube-VN/carbon nanotube supercapacitors  

NASA Astrophysics Data System (ADS)

Composite materials, containing fibrous VN nanoparticles and multiwalled carbon nanotubes (MWCNT) are prepared by a chemical method for application in electrochemical supercapacitors. We demonstrate for the first time that VN-MWCNT electrodes exhibit good capacitive behavior in 0.5 M Na2SO4 electrolyte in a negative voltage window of 0.9 V. Quartz crystal microbalance studies provide an insight into the mechanism of charge storage. Composite VN-MWCNT materials show significant improvement in capacitance, compared to individual VN and MWCNT materials. Testing results indicate that VN-MWCNT electrodes exhibit high specific capacitance at high mass loadings in the range of 10-30 mg cm-2, good capacitance retention at scan rates in the range of 2-200 mV s-1 and good cycling stability. The highest specific capacitance of 160 F g-1 is achieved at a scan rate of 2 mV s-1. The new findings open a new and promising strategy in the fabrication of hybrid devices based on VN. The proof-of-principle is demonstrated by the fabrication of hybrid supercapacitor devices based on VN-MWCNT negative electrodes and MnO2 -MWCNT positive electrodes with voltage window of 1.8 V in aqueous 0.5 M Na2SO4 electrolyte. The hybrid VN-MWCNT/MnO2-MWCNT supercapacitor cells show promising capacitive and power-energy characteristics.

Su, Y.; Zhitomirsky, I.

2014-12-01

61

Controllable synthesis of MnO2/polyaniline nanocomposite and its electrochemical capacitive property  

NASA Astrophysics Data System (ADS)

Polyaniline (PANI) and MnO2/PANI composites are simply fabricated by one-step interfacial polymerization. The morphologies and components of MnO2/PANI composites are modulated by changing the pH of the solution. Formation procedure and capacitive property of the products are investigated by XRD, FTIR, TEM, and electrochemical techniques. We demonstrate that MnO2 as an intermedia material plays a key role in the formation of sample structures. The MnO2/PANI composites exhibit good cycling stability as well as a high capacitance close to 207 F g-1. Samples fabricated with the facile one-step method are also expected to be adopted in other field such as catalysis, lithium ion battery, and biosensor.

Meng, Fanhui; Yan, Xiuling; Zhu, Ye; Si, Pengchao

2013-04-01

62

Controllable synthesis of MnO2/polyaniline nanocomposite and its electrochemical capacitive property.  

PubMed

Polyaniline (PANI) and MnO2/PANI composites are simply fabricated by one-step interfacial polymerization. The morphologies and components of MnO2/PANI composites are modulated by changing the pH of the solution. Formation procedure and capacitive property of the products are investigated by XRD, FTIR, TEM, and electrochemical techniques. We demonstrate that MnO2 as an intermedia material plays a key role in the formation of sample structures. The MnO2/PANI composites exhibit good cycling stability as well as a high capacitance close to 207 F?g-1. Samples fabricated with the facile one-step method are also expected to be adopted in other field such as catalysis, lithium ion battery, and biosensor. PMID:23594724

Meng, Fanhui; Yan, Xiuling; Zhu, Ye; Si, Pengchao

2013-01-01

63

Binder free synthesis of MnO2 nanoplates/graphene composites with enhanced supercapacitive properties  

NASA Astrophysics Data System (ADS)

MnO2 nanoplates grown on graphene sheets have been directly synthesized during the graphite oxide (GO) reduction. The synthetic method is efficient, green and controllable with GO reduced and MnO2 nanoplates formed in one step. Compared with conventional methods, this method is easier to implement without using binders or any conductive additives. The as-prepared MnO2 nanoplates and graphene composites (GM) electrodes exhibit enhanced electrochemical performances, including ultrahigh specific capacitance (385 F g-1, at current density of 1 A g-1) and excellent cycling stabilities with 1 M Na2SO4 electrolytes. This improvement is due to the tighter contact between graphene sheets and MnO2 nanoplates, and the higher conductive and capacitive characteristics of graphene.

Li, Zijiong; Su, Yuling; Yun, Gaoqian; Shi, Kai; Lv, Xiaowei; Yang, Baocheng

2014-08-01

64

Synthesis, characterization and magnetic properties of ?-MnO 2 nanorods  

Microsoft Academic Search

?-MnO2 nanorods were successfully prepared by a simple refluxing route using manganese sulfate (MnSO4·H2O), sodium persulfate (Na2S2O8) and sodium hydroxide (NaOH) as the raw materials. The product was characterized by XRD, SEM, TEM, ED, EDX and TG-DTG. The results showed that the nanostructured materials were exactly manganese dioxides (pyrolusite) with rutile crystal structures and the diameter of ?-MnO2 nanorods ranged

Xian-Ming Liu; Shao-Yun Fu; Chuan-Jun Huang

2005-01-01

65

The reaction between solid UO 2 and MnO 2 in a sulfuric acid solution  

Microsoft Academic Search

In connection with the extensive use of pyrolusite in the sulfuric acid leaching of uranium from ores, a study was made of the reaction between UO2 and MnO2 in a sulfuric acid solution,and possible mechanisms were discussed. The experimental data show that the reaction apparently occurs at the points of contact of the hydrated surface layers of UO2 and MnO2;

E. A. Kanevskii; V. A. Pchelkin

1961-01-01

66

Effects of MnO 2 concentration on dielectric properties of barium strontium titanate glass ceramics  

Microsoft Academic Search

The phase development, microstructural evolution and dielectric properties of manganese-doped barium strontium titanate glass ceramics have been studied. The specimens with (Ba,Sr)TiO3 (BST) as the major crystalline phase were prepared by bulk crystallization process. The results show that the dielectric constant and the dielectric loss measured at room temperature pass through a maximum with increasing MnO2 concentration. This MnO2 concentration

Xiang-Rong Wang; Yong Zhang; Tao Ma; Chang-Sheng Deng; Xia-Ming Dai

67

Functionalization of Biomass Carbonaceous Aerogels: Selective Preparation of MnO2@CA Composites for Supercapacitors.  

PubMed

Functionalized porous carbon materials with hierarchical structure and developed porosity coming from natural and renewable biomass have been attracting tremendous attention recently. In this work, we present a facile and scalable method to synthesize MnO2 loaded carbonaceous aerogel (MnO2@CA) composites via the hydrothermal carbonaceous (HTC) process. We employ two reaction systems of the mixed metal ion precursors to study the optimal selective adsorption and further reaction of MnO2 precursor on CA. Our experimental results show that the system containing KMnO4 and Na2S2O3·5H2O exhibits better electrochemical properties compared with the reaction system of MnSO4·H2O and (NH4)2S2O8. For the former, the obtained MnO2@CA displays the specific capacitance of 123.5 F·g(-1). The enhanced supercapacitance of MnO2@CA nanocomposites could be ascribed to both electrochemical contributions of the loaded MnO2 nanoparticles and the porous structure of three-dimensional carbonaceous aerogels. This study not only indicates that it is vital for the reaction systems to match with porous carbonaceous materials, but also offers a new fabrication strategy to prepare lightweight and high-performance materials that can be used in energy storage devices. PMID:24882146

Ren, Yumei; Xu, Qun; Zhang, Jianmin; Yang, Hongxia; Wang, Bo; Yang, Daoyuan; Hu, Junhua; Liu, Zhimin

2014-06-25

68

MnO2 nanolayers on highly conductive TiO(0.54)N(0.46) nanotubes for supercapacitor electrodes with high power density and cyclic stability.  

PubMed

Pseudo-capacitive MnO2 supercapacitors are attracting intense interest because of the theoretically high specific capacitance (1370 F g(-1)) and low cost of MnO2. For the practical application, the power density and the cyclic stability of MnO2-based supercapacitors are expected to be improved. Increasing the efficiency of the current collection is an effective method to improve the power density for a given supercapacitor. Here, the highly conductive and electrochemically stable material, titanium oxynitride (TiO0.54N0.46), is used as the current collector. Uniform amorphous MnO2 nanolayers were deposited on metal-phase TiO0.54N0.46 nanotube arrays using a modified electrochemical deposition method. The resulting MnO2 supercapacitors exhibited a high power density of 620 kW kg(-1) at an energy density of 9.8 W h kg(-1). This is comparable to high-performance carbon-based electrochemical double layer capacitors in aqueous electrolytes. The high electron transport was enhanced with a highly conductive TiO0.54N0.46 scaffold. Ion transport was promoted in the nanotube structures that had porous walls. In addition, the close interfacial connection between MnO2 and TiO0.54N0.46 contributed to the excellent cyclic stability (ca. 92.0% capacitance retention after 100?000 cycles). These results indicated that the highly conductive and electrochemically stable titanium oxynitride is an excellent candidate for use as an electrode material in high performance supercapacitors. PMID:24668150

Wang, Zhiqiang; Li, Zhaosheng; Feng, Jianyong; Yan, Shicheng; Luo, Wenjun; Liu, Jianguo; Yu, Tao; Zou, Zhigang

2014-05-14

69

Oxidation of dimethylselenide by ??MnO2: Oxidation product and factors affecting oxidation rate  

USGS Publications Warehouse

Volatile dimethylselenide (DMSe) was transformed to a nonvolatile Se compound in a ??-MnO2 suspension. The nonvolatile product was a single compound identified as dimethylselenoxide based on its mass spectra pattern. After 24 h, 100% of the DMSe added to a ??-MnO2 suspension was converted to nonpurgable Se as opposed to 20%, 18%, and 4% conversion for chromate, permanganate, and the filtrate from the suspension, respectively. Manganese was found in solution after reaction. These results imply that the reaction between manganese oxide and DMSe was a heterogeneous redox reaction involving solid phase ??-MnO2 and solution phase DMSe. Oxidation of DMSe to dimethylselenoxide [OSe(CH3)2] by a ??-MnO2 suspension appears to be first order with respect to ??-MnO2, to DMSe, and to hydrogen ion with an overall rate law of d[OSe(CH3)2 ]/dt = 95 M-2 min-1 [MnO2]1[DMSe]1[H+]1 for the MnO2 concentration range of 0.89 ?? 10-3 - 2.46 ?? 10-3 M, the DMSe concentration range of 3.9 ?? 10-7 - 15.5 ?? 10-7 M Se, and a hydrogen ion concentation range of 7.4 ?? 10-6 -9.5 ?? 10-8 M. A general surface site adsorption model is consistent with this rate equation if the uncharged |OMnOH is the surface adsorption site. DMSe acts as a Lewis base, and the manganese oxide surface acts as a Lewis acid. DMSe adsorption to |OMnOH can be viewed as a Lewis acid/ base complex between the largely p orbitals of the DMSe lone pair and the unoccupied eg orbitals on manganese oxide. For such a complex, frontier molecular orbital theory predicts electron transfer to occur via an inner-sphere complex between the DMSe and the manganese oxide. ?? 1995 American Chemical Society.

Wang, B.; Burau, R. G.

1995-01-01

70

Effect of MnO2 Addition on the Electrical Properties of PNZST Ceramics  

NASA Astrophysics Data System (ADS)

(Pb0.99Nb0.02)[(Zr0.70Sn0.30) x Ti1- x ]0.98O3 (PNZST) piezoelectric ceramics of pure perovskite structure were prepared by a conventional ceramic fabrication method, where x = 0.48-0.56. When x = 0.52, the ceramics exhibit a high piezoelectric coefficient ( d 33 ˜ 490), but the mechanical quality factor ( Q m) is only 72. To increase the Q m and not dramatically lower the d 33, MnO2 was chosen as the additive. The effects of adding MnO2 on the sinterability, structure, and electrical properties of PNZST ceramics were investigated in detail. With a small addition of MnO2 (?0.6 wt.%), the Mn ions are homogeneously dissolved in the PNZST ceramic, leading to full densification when sintered at 1,300 °C. However, further addition of MnO2 prevents densification, causing a high porosity and small grain size. The doping of MnO2 transforms the phase structure from tetragonal to rhombohedral. The addition of MnO2 up to a maximum of 0.6 wt.% remarkably improves the mechanical quality factor ( Q m) of PNZST ceramics, simultaneously as well as maintaining a high d 33 and k p. PNZST with 0.6 wt.% MnO2 exhibits excellent electrical properties with piezoelectric coefficient d 33 = 392 pC/N, electromechanical coupling factor k p = 0.60, mechanical quality factor Q m = 1,050, dielectric constant ? r = 1,232, dielectric dissipation tan ? = 0.0058, and Curie temperature T C = 300 °C.

Yan, Yangxi; He, Hongliang; Feng, Yujun

2014-05-01

71

Photoluminescence Spectra and Magnetic Properties of Hydrothermally Synthesized MnO2 Nanorods  

NASA Astrophysics Data System (ADS)

In this paper, single crystalline tetragonal MnO2 nanorods have been synthesized by a simple hydrothermal method using MnSO4? H2O and Na2S2O8 as precursors. The crystalline phase, morphology, particle sizes and component of the as-prepared nanomaterial were characterized by employing X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). The photoluminescence (PL) emission spectrum of MnO2 nanorods at room temperature exhibited a strong ultraviolet (UV) emission band at 380 nm, a prominent blue emission peak at 453 nm as well as a weak defect related green emission at 553 nm. Magnetization (M) as a function of applied magnetic field (H) curve showed that MnO2 nanowires exhibited a superparamagnetic behavior at room temperature which shows the promise of synthesized MnO2 nanorods for applications in ferrofluids and the contrast agents for magnetic resonance imaging. The magnetization versus temperature curve of the as-obtained MnO2 nanorods shows that the Néel transition temperature is 94 K.

Toufiq, Arbab Mohammad; Wang, Fengping; Javed, Qurat-Ul-Ain; Li, Quanshui; Li, Yan

2013-11-01

72

Facile synthesis and electrochemical properties of hierarchical MnO 2 submicrospheres and LiMn 2O 4 microspheres  

Microsoft Academic Search

Hierarchical MnO2 submicrospheres have been successfully synthesized by a wet chemical method. The as-prepared products were characterized by means of XRD, SEM, FTIR, TG, and TEM. With the as-prepared MnO2 submicrospheres as precursors, LiMn2O4 microspheres were conveniently prepared by a simple solid-state reaction between MnO2 and LiOH at a temperature as low as 600°C. Electrochemical properties of the as-prepared MnO2

Hong-En Wang; Dong Qian; Zhouguang Lu; Yongkun Li; Ruijing Cheng; Yujie Li

2007-01-01

73

Facile synthesis and electrochemical properties of hierarchical MnO2 submicrospheres and LiMn2O4 microspheres  

NASA Astrophysics Data System (ADS)

Hierarchical MnO2 submicrospheres have been successfully synthesized by a wet chemical method. The as-prepared products were characterized by means of XRD, SEM, FTIR, TG, and TEM. With the as-prepared MnO2 submicrospheres as precursors, LiMn2O4 microspheres were conveniently prepared by a simple solid-state reaction between MnO2 and LiOH at a temperature as low as 600 °C. Electrochemical properties of the as-prepared MnO2 submicrospheres and LiMn2O4 microspheres as cathode materials in lithium ion cells were investigated by galvanostatic charge/discharge tests.

Wang, Hong-En; Qian, Dong; Lu, Zhouguang; Li, Yongkun; Cheng, Ruijing; Li, Yujie

2007-07-01

74

Magnetic Properties of MnO2 Shrimps-Like Nanostructures Synthesized by Hydrothermal Route  

NASA Astrophysics Data System (ADS)

In this paper, we report the field-dependent magnetization (M-H) and temperature-dependent magnetization (M-T) properties of hexagonal MnO2 shrimps-like nanostructures which have been successfully synthesized by hydrothermal route using KMnO4 and HNO3 as precursors. The magnetic properties were characterized by vibrating sample magnetometer (VSM). Field-dependent magnetization (M-H) measured at 300 K exhibit paramagnetic nature of MnO2 nanostructures, while an antiferromagnetic component is observed for the as-prepared product at 55 K. The Néel temperature (TN) is calculated as 89 K by plotting temperature-dependent magnetization (M-T) curve for the as-prepared MnO2 nanostructures. X-ray photoelectron spectroscopy (XPS) is employed to calculate the binding energies of Mn (2p3/2, 2p1/2) and O (1s) observed in the spectrum.

Toufiq, Arbab Mohammad; Wang, Fengping; Javed, Qurat-Ul-Ain; Li, Yan

2013-11-01

75

Binding of Colloidal MnO2 by Extracellular Polysaccharides of Pedomicrobium manganicum  

PubMed Central

The extracellular acidic polysaccharides of the manganese-oxidizing bacterium Pedomicrobium manganicum were able to bind preformed colloidal MnO2. The capacity of the cells to bind MnO2 was pH dependent. Enhanced binding capacity below pH 5 suggests that ionic bonding forces are involved in the binding mechanism and that there is a charge reversal on the acidic polysaccharides between pH 5 and 4 that is due to increased protonation of carboxyl groups. Images

Sly, L. I.; Arunpairojana, Vullapa; Dixon, D. R.

1990-01-01

76

Hierarchical Mesoporous MnO2 Superstructures Synthesized by Soft-Interface Method and Their Catalytic Performances.  

PubMed

To obtain a highly efficient and stable heterogeneous catalyst in catalytic wet hydrogen peroxide oxidation, we have successfully synthesized hierarchical mesoporous manganese dioxide (MnO2) superstructures by a facile and environmental friendly method on a soft-interface between CH2Cl2 and H2O without templates. The main crystal phase of as-prepared MnO2 was proved to be ?-MnO2 by X-ray diffraction techniques. The structure characterizations indicated that the hierarchical MnO2 superstructures were composed of urchin-like MnO2 hollow submicrospheres assembled by one-dimension nanorods building blocks with rich mesoporosity. The nitrogen sorption analysis confirmed that the as-synthesized MnO2 has an average pore diameter of 5.87 nm, mesoporous volume of 0.451 cm(3) g(-1), and specific surface area of 219.3 m(2) g(-1). Further investigations revealed that a possible formation mechanism of this unique hierarchical superstructure depended upon the synthesis conditions. The catalytic performances of the hierarchical mesoporous MnO2 superstructures were evaluated in catalytic degradation of methylene blue in the presence of H2O2 at neutral pH, which demonstrated highly efficient catalytic degradation of the organic pollutant methylene blue using hierarchical mesoporous MnO2 superstructures as catalyst at room temperature. PMID:24884227

Liu, Yanyu; Chen, Zhiwen; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L

2014-06-25

77

Enhancement of supercapacitance property of electrochemically deposited MnO2 thin films grown in acidic medium  

NASA Astrophysics Data System (ADS)

In this communication we present supercapacitance property of MnO2 thin-films which are fabricated on stainless steel (SS) substrate by electro-deposition method carried out in different pH of the electrolyte. A significant improvement of the device performance of acid mediated grown (AMG) MnO2 over normal MnO2 (grown in neutral medium) has been achieved. We have also investigated role of interfacial structure on the internal resistance of the device material. AMG MnO2 film exhibits superior device performance with specific capacitance of 652 F/g which is 2 times better than that obtained in normal MnO2 and also energy density of 90.69 Wh/kg.

Jana, S. K.; Rao, V. P.; Banerjee, S.

2014-02-01

78

Ultrathin MnO2 nanoflakes as efficient catalysts for oxygen reduction reaction.  

PubMed

Free-standing, ultrathin manganese dioxide nanoflakes were synthesized by cationic surfactant controlled reduction of KMnO4. MnO2 nanoflakes showed a much higher mass activity than other manganese based oxides as well as B and N doped nano carbons. The approach here demonstrates a facile chemical route towards efficient manganese dioxide catalysts. PMID:24911572

Wei, Chao; Yu, Linghui; Cui, Chenlong; Lin, Jiadan; Wei, Chen; Mathews, Nripan; Huo, Fengwei; Sritharan, Thirumany; Xu, Zhichuan

2014-06-24

79

Redox exchange induced MnO2 nanoparticle enrichment in poly(3,4-ethylenedioxythiophene) nanowires for electrochemical energy storage.  

PubMed

MnO2 nanoparticle enriched poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires are fabricated by simply soaking the PEDOT nanowires in potassium permanganate (KMnO4) solution. The structures of these MnO2 nanoparticle enriched PEDOT nanowires are characterized by SEM and TEM, which show that the MnO2 nanoparticles have uniform sizes and are finely dispersed in the PEDOT matrix. The chemical constituents and bonding of these composite nanowires are characterized by energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, which indicate that the formation and dispersion of these MnO2 nanoparticles into the nanoscale pores of the PEDOT nanowires are most likely triggered by the reduction of KMnO4 via the redox exchange of permanganate ions with the functional group on PEDOT. Varying the concentrations of KMnO4 and the reaction time controls the loading amount and size of the MnO2 nanoparticles. Cyclic voltammetry and galvanostatic charge-discharge are used to characterize the electrochemical properties of these MnO2 nanoparticle loaded PEDOT nanowires. Due to their extremely high exposed surface area with nanosizes, the pristine MnO2 nanoparticles in these MnO2 nanoparticle enriched PEDOT nanowires show very high specific capacitance (410 F/g) as the supercapacitor electrode materials as well as high Li+ storage capacity (300 mAh/g) as cathode materials of Li ion battery, which boost the energy storage capacity of PEDOT nanowires to 4 times without causing excessive volume expansion in the polymer. The highly conductive and porous PEDOT matrix facilitates fast charge/discharge of the MnO2 nanoparticles and prevents them from agglomerating. These synergic properties enable the MnO2 nanoparticle enriched PEDOT nanowires to be promising electrode materials for supercapacitors and lithium ion batteries. PMID:20590128

Liu, Ran; Duay, Jonathon; Lee, Sang Bok

2010-07-27

80

Electrochemical formation mechanism for the controlled synthesis of heterogeneous MnO2/Poly(3,4-ethylenedioxythiophene) nanowires.  

PubMed

The formation mechanism of a coaxial manganese oxide/poly(3,4-ethylenedioxythiophene) (MnO(2)/PEDOT) nanowire is elucidated herein by performing electrodeposition of MnO(2) and PEDOT on Au-sputtered nanoelectrodes with different shapes (ring and flat-top, respectively) within the 200 nm diameter pores of an anodized aluminum oxide (AAO) template. It is found that PEDOT prefers to grow on the sharp edge of the ring-shaped electrode, while MnO(2) is more likely to deposit on the flat-top electrode due to its smooth surface. The formation of coaxial nanowires is shown to be a result of simultaneous growth of core MnO(2) and shell PEDOT by an analysis of the current density resulting from electrochemical deposition. Furthermore, the structures of the MnO(2)/PEDOT coaxial nanowires were studied for their application as supercapacitors by modifying their coelectrodeposition potential. A potential of 0.70 V is found to be the most favorable condition for synthesis of MnO(2)/PEDOT coaxial nanowires, resulting in a high specific capacitance of 270 F/g. Additionally, other heterogeneous MnO(2)/PEDOT nanostructures are produced, such as nanowires consisting of MnO(2) nanodomes with PEDOT crowns as well as segmented MnO(2)/PEDOT nanowires. This is accomplished by simply adjusting the parameters of the electrochemical deposition. Finally, in smaller diameter (50 nm) AAO channels, MnO(2) and PEDOT are found to be partially assembled into coaxial nanowires due to the alternative depletion of Mn(II) ions and EDOT monomers in the smaller diameter pores. PMID:21661749

Liu, Ran; Duay, Jonathon; Lee, Sang Bok

2011-07-26

81

?-MnO2 as a cathode material for lithium ion batteries from first principles calculations.  

PubMed

The search for excellent cathodes for lithium batteries is the main topic in order to meet the requirements of low cost, high safety, and high capacity in many real applications. ?-MnO2, as a potential candidate, has attracted great attention because of its high stability and potential high capacity among all the phases. Because of the complexity of ?-MnO2, some fundamental questions at the atomic level during the charge-discharge process, remain unclear. The lithiation process of ?-MnO2 has been systematically examined by first-principles calculations along with cluster expansion techniques. Five stable configurations during the lithium intercalation process are firstly determined, and the electrochemical voltages are from 3.47 to 2.77 eV, indicating the strongly correlated effects of the ?-MnO2-LiMnO2 system. During the lithiation process, the changes in the lattice parameters are not symmetric. The analysis of electronic structures shows that Mn ions are in the mixed valence states of Mn(3+) and Mn(4+) during the lithiation process, which results in Jahn-Teller distortion in Mn(3+)O6 octahedra. Such results uncover the intrinsic origin of the asymmetric deformation during the charge-discharge process, resulting in the irreversible capacity fading during cycling. From the analysis of the thermal reduction of delithiated LixMnO2, the formation of oxygen is thermodynamically infeasible in the whole extraction process. Our results indicate that ?-MnO2 has great potential as a cathode material for high capacity Li-ion batteries. PMID:23646354

Wang, Da; Liu, Li-Min; Zhao, Shi-Jin; Li, Bai-Hai; Liu, Hao; Lang, Xiu-Feng

2013-06-21

82

High aspect ratio ?-MnO2 nanowires and sensor performance for explosive gases  

NASA Astrophysics Data System (ADS)

High aspect ratio ?-MnO2 nanowires have been synthesized based on a facile and green technique without any chemical additive. The precursor solution of Mn3O4 nanocrystals was first synthesized by laser ablation of a manganese target in deionized water. Due to the high reactive and fresh surface of Mn3O4 nanocrystals produced by laser ablation in liquid, these nanocrystals were spontaneously assembled into the ?-MnOOH nanowires in the precursor solution after aging at room temperature. The high aspect ratio ?-MnO2 nanowires were finally produced by the ?-MnOOH nanowires annealing at 300 °C for 3 h. For the high aspect ratio ?-MnO2 nanowires, the high specific surface area is advantaged for gas absorption and the unique tunnel structure is good for gas molecule trapping. A gas sensor was made from the ?-MnO2 nanowires for explosive gases. The investigations were carried out for the detection of various concentration of H2 at different temperatures, and the results demonstrated that the fabricated gas sensor can detect H2 down to 20 ppm with the sensitivity of 0.5 at 300 °C and short response time of 10s. For sensing CO and ethanol, the detecting concentration reached to 20 ppm at an operation temperature of 150 and 250 °C, respectively. These results can be comparable to that of the current advanced gas sensors made from metal oxide such as ZnO and SnO2, which showing that high aspect ratio ?-MnO2 nanowires can be regarded as desirable candidate materials for fabricating gas sensors.

Xiao, J.; Liu, P.; Liang, Y.; Li, H. B.; Yang, G. W.

2013-08-01

83

Controllable synthesis of hollow bipyramid ?-MnO(2) and its high electrochemical performance for lithium storage.  

PubMed

Three types of MnO2 nanostructures, viz., ?-MnO2 nanotubes, hollow ?-MnO2 bipyramids, and solid ?-MnO2 bipyramids, have been synthesized via a simple template-free hydrothermal method. Cyclic voltammetry and galvanostatic charge/discharge measurements demonstrate that the hollow ?-MnO2 bipyramids exhibit the highest specific capacity and the best cyclability; the capacity retains 213 mAh g(-1) at a current density of 100 mA g(-1) after 150 cycles. XRD patterns of the lithiated ?-MnO2 electrodes clearly show the expansion of lattice volume caused by lithiation, but the structure keeps stable during lithium insertion/extraction process. We suggest that the excellent performance for ?-MnO2 can be attributed to its unique electrochemical reaction, compact tunnel-structure and hollow architecture. The hollow architecture can accommodate the volume change during charge/discharge process and improve effective diffusion paths for both lithium ions and electrons. PMID:22658801

Chen, Wei-Min; Qie, Long; Shao, Qing-Guo; Yuan, Li-Xia; Zhang, Wu-Xing; Huang, Yun-Hui

2012-06-27

84

MnO2 nanotube-Pt/graphene mixture as an ORR catalyst for proton exchange membrane fuel cell  

NASA Astrophysics Data System (ADS)

In the present study, MnO2 nanotubes are synthesized by hydrothermal method and Pt/graphene by co reduction of hexachloroplatinic acid and graphite oxide. The formation of MnO2 nanotubes and Pt/graphene are confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy. MnO2 nanotubes are mixed with Pt/graphene is applied as the ORR catalyst in proton exchange membrane fuel cell. The single cell measurement is carried out after fabricating the membrane electrode assembly and polarization curves are recorded at different temperatures and the results are discussed.

Divya, P.; Ramaprabhu, S.

2013-02-01

85

Visible light-sensitive MnO 2- and CeO 2-loaded ZrO 2/carbon cluster/Pt nanocomposite materials  

NASA Astrophysics Data System (ADS)

Nano-sized ZrO 2/carbon cluster composite materials (I c's) were successfully prepared by the calcination of ZrOCl 2/starch complex I. I c's were found to reduce methylene blue under the irradiation of visible light ( ? > 460 nm). The materials obtained by calcining at 400 and 500 °C were selectively loaded with Pt particles to obtain Pt-loaded ZrO 2/carbon cluster composite materials denoted as I c400Pt and I c500Pt, respectively. In addition, the resultant materials were modified with MnO 2 and CeO 2 particles to achieve MnO 2- and CeO 2-loaded ZrO 2/carbon cluster/Pt composite materials denoted as I c400PtMn, I c500PtMn, I c400PtCe and I c500PtCe, respectively. The metal oxides-loaded ZrO 2/carbon cluster/Pt composite materials thus synthesized could decompose an aqueous silver nitrate solution by visible light irradiation to give Ag and O 2 with the [Ag]/[O 2] ratios of ca. 4. Visible light-irradiated water splitting examinations with I c400PtMn and I c400PtCe were also investigated and found to yield H 2 and O 2 with the [H 2]/[O 2] ratios of ca. 2.

Matsui, H.; Ikegami, M.; Karuppuchamy, S.; Hassan, M. A.; Yoshihara, M.

2012-02-01

86

Synthesis and lithium ion insertion\\/extraction properties of hollandite-type MnO 2 prepared by acid digestion of Mn 2O 3  

Microsoft Academic Search

Single-phase specimens of ?-MnO2 (hollandite-type) and ?-MnO2 (rutile-type) were synthesized by the acid digestion of Mn2O3 under reflux conditions. The type of polymorph of MnO2 products was strongly dependent on the reaction temperature, type of acid used, and its concentration. The pH titration curve of ?-MnO2 displayed a monobasic acid behavior toward Li+, but ?-MnO2 showed a poor ion-exchange property.

Norihito Kijima; Yuko Sakata; Yasuhiko Takahashi; Junji Akimoto; Toshiya Kumagai; Kaoru Igarashi; Tadao Shimizu

2009-01-01

87

Sonochemically synthesized MnO2 nanoparticles as electrode material for supercapacitors.  

PubMed

In this study, manganese oxide (MnO2) nanoparticles were synthesized by sonochemical reduction of KMnO4 using polyethylene glycol (PEG) as a reducing agent as well as structure directing agent under room temperature in short duration of time and characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. A supercapacitor device constructed using the ultrasonically-synthesized MnO2 nanoparticles showed maximum specific capacitance (SC) of 282Fg(-1) in the presence of 1M Ca(NO3)2 as an electrolyte at a current density of 0.5mAcm(-2) in the potential range from 0.0 to 1.0V and about 78% of specific capacitance was retained even after 1000 cycles indicating its high electrochemical stability. PMID:24360990

Gnana Sundara Raj, Balasubramaniam; Asiri, Abdullah M; Qusti, Abdullah H; Wu, Jerry J; Anandan, Sambandam

2014-11-01

88

Carbon-based air electrodes carrying MnO 2 in zinc-air batteries  

NASA Astrophysics Data System (ADS)

Catalysts prepared from the carbon black impregnated with manganous nitrate solution and then heated at temperature from 270°C to 450°C were investigated. It was found that the impregnated catalysts heated at temperature of 340°C exhibited the best catalytic activity for oxygen reduction in alkaline electrolyte. It was also found that the XRD spectra of pyrolytic MnO 2 from manganous nitrate over 340°C were different from those below 340°C. The enhanced catalysis of air electrodes was ascribed to the formation of MnO 2 crystal with d-value of 2.72 Å as the impregnated-catalysts was heated at temperature of 340°C. The other factors in preparation of air electrodes were also discussed.

Wei, Zidong; Huang, Wenzhang; Zhang, Shengtao; Tan, Jun

89

Giant Seebeck coefficient thermoelectric device of MnO2 powder.  

PubMed

We report a giant Seebeck coefficient (S) thermoelectric (TE) material-MnO(2) powder-and the design of a practical MnO(2) TE generator to light up a regular light emitting diode (LED). The S of MnO(2) powder was measured to be higher than 20,000 ?V K(-1), which is about 100 times higher than the state-of-the-art of Bi(2)Te(3), one of the best TE materials. The giant S is very possibly closely related to the surface density of the electronic state (DOS), the Fermi energy level. The very high S and therefore high power factor is technologically important for transient TE cooling. PMID:22293218

Song, FangFang; Wu, Liming; Liang, S

2012-03-01

90

Carbon-based air electrodes carrying MnO 2 in zinc–air batteries  

Microsoft Academic Search

Catalysts prepared from the carbon black impregnated with manganous nitrate solution and then heated at temperature from 270°C to 450°C were investigated. It was found that the impregnated catalysts heated at temperature of 340°C exhibited the best catalytic activity for oxygen reduction in alkaline electrolyte. It was also found that the XRD spectra of pyrolytic MnO2 from manganous nitrate over

Zidong Wei; Wenzhang Huang; Shengtao Zhang; Jun Tan

2000-01-01

91

Preconcentration of radium isotopes from natural waters using MnO 2 Resin  

Microsoft Academic Search

We have characterized “MnO2 Resin,” a new resin developed by the PG Research Foundation, for radium adsorption over wide ranges of pH, reaction times and salt concentrations. We show that the sorption of 133Ba (used as a proxy for Ra) is highly dependent on pH with the most useful range from pH 4 to 8. The surface layers of the

D. S Moon; W. C Burnett; S Nour; P Horwitz; A Bond

2003-01-01

92

MnO2 Nanorods Intercalating Graphene Oxide/Polyaniline Ternary Composites for Robust High-Performance Supercapacitors  

NASA Astrophysics Data System (ADS)

New ternary composites of MnO2 nanorods, polyaniline (PANI) and graphene oxide (GO) have been prepared by a two-step process. The 100 nm-long MnO2 nanorods with a diameter ~20 nm are conformably coated with PANI layers and fastened between GO layers. The MnO2 nanorods incorporated ternary composites electrode exhibits significantly increased specific capacitance than PANI/GO binary composite in supercapacitors. The ternary composite with 70% MnO2 exhibits a highest specific capacitance reaching 512 F/g and outstanding cycling performance, with ~97% capacitance retained over 5000 cycles. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications.

Han, Guangqiang; Liu, Yun; Zhang, Lingling; Kan, Erjun; Zhang, Shaopeng; Tang, Jian; Tang, Weihua

2014-04-01

93

MnO2 Nanorods Intercalating Graphene Oxide/Polyaniline Ternary Composites for Robust High-Performance Supercapacitors.  

PubMed

New ternary composites of MnO2 nanorods, polyaniline (PANI) and graphene oxide (GO) have been prepared by a two-step process. The 100?nm-long MnO2 nanorods with a diameter ~20?nm are conformably coated with PANI layers and fastened between GO layers. The MnO2 nanorods incorporated ternary composites electrode exhibits significantly increased specific capacitance than PANI/GO binary composite in supercapacitors. The ternary composite with 70% MnO2 exhibits a highest specific capacitance reaching 512?F/g and outstanding cycling performance, with ~97% capacitance retained over 5000 cycles. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications. PMID:24769835

Han, Guangqiang; Liu, Yun; Zhang, Lingling; Kan, Erjun; Zhang, Shaopeng; Tang, Jian; Tang, Weihua

2014-01-01

94

In situ synthesis of MnO2 coated cellulose nanofibers hybrid for effective removal of methylene blue.  

PubMed

A one-step and energy-efficient synthetic method was developed to fabricate manganese dioxide (MnO2)/cellulose nanofibers (CNFs) hybrid. In this process, bamboo CNFs acted as both a reducing reagent for the Mn (VII) and an ultralight support for the generated MnO2 nanosheets. Neither additional reducing reagents nor heating were adopted during the synthesis process. The phase constitutions, crystal structure and morphology of the hybrid were systematically investigated. Both oxidative and adsorptive decolorization of methylene blue (MB) were investigated to evaluate its efficiency on dye wastewater treatment. The results showed that the few-layer MnO2 nanosheets deposited on CNFs exhibited high decolorization efficiency for the oxidation and adsorption of MB. When slurry containing 25mg MnO2/CNFs hybrid was dispersed in 25mL 80mgL(-1) MB solution, the removal of MB was more than 99.8% within 2min. PMID:24906760

Wang, Yaru; Zhang, Xiaofang; He, Xu; Zhang, Wei; Zhang, Xinxing; Lu, Canhui

2014-09-22

95

Preparation and electrochemistry of one-dimensional nanostructured MnO 2/PPy composite for electrochemical capacitor  

NASA Astrophysics Data System (ADS)

One-dimensional nanostructured manganese dioxide/polypyrrole (MnO 2/PPy) composite was prepared by in situ chemical oxidation polymerization of pyrrole in the host of inorganic matrix of MnO 2, using complex of methyl orange (MO)/FeCl 3 as a reactive self-degraded soft-template. The morphology and structure of the composite were characterized by infrared spectroscopy (IR) X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the MnO 2/PPy composite consists of ?-MnO 2 and PPy with nanotube-like structure. Electrochemical properties of the composite demonstrated the material showed good electrochemical reversibility after 500 charge-discharge cycles in the potential range of -0.4 to 0.6 V, the tube-like nanocomposite has the potential application in electrochemical capacitor.

Li, Juan; Cui, Li; Zhang, Xiaogang

2010-04-01

96

MnO2 Nanorods Intercalating Graphene Oxide/Polyaniline Ternary Composites for Robust High-Performance Supercapacitors  

PubMed Central

New ternary composites of MnO2 nanorods, polyaniline (PANI) and graphene oxide (GO) have been prepared by a two-step process. The 100?nm-long MnO2 nanorods with a diameter ~20?nm are conformably coated with PANI layers and fastened between GO layers. The MnO2 nanorods incorporated ternary composites electrode exhibits significantly increased specific capacitance than PANI/GO binary composite in supercapacitors. The ternary composite with 70% MnO2 exhibits a highest specific capacitance reaching 512?F/g and outstanding cycling performance, with ~97% capacitance retained over 5000 cycles. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications.

Han, Guangqiang; Liu, Yun; Zhang, Lingling; Kan, Erjun; Zhang, Shaopeng; Tang, Jian; Tang, Weihua

2014-01-01

97

Surface complexation of Cu on birnessite (?-MnO 2): Controls on Cu in the deep ocean  

Microsoft Academic Search

Hexagonal birnessite (?-MnO2) is a close analogue to the dominant phase in hydrogenetic marine ferromanganese crusts and nodules. These deposits contain ?0.25wt.% Cu which is believed to be scavenged from the overlying water column where Cu concentrations are near 0.1?g\\/L. Here, we measured the sorption of Cu on ?-MnO2 as a function of pH and surface loading. We characterized the

David M. Sherman; Caroline L. Peacock

2010-01-01

98

One-pot synthesis of MnO 2\\/graphene\\/carbon nanotube hybrid by chemical method  

Microsoft Academic Search

A branched hybrid of MnO2\\/graphene\\/carbon nanotube (CNT) is generated in a one-pot reaction process by chemical method. Some ultrathin MnO2\\/graphene nanosheets, around 5nm in thickness, are randomly distributed on the CNT surface. Morphology, phase structure, microstructure and vibrational properties of the hybrid were characterized by field emission scanning electron microscope, X-ray diffractometer, high resolution transmission electron microscope and Raman spectrometer.

Ying Chen; Yong Zhang; Dognsheng Geng; Ruying Li; Hanlie Hong; Jingzhong Chen; Xueliang Sun

2011-01-01

99

Comparative study on nanostructured MnO 2\\/carbon composites synthesized by spontaneous reduction for supercapacitor application  

Microsoft Academic Search

MnO2 has been deposited onto two types of carbon (C) substrates, including a non-porous multi-wall carbon nano-tube (CNT) and a porous carbon black (CB) powder, by a solution reduction process where MnO4? was reduced at 80°C by the C substrate so as to give nano-crystalline MnO2 directly at the C surface. The nature of the C substrate has profound effects

Yen-Po Lin; Chung-Bo Tsai; Wen-Hsien Ho; Nae-Lih Wu

2011-01-01

100

Synthesis of MnO2-chitosan nanocomposite by one-step electrodeposition for electrochemical energy storage application  

NASA Astrophysics Data System (ADS)

MnO2-chitosan hybrid nanocomposite films with low and high chitosan's molecular weights are synthesized by one-step cathodic electrodeposition on nickel foam substrate for electrochemical capacitors (ECs) application. The films have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The MnO2-chitosan hybrid nanocomposite films show better specific capacitance and rate capability than chitosan-free MnO2 film. For the MnO2-chitosan composite films, the highest specific capacitance is 424 F g-1 obtained at a current density of 1 mA cm-2. The deposited film retains a very stable capacitance over 400 cycles by charging and discharging at 3 mA cm-2, and only 3% capacity loss is observed. The presence of chitosan promotes both ion and electron transport in the matrix of MnO2. Besides, it allows the formation of porous and crack-free deposited films. A deposition mechanism for MnO2-chitosan hybrid nanocomposite films is proposed.

Hassan, Sameh; Suzuki, Masaaki; El-Moneim, Ahmed Abd

101

MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery.  

PubMed

Two ?-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like ?-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance. PMID:24982603

Feng, Lili; Xuan, Zhewen; Zhao, Hongbo; Bai, Yang; Guo, Junming; Su, Chang-Wei; Chen, Xiaokai

2014-01-01

102

MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery  

PubMed Central

Two ?-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like ?-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance.

2014-01-01

103

Synthesis of layered MnO 2 by calcination of KMnO 4 for rechargeable lithium battery cathode  

Microsoft Academic Search

Layered manganese oxide (KxMnO2) powders were synthesized by simple decomposition of KMnO4 at 300–800°C in air. These manganese oxides were characterized by powder X-ray diffractometry, atomic absorption spectrometry, chemical redox titration, and X-ray photoelectron spectroscopy. Their electrochemical performances for secondary lithium batteries were investigated in a LiClO4–propylene carbonate (PC) solution. After removing side products, which were water soluble, the KxMnO2

Shinichi Komaba; Naoaki Kumagai; Shiho Chiba

2000-01-01

104

Electrode performance of romanechite for rechargeable lithium batteries  

Microsoft Academic Search

We studied romanechite, (2×3) tunnel type manganese dioxide, as a positive electrode material for rechargeable lithium batteries. We synthesized the sample by soft chemical techniques, and its chemical composition was Ba0.18MnO2.10·0.42H2O. We obtained a first discharge capacity of 120mAhg?1 (energy density 264mWhg?1). The capacity decreased with cycling. We examined the thermal behavior of this material, revealing its high thermal stability.

Masayuki Tsuda; Hajime Arai; Yasue Nemoto; Yoji Sakurai

2001-01-01

105

Pattern-dependent tunable adhesion of superhydrophobic MnO2 nanostructured film.  

PubMed

Tuning the adhesive force on a superhydrophobic MnO(2) nanostructured film was achieved by fabricating different patterns including meshlike, ball cactus-like, and tilted nanorod structures. The marvelous modulation range of the adhesive forces from 130 to nearly 0 ?N endows these superhydrophobic surfaces with extraordinarily different dynamic properties of water droplets. This pattern-dependent adhesive property is attributed to the kinetic barrier difference resulting from the different continuity of the three-interface contact line. This finding will provide the general strategies for the adhesion adjustment on superhydrophobic surfaces. PMID:21370908

Zhao, Xiao Dan; Fan, Hai Ming; Liu, Xiang Yang; Pan, Haihua; Xu, Hong Yao

2011-04-01

106

Aggregation kinetics of manganese dioxide colloids in aqueous solution: influence of humic substances and biomacromolecules.  

PubMed

In this work, the early stage aggregation kinetics of manganese dioxide (MnO2) colloids in aqueous solution and the effects of constituents of natural organic matter (i.e., Suwannee River fulvic acid (SRFA), Suwannee River humic acid (SRHA), alginate, and bovine serum albumin (BSA)) were investigated by time-resolved dynamic light scattering. MnO2 colloids were significantly aggregated in the presence of monovalent and divalent cations. The critical coagulation concentrations were 28, 0.8, and 0.45 mM for NaNO3, Mg(NO3)2, and Ca(NO3)2, respectively. The Hamaker constant of MnO2 colloids in aqueous solution was 7.84 × 10(-20) J. All the macromolecules tested slowed MnO2 colloidal aggregation rates greatly. The steric repulsive forces, originated from organic layers adsorbed on MnO2 colloidal surfaces, may be mainly responsible for their stabilizing effects. However, the complexes formed by alginate and Ca(2+) (>5 mM) might play a bridging role and thus enhanced MnO2 colloidal aggregation instead. These results may be important for assessing the fate and transport of MnO2 colloids and associated contaminants. PMID:23947796

Huangfu, Xiaoliu; Jiang, Jin; Ma, Jun; Liu, Yongze; Yang, Jing

2013-09-17

107

Morphology-controlled synthesis and novel microwave electromagnetic properties of hollow urchin-like chain Fe-doped MnO 2 under 10 T high magnetic field  

Microsoft Academic Search

Fe-doped MnO2 with a hollow sea urchin-like ball chain shape was first synthesized under a high magnetic field of 10T. The formation mechanism was investigated and discussed in detail. The synthesized samples were characterized by XRD, SEM, TEM, EMPA, and vector network analysis. By doping MnO2 with Fe, the relative complex permittivity of MnO2 and its corresponding loss tangent clearly

Duan Yuping; Zhang Jia; Jing Hui; Liu Shunhua

2011-01-01

108

Carnation-like MnO2 modified activated carbon air cathode improve power generation in microbial fuel cells  

NASA Astrophysics Data System (ADS)

Highly active and low-cost electrocatalysts are of great importance for large-scale commercial applications of microbial fuel cells (MFCs). In this work, we prepared an activated carbon (AC) air cathode containing electrodeposited ?-MnO2 using a potentiostatic method. The results indicated that carnation-like MnO2 crystals were bound to the surface of the AC air cathode after a deposition time of 10 min, which greatly improved the performance of the cathode. BET analysis results demonstrated that the electrodeposition of MnO2 decreased the micropore surface area of the cathode but increased the mesopore surface area. When compared with a bare AC air cathode, the electrodeposited MnO2 cathode exhibited higher catalytic activity for oxygen reduction reaction. The maximum power density of the MFC equipped with the electrodeposited MnO2 AC air cathode was 1554 mW m-2, which is 1.5 times higher than the control cathode.

Zhang, Peng; Li, Kexun; Liu, Xianhua

2014-10-01

109

Synthesis, characterization and study of arsenate adsorption from aqueous solution by ?- and ?-phase manganese dioxide nanoadsorbents  

Microsoft Academic Search

Single-phase ?-MnO2 nanorods and ?-MnO2 nano-fiber clumps were synthesized using manganese pentahydrate in an aqueous solution. These nanomaterials were characterized using the Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Powder X-ray diffraction (XRD) and the Brunauer–Elmet–Teller nitrogen adsorption technique (BET-N2 adsorption). The structural analysis shows that ?-MnO2 (2×2 tunnel structure) has the form of needle-shaped nanorods and

Mandeep Singh; Dong Nguyen Thanh; Pavel Ulbrich; Nina Strnadová; František Št?pánek

2010-01-01

110

Incorporation of MnO2-coated carbon nanotubes between graphene sheets as supercapacitor electrode.  

PubMed

Hierarchical graphene-based composite consisting of graphene sheets intercalated by MnO(2)-coated carbon nanotubes (MnC) was prepared for high-performance supercapacitor electrode. The highly negatively charged graphene oxides reduced by urea (RGO) and the positively charged MnC functionalized with poly(diallyldimethylammonium chloride) created a strong electrostatic interaction, forming a hierarchical nanostructure. The elelctrocapacitive behaviors of MnC/RGO (MnC-G) were systematically investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. A maximum specific capacitance of 193 F/g was achieved for the MnC-G composite with 37% RGO, which was almost 3-fold higher than 69 F/g of carbon nanotubes/RGO and 2-fold higher than 89 F/g of MnO(2)/RGO composite. Moreover, an excellent rate performance, a good capacitance retention (~70%) and a superior Coulombic efficiency (94-96%) were also observed during the continuous 1300 cycles of galvanostatic charge-discharge. PMID:22264121

Lei, Zhibin; Shi, Fuhua; Lu, Li

2012-02-01

111

Facile Synthesis and Microwave Absorption Properties of ?-MnO2 Nanorods  

NASA Astrophysics Data System (ADS)

A low-temperature water-bathing chemical precipitation method was developed to synthesize ?-MnO2 nanorods. The morphological and crystalline structures were investigated by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and X-ray diffraction (XRD) spectra. The electromagnetic properties and microwave absorption properties were examined in the frequency range 2-18 GHz. The results show that the as-synthesized product is ?-MnO2 nanorod with diameters of 30 nm and lengths up to 1-2 ?m. The dielectric permittivity has a trend of decreasing its real and increasing its imaginary parts with the frequency. The magnetic permeability is about 1.0-1.2 and 0-0.1 for its real and imaginary parts at the whole frequency. With the increase of sample thickness, the reflection loss peak value shifts to lower frequency band. With a thickness of 3 mm, an absorption peak value of -25 dB was achieved. And its effective absorption bandwidth in which the reflection loss is lower than -10 dB is as high as 5 GHz.

Guan, Hongtao; Chen, Gang; Zhu, Jing; Wang, Yude

2012-12-01

112

Some clues about the interphase reaction between ZnO and MnO 2 oxides  

NASA Astrophysics Data System (ADS)

Raman spectroscopy is used to evidence both the nature of the interphase reaction between ZnO and MnO 2 particles and its kinetic evolution. Zn cations migrate from the ZnO grains during oxygen vacancies formation process and diffuse into the MnO 2 particles leading to an interphase region with an intermediate valence Mn +3-O-Mn +4. Large amounts of desorbed Zn cations promote the formation of ZnMn 2O 4 structure, in addition to the intermediate valence state. The system evolves towards complete formation of the spinel phase at higher thermal treatment times. The reactivity of the ZnO plays an important role in the formation of this interphase. Low-reactivity ZnO powder, in which the oxygen vacancies are previously produced, shows a stabilization of the intermediate valence state with very limited formation of the spinel phase. A clear correlation between the amount of the intermediate state interphase and the magnetic properties has been established.

Rubio-Marcos, F.; Quesada, A.; García, M. A.; Bañares, M. A.; Fierro, J. L. G.; Martín-Gonzalez, M. S.; Costa-Krämer, J. L.; Fernández, J. F.

2009-05-01

113

Preconcentration of radium isotopes from natural waters using MnO2 Resin.  

PubMed

We have characterized "MnO2 Resin," a new resin developed by the PG Research Foundation, for radium adsorption over wide ranges of pH, reaction times and salt concentrations. We show that the sorption of 133Ba (used as a proxy for Ra) is highly dependent on pH with the most useful range from pH 4 to 8. The surface layers of the Mn oxides apparently become more positively charged under acidic conditions (below pH 4), which prevents diffusion of positively charged alkaline earth species (e.g. Ba2+, Ra2+) into the sorption sites. Adsorption at higher pH is thought to be inhibited because of carbonate complexation. We found that the sorption characteristics for radium onto MnO2 Resin are especially favorable for low-salinity waters but the sorption is still very satisfactory for highly salted solutions (KD=2.8x10(4) in both cases) but with slower kinetics. For analytical purposes, both column and pump experiments showed high recoveries with no measurable discrimination between Ra and Ba regardless of flow rates in fresh water. Seawater tests showed that recoveries of Ra and Ba are lower than fresh water at elevated flow rates with Ra adsorption higher than Ba at flow rates above 10 ml/min. PMID:14522233

Moon, D S; Burnett, W C; Nour, S; Horwitz, P; Bond, A

2003-10-01

114

Effect of hydrothermal dwell time on the diameter-controlled synthesis and magnetic property of MnO2 nanorods  

NASA Astrophysics Data System (ADS)

In this paper, single crystalline 1D tetragonal MnO2 pen-type nanorods were synthesized by varying the dwell time through a facile hydrothermal route at a reaction temperature of 250°C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the diameter of MnO2 nanorods decreases from 460 nm to 250 nm with the increase in hydrothermal reaction time from 5 h to 15 h. Field-emission scanning electron microscopy (FESEM) and TEM studies revealed the evolution of improved surface morphology of MnO2 nanorods that are prepared with longer hydrothermal reaction time. The magnetic properties of the products were evaluated using vibrating sample magnetometer (VSM) at room temperature, which showed that the as-prepared samples exhibit weak ferromagnetic behavior. The effect of diameter on the magnetization values was observed and discussed in detail.

Toufiq, Arbab Mohammad; Wang, Fengping; Javed, Qurat-Ul-Ain; Li, Yan

2014-02-01

115

Synthesis of MnO2-graphene composites with enhanced supercapacitive performance via pulse electrodeposition under supergravity field  

NASA Astrophysics Data System (ADS)

A method of pulse electrodeposition under supergravity field was proposed to synthesize MnO2-graphene composites. Supergravity is very efficient for promoting mass transfer and decreasing concentration polarization during the electrodeposition process. The synthesis was conducted on our homemade supergravity equipment. The strength of supergravity field depended on the rotating speed of the ring electrode. 3D flower like MnO2 spheres composed of nanoflakes were acquired when the rotating speed was 3000 rpm. Graphene nanosheets play as a role of conductive substrates for MnO2 growing. The composites are evaluated as electrode materials for supercapacitors. Electrochemical results show that the maximum specific capacitance of the MnO2-graphene composite is 595.7 F g-1 at a current density of 0.5 A g-1. In addition, the composite exhibits excellent cycle stability with no capacitance attenuation after 1000 cycles. The approach provides new ideas for developing supercapacitor electrode materials with high performance.

Liu, Tingting; Shao, Guangjie; Ji, Mingtong; Wang, Guiling

2014-07-01

116

Graphene oxide-dispersed pristine CNTs support for MnO2 nanorods as high performance supercapacitor electrodes.  

PubMed

A MnO2 -CNT-graphene oxide (MCGO) nanocomposite is fabricated using graphene oxide (GO) as a surfactant to directly disperse pristine carbon nanotubes (CNTs) for the subsequent deposition of MnO2 nanorods. The resulting MCGO nanocomposite is used as a supercapacitor electrode that shows ideal capacitive behavior (i.e., rectangular-shaped cyclic voltammograms), large specific capacitance (4.7?times higher than that of free MnO2 ) even at high mass loading (3.0?mg?cm(-2) ), high energy density (30.4-14.2?Wh?kg(-1) ), large power density (2.6-50.5?kW?kg(-1) ), and still retains approximately 94?% of the initial specific capacitance after 1000?cycles. The advanced capacity, rate capability, and cycling stability may be attributed to the unique architecture, excellent ion wettability of GO with enriched oxygen-containing functional groups, high conductivity of CNTs, and their synergistic effects when combined with the other components. The results suggest that the MnO2 -CNT-GO hybrid nanocomposite architecture is very promising for next generation high-performance energy storage devices. PMID:23417925

You, Bo; Li, Na; Zhu, Hongying; Zhu, Xiaolan; Yang, Jun

2013-03-01

117

Synthesis, characterization and study of arsenate adsorption from aqueous solution by ?- and ?-phase manganese dioxide nanoadsorbents  

NASA Astrophysics Data System (ADS)

Single-phase ?-MnO 2 nanorods and ?-MnO 2 nano-fiber clumps were synthesized using manganese pentahydrate in an aqueous solution. These nanomaterials were characterized using the Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Powder X-ray diffraction (XRD) and the Brunauer-Elmet-Teller nitrogen adsorption technique (BET-N 2 adsorption). The structural analysis shows that ?-MnO 2 (2×2 tunnel structure) has the form of needle-shaped nanorods and ?-MnO 2 (2D-layered structure) consists of fine needle-like fibers arranged in ball-like aggregates. Batch adsorption experiments were carried out to determine the effect of pH on adsorption kinetics and adsorption capacity for the removal of As(V) from aqueous solution onto these two types of nanoadsorbents. The adsorption capacity of As(V) was found to be highly pH dependent. The adsorption of As(V) onto ?-MnO 2 reached equilibrium more rapidly with higher adsorption capacity compared to ?-MnO 2.

Singh, Mandeep; Thanh, Dong Nguyen; Ulbrich, Pavel; Strnadová, Nina; Št?pánek, František

2010-12-01

118

Synthesis of MnO2 nanoparticles from sonochemical reduction of MnO4(-) in water under different pH conditions.  

PubMed

MnO2 was synthesized by sonochemical reduction of MnO4(-) in water under Ar atmosphere at 20°C, where the effects of solution pH on the reduction of MnO4(-) were investigated. The obtained XRD results showed that poor crystallinity ?-MnO2 was formed at pH 2.2, 6.0 and 9.3. When solution pH was increased from 2.2 to 9.3, the morphologies of ?-MnO2 changed from aggregated sheet-like or needle-like structures to spherical nanoparticles and finally to cubic or polyhedron nanoparticles. After further irradiation, MnO2 was readily reduced to Mn(2+). It was confirmed that H2O2 and H atoms formed in the sonolysis of water acted as reductants for both reduction for MnO4(-) to MnO2 and MnO2 to Mn(2+). The optimum irradiation time for the effective synthesis of MnO2 was 13min at pH 2.2, 9min at pH 6.0, 8min at pH 9.3, respectively. PMID:24793308

Abulizi, Abulikemu; Yang, Guo Hai; Okitsu, Kenji; Zhu, Jun-Jie

2014-09-01

119

Electron paramagnetic resonance in MnO 2 powders and comparative estimation of electric characteristics of power sources based on them in the MnO 2-Zn system  

NASA Astrophysics Data System (ADS)

A study was made of the electron paramagnetic resonance (EPR), the Mn 3+/Mn 4+ ratio, the OH - groups contents, the ionic conductivity value and the specific capacity in different electrolytically and chemically prepared manganese dioxides which were intended for use in power sources. Typical EPR signal for the powdered MnO 2 samples is wide single line with g=1.94. The replacement of some Mn 4+ ions by Mn 3+ modified the character of the exchange interaction. A correlation was established between the width of the EPR signal and electrochemical parameters of the samples. It is supposed that the EPR data can be useful for the semi-quantitative expression of chemical and electrochemical activity of different MnO 2 samples.

Kakazey, M.; Ivanova, N.; Boldurev, Y.; Ivanov, S.; Sokolsky, G.; Gonzalez-Rodriguez, J. G.; Vlasova, M.

120

Electron paramagnetic resonance in MnO 2 powders and comparative estimation of electric characteristics of power sources based on them in the MnO 2–Zn system  

Microsoft Academic Search

A study was made of the electron paramagnetic resonance (EPR), the Mn3+\\/Mn4+ ratio, the OH? groups contents, the ionic conductivity value and the specific capacity in different electrolytically and chemically prepared manganese dioxides which were intended for use in power sources. Typical EPR signal for the powdered MnO2 samples is wide single line with g=1.94. The replacement of some Mn4+

M Kakazey; N Ivanova; Y Boldurev; S Ivanov; G Sokolsky; J. G Gonzalez-Rodriguez; M Vlasova

2003-01-01

121

Electronic and magnetic properties of ?-MnO2 from ab initio calculations  

NASA Astrophysics Data System (ADS)

?-MnO2, an active catalyst for oxygen reduction and evolution reactions, has been investigated using ab initio calculations with different exchange-correlation functionals: the generalized-gradient approximation in the version of Perdew, Burke, and Ernzerhof (PBE), PBE+U, and hybrid functionals. Both hybrid functionals and PBE+U (U?2.0 eV) fail to capture the antiferromagnetic (AFM) ground state found experimentally, and a ferromagnetic configuration has the lowest energy. An AFM ground state is then recovered when using PBE or PBE+U (U?1.6 eV). Interestingly, a reduction of the gap is observed at increasing values of the U parameter. We offer a qualitative explanation for the change in the calculated ground state employing the results for the electronic structure and physical arguments similar to those exposed in the Goodenough-Kanamori-Anderson rules. It is argued that the pz orbital of oxygen atoms with sp2 hybridization plays a fundamental role in the superexchange AFM interaction and in the reduction of the gap.

Crespo, Y.; Seriani, N.

2013-10-01

122

As(III) oxidation by MnO2 coated PEEK-WC nanostructured capsules.  

PubMed

PEEK-WC nanostructured capsules were prepared by the phase inversion technique and used as support for the coating of a manganese dioxide layer. The coating was done by a chemical treatment of the capsules followed by a thermal one. The presence of the MnO(2) layer was confirmed by scanning electron microscopy (SEM), back scattering electron (BSE), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The produced capsules were, then, tested for As(III) oxidation in batch. The experiments consisted in treating 165 ml of As(III) solution with 1g of coated capsules at fixed temperature (15°C) and pH (5.7-5.8). In particular, the efficiency of the system was investigated for different As(III) concentrations (0.1, 0.3, 0.7 and 1 ppm). For feeds at lower As(III) content (0.1-0.3 ppm), tests lasted for 8h, while prolonged runs (up to 48 h) were carried out on more concentrated solutions (0.7 and 1 ppm). The produced capsules were able to oxidize As(III) into As(V) leading to complete conversion after 3 and 4h for feed concentrations of 0.1 and 0.3 ppm, respectively. PMID:22137174

Criscuoli, Alessandra; Majumdar, Swachchha; Figoli, Alberto; Sahoo, Ganesh C; Bafaro, Patrizia; Bandyopadhyay, Sibdas; Drioli, Enrico

2012-04-15

123

Transition from Mn4+ to Mn3+ induced by surface reconstruction at ?-MnO2(001)  

NASA Astrophysics Data System (ADS)

Structural and electronic properties of the ?-MnO2(001) surface are investigated applying density functional theory approach. The calculations show that all Mn ions at unreconstructed smooth surface preserve the +4 oxidation state observed in the bulk. Upon the ?-MnO2(001) reconstruction, one fourth of Mn ions at the surface undergo a change of the oxidation state from +4 to +3, although the reconstruction does not change the Mn coordination number with oxygen. This is accompanied with the filling of initially empty 3dz2 states localized on cations with one electron denoted by two neighboring O atoms. Although the reconstruction leads to an energy gain of 0.04 eV per surface unit cell, it is not a spontaneous process since it proceeds with an activation energy of 0.12 eV.

Ouyang, C. Y.; Šljivan?anin, Ž.; Baldereschi, A.

2010-11-01

124

Interruption of the MnO2 oxidative process on dopamine and L-dopa by the action of S2O3(2-).  

PubMed

The oxidation effects of Mn2+, Mn3+ or MnO2 on dopamine can be studied in vitro and, therefore, this offers a model of the auto-oxidation process that appears naturally in neurons causing Parkinson's disease. The use of MnO, as an oxidizer in aqueous solution at pH 7 causes the oxidation of catecholamines (L-dopa, dopamine, noradrenaline and adrenaline) to melanin. However, this work shows that, in water at pH 6-7, the oxidation of catecholamines by MnO2 in the presence of sodium thiosulphate (Na2S2O3) occurs by other mechanisms. For dopamine and L-dopa, MLCT complexes were formed with bands at 312, 350 (sh), 554 (sh) nm, and an intense band at 597 nm (epsilon approximately/= 4 x 10(3) M(-1) cm(-1)) and at ca. 336, 557 (sh) nm, and an intense band at 597 nm (epsilon approximately 6 x 10(3) M(-1) cm(-1)), respectively. The latter transitions were assigned to d(pi)-->pi*-SQ. Noradrenaline and adrenaline do not form this blue complex in solution, but generate soluble oxidized compounds. The resonance Raman spectra of these complexes in solution showed bands at 950, 1006, 1258, 1378, 1508 and 1603 cm(-1) for the complex derivation of L-dopa and at 948, 1010, 1255, 1373, 1510 and 1603 cm(-1) for the dopamine-derived compound. The most intense Raman band at ca. 1378 cm(-1) was assigned to C-O stretching with major C1-C2 characteristics and indicated that dopamine and L-dopa do not occur complexed with manganese in the catecholate or quinone form, but suggests an intermediate compound such as an anionic o-semiquinone (SQ-), forming a complex such as [Mn(II)(SQ-)3]-. All enhanced Raman frequencies are characteristic of the benzenic ring without the participation of the aminic nitrogen. A mechanism is proposed for the formation of the dopamine and L-dopa complexes and a computational simulation was performed to support it. PMID:11330485

Barreto, W J; Barreto, S R; Santos, M A; Schimid, R; Paschoal, F M; Mangrich, A S; deOliveira, L F

2001-03-01

125

Significance of the Henri-Michaelis-Menten theory in abiotic catalysis: catechol oxidation by ?-MnO 2  

NASA Astrophysics Data System (ADS)

The Henri-Michaelis-Menten theory, for more than eight decades, was only restricted to homogeneous enzymatic catalysis. A mimic of an enzymatic kinetics based on the Henri-Michaelis-Menten concept was experimentally observed in heterogeneous catalysis in the present study with ?-MnO 2 as an abiotic catalyst in the oxidation of catechol (1,2-dihydroxybenzene). Using the derived linear forms of Lineweaver-Burk or Hofstee, the data show that similar to the enzyme tyrosinase, the kinetics of the catechol oxidation catalyzed by ?-MnO 2 can be described by the Henri-Michaelis-Menten equation, V0= VmaxS/( Km+ S), where Vmax is the maximum velocity and Km the concentration of the substrate ( S) corresponding to an initial velocity ( V0) half of Vmax. By analogy to the enzymatic kinetics, the parameters Vmax and Km for an heterogeneous abiotic catalysis were derived for the first time. Further, based on the concentration of the active centers of the mineral oxide, the kinetic constants kcat and kcat/ Km, respectively, representing the turnover frequency and the efficiency of the mineral catalyst, were also determined from the derived general rate equation of Briggs and Haldane. As an abiotic catalyst, ?-MnO 2 has a paramount role in the oxidation of phenolic compounds in soil, sediment and water environments. Therefore, the present observation is of fundamental and practical significance in elucidating the affinity between an abiotic catalyst and a substrate based on the Henri-Michaelis-Menten theory.

Naidja, A.; Huang, P. M.

2002-05-01

126

Electrochemically grown nanoporous MnO2 nanowalls on a porous carbon substrate with enhanced capacitance through faster ionic and electrical mobility.  

PubMed

We report the deposition of uniform porous MnO2 nanowalls on a conducting carbon fiber substrate using a simple electrochemical method, which produces ordered nano-channels demarcated by the MnO2 walls for easy ion transport and a continuous electron path created by the carbon backbone. The system achieves a specific capacitance of 1149 F g(-1) and retains 565 F g(-1) even at dragging conditions as high as 100 A g(-1). PMID:24865591

Anothumakkool, Bihag; Kurungot, Sreekumar

2014-06-10

127

Influence of SiO2 on the structure-controlled synthesis and magnetic properties of prismatic MnO2 nanorods.  

PubMed

Silicon dioxide-doped tetragonal MnO2 single crystalline prismatic nanorods have been successfully synthesized through a facile hydrothermal route at a temperature of 250 ° C with a reaction time as quick as 5 h. The synthesized MnO2 prismatic nanorods were characterized by x-ray diffraction, field emission scanning electron microscopy, energy dispersive x-ray analysis, transmission electron microscopy, high resolution transmission electron microscopy with selected area electron diffraction and Raman spectroscopy. Experimental results show that single crystalline tetragonal MnO2 nanorods have been successfully synthesized at all doping concentrations and that nanorods with a prismatic surface morphology have been obtained at 20 mass% of SiO2. The diameter of as-prepared MnO2 nanorods increases from 125 to 250 nm on increasing the dopant concentration. X-ray photoelectron spectroscopy analysis confirms the presence of valence Si (2p) of SiO2 in the as-prepared MnO2 nanostructures. The intensity of Raman modes clearly increases with increasing doping concentration, indicating an improvement in the structural aspects of the MnO2 nanorods. The magnetic properties of the products have been evaluated using a vibrating sample magnetometer, revealing that the as-prepared MnO2 nanorods exhibit weak ferromagnetic behavior at room temperature. The Néel temperature of the as-obtained products is calculated as 97 K. On the basis of the structural information, a growth mechanism is proposed for the formation of prismatic-like 1D MnO2 nanorods. PMID:24045288

Toufiq, Arbab Mohammad; Wang, Fengping; Javed, Qurat-ul-ain; Li, Yan

2013-10-18

128

Highly flexible pseudocapacitor based on freestanding heterogeneous MnO2/conductive polymer nanowire arrays.  

PubMed

Flexible electronics such as wearable electronic clothing, paper-like electronic devices, and flexible biomedical diagnostic devices are expected to be commercialized in the near future. Flexible energy storage will be needed to power these devices. Supercapacitor devices based on freestanding nanowire arrays are promising high power sources for these flexible electronics. Electrodes for these supercapacitor devices consisting of heterogeneous coaxial nanowires of poly (3,4-ethylenedioxythiophene) (PEDOT)-shell and MnO(2)-core materials have been shown in a half cell system to have improved capacitance and rate capabilities when compared to their pure nanomaterials; however, their performance in a full cell system has not been fully investigated. Herein, these coaxial nanowires are tested in both a symmetric and an asymmetric (utilizing a PEDOT nanowire anode) full cell configuration in the aspect of charge storage, charge rate, and flexibility without using any carbon additives and polymer binders. It is found that the asymmetric cell outperforms the symmetric cell in terms of energy density, rate capability, and cycle ability. The asymmetric device's electrode materials display an energy density of 9.8 Wh/kg even at a high power density of 850 W kg(-1). This device is highly flexible and shows fast charging and discharging while still maintaining 86% of its energy density even under a highly flexed state. The total device is shown to have a total capacitance of 0.26 F at a maximum voltage of 1.7 V, which is capable of providing enough energy to power small portable devices. PMID:22298230

Duay, Jonathon; Gillette, Eleanor; Liu, Ran; Lee, Sang Bok

2012-03-14

129

Processing-structure-property-performance investigations of lithium manganese-based oxides for lithium rechargeable batteries  

Microsoft Academic Search

A study of the processing - structure - property - performance interrelationship was performed on several lithium manganese oxides that are candidates for use in lithium rechargeable batteries. The materials studied were LiMn 2O4, Mn-substituted LiMn2O4 (LiMn 2-yMeyO4), and Li1.5Na0.5 MnO2.85I0.12. Processing evaluations pertained to the substitution of Mn by other cations (Me = Li, Co, or Ni). Atomic and

Craig Richard Horne

2000-01-01

130

Low temperature water based electrolytes for MnO2/carbon supercapacitors.  

PubMed

Birnessite nanotubes and activated carbon electrodes have been used in supercapacitor cells to assess the performance of new aqueous based electrolyte systems at temperatures as low as -30 °C. The addition of ethylene glycol to aqueous sodium, lithium, potassium and ammonium sulfates has resulted in electrolytes that are still in liquid phase at such low temperatures. Extensive electrochemical testing showed that in such systems, operation of these aqueous based supercapacitors is possible at -30 °C with a specific capacitance of over 30 F g(-1) and good cycleability. PMID:23377101

Roberts, Alexander J; Danil de Namor, Angela F; Slade, Robert C T

2013-03-14

131

Synthesis of NASICON-type structured NaTi2(PO4)3-graphene nanocomposite as an anode for aqueous rechargeable Na-ion batteries  

NASA Astrophysics Data System (ADS)

A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C.A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C. Electronic supplementary information (ESI) available: Synthesis of graphite oxide, TG curve of NaTi2(PO4)3-GNS, XRD patterns and morphology of GO, TiO2-GNS, Ti5P4O20-GNS, and NaTi2(PO4)3-GNS. See DOI: 10.1039/c3nr06730k

Pang, Gang; Yuan, Changzhou; Nie, Ping; Ding, Bing; Zhu, Jiajia; Zhang, Xiaogang

2014-05-01

132

Synthesis of NASICON-type structured NaTi2(PO4)3-graphene nanocomposite as an anode for aqueous rechargeable Na-ion batteries.  

PubMed

A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g(-1) at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C. PMID:24755904

Pang, Gang; Yuan, Changzhou; Nie, Ping; Ding, Bing; Zhu, Jiajia; Zhang, Xiaogang

2014-06-21

133

Copper(II) removal from aqueous solutions by adsorption on non-treated and chemically modified cactus fibres.  

PubMed

The adsorption efficiency of a biomass by-product (cactus fibres) regarding the removal of copper(II) from aqueous solutions has been investigated before and after its chemical treatment. The chemical treatment of the biomass by-product included phosphorylation and MnO2-coating. The separation/removal efficiency has been studied as a function of pH, Cu(II) concentration, ionic strength, temperature and contact time. Evaluation of the experimental data shows that the MnO2-coated product presents the highest adsorption capacity, followed by the non-treated and phosphorylated material. Regarding the effect of ionic strength/salinity on the adsorption, in contrast to the removal efficiency of the phosphorylated product, which is significantly affected, the MnO2-coated and non-treated material don't show any effect, indicating the formation of inner-sphere surface complexes. The adsorption reaction is in all cases endothermic and relatively fast, particularly the adsorption on the MnO2-coated product. The results of the present study indicate that for the removal of bivalent metal-ions from contaminated waters the MnO2-coated material is expected to be the most effective adsorbent and an alternative to MnO2 resins for the treatment of environmentally relevant waters. PMID:24334902

Prodromou, M; Pashalidis, I

2013-01-01

134

The design of an Fe-12Mn-O.2Ti alloy steel for low temperature use  

NASA Technical Reports Server (NTRS)

An investigation was made to improve the low temperature mechanical properties of Fe-8 approximately 12% Mn-O 2Ti alloy steels. A two-phase(alpha + gamma) tempering in combination with cold working or hot working was identified as an effective treatment. A potential application as a Ni-free cryogenic steel was shown for this alloy. It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated martensitic structure and absence of epsilon phase. A significant reduction of the ductile-brittle transition temperature was obtained in this alloy. The nature and origin of brittle fracture in Fe-Mn alloys were also investigated. Two embrittling regions were found in a cooling curve of an Fe-12Mn-O 2Ti steel which was shown to be responsible for intergranular fracture. Auger electron spectroscopy identified no segregation during solution-annealing treatment. Avoiding the embrittling zones by controlled cooling led to a high cryogenic toughness in a solution-annealed condition.

Hwang, S. K.; Morris, J. W., Jr.

1977-01-01

135

Synthesis of a Thin-Layer MnO2 Nanosheet-Coated Fe3O4 Nanocomposite as a Magnetically Separable Photocatalyst.  

PubMed

A facile hydrothermal method combined with a mild ultrasonic means has been developed for the fabrication of a magnetically recyclable thin-layer MnO2 nanosheet-coated Fe3O4 nanocomposite. The photocatalytic studies suggest that the MnO2/Fe3O4 nanocomposite shows excellent photocatalytic efficiency and stability simultaneously for the degradation of methylene blue under UV-vis light irradiation. Moreover, its good acid resistance and stable recyclability are very important for its future practical application as a photocatalyst. Magnetic measurements verify that the MnO2/Fe3O4 nanocomposite possesses a ferromagnetic nature, which can be effectively separated for reuse by simply applying an external magnetic field after the photocatalytic reaction. This novel composite material may have potential applications in water treatment, degradation of dye pollutants, and environmental cleaning. PMID:24856355

Zhang, Lishu; Lian, Jianshe; Wu, Longyun; Duan, Zhenrong; Jiang, Jun; Zhao, Lijun

2014-06-17

136

Constraints on the utility of MnO2 cartridge method for the extraction of radionuclides: A case study using 234Th  

USGS Publications Warehouse

[1] Large volume (102-103 L) seawater samples are routinely processed to investigate the partitioning of particle reactive radionuclides and Ra between solution and size-fractionated suspended particulate matter. One of the most frequently used methods to preconcentrate these nuclides from such large volumes involves extraction onto three filter cartridges (a prefilter for particulate species and two MnO2-coated filters for dissolved species) connected in series. This method assumes that the extraction efficiency is uniform for both MnO2-coated cartridges, that no dissolved species are removed by the prefilter, and that any adsorbed radionuclides are not desorbed from the MnO2-coated cartridges during filtration. In this study, we utilized 234Th-spiked coastal seawater and deionized water to address the removal of dissolved Th onto prefilters and MnO2-coated filter cartridges. Experimental results provide the first data that indicate (1) a small fraction of dissolved Th (<6%) can be removed by the prefilter cartridge; (2) a small fraction of dissolved Th (<5%) retained by the MnO2 surface can also be desorbed, which undermines the assumption of uniform extraction efficiency for Th; and (3) the absolute and relative extraction efficiencies can vary widely. These experiments provide insight on the variability of the extraction efficiency of MnO 2-coated filter cartridges by comparing the relative and absolute efficiencies and recommend the use of a constant efficiency on the combined activity from two filter cartridges connected in series for future studies of dissolved 234Th and other radionuclides in natural waters using sequential filtration/extraction methods. ?? 2009 by the American Geophysical Union.

Baskaran, M.; Swarzenski, P. W.; Biddanda, B. A.

2009-01-01

137

Thermal Conductivity of AxBO2-type Layered Oxides Na0.77MnO2 and LiCoO2  

Microsoft Academic Search

We prepared polycrystalline samples of the AxBO2-type layered oxides Na0.77MnO2 and LiCoO2, and measured thermal conductivity (kappa) from 15 to 280 K. Na0.77MnO2 shows a low kappa of 15 mW\\/cmK at 280 K, while LiCoO2 shows a much higher kappa of 40 mW\\/cmK at 280 K. By comparing these results with kappa of NaCo2O4, we found that the low kappa

Kazumi Takahata; Ichiro Terasaki

2002-01-01

138

Rechargeable lithium cell  

Microsoft Academic Search

The general object of this invention is to provide an improved rechargeable lithium cell. A more specific object of the invention is to provide a rechargeable lithium cell having an improved low temperature performance and rate capability. It has now been found that the aformentioned objects can be attained using lithium as the anode, a solution of a lithium salt

M. Salomon; E. J. Plichta

1984-01-01

139

Rechargeable lithium battery with spinel-related ?-MnO 2 III. Scaling-up problems associated with LiMn 2O 4 synthesis  

NASA Astrophysics Data System (ADS)

The scaling-up problems connected with the LiMn 2O 4 synthesis were studied. A strong effect of the mass of the starting materials and of the air flow rate through the furnace during the synthesis on the specific capacity was observed. The increase of the batch amount brings about a reduction in the specific surface area of the product, which cannot be compensated by grinding because it leads to considerable reduction of its electrochemical utilization. The very fast or slow cooling of the synthesized material have a negative effect on the specific capacity. The process of preparation of LiMn 2O 4 spinel with high electrochemical performance is a rather complex procedure, but it is possible to obtain a product, which is capable to exchange reversibly up to 0.9 equiv. Li per mole.

Manev, V.; Momchilov, A.; Nassalevska, A.; Sato, Atsushi

140

Persulfate activation by iron oxide-immobilized MnO2 composite: identification of iron oxide and the optimum pH for degradations.  

PubMed

Iron oxide-immobilized manganese oxide (MnO2) composite was prepared and the reactivity of persulfate (PS) with the composite as activator was investigated for degradation of carbon tetrachloride and benzene at various pH levels. Brunauer-Emmett-Teller (BET) surface area of the composite was similar to that of pure MnO2 while the pore volume and diameter of composite was larger than those of MnO2. Scanning electron microscopy couples with energy dispersive spectroscopy (SEM-EDS) showed that Fe and Mn were detected on the surface of the composite, and X-ray diffraction (XRD) analysis indicated the possibilities of the existence of various iron oxides on the composite surface. Furthermore, the analyses of X-ray photoelectron (XPS) spectra revealed that the oxidation state of iron was identified as 1.74. In PS/composite system, the same pH for the highest degradation rates of both carbon tetrachloride and benzene were observed and the value of pH was 9. Scavenger test was suggested that both oxidants (i.e. hydroxyl radical, sulfate radical) and reductant (i.e. superoxide anion) were effectively produced when PS was activated with the iron-immobilized MnO2. PMID:24184048

Jo, Young-Hoon; Do, Si-Hyun; Kong, Sung-Ho

2014-01-01

141

Artificial recharge of groundwater  

SciTech Connect

The vast underground reservoirs formed by aquifers constitute invaluable water supply sources as well as water storage facilities. Because natural replenishment of the supply occurs very slowly, continued excessive exploitation of it causes groundwater levels to decline with time. If not corrected this leads to an eventual depletion of a valuable natural resource. To prevent mining and groundwater pollution, the artificial recharge of groundwater basins is becoming increasingly important in groundwater management as a way to increase this natural supply of water. Artificial recharge can reduce, stop, and even reverse declining levels of groundwater. In addition, it can protect underground freshwater in coastal aquifers against salt-water intrusion from the ocean, and can be used to store surface and reclaimed water for future use. This book is a treatise of the artificial recharge of groundwater, with particular emphasis on recharge with reclaimed municipal wastewater.

Asano, T.

1985-01-01

142

Mechanisms of pH-dependent activity for water oxidation to molecular oxygen by MnO2 electrocatalysts.  

PubMed

Manganese oxides function as efficient electrocatalysts for water oxidation to molecular oxygen in strongly alkaline conditions, but are inefficient at neutral pH. To provide new insight into the mechanism underlying the pH-dependent activity of the electrooxidation reaction, we performed UV-vis spectroelectrochemical detection of the intermediate species for water oxidation by a manganese oxide electrode. Layered manganese oxide nanoparticles, ?-MnO(2) (K(0.17)[Mn(4+)(0.90)Mn(3+)(0.07)?(0.03)]O(2)·0.53H(2)O) deposited on fluorine-doped tin oxide electrodes were shown to catalyze water oxidation at pH from 4 to 13. At this pH range, a sharp rise in absorption at 510 nm was observed with a concomitant increase of anodic current for O(2) evolution. Using pyrophosphate as a probe molecule, the 510 nm absorption was attributable to Mn(3+) on the surface of ?-MnO(2). The onset potential of the water oxidation current was constant at approximately 1.5 V vs SHE from pH 4 to pH 8, but sharply shifted to negative at pH > 8. Strikingly, this behavior was well reproduced by the pH dependence of the onset of 510 nm absorption, indicating that Mn(3+) acts as the precursor of water oxidation. Mn(3+) is unstable at pH < 9 due to the disproportionation reaction resulting in the formation of Mn(2+) and Mn(4+), whereas it is effectively stabilized by the comproportionation of Mn(2+) and Mn(4+) in alkaline conditions. Thus, the low activity of manganese oxides for water oxidation under neutral conditions is most likely due to the inherent instability of Mn(3+), whose accumulation at the surface of catalysts requires the electrochemical oxidation of Mn(2+) at a potential of approximately 1.4 V. This new model suggests that the control of the disproportionation and comproportionation efficiencies of Mn(3+) is essential for the development of Mn catalysts that afford water oxidation with a small overpotential at neutral pH. PMID:22206433

Takashima, Toshihiro; Hashimoto, Kazuhito; Nakamura, Ryuhei

2012-01-25

143

Inter-relationships of MnO 2 precipitation, siderophore-Mn (III) complex formation, siderophore degradation, and iron limitation in Mn (II)-oxidizing bacterial cultures  

NASA Astrophysics Data System (ADS)

To examine the pathways that form Mn (III) and Mn (IV) in the Mn (II)-oxidizing bacterial strains Pseudomonas putida GB-1 and MnB1, and to test whether the siderophore pyoverdine (PVD) inhibits Mn (IV)O 2 formation, cultures were subjected to various protocols at known concentrations of iron and PVD. Depending on growth conditions, P. putida produced one of two oxidized Mn species - either soluble PVD-Mn (III) complex or insoluble Mn (IV)O 2 minerals - but not both simultaneously. PVD-Mn (III) was present, and MnO 2 precipitation was inhibited, both in iron-limited cultures that had synthesized 26-50 ?M PVD and in iron-replete (non-PVD-producing) cultures that were supplemented with 10-550 ?M purified PVD. PVD-Mn (III) arose by predominantly ligand-mediated air oxidation of Mn (II) in the presence of PVD, based on the following evidence: (a) yields and rates of this reaction were similar in sterile media and in cultures, and (b) GB-1 mutants deficient in enzymatic Mn oxidation produced PVD-Mn (III) as efficiently as wild type. Only wild type, however, could degrade PVD-Mn (III), a process linked to the production of both MnO 2 and an altered PVD with absorbance and fluorescence spectra markedly different from those of either PVD or PVD-Mn (III). Two conditions, the presence of bioavailable iron and the absence of PVD at concentrations exceeding those of Mn, both had to be satisfied for MnO 2 to appear. These results suggest that P. putida cultures produce soluble Mn (III) or MnO 2 by different and mutually inhibitory pathways: enzymatic catalysis yielding MnO 2 under iron sufficiency or PVD-promoted oxidation yielding PVD-Mn (III) under iron limitation. Since PVD-producing Pseudomonas species are environmentally prevalent Mn oxidizers, these data predict influences of iron (via PVD-Mn (III) versus MnO 2) on the global oxidation/reduction cycling of various pollutants, recalcitrant organic matter, and elements such as C, S, N, Cr, U, and Mn.

Parker, Dorothy L.; Morita, Takami; Mozafarzadeh, Mylene L.; Verity, Rebecca; McCarthy, James K.; Tebo, Bradley M.

2007-12-01

144

Solid-state rechargeable magnesium cell with poly(vinylidenefluoride)-magnesium triflate gel polymer electrolyte  

NASA Astrophysics Data System (ADS)

A gel polymer electrolyte (GPE) film of poly(vinylidenefluoride) and magnesium triflate is prepared and studied for application in a solid-state rechargeable magnesium battery. The composition of GPE is optimized in view of minimum liquid components and maximum specific conductivity ( ?). The ? of GPE of optimum composition is 2.67×10 -3 S cm -1 at 20°C, and it follows a Vogel, Tamman and Fulcher equation with an activation energy of about 0.4 kJ mol -1. The effect of aging on the Mg/GPE interface is studied. The formation of a passivating film on the Mg surface, which increases in thickness on aging in GPE, is established. Several Mg/GPE/MnO 2 cells are assembled and studied for discharge capacity and cyclic-life data. The results reveal that Mg/GPE/MnO 2 cells at C/8, C/6 and C/4 discharge rates yield, respectively, capacities of 160, 80 and 50 mAh g -1 of MnO 2. These values are nearly constant for about 30 cycles. Further cycling of the cells leads to a decrease in capacity, which is attributed to passivation of the magnesium electrode and poor efficiency of the Mg 2+ ion insertion into the MnO 2 positive electrode.

Girish Kumar, G.; Munichandraiah, N.

145

Thermal Conductivity of AxBO2-type Layered Oxides Na0.77MnO2 and LiCoO2  

NASA Astrophysics Data System (ADS)

We prepared polycrystalline samples of the AxBO2-type layered oxides Na0.77MnO2 and LiCoO2, and measured thermal conductivity (?) from 15 to 280 K. Na0.77MnO2 shows a low ? of 15 mW/cmK at 280 K, while LiCoO2 shows a much higher ? of 40 mW/cmK at 280 K. By comparing these results with ? of NaCo2O4, we found that the low ? of AxBO2 essentially comes from the A-ion deficiency, not from the layered structure itself. The present study reveals that the lattice properties of the layered oxides are essentially three-dimensional, although the electronic states are often highly two-dimensional.

Takahata, Kazumi; Terasaki, Ichiro

2002-02-01

146

Rechargeable lithium cell  

SciTech Connect

The general object of this invention is to provide an improved rechargeable lithium cell. A more specific object of the invention is to provide a rechargeable lithium cell having an improved low-temperature performance and rate capability. It has now been found that the aformentioned objects can be attained using lithium as the anode, a solution of a lithium salt such as LiF/sub 6/ or LiA1C/sup 14/ in a mixed organic solvent as the electrolyte and a lithium intercalating cathode.

Salomon, M.; Plichta, E.J.

1984-09-27

147

Adhesion Improvement of ABS Resin to Electroless Copper by H2SO4–MnO2 Colloid with Ultrasound-Assisted Treatment  

Microsoft Academic Search

The adhesion strength between electroless copper and acrylonitrile-butadiene-styrene (ABS) resin can be improved significantly by an environmentally friendly etching system containing H2SO4–MnO2 colloid as a replacement for conventional chromic acid etching solutions. In this paper, the effects of the H2SO4 concentration and ultrasound-assisted treatment (UAT) on the surface roughness and adhesion strength were investigated. When the H2SO4 concentration was 11.8?12.7

Zhifeng Yang; Yue He; Zhun Li; Na Li; Zenglin Wang

2011-01-01

148

Cu nanoclusters supported on nanocrystalline SiO2-MnO2: a bifunctional catalyst for the one-step conversion of glycerol to acrylic acid.  

PubMed

A material consisting of highly dispersed Cu nanoclusters anchored on nanocrystalline SiO2-MnO2 has been prepared, and was found to act as a bifunctional catalyst for the one- step conversion of glycerol to acrylic acid using H2O2. Under optimized conditions a glycerol conversion of 77.1%, with 74.7% selectivity for acrylic acid, was achieved after 30 h reaction time. PMID:25017454

Sarkar, Bipul; Pendem, Chandrashekar; Sivakumar Konathala, L N; Tiwari, Ritesh; Sasaki, Takehiko; Bal, Rajaram

2014-07-29

149

Low-temperature molar heat capacities and entropies of MnO2 (pyrolusite), Mn3O4 (hausmanite), and Mn2O3 (bixbyite)  

USGS Publications Warehouse

Pyrolusite (MnO2), hausmanite (Mn3O4), and bixbyite (Mn2O3), are important ore minerals of manganese and accurate values for their thermodynamic properties are desirable to understand better the {p(O2), T} conditions of their formation. To provide accurate values for the entropies of these important manganese minerals, we have measured their heat capacities between approximately 5 and 380 K using a fully automatic adiabatically-shielded calorimeter. All three minerals are paramagnetic above 100 K and become antiferromagnetic or ferrimagnetic at lower temperatures. This transition is expressed by a sharp ??-type anomaly in Cpmo for each compound with Ne??el temperatures TN of (92.2??0.2), (43.1??0.2), and (79.45??0.05) K for MnO2, Mn3O4, and Mn2O3, respectively. In addition, at T ??? 308 K, Mn2O3 undergoes a crystallographic transition, from orthorhombic (at low temperatures) to cubic. A significant thermal effect is associated with this change. Hausmanite is ferrimagnetic below TN and in addition to the normal ??-shape of the heat-capacity maxima in MnO2 and Mn2O3, it has a second rounded maximum at 40.5 K. The origin of this subsidiary bump in the heat capacity is unknown but may be related to a similar "anomalous bump" in the curve of magnetization against temperature at about 39 K observed by Dwight and Menyuk.(1) At 298.15 K the standard molar entropies of MnO2, Mn3O4, and Mn2O3, are (52.75??0.07), (164.1??0.2), and (113.7??0.2) J??K-1??mol-1, respectively. Our value for Mn3O4 is greater than that adopted in the National Bureau of Standards tables(2) by 14 per cent. ?? 1985.

Robie, R. A.; Hemingway, B. S.

1985-01-01

150

Pseudocapacitance of MnO 2 originates from reversible insertion\\/desertion of thiocyanate anions studied using in situ X-ray absorption spectroscopy in ionic liquid electrolyte  

Microsoft Academic Search

Charge storage mechanisms of electrodeposited MnO2 in various aprotic ionic liquids (ILs) are studied using in situ X-ray absorption spectroscopy (XAS). The analytical results show that a unique thiocyanate (SCN?) anion can reversibly insert\\/desert into\\/from the tunnels between the [MnO6] octahedral subunits depending on the applied potential. This process charge compensates the Mn3+\\/Mn4+ redox transition upon charging–discharging and thus contributes

Ming-Tsung Lee; Wen-Ta Tsai; Ming-Jay Deng; Hui-Fang Cheng; I-Wen Sun; Jeng-Kuei Chang

2010-01-01

151

MnO 2\\/SiO 2–SO 3H nanocomposite as hydrogen peroxide scavenger for durability improvement in proton exchange membranes  

Microsoft Academic Search

Membrane durability was a key problem to the development of proton exchange membrane fuel cells (PEMFCs). A novel nanocomposite MnO2\\/SiO2–SO3H was prepared to mitigate the hydrogen peroxide attack to the membranes at fuel cell condition. The nanocomposites were synthesized by the wet chemical method and three-step functionalization. The crystal structure was characterized by X-ray powder diffraction (XRD), the crystallite size

D. Zhao; B. L. Yi; H. M. Zhang; H. M. Yu

2010-01-01

152

Aqueous Electrolyte Batteries  

Microsoft Academic Search

Despite the growing interest in advanced lithium batteries, the overwhelming majority of batteries manufactured today are still based on aqueous electrolytes, mostly sulphuric acid or potassium hydroxide solution. The ubiquitous lead-acid battery is, after 150 years, still being improved as regards its design and materials of construction. Rechargeable batteries based on potassium hydroxide electrolyte have nickel oxide or silver oxide

R. M. dell

1996-01-01

153

Lithium rechargeable envelope cells  

NASA Astrophysics Data System (ADS)

Prototype lithium manganese oxide rechargeable cells have been made in an envelope format, which is particularly suitable for scaling up to large batteries. Materials have been tested in laboratory cells. The synthesis of lithium manganese oxide has been investigated and cathode components for cells have been fabricated. Cycling results are reported.

Gilmour, A.; Giwa, C. O.; Lee, J. C.; Ritchie, A. G.

154

Lithium rechargeable envelope cells  

Microsoft Academic Search

Prototype lithium manganese oxide rechargeable cells have been made in an envelope format, which is particularly suitable for scaling up to large batteries. Materials have been tested in laboratory cells. The synthesis of lithium manganese oxide has been investigated and cathode components for cells have been fabricated. Cycling results are reported.

A. Gilmour; C. O. Giwa; J. C. Lee; A. G. Ritchie

1997-01-01

155

REMOTELY RECHARGEABLE EPD  

SciTech Connect

Radiation measurements inside the Contact Decon Maintenance Cell (CDMC) in the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) are required to determine stay times for personnel. A system to remotely recharge the transmitter of an Electronic Personnel Dosimeter (EPD) and bail assembly to transport the EPD within the CDMC was developed by the Savannah River National Laboratory (SRNL) to address this need.

Vrettos, N; Athneal Marzolf, A; Scott Bowser, S

2007-11-13

156

Rechargeable Magnesium Power Cells  

NASA Technical Reports Server (NTRS)

Rechargeable power cells based on magnesium anodes developed as safer alternatives to high-energy-density cells like those based on lithium and sodium anodes. At cost of some reduction in energy density, magnesium-based cells safer because less susceptible to catastrophic meltdown followed by flames and venting of toxic fumes. Other advantages include ease of handling, machining, and disposal, and relatively low cost.

Koch, Victor R.; Nanjundiah, Chenniah; Orsini, Michael

1995-01-01

157

Synthesis of Na xMnO 2+ ? by a Reduction of Aqueous Sodium Permanganate with Sodium Iodide  

NASA Astrophysics Data System (ADS)

Reduction of sodium permanganate with sodium iodide in aqueous solutions has been investigated systematically. The products formed have been characterized by X-ray diffraction, wet-chemical analysis, and surface area and magnetic susceptibility measurements after firing at various temperatures. The results reveal that the sodium content x in the reduction products Na xMnO 2+ ? depends strongly on the reaction pH and mildly on the relative concentrations of the reactants. Na 0.7MnO 2+ ? obtained at pH>11 followed by firing at T>500°C adopts the P2 layer structure (hexagonal) with cation vacancies arising from a ??0.3. Na 0.7MnO 2+ ? crystallizing in a distorted P2 structure (orthorhombic) without cation vacancies ( ??0) could be obtained by annealing the hexagonal Na 0.7MnO 2+ ? ( ??0.3) in N 2 atmosphere around 600°C. While the orthorhombic Na 0.7MnO 2+ ? ( ?<0.05) is stable during ion-exchange reactions with lithium salts at 25? T?180°C, the hexagonal Na 0.7MnO 2+ ? ( ??0.3) transforms to spinel-like phases due to the presence of cation vacancies. Na 0.5MnO 2+ ? obtained at a controlled pH of 9.3 adopts a metastable layer structure on firing at 500°C and a tunnel structure isostructural with Na 4Mn 4Ti 5O 18 on firing at T?600°C. The tunnel structure is stable to ion-exchange reactions without transforming to spinel-like phases. In addition, washing the reduction products with various organic solvents before firing at higher temperatures is found to influence the reaction kinetics, composition, and crystal chemistry.

Jeong, Y. U.; Manthiram, A.

2001-02-01

158

Hierarchical heterostructures of MnO2 nanosheets or nanorods grown on Au-coated Co3O4 porous nanowalls for high-performance pseudocapacitance  

NASA Astrophysics Data System (ADS)

The rational design and fabrication of more multi-component (material-combination) 3D hierarchical heterostructures for high-performance pseudocapacitor applications still remains a challenge. Herein, we have designed and synthesized a 3D hierarchical heterostructure of MnO2 nanosheets or nanorods grown on an Au-coated Co3O4 porous nanowall array, resembling a sandwich configuration of Co3O4@Au@MnO2, by a facial and controllable electrochemical deposition process. Due to their unique self-assembling architecture and characteristics including porous Co3O4 nanowalls, ultrathin MnO2 nanosheets, and a high conductivity Au layer sandwiched between them, each component provides a much-needed critical function for the efficient use of metal oxides for energy storage. The synthesized 3D hierarchical heterostructures exhibited favorable electrochemical performances, such as a high specific capacitances of 851.4 F g-1 at 10 mV s-1 and 1532.4 F g-1 at 1 A g-1, good rate performance and an excellent long-term cycling stability (almost no degradation after 5000 cycles), which are better than those of the reported Co3O4 or MnO2 based electrode materials, and thus could be considered as perspective materials for high-performance electrochemical capacitors.The rational design and fabrication of more multi-component (material-combination) 3D hierarchical heterostructures for high-performance pseudocapacitor applications still remains a challenge. Herein, we have designed and synthesized a 3D hierarchical heterostructure of MnO2 nanosheets or nanorods grown on an Au-coated Co3O4 porous nanowall array, resembling a sandwich configuration of Co3O4@Au@MnO2, by a facial and controllable electrochemical deposition process. Due to their unique self-assembling architecture and characteristics including porous Co3O4 nanowalls, ultrathin MnO2 nanosheets, and a high conductivity Au layer sandwiched between them, each component provides a much-needed critical function for the efficient use of metal oxides for energy storage. The synthesized 3D hierarchical heterostructures exhibited favorable electrochemical performances, such as a high specific capacitances of 851.4 F g-1 at 10 mV s-1 and 1532.4 F g-1 at 1 A g-1, good rate performance and an excellent long-term cycling stability (almost no degradation after 5000 cycles), which are better than those of the reported Co3O4 or MnO2 based electrode materials, and thus could be considered as perspective materials for high-performance electrochemical capacitors. Electronic supplementary information (ESI) available: Experimental process, supplementary figures and specific capacitance calculation. See DOI: 10.1039/c3nr34140b

Li, Wenyao; Li, Gao; Sun, Jianqing; Zou, Rujia; Xu, Kaibing; Sun, Yangang; Chen, Zhigang; Yang, Jianmao; Hu, Junqing

2013-03-01

159

Groundwater recharge in urban areas  

NASA Astrophysics Data System (ADS)

The two interlinked networks of hydrological pathways in urban areas are described with particular reference to the links with groundwater. As well as reducing direct recharge, urbanization creates new pathways and sources of water for recharge, including leaking water mains, sewers, septic tanks and soakaways. The net effect is often to increase recharge to pre-urbanization rates, or higher in dry climates and cities with high densities and large imported water supplies.

Lerner, David N.

160

Thermal and photodegradation of MnO 2-, NaBO 3- and organic hydroperoxide-cured polysulfides: products and pathways  

Microsoft Academic Search

The thermal and photodegradation of a number of linear polysulfides (LP) H(SC2H4OCH2OC2H4S)nH, cured using inorganic (MnO2, NaBO3) and organic (t-butyl hydroperoxide or TBHP) curatives, have been studied by 1H and 13C NMR spectroscopy, IR spectroscopy and electrospray ionisation mass spectrometry (ESI). We have found that cured-LPs degrade thermally and photochemically by two main parallel pathways namely (i) a free radical

Andrea Mahon; Terence J. Kemp; Robert J. Coates

1998-01-01

161

Microstructure and current-voltage characteristics of praseodymium-doped zinc oxide varistors containing MnO 2 , Sb 2 O 3 and Co 3 O 4  

Microsoft Academic Search

The effects of the oxide additives MnO2, Sb2O3 and Co3O4 commonly incorporated in commercial Bi2O3-doped ZnO varistors on the microstructure and the current-voltage characteristics of 0.5 mol% Pr6O11-doped ZnO varistors have been studied. A 1 mol% addition of Co3O4 to the ZnO-Pr6O11 binary system does not produce any additional secondary phases in addition to Pr oxides. In contrast to this,

H. H. Hng; K. M. Knowles

2002-01-01

162

High Power Rechargeable Thermal Battery.  

National Technical Information Service (NTIS)

Report developed under STTR contract; a proof of concept for a portable, rechargeable thermal battery (RTB). Including a superinsulated case, a lightweight (10 lb) RTB can provide 250W for 2-6h at 140 Wh/kg with days of activation between recharging. It c...

T. D. Kaun

1997-01-01

163

Composition Optimization of Al-DOPING Lithium Manganese Oxide from Al2O3-Li2CO3-MnO2 Ternary System  

NASA Astrophysics Data System (ADS)

In order to synthesize eutectic compound of Al doping lithium manganese oxide which can be used as cathode material in lithium battery, using ?-Al2O3, Li2CO3 and MnO2 as starting raw materials, the composition optimization research work has been done by the solid state synthesis method. A limited composition range was found in Al2O3-Li2CO3-MnO2 ternary system, in which the synthesized Al doping lithium manganese oxides have single spinel structure and good electrochemical performance. The results showed that the LiAl0.04Mn1.96O4 material presented better charge-discharge cycling behavior than pure LiMn2O4, and showed the best electrochemistry property among the compounds in the Al2O3-Li2O-Mn2O3 ternary system. LiAl0.04Mn1.96O4 still kept perfect cubic structure, but LiMn2O4 kept the coexistence of the cubic and tetragonal phases after 50 charge-discharge cycles.

He, Gang; Sun, Xinyan; Hong, Jianhe; He, Mingzhong

2013-07-01

164

Magnetic state of the structural separated anion-deficient La0.70Sr0.30MnO2.85 manganite  

NASA Astrophysics Data System (ADS)

The results of neutron diffraction studies of the La0.70Sr0.30MnO2.85 compound and its behavior in an external magnetic field are stated. It is established that in the 4-300 K temperature range, two structural perovskite phases coexist in the sample, which differ in symmetry (groups Rbar 3c and I4/ mcm). The reason for the phase separation is the clustering of oxygen vacancies. The temperature (4-300 K) and field (0-140 kOe) dependences of the specific magnetic moment are measured. It is found that in zero external field, the magnetic state of La0.70Sr0.30MnO2.85 is a cluster spin glass, which is the result of frustration of Mn3+-O-Mn3+ exchange interactions. An increase in external magnetic field up to 10 kOe leads to fragmentation of ferromagnetic clusters and then to an increase in the degree of polarization of local spins of manganese and the emergence of long-range ferromagnetic order. With increasing magnetic field up to 140 kOe, the magnetic ordering temperature reaches 160 K. The causes of the structural and magnetic phase separation of this composition and formation mechanism of its spin-glass magnetic state are analyzed.

Trukhanov, S. V.; Trukhanov, A. V.; Vasiliev, A. N.; Balagurov, A. M.; Szymczak, H.

2011-11-01

165

Removal of manganese ions from synthetic groundwater by oxidation using KMnO(4) and the characterization of produced MnO(2) particles.  

PubMed

The aim of this study is to investigate the conditions for the removal of manganese ions from synthetic groundwater by oxidation using KMnO(4) to keep the concentration below the allowed level (0.05?mg/L). The process includes low-level aeration and addition of KMnO(4) in a Jar test system with Mn(2?+?) concentration of 0.50?mg/L, similar to that of natural groundwater in Taiwan. Different parameters such us aeration-pH, oxidant dose, and stirring speed were studied. Aeration alone was not sufficient to remove Mn(2?+?) ions completely even when the pH was increased. When a stoichiometric amount of KMnO(4) (0.96?mg/L) was used, a complete Mn(2?+?) removal was achieved within 15?min at an optimum pH of 8.0. As the amount of KMnO(4) was doubled, lower removal efficiency was obtained because the oxidant also generated manganese ions. The removal of Mn(2?+?) ions could be completed at pH 9.0 using an oxidant dose of 0.48?mg/L because Mn(2?+?) could be sorbed onto the MnO(2) particles. Finally, The MnO(2) particles were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). PMID:20962386

Phatai, P; Wittayakun, J; Grisdanurak, N; Chen, W H; Wan, M W; Kan, C C

2010-01-01

166

FLUIDIC: Metal Air Recharged  

ScienceCinema

Fluidic, with the help of ARPA-E funding, has developed and deployed the world's first proven high cycle life metal air battery. Metal air technology, often used in smaller scale devices like hearing aids, has the lowest cost per electron of any rechargeable battery storage in existence. Deploying these batteries for grid reliability is competitive with pumped hydro installations while having the advantages of a small footprint. Fluidic's battery technology allows utilities and other end users to store intermittent energy generated from solar and wind, as well as maintain reliable electrical delivery during power outages. The batteries are manufactured in the US and currently deployed to customers in emerging markets for cell tower reliability. As they continue to add customers, they've gained experience and real world data that will soon be leveraged for US grid reliability.

Friesen, Cody

2014-04-02

167

A green and high energy density asymmetric supercapacitor based on ultrathin MnO2 nanostructures and functional mesoporous carbon nanotube electrodes  

NASA Astrophysics Data System (ADS)

A green asymmetric supercapacitor with high energy density has been developed using birnessite-type ultrathin porous MnO2 nanoflowers (UBMNFs) as positive electrode and functional mesoporous carbon nanotubes (FMCNTs) as negative electrode in 1 M Na2SO4 electrolyte. Both of the electrode materials possess excellent electrochemical performances, with high surface areas and narrow pore size distributions. More significantly, the assembled asymmetric supercapacitor with optimal mass ratio can be cycled reversibly in the high-potential range of 0-2.0 V and exhibits an excellent energy density as high as 47.4 W h kg-1, which is much higher than those of symmetric supercapacitors based on UBMNFs//UBMNFs and FMCNTs//FMCNTs supercapacitors. Furthermore, our asymmetric supercapacitor (ASC) device also exhibits a superior cycling stability with 90% retention of the initial specific capacitance after 1000 cycles and stable Coulombic efficiency of ~98%. These intriguing results exhibit great potential in developing high energy density ``green supercapacitors'' for practical applications.A green asymmetric supercapacitor with high energy density has been developed using birnessite-type ultrathin porous MnO2 nanoflowers (UBMNFs) as positive electrode and functional mesoporous carbon nanotubes (FMCNTs) as negative electrode in 1 M Na2SO4 electrolyte. Both of the electrode materials possess excellent electrochemical performances, with high surface areas and narrow pore size distributions. More significantly, the assembled asymmetric supercapacitor with optimal mass ratio can be cycled reversibly in the high-potential range of 0-2.0 V and exhibits an excellent energy density as high as 47.4 W h kg-1, which is much higher than those of symmetric supercapacitors based on UBMNFs//UBMNFs and FMCNTs//FMCNTs supercapacitors. Furthermore, our asymmetric supercapacitor (ASC) device also exhibits a superior cycling stability with 90% retention of the initial specific capacitance after 1000 cycles and stable Coulombic efficiency of ~98%. These intriguing results exhibit great potential in developing high energy density ``green supercapacitors'' for practical applications. Electronic supplementary information (ESI) available: Nitrogen adsorption and desorption isotherms, SEM image, TG and EDS curves of MnO2, EDS spectrum of FMCNTs. See DOI: 10.1039/c1nr11542a

Jiang, Hao; Li, Chunzhong; Sun, Ting; Ma, Jan

2012-01-01

168

Electrical Properties of Al2O3- and MnO2-Doped Thick Film Resistors on AlN Substrates  

NASA Astrophysics Data System (ADS)

Owing to the interaction between lead borosilicate glass and AlN, the commercial resistor pastes which were developed for Al2O3 substrates are not applicable to AlN substrates. The conventional solution is to develop alternate glass compositions such as alkaline earth borosilicate glass to optimize compatibility with the AlN substrates. In this study, an additive-doping method was adopted to solve the problem of incompatibility between AlN substrates and resistor pastes. The Al2O3 and MnO2 powders were deliberately introduced into the as-received resistor pastes, and the interaction between AlN and glass was thus reduced or avoided. With the optimal control of sintering conditions, it is possible to produce stable thick film resistors on AlN substrates with the temperature coefficient of resistance values of less than ± 100 ppm/°C.

Chen, Lih-Shan; Fu, Shen-Li; Wu, Jun-Hong

2002-05-01

169

Groundwater recharge: A hydrogeologic thought  

Microsoft Academic Search

The ensuing paper imparts vital information on an important component of the hydrologic cycle: recharge. Water flows through\\u000a the porous media and forms a definite flow pattern that can be depicted in an elaborate manner through the micro level studies\\u000a at the small watershed level. The estimation of recharge is indispensable for the groundwater budgeting studies. The advantages\\u000a and disadvantages

A. K. Taqveem

2009-01-01

170

Processing and Mechanical Properties of Cast Al (Mg, Mn)-Al2O3 (MnO2) Composites Containing Nanoparticles and Larger Particles  

NASA Astrophysics Data System (ADS)

The composites reinforced with nanoparticles result in improved strength and ductility while those containing coarser particles of micron size have limited ductility. The present study investigates the outcome of mechanical properties in a composite reinforced simultaneously with coarse and fine particles. High energy milling of manganese dioxide particles with excess of aluminum powder ensures that nanoparticles generated, either of MnO2 or alumina, are mostly separate and surrounded by aluminum particles. The milled powder when added to aluminum alloy melt, the excess aluminum particles will melt leaving behind separate oxide nanoparticles without significant agglomeration. Different amounts of milled powder mix have been stirred into molten aluminum alloy where nanoparticles of MnO2 react with melt to form alumina. The resulting slurry is cast into composites, which also contains coarser (nearly micron size) alumina particles formed by internal oxidation of the melt during processing. The microstructure of the composites shows good distribution of both the size categories of particles without significant clustering. The oxide particles are primarily ?-alumina in a matrix of aluminum-magnesium-manganese alloy containing some iron picked up from the stirrer. These composites fail during tensile test by ductile fracture due to debonding of coarser particles. The presence of nanoparticles along with coarser particles in a composite improves both strength and ductility considerably, presumably due to delay in debonding of coarser particles to higher stress because of reduced mismatch in extension caused by increased strain hardening in presence of nanoparticles in the matrix. The composites containing only coarser oxide particles show limited strength and ductility attributed to early debonding of particles at a relatively lower stress due to larger mismatch in extension between matrix and larger particles. Higher addition of powder mix beyond a limit, however, results in deterioration of mechanical properties, possibly due to clustering of nanoparticles. The present work, however, did not optimize the relative amounts of the different sized particles for achieving maximum ductility.

Ghanaraja, S.; Nath, S. K.; Ray, S.

2014-04-01

171

Chemically rechargeable battery  

NASA Technical Reports Server (NTRS)

Batteries (50) containing oxidized, discharged metal electrodes such as an iron-air battery are charged by removing and storing electrolyte in a reservoir (98), pumping fluid reductant such as formalin (aqueous formaldehyde) from a storage tank (106) into the battery in contact with the surfaces of the electrodes. After sufficient iron hydroxide has been reduced to iron, the spent reductant is drained, the electrodes rinsed with water from rinse tank (102) and then the electrolyte in the reservoir (106) is returned to the battery. The battery can be slowly electrically charged when in overnight storage but can be quickly charged in about 10 minutes by the chemical procedure of the invention.

Graf, James E. (Inventor); Rowlette, John J. (Inventor)

1984-01-01

172

Functional materials for rechargeable batteries.  

PubMed

There is an ever-growing demand for rechargeable batteries with reversible and efficient electrochemical energy storage and conversion. Rechargeable batteries cover applications in many fields, which include portable electronic consumer devices, electric vehicles, and large-scale electricity storage in smart or intelligent grids. The performance of rechargeable batteries depends essentially on the thermodynamics and kinetics of the electrochemical reactions involved in the components (i.e., the anode, cathode, electrolyte, and separator) of the cells. During the past decade, extensive efforts have been dedicated to developing advanced batteries with large capacity, high energy and power density, high safety, long cycle life, fast response, and low cost. Here, recent progress in functional materials applied in the currently prevailing rechargeable lithium-ion, nickel-metal hydride, lead acid, vanadium redox flow, and sodium-sulfur batteries is reviewed. The focus is on research activities toward the ionic, atomic, or molecular diffusion and transport; electron transfer; surface/interface structure optimization; the regulation of the electrochemical reactions; and the key materials and devices for rechargeable batteries. PMID:21394791

Cheng, Fangyi; Liang, Jing; Tao, Zhanliang; Chen, Jun

2011-04-19

173

Artificial recharge of groundwater: hydrogeology and engineering  

Microsoft Academic Search

.   Artificial recharge of groundwater is achieved by putting surface water in basins, furrows, ditches, or other facilities\\u000a where it infiltrates into the soil and moves downward to recharge aquifers. Artificial recharge is increasingly used for short-\\u000a or long-term underground storage, where it has several advantages over surface storage, and in water reuse. Artificial recharge\\u000a requires permeable surface soils. Where

Herman Bouwer

2002-01-01

174

High psedocapacitance of MnO2 nanoparticles in graphitic disordered mesoporous carbon at high scan rates  

SciTech Connect

Nanocomposites composed of MnO{sub 2} and graphitic disordered mesoporous carbon (MnO{sub 2}/C) were synthesized for high total specific capacitance and redox pseudocapacitance (C{sub MnO{sub 2}}) at high scan rates up to 200 mV s{sup -1}. High resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray spectroscopy (EDX) demonstrated that MnO{sub 2} nanodomains were highly dispersed throughout the mesoporous carbon structure. According to HRTEM and X-ray diffraction (XRD), the MnO{sub 2} domains are shown to be primarily amorphous and less than 5 nm in size. For these composites in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte, C{sub MnO{sub 2}} reached 500 F/g{sub MnO{sub 2}} at 2 mV s{sup -1} for 8.8 wt% MnO{sub 2}. A capacitance fade of only 20% over a 100-fold change in scan rate was observed for a high loading of 35 wt% MnO{sub 2} with a C{sub MnO{sub 2}} of 310 F/g{sub MnO{sub 2}} at the highest scan rate of 200 mV s{sup -1}. The high electronic conductivity of the graphitic 3D disordered mesoporous carbon support in conjunction with the thin MnO{sub 2} nanodomains facilitate rapid electron and ion transport offering the potential of improved high power density energy storage pseudocapacitors.

Dai, Sheng [ORNL; Patel, Mehul [University of Texas, Austin; Wang, Xiqing [ORNL; Slanac, Daniel A [ORNL; Ferrer, Domingo [University of Texas, Austin; Johnston, Keith [University of Texas, Austin; Stevenson, Keith J [ORNL

2012-01-01

175

High pseudocapacitance of MnO2 nanoparticles in graphitic disordered mesoporous carbon at high scan rates  

SciTech Connect

Nanocomposites composed of MnO{sub 2} and graphitic disordered mesoporous carbon (MnO{sub 2}/C) were synthesized for high total specific capacitance and redox pseudocapacitance (C{sub MnO{sub 2}}) at high scan rates up to 200 mV s{sup -1}. High resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray spectroscopy (EDX) demonstrated that MnO{sub 2} nanodomains were highly dispersed throughout the mesoporous carbon structure. According to HRTEM and X-ray diffraction (XRD), the MnO{sub 2} domains are shown to be primarily amorphous and less than 5 nm in size. For these composites in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte, C{sub MnO{sub 2}} reached 500 F/g{sub MnO{sub 2}} at 2 mV s{sup -1} for 8.8 wt% MnO{sub 2}. A capacitance fade of only 20% over a 100-fold change in scan rate was observed for a high loading of 35 wt% MnO{sub 2} with a C{sub MnO{sub 2}} of 310 F/g{sub MnO{sub 2}} at the highest scan rate of 200 mV s{sup -1}. The high electronic conductivity of the graphitic 3D disordered mesoporous carbon support in conjunction with the thin MnO{sub 2} nanodomains facilitate rapid electron and ion transport offering the potential of improved high power density energy storage pseudocapacitors.

Dai, Sheng [ORNL; Patel, Mehul [University of Texas, Austin; Wang, Xiqing [ORNL; Slanac, Daniel A [ORNL; Ferrer, Domingo [University of Texas, Austin; Johnston, Keith [University of Texas, Austin

2012-01-01

176

Rechargeable nickel-zinc batteries  

NASA Technical Reports Server (NTRS)

Device proves superiority in having two and one half to three times the energy content of popular lead-zinc or nickel-cadmium batteries. Application to electric utility vehicles improved acceleration rate and nearly doubled driving range between rechargings. Unit contributes substantially toward realization of practical urban electrical automobiles.

Soltis, D. G.

1977-01-01

177

High energy lithium rechargeable cells  

Microsoft Academic Search

Methyl formate solutions are noted to be attractive in rechargeable Li cell applications due to their high conductivities and outstanding electrochemical stability; their primary limitation has been their inability to efficiently cycle Li. By doping methyl formate solutions with CO2, however, Li cycling efficiencies of the order of 98 percent have been achieved. A combination of transition metal oxide insertion-type

Walter B. Ebner; John A. Simmons; David L. Chua

1988-01-01

178

A possible evolutionary origin for the Mn4 cluster of the photosynthetic water oxidation complex from natural MnO2 precipitates in the early ocean  

PubMed Central

The photosynthetic water oxidation complex consists of a cluster of four Mn atoms bridged by O atoms, associated with Ca2+ and Cl?, and incorporated into protein. The structure is similar in higher plants and algae, as well as in cyanobacteria of more ancient lineage, dating back more than 2.5 billion years ago on Earth. It has been proposed that the proto-enzyme derived from a component of a natural early marine manganese precipitate that contained a CaMn4O9 cluster. A variety of MnO2 minerals are found in nature. Three major classes are spinels, sheet-like layered structures, and three-dimensional networks that contain parallel tunnels. These relatively open structures readily incorporate cations (Na+, Li+, Mg2+, Ca2+, Ba2+, H+, and even Mn2+) and water. The minerals have different ratios of Mn(III) and Mn(IV) octahedrally coordinated to oxygens. Using x-ray spectroscopy we compare the chemical structures of Mn in the minerals with what is known about the arrangement in the water oxidation complex to define the parameters of a structural model for the photosynthetic catalytic site. This comparison provides for the structural model a set of candidate Mn4 clusters—some previously proposed and considered and others entirely novel.

Sauer, Kenneth; Yachandra, Vittal K.

2002-01-01

179

A green and high energy density asymmetric supercapacitor based on ultrathin MnO2 nanostructures and functional mesoporous carbon nanotube electrodes.  

PubMed

A green asymmetric supercapacitor with high energy density has been developed using birnessite-type ultrathin porous MnO(2) nanoflowers (UBMNFs) as positive electrode and functional mesoporous carbon nanotubes (FMCNTs) as negative electrode in 1 M Na(2)SO(4) electrolyte. Both of the electrode materials possess excellent electrochemical performances, with high surface areas and narrow pore size distributions. More significantly, the assembled asymmetric supercapacitor with optimal mass ratio can be cycled reversibly in the high-potential range of 0-2.0 V and exhibits an excellent energy density as high as 47.4 W h kg(-1), which is much higher than those of symmetric supercapacitors based on UBMNFs//UBMNFs and FMCNTs//FMCNTs supercapacitors. Furthermore, our asymmetric supercapacitor (ASC) device also exhibits a superior cycling stability with 90% retention of the initial specific capacitance after 1000 cycles and stable Coulombic efficiency of ~98%. These intriguing results exhibit great potential in developing high energy density "green supercapacitors" for practical applications. PMID:22159343

Jiang, Hao; Li, Chunzhong; Sun, Ting; Ma, Jan

2012-02-01

180

Direct visualization of the Jahn–Teller effect coupled to Na ordering in Na5/8MnO2  

NASA Astrophysics Data System (ADS)

The cooperative Jahn–Teller effect (CJTE) refers to the correlation of distortions arising from individual Jahn–Teller centres in complex compounds. The effect usually induces strong coupling between the static or dynamic charge, orbital and magnetic ordering, which has been related to many important phenomena such as colossal magnetoresistance and superconductivity. Here we report a Na5/8MnO2 superstructure with a pronounced static CJTE that is coupled to an unusual Na vacancy ordering. We visualize this coupled distortion and Na ordering down to the atomic scale. The Mn planes are periodically distorted by a charge modulation on the Mn stripes, which in turn drives an unusually large displacement of some Na ions through long-ranged Na–O–Mn3+–O–Na interactions into a highly distorted octahedral site. At lower temperatures, magnetic order appears, in which Mn atomic stripes with different magnetic couplings are interwoven with each other. Our work demonstrates the strong interaction between alkali ordering, displacement, and electronic and magnetic structure, and underlines the important role that structural details play in determining electronic behaviour.

Li, Xin; Ma, Xiaohua; Su, Dong; Liu, Lei; Chisnell, Robin; Ong, Shyue Ping; Chen, Hailong; Toumar, Alexandra; Idrobo, Juan-Carlos; Lei, Yuechuan; Bai, Jianming; Wang, Feng; Lynn, Jeffrey W.; Lee, Young S.; Ceder, Gerbrand

2014-06-01

181

A possible evolutionary origin for the Mn4 cluster of the photosynthetic water oxidation complex from natural MnO2 precipitates in the early ocean  

SciTech Connect

The photosynthetic water oxidation complex consists of a cluster of 4 Mn atoms bridged by O atoms, associated with Ca2+ and Cl- and incorporated into protein. The structure is similar in higher plants and algae, as well as in cyanobacteria of more ancient lineage, dating back more than 2.5 Ga on Earth. It has been proposed that the proto-enzyme derived from a component of a natural early marine manganese precipitate that contained a CaMn4O9 cluster. A variety of MnO2 minerals is found in nature. Three major classes are spinels, sheet-like layered structures and 3-dimensional networks that contain parallel tunnels. These relatively open structures readily incorporate cations (Na+, Li+, Mg2+, Ca2+, Ba2+, H+ and even Mn2+) and water. The minerals have different ratios of Mn(III) and Mn(IV) octahedrally coordinated to oxygens. Using X-ray spectroscopy we compare the chemical structures of Mn in the minerals with what is known about the arrangement in the water-oxidation complex to define the parameters of a structural model for the photosynthetic catalytic site. This comparison provides for the structural model a set of candidate Mn4 clusters -- some previously proposed and considered and others entirely novel.

Sauer, Kenneth; Yachandra, Vittal K.

2002-04-30

182

Direct visualization of the Jahn-Teller effect coupled to Na ordering in Na5/8MnO2.  

PubMed

The cooperative Jahn-Teller effect (CJTE) refers to the correlation of distortions arising from individual Jahn-Teller centres in complex compounds. The effect usually induces strong coupling between the static or dynamic charge, orbital and magnetic ordering, which has been related to many important phenomena such as colossal magnetoresistance and superconductivity. Here we report a Na5/8MnO2 superstructure with a pronounced static CJTE that is coupled to an unusual Na vacancy ordering. We visualize this coupled distortion and Na ordering down to the atomic scale. The Mn planes are periodically distorted by a charge modulation on the Mn stripes, which in turn drives an unusually large displacement of some Na ions through long-ranged Na-O-Mn(3+)-O-Na interactions into a highly distorted octahedral site. At lower temperatures, magnetic order appears, in which Mn atomic stripes with different magnetic couplings are interwoven with each other. Our work demonstrates the strong interaction between alkali ordering, displacement, and electronic and magnetic structure, and underlines the important role that structural details play in determining electronic behaviour. PMID:24836735

Li, Xin; Ma, Xiaohua; Su, Dong; Liu, Lei; Chisnell, Robin; Ong, Shyue Ping; Chen, Hailong; Toumar, Alexandra; Idrobo, Juan-Carlos; Lei, Yuechuan; Bai, Jianming; Wang, Feng; Lynn, Jeffrey W; Lee, Young S; Ceder, Gerbrand

2014-06-01

183

High energy lithium rechargeable cells  

NASA Astrophysics Data System (ADS)

Methyl formate solutions are noted to be attractive in rechargeable Li cell applications due to their high conductivities and outstanding electrochemical stability; their primary limitation has been their inability to efficiently cycle Li. By doping methyl formate solutions with CO2, however, Li cycling efficiencies of the order of 98 percent have been achieved. A combination of transition metal oxide insertion-type cathode materials with the methyl formate electrolyte solutions and advanced cathode processing techniques, two promising rechargeable Li technologies have been defined: Li/V2O5, which has demonstrated 250 discharge cycles with little degradation in capacity, and Li/Li(x)CoO2, with excellent low temperature performance.

Ebner, Walter B.; Simmons, John A.; Chua, David L.

184

Survey of rechargeable battery technology  

SciTech Connect

We have reviewed rechargeable battery technology options for a specialized application in unmanned high altitude aircraft. Consideration was given to all rechargeable battery technologies that are available commercially or might be available in the foreseeable future. The LLNL application was found to impose very demanding performance requirements which cannot be met by existing commercially available battery technologies. The most demanding requirement is for high energy density. The technology that comes closest to providing the LLNL requirements is silver-zinc, although the technology exhibits significant shortfalls in energy density, charge rate capability and cyclability. There is no battery technology available ``off-the-shelf` today that can satisfy the LLNL performance requirements. All rechargeable battery technologies with the possibility of approaching/meeting the energy density requirements were reviewed. Vendor interviews were carried out for all relevant technologies. A large number of rechargeable battery systems have been developed over the years, though a much smaller number have achieved commercial success and general availability. The theoretical energy densities for these systems are summarized. It should be noted that a generally useful ``rule-of-thumb`` is that the ratio of packaged to theoretical energy density has proven to be less than 30%, and generally less than 25%. Data developed for this project confirm the usefulness of the general rule. However, data shown for the silver-zinc (AgZn) system show a greater conversion of theoretical to practical energy density than would be expected due to the very large cell sizes considered and the unusually high density of the active materials.

Not Available

1993-07-01

185

Intercalation dynamics in rechargeable batteries  

NASA Astrophysics Data System (ADS)

We consider the ion intercalation of rechargeable battery electrode particles during charging (or discharging). We have developed a general phase-field model which incorporates entropic, enthalpic and elastic effects within the particle as well as the nonlinear chemical reactions at the particle- electrolyte interface. It is shown through linear stability analysis and numerical simulations that particle size and elastic effects will decrease or even eliminate both the spinodal region and the miscibility gap in the phase diagram.

Stanton, Liam; Bazant, Martin

2009-03-01

186

Rechargeable lithium battery technology - A survey  

NASA Technical Reports Server (NTRS)

The technology of the rechargeable lithium battery is discussed with special attention given to the types of rechargeable lithium cells and to their expected performance and advantages. Consideration is also given to the organic-electrolyte and polymeric-electrolyte cells and to molten salt lithium cells, as well as to technical issues, such as the cycle life, charge control, rate capability, cell size, and safety. The role of the rechargeable lithium cell in future NASA applications is discussed.

Halpert, Gerald; Surampudi, Subbarao

1990-01-01

187

Choosing appropriate techniques for quantifying groundwater recharge  

Microsoft Academic Search

.   Various techniques are available to quantify recharge; however, choosing appropriate techniques is often difficult. Important\\u000a considerations in choosing a technique include space\\/time scales, range, and reliability of recharge estimates based on different\\u000a techniques; other factors may limit the application of particular techniques. The goal of the recharge study is important\\u000a because it may dictate the required space\\/time scales of

Bridget R. Scanlon; Richard W. Healy; Peter G. Cook

2002-01-01

188

Fabrication of Polypyrrole/Graphene Oxide Composite Nanosheets and Their Applications for Cr(VI) Removal in Aqueous Solution  

PubMed Central

In this paper, we report on the simple, reliable synthesis of polypyrrole (PPy)/graphene oxide (GO) composite nanosheets by using sacrificial-template polymerization method. Herein, MnO2 nanoslices were chosen as a sacrificial-template to deposit PPy, which served as the oxidant as well. During the polymerization of pyrrole on surface of GO nanosheets, MnO2 component was consumed incessantly. As a result, the PPy growing on the surface of GO nanosheets has the morphology just like the MnO2 nanoslices. This method can provide the fabrication of PPy nanostructures more easily than conventional route due to its independence of removing template, which usually is a complex and tedious experimental process. The as-prepared PPy/GO composite nanosheets exhibited an enhanced properties for Cr(VI) ions removal in aqueous solution based on the synergy effect. The adsorption capacity of the PPy/GO composite nanosheets is about two times as large as that of conventional PPy nanoparticles. We believe that our findings can open a new and effective avenue to improve the adsorption performance in removing heavy metal ions from waste water.

Li, Shangkun; Lu, Xiaofeng; Xue, Yanpeng; Lei, Junyu; Zheng, Tian; Wang, Ce

2012-01-01

189

Synthesis, composition, and structure of sillenite-type solid solutions in the Bi2O3-SiO2-MnO2 system.  

PubMed

Individual compounds and solid solutions are obtained under hydrothermal conditions in the Bi(2)O(3)-SiO(2)-MnO(2) system in the form of faceted crystals and epitaxial films on the Bi(24)Si(2)O(40) substrate. The crystals have the shape of a cube (for the molar ratio of the starting components Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O > 1), a tetrahedron (for Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O < 1), or a tetrahedron-cube combination (for Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O = 1). Crystal-chemical analysis based on the data of single-crystal and powder X-ray diffraction, IR spectra, and the results of calculation of the local balance by the bond-valence method reveals formation of the Bi(24)(Si(4+),Mn(4+))(2)O(40) phases, which probably include Mn(5+) ions (epitaxial films), as well as the Bi(24)(Si(4+),Bi(3+),Mn(4+))(2)O(40) and Bi(24)(Si(4+),Mn(4+))(2)O(40) phases in the (1 - x)Bi(3+)(24)Si(4+)(2)O(40) - x(Bi(3+)(24)Mn(4+)(2)O(40)) system and the Bi(24)(Bi(3+),Mn(4+))(2)O(40) phase in the (1 - x)Bi(3+)(24)Bi(3+)(2)(O(39)?(1)) - x(Bi(3+)(24)Mn(4+)(2)O(40)) system. Precision X-ray diffraction studies of single crystals of the Bi(24)(Bi,Si,Mn)(2)O(40) general composition show that these sillenites crystallize in space group P23 and not I23 as the Bi(24)Si(2)O(40) phase. The dissymmetrization of sillenite phases is observed for the first time. It is explained by a kinetic (growth) phase transition of the order-disorder type due to population of a crystallographic site by atoms with different crystal-chemical properties and quasi-equilibrium conditions of crystal growth in the course of a hydrothermal synthesis below 400 °C at unequal molar amounts of the starting components in the batch. PMID:21319771

Mel'nikova, Tatyana I; Kuz'micheva, Galina M; Rybakov, Victor B; Bolotina, Nadezhda B; Dubovsky, Alexander B

2011-03-01

190

Oxidative degradation of dipeptide (glycyl-glycine) by water-soluble colloidal manganese dioxide in the aqueous and micellar media.  

PubMed

The kinetics of the oxidative degradation of dipeptide glycyl-glycine (Gly-Gly) by water-soluble colloidal MnO(2) in acidic medium has been studied by employing visible spectrophotometer in the aqueous and micellar media at 35°C. To obtain the rate constants as functions of [Gly-Gly], [MnO(2)] and [HClO(4)], pseudo-first-order conditions were maintained in each kinetic run. The first-order-rate is observed with respect to [MnO(2)], whereas fractional-order-rates are determined in both [Gly-Gly] and [HClO(4)]. The addition of sodium pyrophosphate and sodium fluoride has composite effects (catalytic and inhibition). The reaction proceeds through the fast adsorption of Gly-Gly on the surface of the colloidal MnO(2). The observed results are discussed in terms of Michaelis-Menten/Langmuir-Hinshelwood model. The Arrhenius and Eyring equations are found valid for the reaction over a range of temperatures and different activation parameters have been evaluated. A probable reaction mechanism, in agreement with the observed kinetic results, has been proposed and discussed. The influence of changes in the surfactant concentrations on the observed rate constant is also investigated and the reaction followed the same type of kinetic behavior in micellar media. The pseudo-first-order rate constant (k(?)) is found to increase about two-fold with increase in [TX-100]. The catalytic effect of nonionic surfactant TX-100 is explained in terms of the mathematical model proposed by Tuncay et al. PMID:20870395

Akram, Mohd; Altaf, Mohammad; Kabir-ud-Din

2011-01-01

191

NORTH CAROLINA GROUNDWATER RECHARGE RATES 1994  

EPA Science Inventory

North Carolina Groundwater Recharge Rates, from Heath, R.C., 1994, Ground-water recharge in North Carolina: North Carolina State University, as prepared for the NC Department of Environment, Health and Natural Resources (NC DEHNR) Division of Enviromental Management Groundwater S...

192

Reflections on Dry-Zone Recharge  

NASA Astrophysics Data System (ADS)

Quantifying recharge in regions of low precipitation remains a challenging task. The design of permanent nuclear-waste isolation at Yucca Mountain, Nevada, the design of arid-site landfill covers and the pumping of groundwater in desert cities, like Las Vegas, are examples where accurate recharge estimates are needed because they affect billion-dollar decisions. Recharge cannot be measured directly and must rely on estimation methods of various kinds including chemical tracers, thermal profiling, lysimetry, and water-balance modeling. Chemical methods, like chloride-mass-balance can significantly underestimate actual recharge rates and water-balance models are generally limited by large uncertainties. Studies at the U. S. Department of Energy's Hanford Site in Washington State, USA illustrate how estimates of recharge rates have changed over time and how these estimates can affect waste management decisions. Lysimetry has provided reliable estimates of recharge for a wide range of surface condittions. Lysimetric observations of reduced recharge, resulting from advective drying of coarse rock piles, suggest a way to avoid costly recharge protection using titanium shields at Yucca Mountain. The Pacific Northwest National Laboratory is funded by the U. S. Department of Energy under contract DE-AC05-76-RL01830.

Gee, G. W.

2005-05-01

193

Transformer Recharging with Alpha Channeling in Tokamaks  

SciTech Connect

Transformer recharging with lower hybrid waves in tokamaks can give low average auxiliary power if the resistivity is kept high enough during the radio frequency (rf) recharging stage. At the same time, operation in the hot ion mode via alpha channeling increases the effective fusion reactivity. This paper will address the extent to which these two large cost saving steps are compatible. __________________________________________________

N.J. Fisch

2009-12-21

194

Improved Carbon Anodes For Rechargeable Lithium Cells  

NASA Technical Reports Server (NTRS)

Carbon anodes for rechargeable lithium cells improved by choosing binder contents and fabrication conditions to achieve maximum porosity, uniform loading, and maximum reversible lithium capacity. Stacking electrodes under pressure during assembly of cells increases cyclability of lithium. Rechargeable, high-energy-density lithium cells containing improved carbon anodes find use in spacecraft, military, communications, automotive, and other demanding applications.

Huang, Chen-Kuo; Surampudi, Subbarao; Attia, Alan; Halpert, Gerald

1994-01-01

195

Lithium Cells Accept Hundreds Of Recharges  

NASA Technical Reports Server (NTRS)

New mixed-solvent electrolyte increases number of times room-temperature lithium cell discharged and recharged. Conductivity 70 percent higher. Useful in such other room-temperature rechargeable lithium cells as lithium/niobium triselenide and lithium molybdenum disulfide systems.

Shen, David H.; Surampudi, Subbarao; Deligiannis, Fotios; Halpert, Gerald

1991-01-01

196

High-efficient treatment of wastewater contained the carcinogen naphthylamine by electrochemical oxidation with ?-Al2O3 supported MnO2 and Sb-doped SnO2 catalyst.  

PubMed

1-Naphthylamine wastewater causes severe environmental pollution because of its acute toxicity and carcinogenicity in humans, which makes it difficult to reuse by conventional technologies. In this study, we report an investigation of the electrochemical catalytic oxidation of 1-naphthylamine in synthetic wastewater in a 150 mL electrolytic batch reactor with Ti/Sb-SnO(2)/PbO(2) as anode and steel plate as cathode, where the reaction was assisted by MnO(2) and Sn(1-x)Sb(x)O(2) composite materials as the catalyst and ?-Al(2)O(3) as the carrier (MnO(2)-Sn(1-x)Sb(x)O(2)/?-Al(2)O(3)). The catalyst was synthesized by impregnating process and was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The effects of pH and current density on the efficiency of the electrochemical degradation process were also studied. It was found that MnO(2)-Sn(1-x)Sb(x)O(2)/?-Al(2)O(3) exhibited excellent catalytic activity in the electrochemical degradation of 1-naphthylamine wastewater. The results showed that the refractory organics in wastewater can be effectively removed by this process, and a chemical oxygen demand (COD) removal efficiency of 92.2% was obtained in 20 min at pH 7.0 and current density was equal to 50 mA cm(-2). According to the experimental results, a hypothetical mechanism of electrochemical catalytic degradation was also proposed. PMID:22652320

Chen, Fengtao; Yu, Sanchuan; Dong, Xiaoping; Zhang, Shishen

2012-08-15

197

Estimation of emission from an LNAPL contaminated zone considering groundwater recharge  

NASA Astrophysics Data System (ADS)

The aim of this work was to develop an easy to handle semi-analytical method to estimate the temporal development of emission from a multi-component LNAPL pool considering groundwater recharge. The presented approach allows the estimation of the total mass flux out of an LNAPL pool into the gas and the water phase, the latter including the mass fluxes from groundwater recharge, advection through and diffusion out of the LNAPL zone. Therefore, the known set of constitutive relationships to determine fluid saturation profiles of 2- and 3-phase systems is extended in this work to account for dynamic conditions due to groundwater recharge. The methodology is applied to a kerosene pool at a former military airfield and it is found that the mass flux due to groundwater recharge dominates the aqueous mass flux from the kerosene contaminated zone. A sensitivity study using field parameters shows, that the apparent kerosene thicknesses observed in monitoring wells and the lithology control mass flux into the gas phase, whereas the mass flux into groundwater mainly depends on the groundwater recharge rate. For the kerosene found at the site, source emission into the soil gas is estimated to last longer than the emission into groundwater, the latter varying between less than 100 and 400 years.

Peter, A.; Miles, B.; Teutsch, G.

2008-07-01

198

Rechargeable lithium-ion cell  

DOEpatents

The invention relates to a rechargeable lithium-ion cell, a method for its manufacture, and its application. The cell is distinguished by the fact that it has a metallic housing (21) which is electrically insulated internally by two half shells (15), which cover electrode plates (8) and main output tabs (7) and are composed of a non-conductive material, where the metallic housing is electrically insulated externally by means of an insulation coating. The cell also has a bursting membrane (4) which, in its normal position, is located above the electrolyte level of the cell (1). In addition, the cell has a twisting protection (6) which extends over the entire surface of the cover (2) and provides centering and assembly functions for the electrode package, which comprises the electrode plates (8).

Bechtold, Dieter (Bad Vilbel, DE); Bartke, Dietrich (Kelkheim, DE); Kramer, Peter (Konigstein, DE); Kretzschmar, Reiner (Kelkheim, DE); Vollbert, Jurgen (Hattersheim, DE)

1999-01-01

199

Lithium ion rechargeable systems studies  

SciTech Connect

Lithium ion systems, although relatively new, have attracted much interest worldwide. Their high energy density, long cycle life and relative safety, compared with metallic lithium rechargeable systems, make them prime candidates for powering portable electronic equipment. Although lithium ion cells are presently used in a few consumer devices, e.g., portable phones, camcorders, and laptop computers, there is room for considerable improvement in their performance. Specific areas that need to be addressed include: (1) carbon anode--increase reversible capacity, and minimize passivation; (2) cathode--extend cycle life, improve rate capability, and increase capacity. There are several programs ongoing at Sandia National Laboratories which are investigating means of achieving the stated objectives in these specific areas. This paper will review these programs.

Levy, S.C.; Lasasse, R.R.; Cygan, R.T.; Voigt, J.A.

1995-02-01

200

Lithium-ion rechargeable cells with LiCoO2 and carbon electrodes  

Microsoft Academic Search

Cathodes composed of layered transition metal oxides LiMO2 (M = Co, Ni) and spinel manganese oxide LiMn2O4, carbon anodes, and non aqueous electrolyte solutions have been investigated with the aim of achieving higher energy density. The lithium-ion rechargeable cell using the LiCoO2 cathode and the propylene carbonate(PC)-d iethyl carbonate (DEC)\\/LiPF6) electrolyte solution exhibits excellent characteristics. Furthermore, non-graphitizable carbon such as

K. Sekai; H. Azuma; A. Omaru; S. Fujita; H. Imoto; T. Endo; K. Yamaura; Y. Nishi; S. Mashiko; M. Yokogawa

1993-01-01

201

New Mechanically Rechargeable Zinc-Air Batteries.  

National Technical Information Service (NTIS)

This report describes the design, development and testing of new mechanically rechargeable zinc-air batteries. Following research and development of a low cost silver-mercury cathode catalyst, prototype battery tests were conducted. Cycle life tests at 3....

J. Giltner

1975-01-01

202

REVISED NORTH CAROLINA GROUNDWATER RECHARGE RATES 1998  

EPA Science Inventory

Revised North Carolina Groundwater Recharge Rates, from Heath, R.C., 1994, unpublished map: North Carolina State University, as modified by the NC Department of Environment and Natural Resources (DENR) Division of Water Quality (DWQ) Groundwater Section, (polygons)...

203

Issues and challenges facing rechargeable lithium batteries  

Microsoft Academic Search

Technological improvements in rechargeable solid-state batteries are being driven by an ever-increasing demand for portable electronic devices. Lithium-ion batteries are the systems of choice, offering high energy density, flexible and lightweight design, and longer lifespan than comparable battery technologies. We present a brief historical review of the development of lithium-based rechargeable batteries, highlight ongoing research strategies, and discuss the challenges

J.-M. Tarascon; M. Armand

2001-01-01

204

Lithium rechargeable cell with a polymer cathode  

Microsoft Academic Search

Thin films of electropolymerized poly 3-methylthiophene (PMT) were used as a rechargeable cathode in Li(SO2)3AlCl4 electrolyte. Capacity was superior to porous carbon electrodes of like thickness. Pulse power levels of 2 W cm-2 were achieved, and high rate constant current pulses of four-second duration were reproducible over cycles. Cells could be recharged at potentials below 4.0 V, minimizing the formation

Charles W. Walker Jr.

1991-01-01

205

Proposed artificial recharge studies in northern Qatar  

USGS Publications Warehouse

The aquifer system in northern Qatar comprises a water-table aquifer in the Rus Formation which is separated by an aquitard from a partially confined aquifer in the top of the overlying Umm er Radhuma Formation. These two aquifers are composed of limestone and dolomite of Eocene and Paleocene age and contain a fragile lens of freshwater which is heavily exploited as a source of water for agricultural irrigation. Net withdrawals are greatly in excess of total recharge, and quality of ground water is declining. Use of desalinated seawater for artificial recharge has been proposed for the area. Artificial recharge, on a large scale, could stabilize the decline in ground-water quality while allowing increased withdrawals for irrigation. The proposal appears technically feasible. Recharge should be by injection to the Umm er Radhuma aquifer whose average transmissivity is about 2,000 meters squared per day (as compared to an average of about 200 meters squared per day for the Rus aquifer). Implementation of artificial recharge should be preceded by a hydrogeologic appraisal. These studies should include test drilling, conventional aquifer tests, and recharge-recovery tests at four sites in northern Qatar. (USGS)

Kimrey, J. O.

1985-01-01

206

The Li-ion rechargeable battery: a perspective.  

PubMed

Each cell of a battery stores electrical energy as chemical energy in two electrodes, a reductant (anode) and an oxidant (cathode), separated by an electrolyte that transfers the ionic component of the chemical reaction inside the cell and forces the electronic component outside the battery. The output on discharge is an external electronic current I at a voltage V for a time ?t. The chemical reaction of a rechargeable battery must be reversible on the application of a charging I and V. Critical parameters of a rechargeable battery are safety, density of energy that can be stored at a specific power input and retrieved at a specific power output, cycle and shelf life, storage efficiency, and cost of fabrication. Conventional ambient-temperature rechargeable batteries have solid electrodes and a liquid electrolyte. The positive electrode (cathode) consists of a host framework into which the mobile (working) cation is inserted reversibly over a finite solid-solution range. The solid-solution range, which is reduced at higher current by the rate of transfer of the working ion across electrode/electrolyte interfaces and within a host, limits the amount of charge per electrode formula unit that can be transferred over the time ?t = ?t(I). Moreover, the difference between energies of the LUMO and the HOMO of the electrolyte, i.e., electrolyte window, determines the maximum voltage for a long shelf and cycle life. The maximum stable voltage with an aqueous electrolyte is 1.5 V; the Li-ion rechargeable battery uses an organic electrolyte with a larger window, which increase the density of stored energy for a given ?t. Anode or cathode electrochemical potentials outside the electrolyte window can increase V, but they require formation of a passivating surface layer that must be permeable to Li(+) and capable of adapting rapidly to the changing electrode surface area as the electrode changes volume during cycling. A passivating surface layer adds to the impedance of the Li(+) transfer across the electrode/electrolyte interface and lowers the cycle life of a battery cell. Moreover, formation of a passivation layer on the anode robs Li from the cathode irreversibly on an initial charge, further lowering the reversible ?t. These problems plus the cost of quality control of manufacturing plague development of Li-ion rechargeable batteries that can compete with the internal combustion engine for powering electric cars and that can provide the needed low-cost storage of electrical energy generated by renewable wind and/or solar energy. Chemists are contributing to incremental improvements of the conventional strategy by investigating and controlling electrode passivation layers, improving the rate of Li(+) transfer across electrode/electrolyte interfaces, identifying electrolytes with larger windows while retaining a Li(+) conductivity ?(Li) > 10(-3) S cm(-1), synthesizing electrode morphologies that reduce the size of the active particles while pinning them on current collectors of large surface area accessible by the electrolyte, lowering the cost of cell fabrication, designing displacement-reaction anodes of higher capacity that allow a safe, fast charge, and designing alternative cathode hosts. However, new strategies are needed for batteries that go beyond powering hand-held devices, such as using electrode hosts with two-electron redox centers; replacing the cathode hosts by materials that undergo displacement reactions (e.g. sulfur) by liquid cathodes that may contain flow-through redox molecules, or by catalysts for air cathodes; and developing a Li(+) solid electrolyte separator membrane that allows an organic and aqueous liquid electrolyte on the anode and cathode sides, respectively. Opportunities exist for the chemist to bring together oxide and polymer or graphene chemistry in imaginative morphologies. PMID:23294028

Goodenough, John B; Park, Kyu-Sung

2013-01-30

207

Anodes for rechargeable lithium batteries  

DOEpatents

A negative electrode (12) for a non-aqueous electrochemical cell (10) with an intermetallic host structure containing two or more elements selected from the metal elements and silicon, capable of accommodating lithium within its crystallographic host structure such that when the host structure is lithiated it transforms to a lithiated zinc-blende-type structure. Both active elements (alloying with lithium) and inactive elements (non-alloying with lithium) are disclosed. Electrochemical cells and batteries as well as methods of making the negative electrode are disclosed.

Thackeray, Michael M. (Naperville, IL); Kepler, Keith D. (Mountain View, CA); Vaughey, John T. (Elmhurst, IL)

2003-01-01

208

Estimated recharge rates at the Hanford Site  

SciTech Connect

The Ground-Water Surveillance Project monitors the distribution of contaminants in ground water at the Hanford Site for the U.S. Department of Energy. A subtask called {open_quotes}Water Budget at Hanford{close_quotes} was initiated in FY 1994. The objective of this subtask was to produce a defensible map of estimated recharge rates across the Hanford Site. Methods that have been used to estimate recharge rates at the Hanford Site include measurements (of drainage, water contents, and tracers) and computer modeling. For the simulations of 12 soil-vegetation combinations, the annual rates varied from 0.05 mm/yr for the Ephrata sandy loam with bunchgrass to 85.2 mm/yr for the same soil without vegetation. Water content data from the Grass Site in the 300 Area indicated that annual rates varied from 3.0 to 143.5 mm/yr during an 8-year period. The annual volume of estimated recharge was calculated to be 8.47 {times} 10{sup 9} L for the potential future Hanford Site (i.e., the portion of the current Site bounded by Highway 240 and the Columbia River). This total volume is similar to earlier estimates of natural recharge and is 2 to 10x higher than estimates of runoff and ground-water flow from higher elevations. Not only is the volume of natural recharge significant in comparison to other ground-water inputs, the distribution of estimated recharge is highly skewed to the disturbed sandy soils (i.e., the 200 Areas, where most contaminants originate). The lack of good estimates of the means and variances of the supporting data (i.e., the soil map, the vegetation/land use map, the model parameters) translates into large uncertainties in the recharge estimates. When combined, the significant quantity of estimated recharge, its high sensitivity to disturbance, and the unquantified uncertainty of the data and model parameters suggest that the defensibility of the recharge estimates should be improved.

Fayer, M.J.; Walters, T.B.

1995-02-01

209

Transient, spatially varied groundwater recharge modeling  

NASA Astrophysics Data System (ADS)

The objective of this work is to integrate field data and modeling tools in producing temporally and spatially varying groundwater recharge in a pilot watershed in North Okanagan, Canada. The recharge modeling is undertaken by using the Richards equation based finite element code (HYDRUS-1D), ArcGIS™, ROSETTA, in situ observations of soil temperature and soil moisture, and a long-term gridded climate data. The public version of HYDUS-1D and another version with detailed freezing and thawing module are first used to simulate soil temperature, snow pack, and soil moisture over a one year experimental period. Statistical analysis of the results show both versions of HYDRUS-1D reproduce observed variables to the same degree. After evaluating model performance using field data and ROSETTA derived soil hydraulic parameters, the HYDRUS-1D code is coupled with ArcGIS™ to produce spatially and temporally varying recharge maps throughout the Deep Creek watershed. Temporal and spatial analysis of 25 years daily recharge results at various representative points across the study watershed reveal significant temporal and spatial variations; average recharge estimated at 77.8 ± 50.8 mm/year. Previous studies in the Okanagan Basin used Hydrologic Evaluation of Landfill Performance without any attempt of model performance evaluation, notwithstanding its inherent limitations. Thus, climate change impact results from this previous study and similar others, such as Jyrkama and Sykes (2007), need to be interpreted with caution.

Assefa, Kibreab Amare; Woodbury, Allan D.

2013-08-01

210

Rechargeable lithium thin film cells with inorganic electrolytes  

Microsoft Academic Search

A possibility of the lithium vanadium silicate film for the use of lithium cells is studied by making cells with WO3 ? x, MnO2 ?x and MoO3 ? x cathode thin films. The solid electrolyte of lithium vanadium silicate is deposited on the cathode film, followed by lithium deposition on the electrolyte by vacuum evaporation. The stable capacities of WO3

Jun-ichi Yamaki; Hideaki Ohtsuka; Takahisa Shodai

1996-01-01

211

All Inorganic Ambient Temperature Rechargeable Lithium Battery: Final Report.  

National Technical Information Service (NTIS)

Having the advantages of high energy density and good charge retention, rechargeable lithium batteries have been of interest to many companies and research organizations within the last 15 years. Various lithium rechargeable systems with different positiv...

H. C. Kuo A. N. Dey C. Schlaikjer D. Foster M. Kallianidis

1987-01-01

212

REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures  

National Institute of Standards and Technology Data Gateway

SRD 73 NIST REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures (PC database for purchase)   REFLEAK estimates composition changes of zeotropic mixtures in leak and recharge processes.

213

Electrolyte Additive for Lithium Rechargeable Organic Electrolyte Battery.  

National Technical Information Service (NTIS)

The invention relates in general to a rechargeable lithium organic electrolyte battery and, in particular, to an electrolyte additive for such a battery that provides overcharge protection. Rechargeable lithium-organic electrolyte batteries are being deve...

W. K. Behl D. T. Chin

1988-01-01

214

Solar recharging system for hearing aid cells.  

PubMed

We present a solar recharging system for nickel-cadmium cells of interest in areas where batteries for hearing aids are difficult to obtain. The charger has sun cells at the top. Luminous energy is converted into electrical energy, during the day and also at night if there is moonlight. The cost of the charger and hearing aid is very low at 35 US$. The use of solar recharging for hearing aids would be useful in alleviating the problems of deafness in parts of developing countries where there is no electricity. PMID:7964140

Gòmez Estancona, N; Tena, A G; Torca, J; Urruticoechea, L; Muñiz, L; Aristimuño, D; Unanue, J M; Torca, J; Urruticoechea, A

1994-09-01

215

Lithium-manganese oxide rechargeable battery  

SciTech Connect

A new type of rechargeable battery in which lithium ions shuttle between a lithium-manganese oxide electrode and a carbon electrode was unveiled recently by chemists from Bell Communications Research (Bellcore), Red Bank, N.J. The new battery--still experimental--is safer, longer lasting, and potentially cheaper to manufacture than other lithium-ion batteries. In addition, it provides three times the energy of nickel-cadmium cells, the most popular type of rechargeable battery. Bellcore scientists believe the new battery could replace nickel-cadmium and small lead-acid batteries in many applications.

Dagani, R.

1993-01-04

216

Improved Separators For Rechargeable Lithium Cells  

NASA Technical Reports Server (NTRS)

Improved pairs of separators proposed for use in rechargeable lithium cells operating at ambient temperature. Block growth of lithium dendrites and help prevent short circuits. Each cell contains one separator made of microporous polypropylene placed next to anode, and one separator made of microporous polytetrafluoroethylene (PTFE) next to cathode. Separators increase cycle lives of secondary lithium cells. Cells to which concept applicable those of Li/TiS(2), Li/NbSe(3), Li/CoO(2), Li/MoS(2), Li/VO(x), and Li/MnO(2) chemical systems. Advantageous in spacecraft, military, communications, automotive, and other applications in which high energy density and rechargeability needed.

Shen, David; Surampudi, Subbarao; Huang, Chen-Kuo; Halpert, Gerald

1994-01-01

217

Karst and artificial recharge: Theoretical and practical problems. A preliminary approach to artificial recharge assessment  

NASA Astrophysics Data System (ADS)

SummaryManaged Aquifer Recharge (MAR) is an emerging sustainable technique that has already generated successful results and is expected to solve many water resource problems, especially in semi-arid and arid zones. It is of great interest for karst aquifers that currently supply 20-25% of the world's potable water, particularly in Mediterranean countries. However, the high heterogeneity in karst aquifers is too complex to be able to locate and describe them simply via field observations. Hence, as compared to projects in porous media, MAR is still marginal in karst aquifers. Accordingly, the present work presents a conceptual methodology for Aquifer Rechargeability Assessment in Karst - referred to as ARAK. The methodology was developed noting that artificial recharge in karst aquifers is considered an improbable challenge to solve since karst conduits may drain off recharge water without any significant storage, or recharge water may not be able to infiltrate. The aim of the ARAK method is to determine the ability of a given karst aquifer to be artificially recharged and managed, and the best sites for implementing artificial recharge from the surface. ARAK is based on multi-criteria indexation analysis modeled on karst vulnerability assessment methods. ARAK depends on four independent criteria, i.e. Epikarst, Rock, Infiltration and Karst. After dividing the karst domain into grids, these criteria are indexed using geological and topographic maps refined by field observations. ARAK applies a linear formula that computes the intrinsic rechargeability index based on the indexed map for every criterion, coupled with its attributed weighting rate. This index indicates the aptitude for recharging a given karst aquifer, as determined by studying its probability first on a regional scale for the whole karst aquifer, and then by characterizing the most favorable sites. Subsequently, for the selected sites, a technical and economic feasibility factor is applied, weighted by the difficulties that could occur when trying to undertake a recharge operation at a selected site from the surface. Each site is finally rated by its rechargeability index - the product of two factors, the intrinsic rechargeability and the feasibility index. ARAK was applied to the region of Damour, Lebanon, on the Mediterranean coast where uncontrolled exploitation of public and private wells led to its partial salinization by seawater. A MAR system in Damour region represents an interesting solution to cope with salinization and the insufficiency of the resource.

Daher, Walid; Pistre, Séverin; Kneppers, Angeline; Bakalowicz, Michel; Najem, Wajdi

2011-10-01

218

Regional Estimation of Total Recharge to Ground Water in Nebraska  

Microsoft Academic Search

Naturally occurring long-term mean annual recharge to ground water in Nebraska was estimated by a novel water-balance approach. This approach uses geographic information systems (GIS) layers of land cover, elevation of land and ground water surfaces, base recharge, and the recharge potential in combination with monthly climatic data. Long-term mean recharge > 140 rnm per year was estimated in eastern

Jozsef Szilagyi; F. Edwin Harvey; Jerry F. Ayers

2005-01-01

219

Global synthesis of groundwater recharge in semiarid and arid regions  

Microsoft Academic Search

Global synthesis of the findings from ¾140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique

Bridget R. Scanlon; Kelley E. Keese; Alan L. Flint; Lorraine E. Flint; Cheikh B. Gaye; W. Michael Edmunds; Ian Simmers

2006-01-01

220

Global synthesis of groundwater recharge in semiarid and arid regions  

Microsoft Academic Search

Global synthesis of the findings from 140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique

Bridget R. Scanlon; Kelley E. Keese; Alan L. Flint; Lorraine E. Flint; Cheikh B. Gaye; W. Michael Edmunds; Ian Simmers

2006-01-01

221

Natural vs. artificial groundwater recharge, quantification through inverse modeling  

NASA Astrophysics Data System (ADS)

Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady- and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events, the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system, the recharge volume can be increased even for small flood events, while the recharge through the river channel increases only for major flood events.

Hashemi, H.; Berndtsson, R.; Kompani-Zare, M.; Persson, M.

2013-02-01

222

Natural vs. artificial groundwater recharge, quantification through inverse modeling  

NASA Astrophysics Data System (ADS)

Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system the recharge volume can be increased even for small flood events while the recharge through the river channel increases only for major flood events.

Hashemi, H.; Berndtsson, R.; Kompani-Zare, M.; Persson, M.

2012-08-01

223

Estimating recharge rates with analytic element models and parameter estimation  

USGS Publications Warehouse

Quantifying the spatial and temporal distribution of recharge is usually a prerequisite for effective ground water flow modeling. In this study, an analytic element (AE) code (GFLOW) was used with a nonlinear parameter estimation code (UCODE) to quantify the spatial and temporal distribution of recharge using measured base flows as calibration targets. The ease and flexibility of AE model construction and evaluation make this approach well suited for recharge estimation. An AE flow model of an undeveloped watershed in northern Wisconsin was optimized to match median annual base flows at four stream gages for 1996 to 2000 to demonstrate the approach. Initial optimizations that assumed a constant distributed recharge rate provided good matches (within 5%) to most of the annual base flow estimates, but discrepancies of >12% at certain gages suggested that a single value of recharge for the entire watershed is inappropriate. Subsequent optimizations that allowed for spatially distributed recharge zones based on the distribution of vegetation types improved the fit and confirmed that vegetation can influence spatial recharge variability in this watershed. Temporally, the annual recharge values varied >2.5-fold between 1996 and 2000 during which there was an observed 1.7-fold difference in annual precipitation, underscoring the influence of nonclimatic factors on interannual recharge variability for regional flow modeling. The final recharge values compared favorably with more labor-intensive field measurements of recharge and results from studies, supporting the utility of using linked AE-parameter estimation codes for recharge estimation. Copyright ?? 2005 The Author(s).

Dripps, W. R.; Hunt, R. J.; Anderson, M. P.

2006-01-01

224

Rechargeable Lithium-Inorganic Electrolyte Cell.  

National Technical Information Service (NTIS)

The overall objective of the present contract research is to develop and improve performance of Li/SO2Cl2 rechargeable cells with particular emphasis on: safety, discharge capacity, and cycle life. In order to achieve these objectives our approach is to i...

S. Hossain P. Harris R. McDonald C. Todino R. Witter

1990-01-01

225

Prototype systems for rechargeable magnesium batteries  

Microsoft Academic Search

The thermodynamic properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries, because it may provide a considerably higher energy density than the commonly used lead-acid and nickel-cadmium systems. Moreover, in contrast to lead and cadmium, magnesium is inexpensive, environmentally friendly and safe to handle. But the development of Mg batteries has been

D. Aurbach; Z. Lu; A. Schechter; Y. Gofer; H. Gizbar; R. Turgeman; Y. Cohen; M. Moshkovich; E. Levi

2000-01-01

226

Recharging "Hot-Melt" Adhesive Film  

NASA Technical Reports Server (NTRS)

Technique for recharging surface with "hot-melt" film makes use of one sided, high-temperature, pressure-sensitive adhesive tape. Purpose of the one-sided tape is to hold hot-melt charge in place until fused to surface. After adhesive has fused to surface and cooled, tape is removed, leaving adhesive on surface.

Progar, D. J.

1983-01-01

227

Lithium electronic environments in rechargeable battery electrodes  

Microsoft Academic Search

This work investigates the electronic environments of lithium in the electrodes of rechargeable batteries. The use of electron energy-loss spectroscopy (EELS) in conjunction with transmission electron microscopy (TEM) is a novel approach, which when coupled with conventional electrochemical experiments, yield a thorough picture of the electrode interior. Relatively few EELS experiments have been preformed on lithium compounds owing to their

Adrian Hightower

2001-01-01

228

Prototype Rechargeable Lithium Batteries. Phase 1.  

National Technical Information Service (NTIS)

This report details the work performed on Phase I of an overall two-phase program. The aim of Phase I is to select a room-temperature lithium (Li) rechargeable couple that offers high energy density (60-90 Wh/1b), good rate capability (C/6-C/1), and low t...

W. B. Ebner H. W. Lin

1987-01-01

229

Mechanically Rechargeable Zinc-Air Battery.  

National Technical Information Service (NTIS)

The mechanically rechargeable zinc-air battery is a new power source that has an energy density in the order of 100 watthours per pound, twice that of the closest competing battery system. The many advantageous characteristics of this battery have encoura...

D. Linden

1969-01-01

230

Characteristics of carbon-lithium rechargeable batteries  

Microsoft Academic Search

Carbon-lithium rechargeable batteries are composed of an activated carbon positive electrode, a lithium-occluded alloy negative electrode, and an organic electrolyte. The discharge curve obtainable from batteries of this type exhibits the slightly inclining linearity of a capacitor. Potential applications are envisioned in computer memory backup power sources and maintenance-free power source applications involving solar cell arrays.

K. Momose; H. Hayakawa; N. Koshiba; T. Ikehata

1987-01-01

231

High reliability lithium rechargeable batteries for specialties  

Microsoft Academic Search

Since their development in the late 1980s, lithium rechargeable batteries have enjoyed rapid growth and wide use as a commodity battery known for its higher energy density storage and lightweight convenience. These same attributes are emerging as a strong platform in power source development for the medical and aerospace sectors with highly customized applications and narrowly defined criteria. Accordingly, this

H. Tsukamoto

2003-01-01

232

Anode for rechargeable ambient temperature lithium cells  

NASA Technical Reports Server (NTRS)

An ambient room temperature, high density, rechargeable lithium battery includes a Li(x)Mg2Si negative anode which intercalates lithium to form a single crystalline phase when x is up to 1.0 and an amorphous phase when x is from 1 to 2.0. The electrode has good reversibility and mechanical strength after cycling.

Huang, Chen-Kuo (inventor); Surampudi, Subbarao (inventor); Attia, Alan I. (inventor); Halpert, Gerald (inventor)

1994-01-01

233

Anode for Rechargeable Ambient Temperature Lithium Cells.  

National Technical Information Service (NTIS)

An ambient room temperature, high density, rechargeable lithium battery includes a Li(x)Mg2Si negative anode which intercalates lithium to form a single crystalline phase when x is up to 1.0 and an amorphous phase when x is from 1 to 2.0. The electrode ha...

C. Huang S. Surampudi A. I. Attia G. Halpert

1992-01-01

234

High temperature rechargeable molten salt cell  

Microsoft Academic Search

This patent describes a high temperature rechargeable molten salt cell. It comprises: a member of the group consisting of lithium, lithium aluminum alloy, lithium silicon alloy, sodium, potassium, calcium, magnesium, an alkali metal, a group II A element, a group II A alloy and composite mixtures thereof, as the anode, a chemical compound of the composition XYSâ wherein X is

E. J. Plichta; W. K. Behl

1991-01-01

235

Recharging Our Sense of Idealism: Concluding Thoughts  

ERIC Educational Resources Information Center

In this article, the authors aim to recharge one's sense of idealism. They argue that idealism is the Vitamin C that sustains one's commitment to implementing humanistic principles and social justice practices in the work of counselors and educators. The idealism that characterizes counselors and educators who are humanistic and social justice…

D'Andrea, Michael; Dollarhide, Colette T.

2011-01-01

236

Monitoring Cave Recharge in the Edwards Aquifer Recharge Zone for Natural and Simulated Rainfall Events  

NASA Astrophysics Data System (ADS)

Across semi-arid regions of the world, woody plant encroachment is widespread with potential implications for groundwater recharge and streamflow. In an effort to better understand the interactions between woody plants and recharge, we are monitoring drip rates in shallow caves in the Edwards Aquifer recharge zone of Central Texas. The surface is covered by a dense stand of ashe juniper (Juniperus ashei). In addition to stemflow, throughfall, and surface runoff was monitored for both natural precipitation events as well as simulated rainfall. Interception and throughfall are measured using a grid of rain gauges and throughfall collectors. Surface runoff measurements were quantified with a 15.24 centimeter H- flume instrumented with an ultrasonic water level sensor. Drip collectors constructed inside the cave collect recharge entering the cave from the ceiling. Large scale rainfall simulation equipment onsite allows us to "re-create" these naturally occurring rainfall events and compare the resulting data with that from the original event. Performing these types of tests allows us to learn important information about the cave footprint's ability to transmit recharge waters into the cave. During a simulation, water is applied directly to the cave footprint and not to the entire hillslope as in a natural rain event. We found that recharge for the natural and simulated events were similar. In each case, recharge makes up less than 5% of the water budget, in spite of the fact that there was little, if any, surface runoff. The working hypothesis is that most of the rainfall is routed off the hillslope as lateral subsurface flow.

Gregory, L.; Veni, G.; Shade, B.; Wilcox, B. P.; Munster, C. L.; Owens, M. K.

2005-12-01

237

Lithium rechargeable cell with a polymer cathode  

NASA Astrophysics Data System (ADS)

Thin films of electropolymerized poly 3-methylthiophene (PMT) were used as a rechargeable cathode in Li(SO2)3AlCl4 electrolyte. Capacity was superior to porous carbon electrodes of like thickness. Pulse power levels of 2 W cm-2 were achieved, and high rate constant current pulses of four-second duration were reproducible over cycles. Cells could be recharged at potentials below 4.0 V, minimizing the formation of chlorine and thereby diminishing the capacity for corrosion. For a primary cell, greater discharge capacity was obtained with thionyl chloride and sulfuryl chloride electrolytes. Since PMT becomes electrically insulating in the reduced state, this could be used as a built-in safety feature to avert the hazards associated with abuse over-discharge.

Walker, Charles W., Jr.

1991-11-01

238

Rechargeable Infection-responsive Antifungal Denture Materials  

PubMed Central

Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be “washed out” by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions.

Cao, Z.; Sun, X.; Yeh, C.-K.; Sun, Y.

2010-01-01

239

Rechargeable infection-responsive antifungal denture materials.  

PubMed

Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be "washed out" by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions. PMID:20940361

Cao, Z; Sun, X; Yeh, C-K; Sun, Y

2010-12-01

240

New mechanically rechargeable zinc-air batteries  

Microsoft Academic Search

This report describes the design, development and testing of new mechanically rechargeable zinc-air batteries. Following research and development of a low cost silver-mercury cathode catalyst, prototype battery tests were conducted. Cycle life tests at 3.5 amperes indicated satisfactory performance through at least 26 cycles when this test was terminated for the final hardware build. The cathode bi-cell design utilized the

J. Giltner

1975-01-01

241

Dynamically compacted rechargeable ceramic lithium batteries  

Microsoft Academic Search

A rechargeable ceramic battery is made of a LixMn2O4 (x = 1.1) cathode, a graphite anode and a BPO4:yLi2O (y ?- 0.035) solid electrolyte by dynamic compaction. This battery system has a theoretical open-circuit potential of 4.2 V and a high energy density, which makes it interesting for application in electric vehicles.

M. J. G. Jak; E. M. Kelder; M. Stuivinga; J. Schoonman

1996-01-01

242

Rechargeable alkaline zinc\\/ferricyanide battery  

Microsoft Academic Search

Technical and economic feasibility of the alkaline zinc\\/ferricy anide rechargeable battery for utility load leveling applications was assessed. This battery meets the requirements for this application with cell voltages of 1.94 V on charge and 1.78 V on discharge. Mean energy efficiency is 84% at 760 and 86% at 1110 4 hour cycles in full cell and redox half cell

G. B. Adams; R. P. Hollandsworth; B. D. Webber

1979-01-01

243

High specific power lithium polymer rechargeable battery  

Microsoft Academic Search

PolyPlus Battery Company (PPBC) is developing an advanced lithium polymer rechargeable battery based on its proprietary positive electrode. This battery offers high steady-state (>250 W\\/kg) and peak power densities (3000 W\\/kg), in a low cost and environmentally benign format. This PolyPlus lithium polymer battery also delivers high specific energy. The first generation battery has a energy density of 100 Wh\\/kg

May-Ying Chu; Lutgard De Jonghe; Steven Visco

1996-01-01

244

Design and simulation of lithium rechargeable batteries  

Microsoft Academic Search

Lithium -based rechargeable batteries that utilize insertion electrodes are being considered for electric-vehicle applications because of their high energy density and inherent reversibility. General mathematical models are developed that apply to a wide range of lithium-based systems, including the recently commercialized lithium-ion cell. The modeling approach is macroscopic, using porous electrode theory to treat the composite insertion electrodes and concentrated

1995-01-01

245

Capacity degradation of lithium rechargeable batteries  

Microsoft Academic Search

Li rechargeable cells made with structural arrangement Li\\/membrane\\/LixV2O5 were examined under different charge states using ac impedance, environmental scanning electron microscope (ESEM), transmission electron microscope (TEM) and the high-resolution nuclear magnetic resonance (NMR). These states include charged, discharged, and over cycled. The lowest internal resistance was obtained from the cell at charged state; the resistance increased when the cell was

J. P. Zheng; P. L. Moss; R. Fu; Z. Ma; Y. Xin; G. Au; E. J. Plichta

2005-01-01

246

Charge control investigation of rechargeable lithium cells  

NASA Technical Reports Server (NTRS)

An ambient temperature rechargeable Li-TiS2 cell was cycled under conditions which simulate aerospace applications. A novel charge/discharge state-of-charge control scheme was used, together with tapered current charging, to overcome deleterious effects associated with end-of-charge and end-of-discharge voltages. The study indicates that Li-TiS2 cells hold promise for eventual synchronous satellite-type applications. Problem areas associated with performance degradation and reconditioning effects are identified.

Otzinger, B.; Somoano, R.

1984-01-01

247

Charge control investigation of rechargeable lithium cells  

Microsoft Academic Search

An ambient temperature rechargeable Li-TiS2 cell was cycled under conditions which simulate aerospace applications. A novel charge\\/discharge state-of-charge control scheme was used, together with tapered current charging, to overcome deleterious effects associated with end-of-charge and end-of-discharge voltages. The study indicates that Li-TiS2 cells hold promise for eventual synchronous satellite-type applications. Problem areas associated with performance degradation and reconditioning effects are

B. Otzinger; R. Somoano

1984-01-01

248

Advanced rechargeable lithium sulfur dioxide cell  

Microsoft Academic Search

The electrochemical performance and safety of the rechargeable lithium sulfur dioxide system has been investigated in laboratory cells and in high rate D cells. Small design and active materials were optimized to that cathode utilization of 1.6Ah\\/grams of carbon and 0.19Ah\\/cm3 of cathode were achieved with 100-200 cycles. Discharge and charge of cells at temperatures down to -30 C were

R. C. McDonald; P. Harris; F. Goebel; S. Hossain; R. Vierra

1991-01-01

249

Rechargeable Infection-responsive Antifungal Denture Materials  

Microsoft Academic Search

Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin

Z. Cao; X. Sun; C.-K. Yeh; Y. Sun

2010-01-01

250

Magnetic bioactive glass ceramic in the system CaO-P2O5-SiO2-MgO-CaF2-MnO2-Fe2O3 for hyperthermia treatment of bone tumor.  

PubMed

Magnetic bioactive glass ceramic (MG) in the system CaO-SiO(2)-P(2)O(5)-MgO-CaF(2)-MnO(2)-Fe(2)O(3) for hyperthermia treatment of bone tumor was synthesized. The phase composition was investigated by XRD. The magnetic property was measured by VSM. The in vitro bioactivity was investigated by simulated body fluid (SBF) soaking experiment. Cell growth on the surface of the material was evaluated by co-culturing osteoblast-like ROS17/2.8 cells with materials for 7 days. The results showed that MG contained CaSiO(3) and Ca(5)(PO(4))(3)F as the main phases, and MnFe(2)O(4) and Fe(3)O(4) as the magnetic phases. Under a magnetic field of 10,000 Oe, the saturation magnetization and coercive force of MG were 6.4 emu/g and 198 Oe, respectively. After soaking in SBF for 14 days, hydroxyapatite containing CO(3)(2-) was observed on the surface of MG. The experiment of co-culturing cells with material showed that cells could successfully attach and well proliferate on MG. PMID:21870083

Li, Guangda; Feng, Shuying; Zhou, Dali

2011-10-01

251

Nanomaterials for lithium-ion rechargeable batteries.  

PubMed

In lithium-ion batteries, nanocrystalline intermetallic alloys, nanosized composite materials, carbon nanotubes, and nanosized transition-metal oxides are all promising new anode materials, while nanosized LiCoO2, LiFePO4, LiMn2O4, and LiMn2O4 show higher capacity and better cycle life as cathode materials than their usual larger-particle equivalents. The addition of nanosized metal-oxide powders to polymer electrolyte improves the performance of the polymer electrolyte for all solid-state lithium rechargeable batteries. To meet the challenge of global warming, a new generation of lithium rechargeable batteries with excellent safety, reliability, and cycling life is needed, i.e., not only for applications in consumer electronics, but especially for clean energy storage and for use in hybrid electric vehicles and aerospace. Nanomaterials and nanotechnologies can lead to a new generation of lithium secondary batteries. The aim of this paper is to review the recent developments on nanomaterials and nanotechniques used for anode, cathode, and electrolyte materials, the impact of nanomaterials on the performance of lithium batteries, and the modes of action of the nanomaterials in lithium rechargeable batteries. PMID:16573064

Liu, Hua Kun; Wang, Guo Xiu; Guo, Zaiping; Wang, Jiazhao; Konstantinov, Kosta

2006-01-01

252

Ground water recharge from Lake Chad  

SciTech Connect

Lake Chad is a shallow, closed basin lake located in Sub-Sharan Africa. It has the largest drainage basin of any lake in the world, and is also very old, being formed by tectonic processes during the Cretaceous. These features should combine to form a saline lake, but the open waters of Lake Chad are reasonably fresh, having a total dissolved solids concentration of about 320 mg/1. This apparent discrepancy can be explained by noting that recharge of the unconfined aquifer to the SW in Nigeria by ground water infiltration through the lakebed can remove significant quantities of water and dissolved solutes from the lake. The authors have measured and calculated ground water infiltration and velocities by several techniques. Direct, volumetric measurements of ground water recharge seepage give velocities on the order of .28-8.8 x 10/sup -3/ m/day. Tracer monitoring in a borehole dilution test yielded ground water velocities of 3.6 m/day to the SW (away from the lake). Hydraulic conductivities approx. .004-.6 m/day were determined by falling head measurements. Finally, using static water levels, the potentiometric surface within approx. 80 km of the southwest portion of Lake Chad yields water table gradients of 1.0-1.7 x 10/sup -4/ away from the lake. These results confirm that surface water and solute inflow to Lake Chad is removed by recharge to the unconfined aquifer in Nigeria.

Isiorho, S.; Matisoff, G.; McCall, P.L.

1985-01-01

253

Electrode properties of manganese oxide synthesized by sonochemical method in non-aqueous system  

NASA Astrophysics Data System (ADS)

Manganese oxide was prepared by an irradiation of ultrasound to an acetone solution of potassium permanganate. The chemical analyses of gas, solution and products have shown that the synthetic reaction was not peculiar to sonochemistry but similar to the reaction in the basic aqueous solution. The product contained manganese oxide and by-products such as acetate and oxalate. Those by-products were difficult to be removed thoroughly and a part of them resided even after wash. From XRD, the obtained manganese oxide was likely to be ?-MnO 2. The product was examined as electrode material of lithium ion battery, and showed 180 mAh g -1 of specific capacity under 0.5 A g -1 of current density. Moreover, it could be discharged and charged under a high level of current density (ca. 100 mAh g -1 at 17 C). The capacity deterioration caused by cycle repetition was also found to be much small.

Hibino, Mitsuhiro; Zhou, Haoshen; Honma, Itaru

254

Determination of radium-226 in aqueous solutions by alpha-spectrometry.  

PubMed

The new European legislation imposes a lower threshold for radioactivity in drinking water. This requires the development of more sensitive and reliable analytical methods. This work presents an improved alpha-spectrometric technique to determine the radium-226 activity in aqueous solution relying on the radium adsorption onto a thin manganese oxide layer followed by alpha-measurement. The preparation of the MnO2 deposit has been optimized as well as the radium adsorption conditions. Detection threshold and limit of 5 and 10 mBq x L(-1), respectively, with a 10% (95% confidence) uncertainty are currently reached. This paper reports on the overall technique and on its application to assess the radium-226 activity in 28 French mineral waters. In addition, the gross alpha- and beta-activities have been evaluated using proportional counting while the uranium concentrations were derived from ICPMS. PMID:11569812

Morvan, K; Andres, Y; Mokili, B; Abbe, J C

2001-09-01

255

Ceria based catalyst for cathode in non-aqueous electrolyte based Li/O2 batteries  

NASA Astrophysics Data System (ADS)

This study suggests combustion synthesized Ce1-xZrxO2 (CZO; x = 0.1-0.5) as a new catalyst for the cathode in non-aqueous electrolyte based Li/O2 cells. The spherical catalysts have a fluorite structure with a mean diameter of 5-17 nm. Zr doping into the ceria lattice leads to the reduction of Ce4+ to Ce3+, which further improves the catalyst performance. Electrochemical studies of CZO as a cathode catalyst in the Li/O2 cell show that CZO follows a two-electron pathway for oxygen reduction. A maximum discharge capacity of 1620 mAh g-1 is obtained for the Ce0.8Zr0.2O2 catalyst due to its high surface area and porosity. A composite of CZO and MnO2 shows even better performance as a cathode catalyst for the Li/O2 cell.

Kalubarme, Ramchandra S.; Cho, Min-Seung; Kim, Jae-Kook; Park, Chan-Jin

2012-11-01

256

Regional estimation of total recharge to ground water in Nebraska.  

PubMed

Naturally occurring long-term mean annual recharge to ground water in Nebraska was estimated by a novel water-balance approach. This approach uses geographic information systems (GIS) layers of land cover, elevation of land and ground water surfaces, base recharge, and the recharge potential in combination with monthly climatic data. Long-term mean recharge > 140 mm per year was estimated in eastern Nebraska, having the highest annual precipitation rates within the state, along the Elkhorn, Platte, Missouri, and Big Nemaha River valleys where ground water is very close to the surface. Similarly high recharge values were obtained for the Sand Hills sections of the North and Middle Loup, as well as Cedar River and Beaver Creek valleys due to high infiltration rates of the sandy soil in the area. The westernmost and southwesternmost parts of the state were estimated to typically receive < 30 mm of recharge a year. PMID:15726925

Szilagyi, Jozsef; Harvey, F Edwin; Ayers, Jerry F

2005-01-01

257

Modelling overbank flood recharge at a continental scale  

NASA Astrophysics Data System (ADS)

Accounting for groundwater recharge from overbank flooding is required to reduce uncertainty and error in river-loss terms and groundwater sustainable-yield calculations. However, continental- and global-scale models of surface water-groundwater interactions rarely include an explicit process to account for overbank flood recharge (OFR). This paper upscales previously derived analytical equations to a continental scale using national soil atlas data and satellite imagery of flood inundation, resulting in recharge maps for seven hydrologically distinct Australian catchments. Recharge for three of the catchments was validated against independent recharge estimates from bore hydrograph responses and one catchment was additionally validated against point-scale recharge modelling and catchment-scale change in groundwater storage. Flood recharge was predicted for four of the seven catchments modelled, but there was also unexplained recharge present from the satellite's flood inundation mapping data. At a catchment scale, recharge from overbank flooding was somewhat under-predicted using the analytical equations, but there was good confidence in the spatial patterns of flood recharge produced. Due to the scale of the input data, there were no significant relationships found when compared at a point scale. Satellite-derived flood inundation data and uncertainty in soil maps were the key limitations to the accuracy of the modelled recharge. Use of this method to model OFR was found to be appropriate at a catchment to continental scale, given appropriate data sources. The proportion of OFR was found to be at least 4% of total change in groundwater storage in one of the catchments for the period modelled, and at least 15% of the riparian recharge. Accounting for OFR is an important, but often overlooked, requirement for closing water balances in both the surface water and groundwater domains.

Doble, R.; Crosbie, R.; Peeters, L.; Joehnk, K.; Ticehurst, C.

2014-04-01

258

Shale recharge and production behavior of geopressured reservoirs  

SciTech Connect

The reservoir simulator MUSHRM was used to study the conditions under which significant shale recharge may be expected. The calculations presented herein show that shale recharge is a strong function of the vertical shale permeability but is not greatly influenced by the shale compressibility. Significant shale recharge will occur only if the vertical shale permeability is at least of the order of 0.01 ..mu..d.

Garg, S.K.

1980-04-01

259

Rechargeable zinc-air battery technology implementations in portable electronics  

Microsoft Academic Search

AER Energy's rechargeable zinc-air battery technology has the unique set of characteristics to provide long battery run-time for portable electronics. With more energy per pound and high energy content cells, rechargeable zinc-air can provide sufficient energy in a lightweight battery that is practical to build. Improvements made in the past year make AER Energy's rechargeable zinc-air even more flexible and

T. Cutler

1997-01-01

260

Making Li-air batteries rechargeable: material challenges  

SciTech Connect

A Li-air battery could potentially provide three to five times higher energy density/specific energy than conventional batteries, thus enable the driving range of an electric vehicle comparable to a gasoline vehicle. However, making Li-air batteries rechargeable presents significant challenges, mostly related with materials. Herein, we discuss the key factors that influence the rechargeability of Li-air batteries with a focus on nonaqueous system. The status and materials challenges for nonaqueous rechargeable Li-air batteries are reviewed. These include electrolytes, cathode (electocatalysts), lithium metal anodes, and oxygen-selective membranes (oxygen supply from air). The perspective of rechargeable Li-air batteries is provided.

Shao, Yuyan; Ding, Fei; Xiao, Jie; Zhang, Jian; Xu, Wu; Park, Seh Kyu; Zhang, Jiguang; Wang, Yong; Liu, Jun

2013-02-25

261

A review of groundwater recharge under irrigated agriculture in Australia  

NASA Astrophysics Data System (ADS)

Quantification of recharge under irrigated agriculture is one of the most important but difficult tasks. It is the least understood component in groundwater studies because of its large variability in space and time and the difficulty of direct measurement. Better management of groundwater resources is only possible if we can accurately determine all fluxes going into and out of a groundwater system. One of the major challenges facing irrigated agriculture in Australia, and the world, is to reduce uncertainty in estimating or measuring the recharge flux. Reducing uncertainty in groundwater recharge under irrigated agriculture is a pre-requisite for effective, efficient and sustainable groundwater resource management especially in dry areas where groundwater usage is often the key to economic development. An accurate quantification of groundwater recharge under irrigated systems is also crucial because of its potential impacts on soil profile salinity, groundwater levels and groundwater quality. This paper aims to identify the main recharge control parameters thorough a review of past field and modelling recharge studies in Australia. We find that the main recharge control parameters under irrigated agriculture are soil type, irrigation management, watertable depth, land cover or plant water uptake, soil surface conditions, and soil, irrigation water and groundwater chemistry. The most commonly used recharge estimation approaches include chloride mass balance, water budget equation, lysimeters, Darcy's law and numerical models. Main sources and magnitude of uncertainty in recharge estimates associated with these approaches are discussed.

Riasat, Ali; Mallants, Dirk; Walker, Glen; Silberstein, Richard

2014-05-01

262

Seismicity induced by seasonal ground-water recharge at Mt  

Microsoft Academic Search

Abstract Groundwater recharge at Mt. Hood, Oregon, is dominated by spring snow melt which provides a natural large- amplitude,and narrow-width,pore-fluid pressure signal. Time delays between,this seasonal groundwater,recharge,and seismicity triggered by groundwater,recharge,can thus be used to estimate large-scale hydraulic,diffusivities and,the state of stress in the crust. We approximate,seasonal,variations in groundwater,recharge,with discharge in runoff- dominated streams at high elevations. We interpolate the

M. Saar; M. Manga

2003-01-01

263

Rechargeability of manganese dioxide/zinc cell using zinc sulfate electrolyte  

NASA Astrophysics Data System (ADS)

The charge/discharge of electrolytic ?-MnO 2 (EMD) in sulfate solution rather than chloride was investigated. Discharge potential-time curves at different conditions of current density, charging schemes and solutions were registered. The charge/discharge cycle can be repeated up to the 20th cycle with no significant change in the discharge behaviour. The charge/discharge products are characterized by X-ray diffraction pattern indicating recovery of ?-MnO 2 during charging process. The results are promising and encouraging. They are discussed in the light of recent views.

Askar, M. H.; Abbas, H.; Afifi, S. E.

264

Organic electrolyte for use in a lithium rechargeable electrochemical cell and lithium rechargeable electrochemical cell including said organic electrolyte  

SciTech Connect

This invention relates in general to use of an organic electrolyte in a lithium rechargeable electrochemical cell and to a lithium rechargeable electrochemical cell including said electrolyte; and, in particular, to the use of 1 to 2 mol/dm/sup 3/ LiAsF/sub 6/ in dimethylcarbonate (DMC) or 1 to 2 mol/dm/sup 3/ LiAsF/sub 6/ in (DMC) mixtures with methyl formate (MF) in which the mass percent of the (DMC) can vary from 25 to 100 mass percent as the electrolyte in a lithium rechargeable electrochemical cell, and to a lithium rechargeable electrochemical cell including said electrolyte.

Plichta, E.J.; Slane, S.M.; Salomon, M.

1987-07-06

265

Experimental survey of rechargeable alkaline zinc electrodes  

NASA Astrophysics Data System (ADS)

Rechargeable alkaline zinc-air cells and zinc-manganese dioxide cells need zinc electrodes working for at least 100 cycles under anode limiting conditions. The discharge of the manganese dioxide cathode especially must be limited to a definite fraction (1/3) of its available capacity to obtain a good cycle life. This study proposes a new test cell for investigations on pasted alkaline zinc powder electrodes. When, following experimentation, the value of the construction was established, a series of different electrode mixtures was cycled. It was found that 100 full discharges could be obtained with a zinc utilization of about 30 percent in the final cycles.

Binder, L.; Odar, W.

1984-09-01

266

Characterization of AA size lithium rechargeable cells  

Microsoft Academic Search

Testing of AA size rechargeable cells for underwater vehicle and other naval applications is complete for AT&T's lithium\\/niobium triselenide (Li\\/NbSe3) and Moli Energy's lithium\\/molybdenum disulfide (Li\\/MoS2) and in progress on Moli Energy's lithium\\/manganese dioxide (Li\\/MnO2) and W. R. Grace's lithium\\/titanium disulfide (Li\\/TiS2). Cell cycling was performed at various discharge rates, temperatures, and depths of discharge. At 25 C and 1

T. C. Murphy; D. M. Cason-Smith; S. D. James; P. H. Smith

1990-01-01

267

Thin-film rechargeable lithium batteries  

SciTech Connect

Thin-film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin-film battery.

Dudney, N.J.; Bates, J.B.; Lubben, D. [Oak Ridge National Lab., TN (United States). Solid State Div.

1995-06-01

268

Characterization of AA size lithium rechargeable cells  

Microsoft Academic Search

Testing of AA size rechargeable cells for underwater vehicle and other naval applications is complete for AT&T's lithium\\/niobium triselenide (Li\\/NbSe3) and Moli Energy's lithium\\/molybdenum disulfide (Li\\/MoS2) and is in progress on Moli Energy's lithium\\/manganese dioxide (Li\\/MnO2) and W.R. Grace's lithium\\/titanium disulfide (Li\\/TiS2). Cell cycling was performed at various discharge rates, temperatures, and depths of discharge. At 25°C and 1 mA\\/cm2

T. C. Murphy; D. M. Cason-Smith; S. D. James; P. H. Smith

1990-01-01

269

Low temperature studies on rechargeable lithium cells  

Microsoft Academic Search

Rechargeable lithium cells using intercalating cathodes of TiS2, a-MoS3, and mixed a-MoS3\\/TiS2 were studied at temperatures from 25 to -40 C. On the basis of conductivity investigations, LiAsF6 and LiAlCl4 electrolytes were selected for use in a binary solvent containing 24.4 mass percent 4-butyrolactone in 1,2-dimethoxyethane. The Li\\/TiS2 and Li\\/a-MoS3-TiS2 cells cycled well at 2 mA\\/sq cm down to -30

E. J. Plichta; M. Salomon

1984-01-01

270

Sediment and microbial fouling of experimental groundwater recharge trenches  

NASA Astrophysics Data System (ADS)

A common method of recharging groundwater is by the use of injection wells and/or recharge trenches. With time the recharge capacities of the wells/trenches progressively decline. Deposition of suspended fines in the recharge water and growth of microorganisms in the aquifer are common causes of this decline. This paper presents an investigation of the relative significance of these two factors under controlled laboratory conditions. Large-scale physical models of recharge trenches were conducted in the laboratory to monitor the decline with time of the recharge capacity under controlled conditions. The physical models consisted of four hydraulically separate cells in which six different experiments were conducted. In three of the experiments microorganism were added as an inoculant. A nutrient and carbon fine solution was constantly injected into the influent stream entering through the inflow pipe. Both carbon fines and microorganisms caused plugging of the model recharge trenches in the laboratory. However, initialy the microbes appeared to have a beneficial effect by hindering the transport of the carbon fines from the gravel pack in the trench. Later the microbes contributed to the plugging of the gravel pack. A significant correlation was determined between the extent of carbon fine deposition and microbial growth. In the experiment using a biodegradable slurry, microbial growth did not affect the recharge capacity of the trench. One laboratory experiment involved the introduction of silt as a source of sediment fines to the model recharge trench. This experiment simulated conditions often found in the field when no carbon fine adsoprtion system is used and natural surface water is recharged into aquifer. This research will be useful in understanding the relative importance of factors contributing to the decline of recharge capacity observed in the field.

Warner, James W.; Gates, Timothy K.; Namvargolian, Reza; Miller, Paul; Comes, Gregory

1994-04-01

271

Challenges of Artificial Recharge at the Chain of Lakes  

NASA Astrophysics Data System (ADS)

A series of gravel quarry lakes, A through I (i.e. Chain of Lakes) in Alameda County, California are planned to convert to off-channel spreading lakes for artificial groundwater recharge. An operational plan is needed for the near-term improvements that would allow safe and efficient operations of Lake H and Lake I recently acquired for artificial recharge operations. Water source for the groundwater recharge comes from State Water Project (SWP) water releases at the South Bay Aqueduct turnout. The released water flows approximately nine miles in Arroyo Mocho Creek to the planned diversion facility. The recharge system includes multiple water delivery components and recharge components. Reliability of SWP water delivery is a water supply constraint to the recharge system. Hydraulic capacities of each delivery component and recharge capacities of each recharge component are physical constraints to the development of the operational plan. Policy issues identified in the Mitigated Negative Declaration which contains mitigation measures addressing potential impacts of fisheries and erosion are regulatory constraints to the operational plan development. Our approach that addresses technical challenges and policy issues in the development of the operational plan includes i) determination of lake recharge under observed conditions using water budget method; ii) development and calibration of a ground water flow model using MODFLOW; iii) estimation of lake recharge capacity for a range of lake levels using the calibrated ground water flow model; iv) analysis of clogging layer effects on recharge capacity; and v) development and application of operations models for the stream delivery system and the lake system.

Zeng, X.

2004-12-01

272

Reliability of Rechargeable Batteries in a Photovoltaic Power Supply System  

Microsoft Academic Search

We investigate the reliability If a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. A model system was constructed for this that includes the solar resource, the photovoltaic power supp Iy system, the rechargeable battery and a load. The solar resource and the system load are modeled as SI ochastic processes. The photovoltaic system

P. Barney; R. G. Jungst; D. Ingersoll; C. OGorman; T. L. Paez; A. Urbina

1998-01-01

273

Determining the recharge mode of Sahelian aquifers using water isotopes  

Microsoft Academic Search

It is proposed that the drainage network plays an important role in the recharge process of the fractured aquifers in the African Precambrian shield and that the fractured aquifer system is likely to be hydraulically continuous; this contrasts with most previous studies, which suggested direct recharge by rainwater percolation. Two areas were selected in Niger for the study of the

Pierre Girard; Claude Hillaire-Marcel; Marie Solange Oga

1997-01-01

274

Downstream of downtown: urban wastewater as groundwater recharge  

Microsoft Academic Search

Wastewater infiltration is often a major component of overall recharge to aquifers around urban areas, especially in more arid climates. Despite this, such recharge still represents only an incidental (or even accidental) byproduct of various current practices of sewage effluent handling and wastewater reuse. This topic is reviewed through reference to certain areas of detailed field research, with pragmatic approaches

S. S. D. Foster; P. J. Chilton

2004-01-01

275

Electrochemically active polymers for rechargeable batteries  

SciTech Connect

Electrochemical energy storage systems (batteries) have a tremendous role in technical applications. In this review the authors examine the prospects of electroactive polymers in view of the properties required for such batteries. Conducting organic polymers are considered here in the light of their rugged chemical environment: organic solvents, acids, and alkalis. The goal of the present article is to provide, first of all in tabular form, a survey of electroactive polymers in view of potential applications in rechargeable batteries. It reviews the preparative methods and the electrochemical performance of polymers as rechargeable battery electrodes. The theoretical values of specific charge of the polymers are comparable to those of metal oxide electrodes, but are not as high as those of most of the metal electrodes normally used in batteries. Therefore, it is an advantage in conventional battery designs to use the conducting polymer as a positive electrode material in combination with a negative electrode such as Li, Na, Mg, Zn, MeH{sub x}, etc. 504 refs.

Novak, P.; Haas, O. [Paul Scherrer Inst., Villigen PSI (Switzerland). Electrochemistry Section] [Paul Scherrer Inst., Villigen PSI (Switzerland). Electrochemistry Section; Santhanam, K.S.V. [Tata Inst. of Fundamental Research, Mumbai (India)] [Tata Inst. of Fundamental Research, Mumbai (India); Mueller, K.

1997-01-01

276

Global synthesis of groundwater recharge in semiarid and arid regions  

USGS Publications Warehouse

Global synthesis of the findings from ???140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40-374000 km2) range from 0.2 to 35 mm year-1, representing 0.1-5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to ???720 m year-1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Nin??o Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Nin??os (1977-1998) relative to periods dominated by La Nin??as (1941-1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year-1 during the Sahel drought (1970-1986) to 150 mm year-1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (??? 10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in the SW US. The impact of LU change was much greater than climate variability in Niger (Africa), where replacement of savanna by crops increased recharge by about an order of magnitude even during severe droughts. Sensitivity of recharge to LU/LC changes suggests that recharge may be controlled through management of LU. In irrigated areas, recharge varies from 10 to 485 mm year-1, representing 1-25% of irrigation plus precipitation. However, irrigation pumpage in groundwater-fed irrigated areas greatly exceeds recharge rates, resulting in groundwater mining. Increased recharge related to cultivation has mobilized salts that accumulated in the unsaturated zone over millennia, resulting in widespread groundwater and surface water contamination, particularly in Australia. The synthesis of recharge rates provided in this study contains valuable information for developing sustainable groundwater resource programmes within the context of climate variability and LU/LC change. Copyright ?? 2006 John Wiley & Sons, Ltd.

Scanlon, B. R.; Keese, K. E.; Flint, A. L.; Flint, L. E.; Gaye, C. B.; Edmunds, W. M.; Simmers, I.

2006-01-01

277

Groundwater Recharge Rate and Zone Structure Estimation Using PSOLVER Algorithm.  

PubMed

The quantification of groundwater recharge is an important but challenging task in groundwater flow modeling because recharge varies spatially and temporally. The goal of this study is to present an innovative methodology to estimate groundwater recharge rates and zone structures for regional groundwater flow models. Here, the unknown recharge field is partitioned into a number of zones using Voronoi Tessellation (VT). The identified zone structure with the recharge rates is associated through a simulation-optimization model that couples MODFLOW-2000 and the hybrid PSOLVER optimization algorithm. Applicability of this procedure is tested on a previously developed groundwater flow model of the Tahtal? Watershed. Successive zone structure solutions are obtained in an additive manner and penalty functions are used in the procedure to obtain realistic and plausible solutions. One of these functions constrains the optimization by forcing the sum of recharge rates for the grid cells that coincide with the Tahtal? Watershed area to be equal to the areal recharge rate determined in the previous modeling by a separate precipitation-runoff model. As a result, a six-zone structure is selected as the best zone structure that represents the areal recharge distribution. Comparison to results of a previous model for the same study area reveals that the proposed procedure significantly improves model performance with respect to calibration statistics. The proposed identification procedure can be thought of as an effective way to determine the recharge zone structure for groundwater flow models, in particular for situations where tangible information about groundwater recharge distribution does not exist. PMID:23746002

Ayvaz, M Tamer; Elçi, Alper

2014-05-01

278

Determining the recharge mode of Sahelian aquifers using water isotopes  

NASA Astrophysics Data System (ADS)

It is proposed that the drainage network plays an important role in the recharge process of the fractured aquifers in the African Precambrian shield and that the fractured aquifer system is likely to be hydraulically continuous; this contrasts with most previous studies, which suggested direct recharge by rainwater percolation. Two areas were selected in Niger for the study of the aquifer recharge process using isotopic analyses of water ( 2H, 18O, 3H). The first area, centred on the village of Kobio, is the 21-km 2 drainage basin of the Lomona intermittent stream, some 60 km southwest of Niamey (the capital city of Niger). The second area, in the vicinity of Niamey, represents a portion of the Niger basin, draining a surface area many orders of magnitude larger than the Lomona basin. The mean 18O composition of water from all wells in the Kobio aquifer provides evidence for recharge by evaporated water. This is confirmed by the concomitant increase of 18O content with rising static water levels as recharge proceeded. Tritium data suggest progressive aging of the Kobio aquifer water in the flow direction inferred from static water levels, with a down-gradient depletion of 18O composition, suggesting that `enriched' recharge water is progressively mixed with `depleted' aquifer water. Recharge by a reach of the Lomona is proposed to explain these results. In the Niamey area wells, the 18O time series clearly define an injection of evaporated water from the surface into the fractured aquifer. This recharging plume of evaporated water most likely originates from the Niger River. Thus, isotope data for two drainage basins of very different sizes indicate that aquifers are recharged by water from the rivers and that the flow regime of surface waters controls the recharge process.

Girard, Pierre; Hillaire-Marcel, Claude; Oga, Marie Solange

1997-10-01

279

Climate variability effects on urban recharge beneath low impact development  

NASA Astrophysics Data System (ADS)

Groundwater resources in urban and coastal environments are highly vulnerable to human pressures and climate variability and change, and many communities face water shortages and need to find alternative water supplies. Therefore, understanding how low impact development (LID) site planning and integrated/best management practices (BMPs) affect recharge rates and volumes is important because of the increasing use of LID and BMP to reduce stormwater runoff and improve surface-water quality. Often considered a secondary management benefit, many BMPs may also enhance recharge to local aquifers; however these hypothesized benefits have not been thoroughly tested or quantified. In this study, we quantify stormwater capture and recharge enhancement beneath a BMP infiltration trench of the LID research network at San Francisco State University, San Francisco, California. Stormwater capture and retention was analyzed using the SCS TR-55 curve number method and in-situ infiltration rates to assess LID storage. Recharge was quantified using vadose zone monitoring equipment, a detailed water budget analysis, and a Hydrus-2D model. Additionally, the effects of historical and predicted future precipitation on recharge rates were examined using precipitation from the Geophysical Fluid Dynamic Laboratory (GFDL) A1F1 climate scenario. Observed recharge rates beneath the infiltration trench range from 1,600 to 3,700 mm/year and are an order of magnitude greater than recharge beneath an irrigated grass lawn and a natural setting. The Hydrus-2D model results indicate increased recharge under the GFDL A1F1 scenario compared with historical and GFDL modeled 20th century rates because of the higher frequency of large precipitation events that induce runoff into the infiltration trench. However, under a simulated A1F1 El Niño year, recharge calculated by a water budget does not increase compared with current El Niño recharge rates. In comparison, simulated recharge rates were considerably lower beneath the grass lawn for historical and future precipitation years. This work highlights the potential management strategy of using LID to capture excess runoff during El Niño years that can be recharged and stored as groundwater. An additional benefit of LID in coastal aquifer systems is the ability to capture and redirect precipitation from runoff to recharge that may help mitigate the negative effects from groundwater pumping and sea-water intrusion.

Newcomer, M. E.; Gurdak, J. J.

2012-12-01

280

Rechargeable metal hydrides for spacecraft application  

NASA Technical Reports Server (NTRS)

Storing hydrogen on board the Space Station presents both safety and logistics problems. Conventional storage using pressurized bottles requires large masses, pressures, and volumes to handle the hydrogen to be used in experiments in the U.S. Laboratory Module and residual hydrogen generated by the ECLSS. Rechargeable metal hydrides may be competitive with conventional storage techniques. The basic theory of hydride behavior is presented and the engineering properties of LaNi5 are discussed to gain a clear understanding of the potential of metal hydrides for handling spacecraft hydrogen resources. Applications to Space Station and the safety of metal hydrides are presented and compared to conventional hydride storage. This comparison indicates that metal hydrides may be safer and require lower pressures, less volume, and less mass to store an equivalent mass of hydrogen.

Perry, J. L.

1988-01-01

281

Oxygen electrodes for rechargeable alkaline fuel cells  

NASA Technical Reports Server (NTRS)

Electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells were investigated and developed. The electrocatalysts are defined as the material with a higher activity for the oxygen electrode reaction than the support. Advanced development will require that the materials be prepared in high surface area forms, and may also entail integration of various candidate materials. Eight candidate support materials and seven electrocatalysts were investigated. Of the 8 support, 3 materials meet the preliminary requirements in terms of electrical conductivity and stability. Emphasis is now on preparing in high surface area form and testing under more severe corrosion stress conditions. Of the 7 electrocatalysts prepared and evaluated, at least 5 materials remain as potential candidates. The major emphasis remains on preparation, physical characterization and electrochemical performance testing.

Swette, Larry; Giner, Jose

1987-01-01

282

Spinel electrodes for rechargeable lithium batteries.  

SciTech Connect

This paper gives a historical account of the development of spinel electrodes for rechargeable lithium batteries. Research in the late 1970's and early 1980's on high-temperature . Li/Fe{sub 3}O{sub 4} cells led to the evaluation of lithium spinels Li[B{sub 2}]X{sub 4} at room temperature (B = metal cation). This work highlighted the importance of the [B{sub 2}]X{sub 4}spinel framework as a host electrode structure and the ability to tailor the cell voltage by selection of different B cations. Examples of lithium-ion cells that operate with spinel anode/spinel cathode couples are provided. Particular attention is paid to spinels within the solid solution system Li{sub 1+x}Mn{sub 2-x}O{sub 4} (0 {le} x {le} 0.33).

Thackeray, M. M.

1999-11-10

283

Polymer Energy Rechargeable System (PERS) Development Program  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) and the Air Force Research Laboratory (AFRL) have recently established a collaborative effort to support the development of polymer-based, lithium-based cell chemistries and battery technologies to address the next generation of aerospace applications and mission needs. The overall objective of this development program, which is referred to as PERS, Polymer Energy Rechargeable System, is to establish a world-class technology capability and U.S. leadership in polymer-based battery technology for aerospace applications. Programmatically, the PERS initiative will exploit both interagency collaborations to address common technology and engineering issues and the active participation of academia and private industry. The initial program phases will focus on R&D activities to address the critical technical issues and challenges at the cell level.

Baldwin, Richard S.; Manzo, Michelle A.; Dalton, Penni J.; Marsh, Richard A.; Surampudi, Rao

2001-01-01

284

Thin-film rechargeable lithium batteries  

SciTech Connect

Small thin-film rechargeable cells have been fabricated with a lithium phosphorus oxyniuide electrolyte, Li metal anode, and Li{sub 1-x}Mn{sub 2}O{sub 4} as the cathode film. The cathode films were fabricated by several different techniques resulting in both crystalline and amorphous films. These were compared by observing the cell discharge behavior. Estimates have been made for the scale-up of such a thin-film battery to meet the specifications for the electric vehicle application. The specific energy, energy density, and cycle life are expected to meet the USABC mid-term criteria. However, the areas of the thin-films needed to fabricate such a cell are very large. The required areas could be greatly reduced by operating the battery at temperatures near 100{degrees}C or by enhancing the lithium ion transport rate in the cathode material.

Dudney, N.J.; Bates, J.B.; Lubben, D.

1994-11-01

285

Polymer Energy Rechargeable System Battery Being Developed  

NASA Technical Reports Server (NTRS)

Long description. Illustrations of discotic liquid crystals, rod-coil polymers, lithium-ion conducting channel dilithium phthalocyanine (Li2Pc) from top and side, novel star polyethylene oxide structures, composite polyethylene oxide materials (showing polyethylene oxide + lithium salt, carbon atoms and oxygen atoms), homopolyrotaxanes, and diblock copolymers In fiscal year 2000, NASA established a program to develop the next generation, lithium-based, polymer electrolyte batteries for aerospace applications. The goal of this program, known as Polymer Energy Rechargeable Systems (PERS), is to develop a space-qualified, advanced battery system embodying polymer electrolyte and lithium-based electrode technologies and to establish world-class domestic manufacturing capabilities for advanced batteries with improved performance characteristics that address NASA s future aerospace battery requirements.

Manzo, Michelle A.

2003-01-01

286

Advanced rechargeable sodium batteries with novel cathodes  

NASA Technical Reports Server (NTRS)

Various high energy density rechargeable batteries are being considered for future space applications. Of these, the sodium sulfur battery is one of the leading candidates. The primary advantage is the high energy density (760 Wh/kg theoretical). Energy densities in excess of 180 Wh/kg have been realized in practical batteries. More recently, cathodes other than sulfur are being evaluated. Researchers at JPL are evaluating various new cathode materials for use in high energy density sodium batteries for advanced space applications. The approach is to carry out basic electrochemical studies of these materials in a sodium cell configuration in order to understand their fundamental behaviors. Thus far studies have focused on alternate metal chlorides such as CuCl2 and organic cathode materials such as tetracyanoethylene (TCNE).

Distefano, S.; Ratnakumar, B. V.; Bankston, C. P.

1989-01-01

287

Rechargeable thin-film lithium batteries  

SciTech Connect

Rechargeable thin-film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have recently been developed. The batteries, which are typically less than 6-{mu}m thick, can be fabricated to any specified size, large or small, onto a variety of substrates including ceramics, semiconductors, and plastics. The cells that have been investigated include Li-TiS{sub 2}, Li-V{sub 2}O{sub 5}, and Li-Li{sub x}Mn{sub 2}O{sub 4}, with open circuit voltages at full charge of about 2.5, 3.6, and 4.2, respectively. The development of these batteries would not have been possible without the discovery of a new thin-film lithium electrolyte, lithium phosphorus oxynitride, that is stable in contact with metallic lithium at these potentials. Deposited by rf magnetron sputtering of Li{sub 3}PO{sub 4} in N{sub 2}, this material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25{degrees}C of 2 {mu}S/cm. The maximum practical current density obtained from the thin-film cells is limited to about 100 {mu}A/cm{sup 2} due to a low diffusivity of Li{sup +} ions in the cathodes. In this work, the authors present a short review of their work on rechargeable thin-film lithium batteries.

Bates, J.B.; Gruzalski, G.R.; Dudney, N.J.; Luck, C.F.; Yu, Xiaohua

1993-08-01

288

Quantifying the modern recharge of the "fossil" Sahara aquifers  

NASA Astrophysics Data System (ADS)

The North-Western Sahara Aquifer System (NWSAS), one of the world's largest groundwater systems, shows an overall piezometric decline associated with increasing withdrawals. Estimating the recharge rate in such a semiarid system is challenging but crucial for sustainable water development. In this paper, the recharge of the NWSAS is estimated using a regional water budget based on GRACE terrestrial water storage monthly records, soil moisture from the GLDAS (a land data system that assimilates hydrological information), and groundwater pumping rates. A cumulated natural recharge rate of 1.40 ± 0.90 km3 yr-1is estimated for the two main aquifers. Our results suggest a renewal rate of about 40% which partly contradicts the premise that recharge in this area should be very low or even null. Aquifer depletion inferred from our analysis is consistent with observed piezometric head decline in the two main aquifers in the region. Annual recharge variations were also estimated and vary between 0 and 4.40 km3 yr-1for the period 2003-2010. These values correspond to a recharge between 0 and 6.75 mm yr-1 on the 650,000 km2of outcropping areas of the aquifers, which is consistent with the expected weak and sporadic recharge in this semiarid environment. These variations are also in line with annual rainfall variation with a lag time of about 1 year.

GonçAlvèS, J.; Petersen, J.; Deschamps, P.; Hamelin, B.; Baba-Sy, O.

2013-06-01

289

Echo Meadows Project Winter Artificial Recharge.  

SciTech Connect

This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echo Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further found that this water can be timed to return to the river during the desired time of the year (summer to early fall). This is because the river stage, which remains relatively high until this time, drops during the irrigation season-thereby releasing the stored groundwater and increasing river flows. A significant side benefit is that these enhanced groundwater return flows will be clean and cold, particularly as compared to the Umatilla River. We also believe that this same type of application of water could be done and the resulting stream flows could be realized in other watersheds throughout the Pacific Northwest. This means that it is critical to compare the results from this baseline report to the full implementation of the project in the next phase. As previously stated, this report only discusses the results of data gathered during the baseline phase of this project. We have attempted to make the data that has been gathered accessible with the enclosed databases and spreadsheets. We provide computer links in this report to the databases so that interested parties can fully evaluate the data that has been gathered. However, we cannot emphasize too strongly that the real value of this project is to implement the phases to come, compare the results of these future phases to this baseline and develop the science and strategies to successfully implement this concept to other rivers in the Pacific Northwest. The results from our verified and calibrated groundwater model matches the observed groundwater data and trends collected during the baseline phase. The modeling results indicate that the return flows may increase to their historic values with the addition of 1 acre-ft/acre of recharge water to the groundwater system (about 9,600 acre-feet total). What this means is that through continued recharge project, you can double to quadruple the annual baseflow of the Umatilla River during the low summer and fall flow periods as compared to the present base-flow. The cool and high quality recharge water is a significant beneficial impact to the river system.

Ziari, Fred

2002-12-19

290

Spatial and temporal distribution of groundwater recharge in northern Nigeria  

NASA Astrophysics Data System (ADS)

Moisture samples obtained from unsaturated-zone profiles in sands from northern Nigeria were used to obtain recharge estimates using the chloride (Cl) mass-balance method and to produce records of past recharge and climatic events. Recharge rates range from 14-49 mm/year, on the basis of unsaturated-zone Cl values and rainfall chemistry measured over eight years at three local stations. The unsaturated-zone results also provide a record of the changing recharge and climatic events of the past 80 years; this record compares quite well with modelling results using precipitation data from Maiduguri, especially for the late 20th-century period of drought. The best fit for the model is made, however, by using a lower mean rainfall Cl (0.65 mg/l) than that obtained from the mean of the field results (1.77 mg/l Cl). This result implies that the measured rainfall Cl probably overestimates the depositional flux of Cl, although the lower value is comparable to the minimum of the measured rainfall Cl values (0.6 mg/l Cl). Recharge estimates made using these lower Cl values range from 16-30 mm/year. The spatial variability was then determined using results from 360 regional shallow wells over 18,000 km2. Using the revised rainfall estimate, the Cl balance indicates a value of 43 mm for the regional recharge, suggesting that either additional preferential flow is taking place over and above that from the vadose one, or that the regional recharge represents inputs from earlier wetter periods. These recharge estimates compare favourably with those from hydraulic modelling in the same area and suggest that the recharge rates are much higher than values previously published for this area. High nitrate (NO3) concentrations (NO3-N>Cl) preserved under aerobic conditions in the vadose zone reflect secondary enrichment from N-fixing vegetation, as occurs elsewhere in the Sahel.

Edmunds, W. M.; Fellman, E.; Goni, I. B.; Prudhomme, C.

2002-02-01

291

Soil Water Balance and Recharge Monitoring at the Hanford Site – FY 2010 Status Report  

SciTech Connect

This report summarizes the recharge data collected in FY 2010 at five locations on the Hanford Site in southeastern Washington State. Average monthly precipitation and temperature conditions in FY 2010 were near normal and did not present an opportunity for increased recharge. The recharge monitoring data confirmed those conditions, showing normal behavior in water content, matric head, and recharge rates. Also provided in this report is a strategy for recharge estimation for the next 5 years.

Fayer, Michael J.; Saunders, Danielle L.; Herrington, Ricky S.; Felmy, Diana

2010-10-27

292

GROUNDWATER RECHARGE/DISCHARGE, NEUSE RIVER WATERSHED, NC  

EPA Science Inventory

The North Carolina Department of Environment and Natural Resources, Division of Water Quality and Groundwater Section, in cooperation with the NC Center for Geographic Information and Analysis, developed the Groundwater Recharge/Discharge digital data to enhance planning, siting ...

293

Waste Water Recharge and Dispersion in Porous Media.  

National Technical Information Service (NTIS)

The recharge and disposal of treated and untreated waste waters in aquifers results in a mixing of these waters with the natural groundwater. The distribution and boundaries of the ensuing mixture are determined by dispersion and diffusion. This study inc...

J. A. Hoopes D. R. F. Harleman

1965-01-01

294

Reliability of Rechargeable Batteries in a Photovoltaic Power Supply System.  

National Technical Information Service (NTIS)

We investigate the reliability If a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. A model system was constructed for this that includes the solar resource, the photovoltaic power supp Iy system, the rec...

P. Barney R. G. Jungst C. O'Gorman T. L. Paez A. Urbina

1998-01-01

295

New Mechanically Rechargeable Zinc/Air Battery Design.  

National Technical Information Service (NTIS)

Performance characteristics of the Yardney 20 AH Zinc/Air mechanically rechargeable systems are discussed in the light of the high power output requirements of the Technical Guidelines. Several design changes and improvements were incorporated into the bi...

R. F. Chireau R. G. Gunther

1972-01-01

296

Improved zinc electrode and rechargeable zinc-air battery  

Microsoft Academic Search

The invention comprises an improved rechargeable zinc-air cell\\/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

P. N. Jr

1988-01-01

297

Improved zinc electrode and rechargeable zinc-air battery  

DOEpatents

The invention comprises an improved rechargeable zinc-air cell/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

Ross, P.N. Jr.

1988-06-21

298

ENGINEERING ECONOMIC ANALYSIS OF A PROGRAM FOR ARTIFICIAL GROUNDWATER RECHARGE.  

USGS Publications Warehouse

This study describes and demonstrates two alternate methods for evaluating the relative costs and benefits of artificial groundwater recharge using percolation ponds. The first analysis considers the benefits to be the reduction of pumping lifts and land subsidence; the second considers benefits as the alternative costs of a comparable surface delivery system. Example computations are carried out for an existing artificial recharge program in Santa Clara Valley in California. A computer groundwater model is used to estimate both the average long term and the drought period effects of artificial recharge in the study area. Results indicate that the costs of artificial recharge are considerably smaller than the alternative costs of an equivalent surface system. Refs.

Reichard, Eric, G.; Bredehoeft, John, D.

1984-01-01

299

Materials issues in lithium ion rechargeable battery technology.  

National Technical Information Service (NTIS)

Lithium ion rechargeable batteries are predicted to replace Ni/Cd as the workhorse consumer battery. The pace of development of this battery system is determined in large part by the availability of materials and the understanding of interfacial reactions...

D. H. Doughty

1995-01-01

300

Transition Metal Compounds as Cathodic Materials in Rechargeable Lithium Cells.  

National Technical Information Service (NTIS)

A comparison was made between rechargeable lithium batteries, based on lithium intercalation or lithium interstitial compounds of transition metal chalcogenides or oxides, and nickel-cadmium batteries. Several chalcogenides and oxides show promise as cath...

H. F. Hunger J. E. Ellison

1977-01-01

301

Status of the Development of Rechargeable Lithium Cells.  

National Technical Information Service (NTIS)

The progress in the development of the ambient temperature lithium - titanium disulfide rechargeable cell under development at the Jet Propulsion Laboratory is described in this paper. Originally aimed at achieving a specific energy of 100 Wh/kg, 'AA' cel...

G. Halpert S. Surampudi D. Shen C. Huang S. Narayanan

1993-01-01

302

Reliability of Rechargeable Batteries in a Photovoltaic Power Supply System  

SciTech Connect

We investigate the reliability If a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. A model system was constructed for this that includes the solar resource, the photovoltaic power supp Iy system, the rechargeable battery and a load. The solar resource and the system load are modeled as SI ochastic processes. The photovoltaic system and the rechargeable battery are modeled deterministically, imd an artificial neural network is incorporated into the model of the rechargeable battery to simulate dartage that occurs during deep discharge cycles. The equations governing system behavior are solved simultaneously in the Monte Carlo framework and a fwst passage problem is solved to assess system reliability.

Barney, P.; Jungst, R.G., Ingersoll, D.; O'Gorman, C.; Paez, T.L.; Urbina, A.

1998-11-30

303

Bipolar rechargeable lithium battery for high power applications  

NASA Technical Reports Server (NTRS)

Viewgraphs of a discussion on bipolar rechargeable lithium battery for high power applications are presented. Topics covered include cell chemistry, electrolytes, reaction mechanisms, cycling behavior, cycle life, and cell assembly.

Hossain, Sohrab; Kozlowski, G.; Goebel, F.

1993-01-01

304

Graphite fiber as a positive electrode of rechargeable lithium cells  

SciTech Connect

Graphite compounds have gained interest as possible positive electrodes for rechargeable lithium cells. Their charge-discharge characteristics have been studied in organic electrolytic solutions such as sulfolane dimethylsulfite, and propylene carbonate.

Matsuda, Y.; Katsuma, H.; Morita, M.

1984-01-01

305

Layer cathode methods of manufacturing and materials for Li-ion rechargeable batteries  

DOEpatents

A positive electrode active material for lithium-ion rechargeable batteries of general formula Li.sub.1+xNi.sub..alpha.Mn.sub..beta.A.sub..gamma.O.sub.2 and further wherein A is Mg, Zn, Al, Co, Ga, B, Zr, or Ti and 0aqueous solution method or a sol-gel method which is followed by a rapid quenching from high temperatures into liquid nitrogen or liquid helium.

Kang, Sun-Ho (Naperville, IL) [Naperville, IL; Amine, Khalil (Downers Grove, IL) [Downers Grove, IL

2008-01-01

306

Cryogenic Transport of High-Pressure-System Recharge Gas  

NASA Technical Reports Server (NTRS)

A method of relatively safe, compact, efficient recharging of a high-pressure room-temperature gas supply has been proposed. In this method, the gas would be liquefied at the source for transport as a cryogenic fluid at or slightly above atmospheric pressure. Upon reaching the destination, a simple heating/expansion process would be used to (1) convert the transported cryogenic fluid to the room-temperature, high-pressure gaseous form in which it is intended to be utilized and (2) transfer the resulting gas to the storage tank of the system to be recharged. In conventional practice for recharging high-pressure-gas systems, gases are transported at room temperature in high-pressure tanks. For recharging a given system to a specified pressure, a transport tank must contain the recharge gas at a much higher pressure. At the destination, the transport tank is connected to the system storage tank to be recharged, and the pressures in the transport tank and the system storage tank are allowed to equalize. One major disadvantage of the conventional approach is that the high transport pressure poses a hazard. Another disadvantage is the waste of a significant amount of recharge gas. Because the transport tank is disconnected from the system storage tank when it is at the specified system recharge pressure, the transport tank still contains a significant amount of recharge gas (typically on the order of half of the amount transported) that cannot be used. In the proposed method, the cryogenic fluid would be transported in a suitably thermally insulated tank that would be capable of withstanding the recharge pressure of the destination tank. The tank would be equipped with quick-disconnect fluid-transfer fittings and with a low-power electric heater (which would not be used during transport). In preparation for transport, a relief valve would be attached via one of the quick-disconnect fittings (see figure). During transport, the interior of the tank would be kept at a near-ambient pressure far below the recharge pressure. As leakage of heat into the tank caused vaporization of the cryogenic fluid, the resulting gas would be vented through the relief valve, which would be set to maintain the pressure in the tank at the transport value. Inasmuch as the density of a cryogenic fluid at atmospheric pressure greatly exceeds that of the corresponding gas in a practical high-pressure tank at room temperature, a tank for transporting a given mass of gas according to the proposed method could be smaller (and, hence, less massive) than is a tank needed for transporting the same mass of gas according to the conventional method.

Ungar, Eugene K,; Ruemmele, Warren P.; Bohannon, Carl

2010-01-01

307

Estimating ground-water recharge from streamflow records  

Microsoft Academic Search

The purpose of this paper is to estimate ground-water recharge based on the investigation of the balance between ground-water recharge and discharge from streamflow hydrographs. Two methods of hydrograph analysis are employed in a case study of Cho-Shui River basin, Taiwan. The first is the recession-curve-displacement method, which assumes the linearity of the master recession curve while the profile of

Wei-Ping Chen; Cheng-Haw Lee

2003-01-01

308

Delineating volcanic aquifer recharge areas using geochemical and isotopic tools  

Microsoft Academic Search

Relative recharge areas are evaluated using geochemical and isotopic tools, and inverse modeling. Geochemistry and water quality\\u000a in springs discharging from a volcanic aquifer system in Guatemala are related to relative recharge area elevations and land\\u000a use. Plagioclase feldspar and olivine react with volcanically derived CO2 to produce Ca-montmorillonite, chalcedony and goethite in the groundwater. Alkalinity, Mg, Ca, Na, and

Brendan M. Mulligan; M. Cathryn Ryan; Tomás Padilla Cámbara

309

An approach for predicting groundwater recharge in mountainous watersheds  

NASA Astrophysics Data System (ADS)

SummaryPredicting groundwater supply for an entire watershed in mountainous terrain required an approach that considered a wide range in data availability between valley bottom and headwater areas, large change in elevation, and steep topography. The methodology utilized the MIKE-SHE numerical code to simulate overland flow, actual evapotranspiration and recharge for data-rich areas, and a simpler, seasonal water budget for data-limited areas. Recharge estimates were combined to form spatially variable recharge boundary conditions for a larger-scale groundwater flow model of the entire mountainous watershed. Research focused on the BX Creek watershed, located in the north Okanagan Basin in British Columbia, one of Canada's fastest growing and most water-limited regions. Groundwater recharge was found to vary from 0 to 20 mm/yr at lower elevations, and from 20 to 50 mm/yr at higher elevations. Simulation of the whole flow system illustrated that 58% of the groundwater flux from upland areas occurs through a relatively narrow alluvial fan aquifer that extends to the valley bottom, and the remaining recharge is nearly equally divided between groundwater flow through the mountain block (20%) and direct recharge (22%). Geochemical data from domestic water wells within the watershed suggest that water in the alluvial aquifer and bedrock are generally similar (i.e., common origin); however, stable isotope data indicate that groundwater in the alluvial aquifer may be derived from snowmelt recharge at a different time and elevation than snowmelt recharge to the bedrock. The combination of modelling results and complimentary geochemical and isotopic analyses of surface water and groundwater, provide an adequate first-order approximation of groundwater flow in the watershed.

Smerdon, B. D.; Allen, D. M.; Grasby, S. E.; Berg, M. A.

2009-02-01

310

Zinc electrode and rechargeable zinc-air battery  

SciTech Connect

This patent describes an improved zinc electrode for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed.

Ross, P.N. Jr.

1989-06-27

311

Electrochemical behavior of hydrated molybdenum oxides in rechargeable lithium batteries  

Microsoft Academic Search

Oxide-hydrates of molybdenum (OHM) are investigated as 3-volt cathode materials for rechargeable lithium batteries. These\\u000a materials with different water content showed a much better performance than that of MoO3 as cathode of the rechargeable lithium battery. We report the electrochemical characteristics of Li\\/\\/OHM batteries using\\u000a the oxides and oxide-hydrates of molybdenum which were synthesized from molybdic acid. The oxide has

B. Yebka; C. Julien; G. A. Nazri

1999-01-01

312

Inorganic electrolyte Li\\/CuCl2 rechargeable cell  

Microsoft Academic Search

A rechargeable lithium battery using a cathode of copper(II) chloride and an electrolyte consisting of LiAlCl4.3SO2 has been developed. The efficiency of lithium plating was evaluated in lithium-limited prototype cells. Cathode rechargeability was evaluated in cathode-limited prototypes, and system energy density was demonstrated by use of a wound D cell. The use of an electrolyte system which reacts reversibly with

A. N. Dey; W. L. Bowden; H. C. Kuo; M. L. Gopikanth; C. Schlaikjer; D. Foster

1989-01-01

313

Rechargeable Li\\/V2O5 D cell development  

Microsoft Academic Search

The authors report on practical ambient temperature rechargeable lithium cells and batteries using V2O5. V2 O5 has interesting characteristics as a positive for lithium rechargeable cells. The material can be used to a 2.8 V discharge cutoff (upper plateau) or to 2 V. The development of practical D size cells for both uses is discussed, and capacity retention date and

R. J. Staniewicz; A. Romero; M. Broussely; J. M. Bodet; J. Labat

1992-01-01

314

Estimating aquifer channel recharge using optical data interpretation.  

PubMed

Recharge through intermittent and ephemeral stream channels is believed to be a primary aquifer recharge process in arid and semiarid environments. The intermittent nature of precipitation and flow events in these channels, and their often remote locations, makes direct flow and loss measurements difficult and expensive. Airborne and satellite optical images were interpreted to evaluate aquifer recharge due to stream losses on the Frio River in south-central Texas. Losses in the Frio River are believed to be a major contributor of recharge to the Edwards Aquifer. The results of this work indicate that interpretation of readily available remote sensing optical images can offer important insights into the spatial distribution of aquifer recharge from losing streams. In cases where upstream gauging data are available, simple visual analysis of the length of the flowing reach downstream from the gauging station can be used to estimate channel losses. In the case of the Frio River, the rate of channel loss estimated from the length of the flowing reach at low flows was about half of the loss rate calculated from in-stream gain-loss measurements. Analysis based on water-surface width and channel slope indicated that losses were mainly in a reach downstream of the mapped recharge zone. The analysis based on water-surface width, however, did not indicate that this method could yield accurate estimates of actual flow in pool and riffle streams, such as the Frio River and similar rivers draining the Edwards Plateau. PMID:21434908

Walter, Gary R; Necsoiu, Marius; McGinnis, Ronald

2012-01-01

315

Seasonal variation in natural recharge of coastal aquifers  

NASA Astrophysics Data System (ADS)

Many coastal zones around the world have irregular precipitation throughout the year. This results in discontinuous natural recharge of coastal aquifers, which affects the size of freshwater lenses present in sandy deposits. Temperature data for the period 1960-1990 from LocClim (local climate estimator) and those obtained from the Intergovernmental Panel on Climate Change (IPCC) SRES A1b scenario for 2070-2100, have been used to calculate the potential evapotranspiration with the Thornthwaite method. Potential recharge (difference between precipitation and potential evapotranspiration) was defined at 12 locations: Ameland (The Netherlands), Auckland and Wellington (New Zealand); Hong Kong (China); Ravenna (Italy), Mekong (Vietnam), Mumbai (India), New Jersey (USA), Nile Delta (Egypt), Kobe and Tokyo (Japan), and Singapore. The influence of variable/discontinuous recharge on the size of freshwater lenses was simulated with the SEAWAT model. The discrepancy between models with continuous and with discontinuous recharge is relatively small in areas where the total annual recharge is low (258-616 mm/year); but in places with Monsoon-dominated climate (e.g. Mumbai, with recharge up to 1,686 mm/year), the difference in freshwater-lens thickness between the discontinuous and the continuous model is larger (up to 5 m) and thus important to consider in numerical models that estimate freshwater availability.

Mollema, Pauline N.; Antonellini, Marco

2013-06-01

316

Rechargeable Magnesium Batteries: Low-Cost Rechargeable Magnesium Batteries with High Energy Density  

SciTech Connect

BEEST Project: Pellion Technologies is developing rechargeable magnesium batteries that would enable an EV to travel 3 times farther than it could using Li-ion batteries. Prototype magnesium batteries demonstrate excellent electrochemical behavior; delivering thousands of charge cycles with very little fade. Nevertheless, these prototypes have always stored too little energy to be commercially viable. Pellion Technologies is working to overcome this challenge by rapidly screening potential storage materials using proprietary, high-throughput computer models. To date, 12,000 materials have been identified and analyzed. The resulting best materials have been electrochemically tested, yielding several very promising candidates.

None

2010-10-01

317

Rechargeable wireless EMG sensor for prosthetic control.  

PubMed

Surface electrodes in modern myoelectric prosthetics are often embedded in the prosthesis socket and make contact with the skin. These electrodes detect and amplify muscle action potentials from voluntary contractions of the muscle in the residual limb and are used to control the prosthetic's movement and function. There are a number of performance-related deficiencies associated with external electrodes including the maintenance of sufficient electromyogram (EMG) signal amplitude, extraneous noise acquisition, and proper electrode interface maintenance that are expected to be improved or eliminated using the proposed implanted sensors. This research seeks to investigate the design components for replacing external electrodes with fully-implantable myoelectric sensors that include a wireless interface to the prosthetic limbs. This implanted technology will allow prosthetic limb manufacturers to provide products with increased performance, capability, and patient-comfort. The EMG signals from the intramuscular recording electrode are amplified and wirelessly transmitted to a receiver in the prosthetic limb. Power to the implant is maintained using a rechargeable battery and an inductive energy transfer link from the prosthetic. A full experimental system was developed to demonstrate that a wireless biopotential sensor can be designed that meets the requirements of size, power, and performance for implantation. PMID:21095801

Lichter, P A; Lange, E H; Riehle, T H; Anderson, S M; Hedin, D S

2010-01-01

318

Wearable textile battery rechargeable by solar energy.  

PubMed

Wearable electronics represent a significant paradigm shift in consumer electronics since they eliminate the necessity for separate carriage of devices. In particular, integration of flexible electronic devices with clothes, glasses, watches, and skin will bring new opportunities beyond what can be imagined by current inflexible counterparts. Although considerable progresses have been seen for wearable electronics, lithium rechargeable batteries, the power sources of the devices, do not keep pace with such progresses due to tenuous mechanical stabilities, causing them to remain as the limiting elements in the entire technology. Herein, we revisit the key components of the battery (current collector, binder, and separator) and replace them with the materials that support robust mechanical endurance of the battery. The final full-cells in the forms of clothes and watchstraps exhibited comparable electrochemical performance to those of conventional metal foil-based cells even under severe folding-unfolding motions simulating actual wearing conditions. Furthermore, the wearable textile battery was integrated with flexible and lightweight solar cells on the battery pouch to enable convenient solar-charging capabilities. PMID:24164580

Lee, Yong-Hee; Kim, Joo-Seong; Noh, Jonghyeon; Lee, Inhwa; Kim, Hyeong Jun; Choi, Sunghun; Seo, Jeongmin; Jeon, Seokwoo; Kim, Taek-Soo; Lee, Jung-Yong; Choi, Jang Wook

2013-01-01

319

Rechargeable thin-film lithium batteries  

SciTech Connect

Rechargeable thin-film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have been fabricated and characterized. These include Li-TiS{sub 2}, Li-V{sub 2}O{sub 5}, and Li-Li{sub x}Mn{sub 2}O{sub 4} cells with open circuit voltages at full charge of about 2.5 V, 3.7 V, and 4.2 V, respectively. The realization of these robust cells, which can be cycled thousands of times, was possible because of the stability of the amorphous lithium electrolyte, lithium phosphorus oxynitride. This material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46}and a conductivity at 25 C of 2 {mu}S/cm. The thin-film cells have been cycled at 100% depth of discharge using current densities of 5 to 100 {mu}A/cm{sup 2}. Over most of the charge-discharge range, the internal resistance appears to be dominated by the cathode, and the major source of the resistance is the diffusion of Li{sup +} ions from the electrolyte into the cathode. Chemical diffusion coefficients were determined from ac impedance measurements.

Bates, J.B.; Gruzalski, G.R.; Dudney, N.J.; Luck, C.F.; Yu, X.

1993-09-01

320

Electrolyte for laminated polymer lithium rechargeable battery  

NASA Astrophysics Data System (ADS)

Proposed thin film battery is comprised of a polymer-lithium ion cell material with barrier-layer packaging and mechanical reinforcing layers. A semi-solid/ solid electrolyte and a mesoporous polymer separator are sandwiched in between of anode and cathode. A composite film with a carbon nanotube (CNT) network serves as the anode and a mesoporous transitional metal oxide LixCoO2 as the cathode, where porous metal sheets serve as the current collector. The CNT network fabrics have high in-plane tensile strength. LiCoO2 is used as the cathode, because the Co atoms do not migrate to Li layers, so that cathode does not generate flammable gases during charging that create safety problems. Merit of this study is using the porous metal sheet, which is flexible, lightweight, low electric resistance, high strength and strong stability in alkaline solution. This paper presented development of electrolyte for laminated polymer lithium rechargeable battery. Two-type electrolytes, semi-solid and solid, were attempted; high ionic conductivity of Li ion electrolytes was achieved.

Xu, Chunye; Ma, Chao; Taya, Minoru

2008-05-01

321

Organic electrolyte for use in a lithium rechargeable electrochemical cell and lithium rechargeable electrochemical cell including said organic electrolyte  

Microsoft Academic Search

This invention relates in general to use of an organic electrolyte in a lithium rechargeable electrochemical cell and to a lithium rechargeable electrochemical cell including said electrolyte; and, in particular, to the use of 1 to 2 mol\\/dm³ LiAsFâ in dimethylcarbonate (DMC) or 1 to 2 mol\\/dm³ LiAsFâ in (DMC) mixtures with methyl formate (MF) in which the mass percent

E. J. Plichta; S. M. Slane; M. Salomon

1987-01-01

322

Competitive systems - Ambient temperature rechargeable batteries  

NASA Astrophysics Data System (ADS)

Recent in designs of aqueous electrolyte secondary batteries are presented. Operation principles, performance characteristics, and applications of various types of lead/acid batteries, alkaline electrolyte batteries, flow batteries, and battery/fuel cell hybrids (such as metal/air and hydrogen/metal oxide systems) are discussed. Consideration is given to the relative importance of such battery parameters as deep discharge capability, freedom from maintenance, shelf life, and cost, depending upon the specific application.

dell, R. M.

323

Estimated Infiltration, Percolation, and Recharge Rates at the Rillito Creek Focused Recharge Investigation Site, Pima County, Arizona  

USGS Publications Warehouse

A large fraction of ground water stored in the alluvial aquifers in the Southwest is recharged by water that percolates through ephemeral stream-channel deposits. The amount of water currently recharging many of these aquifers is insufficient to meet current and future demands. Improving the understanding of streambed infiltration and the subsequent redistribution of water within the unsaturated zone is fundamental to quantifying and forming an accurate description of streambed recharge. In addition, improved estimates of recharge from ephemeral-stream channels will reduce uncertainties in water-budget components used in current ground-water models. This chapter presents a summary of findings related to a focused recharge investigation along Rillito Creek in Tucson, Arizona. A variety of approaches used to estimate infiltration, percolation, and recharge fluxes are presented that provide a wide range of temporal- and spatial-scale measurements of recharge beneath Rillito Creek. The approaches discussed include analyses of (1) cores and cuttings for hydraulic and textural properties, (2) environmental tracers from the water extracted from the cores and cuttings, (3) seepage measurements made during sustained streamflow, (4) heat as a tracer and numerical simulations of the movement of heat through the streambed sediments, (5) water-content variations, (6) water-level responses to streamflow in piezometers within the stream channel, and (7) gravity changes in response to recharge events. Hydraulic properties of the materials underlying Rillito Creek were used to estimate long-term potential recharge rates. Seepage measurements and analyses of temperature and water content were used to estimate infiltration rates, and environmental tracers were used to estimate percolation rates through the thick unsaturated zone. The presence or lack of tritium in the water was used to determine whether or not water in the unsaturated zone infiltrated within the past 40 years. Analysis of water-level and temporal-gravity data were used to estimate recharge volumes. Data presented in this chapter were collected from 1999 though 2002. Precipitation and streamflow during this period were less than the long-term average; however, two periods of significant streamflow resulted in recharge?one in the summer of 1999 and the other in the fall/winter of 2000. Flux estimates of infiltration and recharge vary from less than 0.1 to 1.0 cubic meter per second per kilometer of streamflow. Recharge-flux estimates are larger than infiltration estimates. Larger recharge fluxes than infiltration fluxes are explained by the scale of measurements. Methods used to estimate recharge rates incorporate the largest volumetric and temporal scales and are likely to have fluxes from other nearby sources, such as unmeasured tributaries, whereas the methods used to estimate infiltration incorporate the smallest scales, reflecting infiltration rates at individual measurement sites.

Hoffmann, John P.; Blasch, Kyle W.; Pool, Don R.; Bailey, Matthew A.; Callegary, James B.

2007-01-01

324

Fundamental Concepts of Recharge in the Desert Southwest  

NASA Astrophysics Data System (ADS)

Recharge in arid basins does not occur in all years or at all locations. To address the temporal and spatial variability of recharge, one must (1) distinguish between recharge and net infiltration, (2) understand travel time in the unsaturated zone, and (3) comprehend the local- and basin-scale deterministic processes and surficial properties that control net infiltration. Net infiltration is the quantity of water that moves below the zone of surface evapotranspiration whereas recharge is the quantity or process of water entering the saturated zone. Under steady-state conditions, net infiltration becomes recharge unless diverted to an area of spring flow, generally by laterally extensive, low-permeability rock. The rate of net infiltration, thickness of unsaturated zone, and the effective porosity of the flow-pathway control travel time through the unsaturated zone. Net infiltration and recharge vary spatially owing to variations in surface microclimates, root zone and unconsolidated material thickness, faults and fractures, and thickness and hydrologic properties of geologic strata in the unsaturated zone. Although temporal fluctuations in net infiltration diminish with depth, resultant recharge is expected to vary on timescales of days to centuries making decadal-scale climate cycles significant to understanding recharge. Results of model simulations of recharge indicate that net infiltration occurs in less than 5 percent of the area of a typical southwest basin and only when the surface-water supply exceeds the storage capacity of the root zone and evapotranspiration over a fixed period of time. The critical components controlling net infiltration and recharge are precipitation, as rain or snow (and snow accumulation and melt); infiltration and water storage capacity of the overlying soil (within the zone of evapotranspiration); potential and actual evapotranspiration; and bedrock permeability. In the desert Southwest, potential evapotranspiration exceeds precipitation on a yearly basis. However, on shorter time scales and in certain areas of a basin, precipitation and (or) snowmelt exceed the infiltration capacity of the soil and becomes runoff or exceed the storage capacity of the soil and becomes runoff in shallow soils or percolates below the root zone in deeper soils. A method to simulate the spatial and temporal variability of net infiltration was developed using a deterministic water-balance model and extensive GIS coverages. The GIS coverages include a digital elevation model and maps of geology, soils, vegetation, precipitation, and air temperature. Other required surficial properties for the model, such as permeability, porosity, and water-retention functions, have been calculated from associated data sets. The deterministic model identifies the areas and climatic conditions that allow for excess water, quantifies the amount of water available either as runoff or in-place recharge, and allows inter-basin comparison of recharge mechanisms (i.e. mountain front, mountain block, ephemeral stream) and potential recharge for current, wetter, and drier climates. Travel time through the unsaturated zone can be estimated if unsaturated zone thickness and permeability data are available. The model, which uses a monthly time step, is being used to evaluate the role of decadal-scale climate cycles (El Niño/La Niña and the Pacific Decadal Oscillation) and recharge potential at a pixel scale (generally 30 - 90 meters) across the entire desert Southwest.

Flint, A. L.; Flint, L. E.; Blainey, J. B.; Hevesi, J. A.

2001-12-01

325

Coupling Stormwater Capture and Managed Aquifer Recharge  

NASA Astrophysics Data System (ADS)

We are quantifying the performance of a system that couples stormwater capture and managed aquifer recharge (MAR). Our field site is a working ranch in the Pajaro Valley, central coastal California, where runoff from ~125 acres of farmed and grazed land is directed into a 2.5-acre infiltration basin. Stormwater captured for MAR at this site would otherwise be routed off the property and eventually into the ocean. We instrumented the site prior to the start of the 2013 water year (1 October 2012) to measure local precipitation, total inflow to the basin, and point-specific infiltration rates across the bottom of the basin using heat as a tracer. We also deployed sediment measurement and collection instruments to quantify the amount, texture, and biochemical nature of sediment accumulating in the basin, and to evaluate associated maintenance requirements for the system. The 2013 water year was relatively dry, with total precipitation less than 50% of the long-term average for this region; most of this precipitation occurred in December 2012. Water level and flow records indicate 17 distinct rain events that generated runoff, most early in the water year. The total inflow to the infiltration basin was 4.1 x 104 m3, equivalent to ~33 ac-ft. During a water year with average precipitation, it appears that this system could collect 80-100 ac-ft of runoff. There was up to 10 cm of sediment accumulation in some parts of the infiltration basin by the end of the rainy season. Sediment samples collected at the end of the season are being processed for analysis of sediment distribution and character. Thermal data are being analyzed to calculate spatial and temporal variations in infiltration rates across the basin. These data will be combined to assess the efficacy of coupling stormwater capture and MAR, and can guide future projects in this region of high groundwater demand and limited resources.

Beganskas, S.; Hill, C. L.; Fisher, A. T.; Los Huertos, M.

2013-12-01

326

Artificial-Recharge Experiments and Operations on the Southern High Plains of Texas and New Mexico  

USGS Publications Warehouse

Experiments using highly turbid water from playa lakes for injection into the Ogallala Formation have resulted in greatly decreased yield of the recharge wells, Recharge of ground or surface water of good quality has indicated, however, that injection through wells is an effective method of recharging the aquifer. Water that is slightly turbid can be successfully injected for a period of time, but generally results in constantly declining yields and capacity for recharge. Redevelopment through pumping and surging significantly prolongs the life of recharge wells under some conditions. Surface spreading is little practiced on the High Plains, but locally may be a feasible means of artificial recharge.

Brown, Richmond F.; Signor, Donald C.

1973-01-01

327

Fate of human viruses in groundwater recharge systems  

SciTech Connect

The overall objective of this research program was to determine the ability of a well-managed tertiary effluent-recharge system to return virologically acceptable water to the groundwater aquifer. The study assessed the quality of waters renovated by indigenous recharge operations and investigated a number of virus-soil interrelationships. The elucidation of the interactions led to the establishment of basin operating criteria for optimizing virus removal. Raw influents, chlorinated tertiary effluents, and renovated wastewater from the aquifer directly beneath a uniquely designed recharge test basin were assayed on a weekly basis for the presence of human enteroviruses and coliform bacteria. High concentrations of viruses were routinely isolated from influents but were isolated only on four occasions from tertiary-treated sewage effluents. In spite of the high quality effluent being recharged, viruses were isolated from the groundwater observation well, indicating their ability to penetrate the unsaturated zone. Results of poliovirus seeding experiments carried out in the test basin clearly indicated the need to operate recharge basins at low (e.g. 1 cm/h) infiltration rates in areas having soil types similar to those found at the study site. The method selected for reducing the test basin infiltration rate involved clogging the basin surface with settled organic material from highly turbid effluent. Alternative methods for slowing infiltration rates are discussed in the text.

Vaughn, J.M.; Landry, E.F.

1980-03-01

328

Estimating infiltration recharge using a response function model  

NASA Astrophysics Data System (ADS)

Rainfall infiltration influences both the quantity and quality of groundwater systems. The knowledge of the process of infiltration recharge is of great importance to the management of groundwater systems and the hydraulically connected streams. In this study, a response function model is developed to estimate soil water flux at the water table or the process of infiltration recharge from rainfall and evaporation data. The gamma probability density function is modified to represent the travel time distribution of infiltrating water by rainfall events. The travel time distribution is used to determine the recharge process according to the effective infiltration of a rainfall event. The effective infiltration is the amount of soil water pushed down into groundwater by infiltrating water of a rainfall event and is evaluated based on the vadose-zone soil water balance. Superposition is employed to compute the recharge rate produced by a sequence of rainfall events. Estimations of soil water flux at different groundwater depths are compared with lysimetric observations in the field. Good agreements between the estimated and observed results confirm the reliability of the response function model for predicting infiltration recharge processes.

Wu, Jinquan; Zhang, Renduo; Yang, Jinzhong

1997-11-01

329

Biologically derived melanin electrodes in aqueous sodium-ion energy storage devices  

PubMed Central

Biodegradable electronics represents an attractive and emerging paradigm in medical devices by harnessing simultaneous advantages afforded by electronically active systems and obviating issues with chronic implants. Integrating practical energy sources that are compatible with the envisioned operation of transient devices is an unmet challenge for biodegradable electronics. Although high-performance energy storage systems offer a feasible solution, toxic materials and electrolytes present regulatory hurdles for use in temporary medical devices. Aqueous sodium-ion charge storage devices combined with biocompatible electrodes are ideal components to power next-generation biodegradable electronics. Here, we report the use of biologically derived organic electrodes composed of melanin pigments for use in energy storage devices. Melanins of natural (derived from Sepia officinalis) and synthetic origin are evaluated as anode materials in aqueous sodium-ion storage devices. Na+-loaded melanin anodes exhibit specific capacities of 30.4 ± 1.6 mAhg?1. Full cells composed of natural melanin anodes and ?-MnO2 cathodes exhibit an initial potential of 1.03 ± 0.06 V with a maximum specific capacity of 16.1 ± 0.8 mAhg?1. Natural melanin anodes exhibit higher specific capacities compared with synthetic melanins due to a combination of beneficial chemical, electrical, and physical properties exhibited by the former. Taken together, these results suggest that melanin pigments may serve as a naturally occurring biologically derived charge storage material to power certain types of medical devices.

Kim, Young Jo; Wu, Wei; Chun, Sang-Eun; Whitacre, Jay F.; Bettinger, Christopher J.

2013-01-01

330

Heat transport in the vicinity of an artificial recharge site  

NASA Astrophysics Data System (ADS)

Since July 2002, the Intermunicipal Water Company of the Veurne region (IWVA) artificially recharges fresh water in the dunes of the western Belgian coastal plain by means of two recharge ponds. This recharge water is produced from secondary treated waste water effluent by the combination of ultra filtration and reverse osmosis. Extraction wells (112) are located north and south of the ponds. The artificial recharge project loops the water cycle: extracted water goes to the users and their waste water is purified and re-used. Therefore, it is an example of sustainable water management in coastal aquifers. Groundwater flow of this recharge site has been examined in the past by the use of a tracer test, hydrochemistry (environmental isotopes, conservative tracers) and groundwater flow modelling. Temperature, however, forms a relatively easy measurement which can add to or confirm the knowledge of the groundwater flow. Temperature time series (temperature as function of time) were measured at different levels in a number of wells located between the recharge ponds and the extraction wells, and in one well south of the recharge and extraction area. Secondly, temperature logs (temperature as function of depth) were measured in these wells at different times over the course of 2 years. Finally, the temperature of the recharged and extracted water is constantly monitored by the water company. The temperature of the recharge water shows a yearly fluctuation, ranging from 25 °C during summer to slightly above 0 °C during the winter. The temperature of the extracted water (combination of water extracted in all the wells) ranges between 17 °C during summer and 10 °C during winter. Minima and maxima in the extracted water are observed between 76 and 110 days (mean of 90 days and standard deviation of 13.5 days) later in the extracted water with respect to the recharged water. Measurements show that the difference in time when maxima and minima are observed in an observation well with reference to the ponds increases with depth (for instance from 28 days 4.1 m below surface to 154 days 10 m below surface for an observation well at 10 m from the ponds). This confirms previous flow modelling which showed that groundwater flows relatively rapidly laterally from the recharge ponds towards the extraction wells. Additionally, part of the recharge water flows in a deeper flow cycle towards the extraction wells. Residence times in this deeper flow cycle are evidently larger than in the direct lateral flow cycle from the ponds towards the wells. This explains the increase with depth. The 154 days (with respect to a mean time of 90 days) points to the fact that the extracted water contains a large spectrum of residence times with mean of 90 days for the heat transport, as was also derived by the flow modelling previously

Vandenbohede, Alexander; van Houtte, Emmanuel; Lebbe, Luc

2010-05-01

331

The development and challenges of rechargeable non-aqueous lithium–air batteries  

Microsoft Academic Search

Lithium–air (Li–air) batteries have recently received much attention due to their extremely high theoretical energy densities. The significantly larger theoretical energy density of Li–air batteries is due to the use of a pure lithium metal anode and the fact that the cathode oxidant, oxygen, is stored externally since it can be readily obtained from the surrounding air. However, before Li–air

Lei-Lei Zhang; Zhong-Li Wang; Dan Xu; Xin-Bo Zhang; Li-Min Wang

2012-01-01

332

Hydrogeology of Regional Valley Fill Aquifers with Mountain System Recharge  

NASA Astrophysics Data System (ADS)

Groundwater in the North Okanagan was investigated using an integrated physical, geochemical and numerical approach. The North Okanagan Groundwater Characterization and Assessment (NOGWCA) project began with an investigation of the geology and hydrostratigraphy of the North Okanagan region. The Deep Creek and Fortune Creek watersheds were found to contain multiple valley-fill aquifers which are recharged via mountain system recharge (MSR) and direct recharge to unconfined aquifers in the valley bottom. Detailed hydrometric data indicates groundwater recharge within the alluvial fan of Fortune Creek, and discharge to surface water in the lower reaches of Deep Creek. Valley side recharge from the adjacent mountains generates artesian conditions in the valley center. Physical hydrogeological measurements and groundwater and surface water geochemistry were used to determine the overall groundwater flow regime, inter-aquifer exchange and surface-water groundwater interactions. Conservative elements and deuterium/oxygen isotopes were used in a mixing cell model (MCM) approach to assess groundwater flow between aquifers. Efforts to accurately quantify and understand MSR are hampered by sparse data on the geochemical character of bedrock aquifers. Watershed scale recharge estimates and water balances were derived from a regional integrated climate dataset coupled to FEFLOW simulations. The first stage modeled steady state conditions within the main valley center aquifer. Integrated surface water and groundwater modeling is to be carried out in the future. The groundwater flow modeling will contribute to subsequent water management decisions at the watershed scale. Climate change and economic change scenarios will be considered in the integrated surface water and groundwater modeling.

Ping, J.; Nichol, C.; Wei, A.

2009-05-01

333

Study plan for determining recharge rates at the Hanford Site using environmental tracers.  

National Technical Information Service (NTIS)

This report presents a study plan for estimating recharge at the Hanford Site using environmental tracers. Past operations at the Hanford Site have led to both soil and groundwater contamination, and recharge is one of the primary mechanisms for transport...

E. M. Murphy J. E. Szercsody

1991-01-01

334

77 FR 8325 - Sixth Meeting: RTCA Special Committee 225, Rechargeable Lithium Batteries and Battery Systems...  

Federal Register 2010, 2011, 2012, 2013

...Committee 225, Rechargeable Lithium Batteries and Battery Systems, Small and Medium Size...Committee 225, Rechargeable Lithium Batteries and Battery Systems, Small...15 min). Results of EFB thermal runaway on flightdeck...

2012-02-14

335

Transmission losses, infiltration and groundwater recharge through ephemeral and intermittent streambeds: A review of applied methods  

NASA Astrophysics Data System (ADS)

Overview of methods to quantify recharge in ephemeral and intermittent streams.Provides temporal and spatial scales of recharge measured using each method.Identifies gaps in the literature and suggests future directions.

Shanafield, Margaret; Cook, Peter G.

2014-04-01

336

Thin rechargeable batteries for CMOS SRAM memory protection  

NASA Astrophysics Data System (ADS)

New rechargeable battery technology is described and compared with classical primary battery back-up of SRAM PC cards. Thin solid polymer electrolyte cells with the thickness of TSOP memory components (1 mm nominal, 1.1 mm max) and capacities of 14 mAh/sq cm can replace coin cells. The SRAM PC cards with permanently installed rechargeable cells and optional electrochromic low battery voltage indicators will free the periodic PC card user from having to 'feed' their PC cards with coin cells and will allow a quick visual check of stored cards for their battery voltage status.

Crouse, Dennis N.

1993-02-01

337

Thin rechargeable batteries for CMOS SRAM memory protection  

NASA Technical Reports Server (NTRS)

New rechargeable battery technology is described and compared with classical primary battery back-up of SRAM PC cards. Thin solid polymer electrolyte cells with the thickness of TSOP memory components (1 mm nominal, 1.1 mm max) and capacities of 14 mAh/sq cm can replace coin cells. The SRAM PC cards with permanently installed rechargeable cells and optional electrochromic low battery voltage indicators will free the periodic PC card user from having to 'feed' their PC cards with coin cells and will allow a quick visual check of stored cards for their battery voltage status.

Crouse, Dennis N.

1993-01-01

338

Lithium Ion Aqueous Cells.  

National Technical Information Service (NTIS)

Lithium ion aqueous cells were investigated using lithium intercalating compounds as anodes and cathodes. The aqueous electrolyte consisted of 4 to 5 molar solutions of either lithium perchlorate or lithium nitrate which contained lithium hydroxide in mil...

E. J. Plichta W. K. Behl

1995-01-01

339

Ground-Water Recharge Through Active Sand Dunes in Northwestern Nevada  

Microsoft Academic Search

Most water-resouree investigations in semiarid basins of the Great Basin in western North America conclude that groundwater recharge from direct precipitation on the valley floor is negligible. However, many of these basins contain large areas covered by unvegetated, active sand dunes that may act as conduits for ground-water recharge. The potential for this previously undocumented recharge was investigated in an

David L. Berger

1992-01-01

340

A dimensionless number describing the effects of recharge and geometry on discharge from simple karstic aquifers  

Microsoft Academic Search

The responses of karstic aquifers to storms are often used to obtain information about aquifer geometry. In general, spring hydrographs are a function of both system geometry and recharge. However, the majority of prior work on storm pulses through karst has not studied the effect of recharge on spring hydrographs. To examine the relative importance of geometry and recharge, we

M. D. Covington; C. M. Wicks; M. O. Saar

2009-01-01

341

Characterizing Field Biodegradation of N-nitrosodimethylamine (NDMA) in Groundwater with Active Reclaimed Water Recharge  

NASA Astrophysics Data System (ADS)

N-Nitrosodimethylamine (NDMA) is an emerging contaminant in groundwater, because of its aqueous miscibility, exceptional animal toxicity, and human carcinogenicity. NDMA detections in groundwater have been tracked to either decomposition of unsymmetrical dimethylhydrazine (UDMH) used in rocket fuel facilities or chlorine disinfection in wastewater reclamation plants. Laboratory experiments on both unsaturated and saturated soil samples have demonstrated that NDMA can be biodegraded by microbial activity, under both aerobic and anaerobic conditions. However, very limited direct evidence for its biodegradation has been found from the field in saturated groundwater. Our research aimed to evaluate photolysis and biodegradation of NDMA occurring along the full travel path - from wastewater reclamation plant effluent, through rivers and spreading grounds, to groundwater. For this evaluation, we established an extensive monitoring network to characterize NDMA concentrations at effluent discharge points, surface water stations, and groundwater monitoring and production wells, during the operation of the Montebello Forebay Groundwater Recharge facilities in Los Angeles County, California. Field monitoring for NDMA has been conducted for more than six years, including 32 months of relatively lower NDMA concentrations in effluent, 43 months of elevated NDMA effluent concentrations, and 7 months with significantly reduced NDMA effluent concentrations. The NDMA effluent concentration increase and significant concentration decrease were caused by changes in treatment processes. The NDMA sampling data imply that significant biodegradation occurred in groundwater, accounting for a 90% mass reduction of NDMA over the six-year monitoring period. In addition, the occurrence of a discrete well monitored effluent release during the study period allowed critical analysis of the fate of NDMA in a well- characterized, localized groundwater flow subsystem. The data indicate that 80% of the recharged NDMA mass was biodegraded in groundwater with the remaining mass pumped out by extraction wells. To reproduce the observation data, a groundwater flow and transport model was developed and calibrated against groundwater elevation and NDMA concentration data. The calibrated half-life of NDMA in groundwater is 69 days, which is consistent with the values obtained through laboratory incubation using soil samples from the Montebello Forebay Spreading Grounds. Given the photolysis of NDMA in surface water and biodegradation in groundwater observed during this study, reclaimed wastewater with limited NDMA concentrations can be safely used for groundwater recharge under the study area conditions.

McCraven, S.; Zhou, Q.; Garcia, J.; Gasca, M.; Johnson, T.

2007-12-01

342

Oxygen electrodes for rechargeable alkaline fuel cells, 3  

NASA Technical Reports Server (NTRS)

The investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells is described. Focus is on chemical and electrochemical stability and O2 reduction/evolution activity of the electrode in question.

Swette, L.; Kackley, N.; Mccatty, S. A.

1991-01-01

343

WASTEWATER CONTAMINATE REMOVAL FOR GROUNDWATER RECHARGE AT WATER FACTORY 21  

EPA Science Inventory

This is the second report in a series which describes the performance of Water Factory 21, a 0.66 cu m/s advanced wastewater treatment plant designed to reclaim secondary effluent from a municipal wastewater treatment plant so that it can be used for injection and recharge of a g...

344

Trench infiltration for managed aquifer recharge to permeable bedrock  

USGS Publications Warehouse

Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0.5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. ?? 2010.

Heilweil, V. M.; Watt, D. E.

2011-01-01

345

New Mechanically Rechargeable Zinc/Air Battery Design.  

National Technical Information Service (NTIS)

The report discusses a program of study, design and development leading to the fabrication of new high performance 20 amphere hour mechanically rechargeable zinc/air batteries capable of meeting the requirements listed in the U.S. Army Electronics Command...

R. F. Chireau

1973-01-01

346

Zinc electrode and rechargeable zinc-air battery  

Microsoft Academic Search

An improved zinc electrode is disclosed for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the

Philip N

1989-01-01

347

Rechargeable zinc air batteries market and technology overview  

Microsoft Academic Search

AER Energy Resources is an Atlanta based technology company that has developed a rechargeable zinc air battery system. The primary advantage of the AER Energy Advanced Technology Battery is that its energy density on a weight basis is three times that of nickel cadmium, nickel metal hydride and lead acid batteries, and fifty percent higher than lithium ion batteries. This

M. Schimpf

1995-01-01

348

Zinc electrode and rechargeable zinc-air battery  

Microsoft Academic Search

This patent describes an improved zinc electrode for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through

P. N. Jr

1989-01-01

349

Recent advances in rechargeable zinc-air battery technology  

Microsoft Academic Search

AER Energy's battery development effort is focused on improving the zinc-air rechargeable battery system to serve the portable computer market. Therefore system attributes such as energy density, power, life, form factor, environmental impact and safety are areas of active investigation. The battery system consists of cells in series, an air manager housing and an electronic control system for battery charge

D. Sieminski

1997-01-01

350

Rechargeable lithium battery anodes: alternatives to metallic lithium  

Microsoft Academic Search

This review is concerned with alternatives to metallic lithium for use in rechargeable lithium batteries. Emphasis is placed on the use of various materials and combinations of materials in different types of electrodes rather than on the properties of the materials themselves. The review includes carbon based electrodes, alloys, conducting polymers and transition metal compounds. Special consideration is given to

D. Fauteux; R. Koksbang

1993-01-01

351

Rechargeable lithium batteries in the Navy-policy and protocol  

Microsoft Academic Search

Rechargeable lithium batteries are an emerging technology that is finding widespread use in a myriad of applications. These batteries are supplanting many others because of superior performance characteristics, including high energy density and improved cycle life. The newest model laptop computers, camcorders and cellular phones are using these systems to provide lighter products with longer battery life. Potential military-use scenarios

Julie A. Banner; Clinton S. Winchester

1996-01-01

352

Hysteresis in Thin-Film Rechargeable Lithium Batteries.  

National Technical Information Service (NTIS)

Discharge - charge cycling of thin-film rechargeable lithium batteries with an amorphous or nanocrystalline LiXMn2.Y04 cathode reveals evidence for a true hysteresis in the lithium insertion reaction. This is compared with an apparent hysteresis attribute...

J. B. Bates N. J. Dudney C. D. Evans F. X. Hart

1999-01-01

353

Oxygen electrodes for rechargeable alkaline fuel cells-II  

NASA Technical Reports Server (NTRS)

The primary objective of this program is the investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single-unit rechargeable alkaline fuel cells. Approximately six support materials and five catalyst materials have been identified to date for further development.

Swette, L.; Kackley, N.

1989-01-01

354

Method of Increasing the Useful Life of Rechargeable Lithium Batteries.  

National Technical Information Service (NTIS)

The cycle life of rechargeable lithium batteries is significantly prolonged by applying to the battery as a charging mode a current interrupted at intervals of 1 milliseconds to 9 seconds in a frequency range of about 0.1 to about 10 Hertz.

O. C. Wagner

1986-01-01

355

Rechargeable Battery Management and Recycling: A Green Design Educational Module  

Microsoft Academic Search

Rechargeable battery use is expected to continue growing with the increasing prevalence of portable electronics, appliances, and tools. Batteries represent a large volume of toxic and hazardous materials in common use, and these materials must be managed to avoid or minimize dissipation into the environment. One type of battery widely used in portable applications is nickel-cadmium batteries (NiCds). This module

Rebecca Lankey; Francis McMichael

356

Preliminary Study of Rechargeable Lithium Cells for Space Applications.  

National Technical Information Service (NTIS)

Research carried out on lithium rechargeable cells using on organic electrolyte and intercalation compounds is described. Metal oxides such as V2O5, MoO3, and MoV2O8 are investigated as possible cathode materials. V2O5 shows the most potential of the thre...

J. Labat J. Goualard

1989-01-01

357

Characterization of Ether Electrolytes for Rechargeable Lithium Cells.  

National Technical Information Service (NTIS)

2Methyl-tetrahydrofuran (2Me-THF)/LiAsF6 and several diethyl ether (DEE)/LiAsF6-based electrolytes have been characterized for their usefulness in rechargeable Li/TiS2 cells. This characterization has involved extended room temperature cell cycling at var...

K. M. Abraham J. L. Goldman D. L. Natwig

1982-01-01

358

Electrolytic characteristics of fluoromethyl methyl carbonate for lithium rechargeable batteries  

Microsoft Academic Search

Monofluorinated solvents exert the polar effect on various properties. We have investigated the electrolytic properties of fluoromethyl methyl carbonate (FMMC, monofluorinated dimethyl carbonate) and its application to lithium rechargeable batteries. We describe the dependence of electrolytic conductivity on the temperature, the molar concentrations of three lithium salts, and the molar fractions of the binary solvents. The conductivities of the FMMC

Noritoshi Nanbu; Susumu Watanabe; Masahiro Takehara; Makoto Ue; Yukio Sasaki

2009-01-01

359

Development of new safe electrode for lithium rechargeable battery  

Microsoft Academic Search

A new concept cathode was proposed to improve the safety of lithium rechargeable batteries. The cathode contains a positive temperature coefficient (PTC) compound that can drastically increase resistivity at more than a specified temperature (PTC properties). A PTC cathode containing the PTC compound was fabricated and its resistivity was evaluated. The resistivity of PTC cathodes increased by several tens at

Makiko Kise; Shoji Yoshioka; Kouji Hamano; Daigo Takemura; Takashi Nishimura; Hiroaki Urushibata; Hajimu Yoshiyasu

2005-01-01

360

NbSe3 Cathodes For Li Rechargeable Cells  

NASA Technical Reports Server (NTRS)

Report describes experimental studies involving preparation, characterization, and measurements of performance of NbSe3, intended for use as cathode material in lithium rechargeable electrochemical cells. Characteristics superior to those of other intercalating cathode materials, including high volumetric and gravimetric energy densities and ability to sustain discharges at high rates.

Bugga, Ratnakumar V.; Ni, Ching-Ion; Distefano, Salvador; Somoano, Robert B.; Bankston, C. Perry

1990-01-01

361

Lithium rechargeable cell with a poly 3-methylthiophene cathode  

Microsoft Academic Search

A poly 3-methylthiophene (PMT) cathode showed excellent coulombic efficiency during cycling in a lithium rechargeable cell. An electrolyte containing dimethyl carbonate was used since it is stable at the high anodic potentials reached during cell charging. The polymer cathode tolerated modest overcharge and was able to continue cycling after a severe short-circuit with minimal loss of capacity.

Charles W. Walker Jr.; Steven M. Slane

1992-01-01

362

Polypyrrole Electrodes as Cathodes in a Rechargeable Cell  

Microsoft Academic Search

A study on Li ion rechargeable cells fabricated with polypyrrole (PPy) conducting polymer cathodes is reported in this paper. The PPy was prepared by electropolymerization of pyrrole in the presence of large surfactant anion dodecylbenzene sulphonate. Polyacrylonitrile based solid polymer electrolytes containing lithium triflate and ethylene carbonate (EC) and propylene carbonate (PC) as plasticisers were used as the separators. Cycling

K. P. Vidanapathirana; M. A. Careem; S. Skaarup

2002-01-01

363

Rechargeable LiNiO sub 2 \\/carbon cells  

Microsoft Academic Search

Rechargeable cells can be made using two different intercalation compounds, in which the chemical potential of the intercalant differs by several eV, for the electrodes. In this paper, the authors discuss the factors that play a role in the selection of appropriate lithium intercalation compounds for such cells. For ease of cell assembly the cathode should be stable in air

J. R. Dahn; U. von Saken; M. W. Juzkow; H. Al-Janaby

1991-01-01

364

Rechargeable LiNiO2\\/carbon cells  

Microsoft Academic Search

Rechargeable cells can be made using two different intercalation compounds, in which the chemical potential of the intercalant differs by several eV, for the electrodes. The factors that play a role in the selection of appropriate lithium intercalation compounds for such cells are discussed. For the ease of cell assembly, the cathode should be stable in air when it is

J. R. Dahn; U. von Sacken; M. W. Juzkow; H. Al-Janaby

1991-01-01

365

Materials issues in lithium ion rechargeable battery technology  

Microsoft Academic Search

Lithium ion rechargeable batteries are predicted to replace Ni\\/Cd as the workhorse consumer battery. The pace of development of this battery system is determined in large part by the availability of materials and the understanding of interfacial reactions between materials. Lithium ion technology is based on the use of two lithium intercalating electrodes. Carbon is the most commonly used anode

Doughty

1995-01-01

366

Materials issues in lithium ion rechargeable battery technology  

Microsoft Academic Search

Lithium ion rechargeable batteries are predicted to replace Ni\\/Cd as the workhorse consumer battery. The pace of development of this battery system is determined in large part by the availability of materials and the understanding of interfacial reactions between materials. Lithium ion technology is based on the use of two lithium intercalating electrodes. Carbon is the most commonly used anode

Doughty

1996-01-01

367

Status of the development of rechargeable lithium cells  

Microsoft Academic Search

The progress in the development of the ambient temperature lithium - titanium disulfide rechargeable cell under development at the Jet Propulsion Laboratory is described in this paper. Originally aimed at achieving a specific energy of 100 Wh\\/kg, 'AA' cells have demonstrated 125 Wh\\/kg at the C\\/3 discharge rate. The results of evaluating cell design parameters are discussed and cycling test

G. Halpert; S. Surampudi; D. Shen; C.-K. Huang; S. Narayanan; E. Vamos; D. Perrone

1993-01-01

368

PRIORITY POLLUTANTS IN THE CEDAR CREEK WASTEWATER RECLAMATION - RECHARGE FACILITIES  

EPA Science Inventory

The Cedar Creek Wastewater Reclamation Plant (CCWRP) located in Nassau County, NY is a 0.24 cu m/s (5.5 mgd) advanced wastewater treatment (AWT) plant designed to produce a high quality effluent suitable for groundwater recharge. The CCWRP was constructed as a demonstration proje...

369

LOCALIZED RECHARGE INFLUENCES ON MTBE TRANSPORT AND WELL PLACEMENT CONSIDERATIONS  

EPA Science Inventory

Vertical characterization of a gasoline release site at East Patchogue, New York showed that methyl tert-butyl ether (MTBE) and aromatic plumes "dived" as they passed beneath a sand pit. That this behavior was caused by aquifer recharge was shown by two pieces of evidence. Fir...

370

Lithium-Air Battery: Study of Rechargeability and Scalability.  

National Technical Information Service (NTIS)

Lithium-air battery is anticipated as the battery with highest energy density among all existing rechargeable battery systems known now. Literature reports suggest that the theoretical energy density of Li-air battery is close to that of gasoline. Thus, i...

M. Nookala

2012-01-01

371

Rechargeable batteries: advances since 1977. [Collection of US patents  

Microsoft Academic Search

This book is based on US patents (including DOE patents) issued since January 1978 that deal with rechargeable batteries. It both supplies detailed technical information and can be used as a guide to the patent literature. Subjects treated are as follows: lead-acid batteries (grids, electrodes, terminals and connectors, polyolefin separators, polyvinyl chloride separators, other polymeric separators, other separators, electrolytes, venting

1980-01-01

372

A polymer electrolyte-based rechargeable lithium\\/oxygen battery  

Microsoft Academic Search

A novel rechargeable Li\\/Oâ battery is reported. It comprises a Li{sup +} conductive organic polymer electrolyte membrane sandwiched by a thin Li metal foil anode, and a thin carbon composite electrode on which oxygen, the electroactive cathode material, accessed from the environment, is reduced during discharge to generate electric power. It features an all solid state design in which electrode

K. M. Abraham; Z. Jiang

1996-01-01

373

Application of the Chloride Mass-balance Approach for Recharge Estimation in a Humid Environment  

NASA Astrophysics Data System (ADS)

Recharge is a critical variable for water-balance within a hydrologic basin, and is thus an essential quantity for evaluating long-term ground-water resource sustainability and quality. Recharge studies have generally focused on arid and semi-arid regions, where water resources are most scarce and recharge is most influenced by near-surface conditions. Recharge processes have been addressed to a lesser degree in humid regions. Furthermore, recharge estimation in humid regions has focused more on regional-scale estimates, either from water-balance models or ground-water flow models. However, to address issues such as focused recharge and land-use impacts on recharge, point or local-scale values of recharge integrated over varying time intervals are necessary. Environmental tracers offer the opportunity to finely quantify recharge spatially and temporally over an area. The utility of tracers in estimating recharge has been demonstrated in arid and semi-arid environments, where the water-balance approaches are inapplicable. In this setting, recharge rates are relatively small compared to the measurements of precipitation (P) and evapotranspiration (ET). As a result, small errors associated with measurement of P and ET lead to large recharge estimation errors and limit the utility of soil- water balance methods. Applications of environmental tracers to determine recharge through the vadose zone have included chloride, 18O and 2H, and the radioactive isotopes, tritium and 36Cl, with chloride and tritium being the most common tracers used. In this study we use the chloride mass-balance approach, applied to both the vadose and saturated zones, to investigate recharge to a sand aquifer in a humid setting. The results are evaluated in light of the detailed soil and sediment stratigraphy and variations in chloride loading, and compared to recharge rates determined at differing scales using other methods.

Waldron, B.; Larsen, D.

2008-12-01

374

Enhanced recharge and karst, Edwards aquifer, south central Texas  

SciTech Connect

Enhanced recharge is a water management strategy which can add significant quantities of ground water to the available water resources of the San Antonio region by utilizing the immense storage capacity of the unconfined zone of the Edwards aquifer. The Edwards aquifer presently is the sole source of water for a population of over 1,200,000, meeting public supply, industrial, and irrigation demands over a wide area of south central Texas. Valdina Farms Sinkhole is located adjacent to Seco Creek in Medina County and is in the recharge zone of the aquifer. Initial studies indicated that the sinkholes was capable of taking flood flows from Seco Creek and functioning as a recharge structure. Stream channels in the cavern system associated with Valdina Farms Sinkhole were incised into cave deposits and flood debris was present in the caverns at some distance from the sinkhole. Chemical analyses of samples of water from the cave and from nearby wells showed nitrate concentrations that decreased with distance from the cavern. Gradient of the potentiometric surface in the vicinity of the cave was very low, indicating high values of hydraulic conductivity for the aquifer. Based on evidence from these field studies a dam was constructed in 1982 on Seco Creek and a flood diversion channel was excavated to the sinkhole. Reservoir capacity is 2 acre-feet and design recharge rate is 3.8-6.7 m[sup 3]/sec. Annual recharge at the sinkhole has varied from 0 during periods of low runoff to 12,915 acre-feet.

Hammond, W.W. Jr. (Univ. of Texas, San Antonio, TX (United States). Center for Water Research)

1993-02-01

375

Groundwater recharge measurements in gravel sandy sediments with monolith lysimeter  

NASA Astrophysics Data System (ADS)

Ljubljana field aquifer is recharging through precipitation and the river Sava, which has the snow-rain flow regime. The sediments of the aquifer have high permeability and create fast flow as well as high regeneration of the dynamic reserves of the Ljubljana field groundwater resource. Groundwater recharge is vulnerable to climate change and it is very important for drinking water supply management. Water stored in the soil and less permeable layers is important for water availability under extreme weather conditions. Measurements of water percolation through the vadose zone provide important input for groundwater recharge assessment and estimation of contaminant migration from land surface to the groundwater. Knowledge of the processes governing groundwater recharge in the vadose zone is critical to understanding the overall hydrological cycle and quantifying the links between land uses and groundwater quantity and quality. To improve the knowledge on water balance for Ljubljana field aquifer we establish a lysimeter for measurements of processes in unsaturated zone in well field Kle?e. The type of lysimeter is a scientific lysimeter designed to solve the water balance equation by measuring the mass of the lysimeter monolith as well as that of outflow tank with high accuracy and high temporal resolution. We evaluated short period data, however the chosen month demonstrates weather extremes of the local climate - relatively dry periods, followed by high precipitation amount. In time of high water usage of vegetation only subsequent substantial precipitation events directly results in water flow towards lower layers. At the same time, gravely layers of the deeper parts of the unsaturated zone have little or no capacity for water retention, and in the event that water line leaves top soil, water flow moves downwards fairly quickly. On one hand this confirms high recharge capacity of Ljubljana field aquifer from precipitation on green areas; on the other hand it shows tremendous susceptibility of the aquifer to pollution and reinforces the position of groundwater protection zones above aquifer.

Bracic Zeleznik, Branka; Souvent, Petra; Cencur Curk, Barbara; Zupanc, Vesna

2013-04-01

376

Defining Flood Recharge Processes: Lower Bill Williams River, Western Arizona  

NASA Astrophysics Data System (ADS)

River networks provide hydrologic connections between upland and headwater catchments and downstream reaches. In arid and semi-arid regions, full connectivity of a river system is rare and moments of connection may only occur during large flood events. Here we investigate the Bill Williams River, among the most arid river basins in the United States. The aridity of this system-and the associated lack of complicating hillslope processes adjacent to the river-provides a unique opportunity to study flood recharge processes in relative isolation. During all but the highest flows, the river infiltrates completely at the east end of Planet Valley and reemerges at the west end where it enters the Bill Williams River National Wildlife Refuge (NWR). Determining the source of baseflow in the lower Bill Williams/NWR, and the residence time of this water in the Planet Valley aquifer, will provide insight into the dependence of streamflow on earlier recharge-inducing floods. Defining this dependence more clearly is the next step toward a detailed knowledge of the long-term, basin-scale impacts of floods on water quality and quantity. To determine the impact of floods and the recharge they induce, surface and groundwater samples were collected during high and low flows throughout the basin from April 2007 through the present. Isotopic (?18OH2O, ?2HH2O) and chemical differences (most notably SO4) in streamflow and groundwater along the system indicate the importance of older groundwater in NWR baseflow-either in the form of prior flood recharge or influxes from local springs. Sulfate isotope analysis (?34SSO4, ?18OSO4) is pending for samples throughout the lower basin and this information should allow streamflow sources to be defined and quantified. This study provides a better characterization of the hydrologic and hydrochemical behavior of a Basin and Range river, and allows the effects of flood recharge processes to be more clearly defined at the basin scale.

Simpson, S. C.; Meixner, T.; Hogan, J.

2008-12-01

377

Classification of ground-water recharge potential in three parts of Santa Cruz County, California  

USGS Publications Warehouse

Ground-water recharge potential was classified in the Santa Cruz coastal area, North-central area, and Soquel-Aptos area in Santa Cruz County, Calif., for three data elements that affect recharge; slope, soils, and geology. Separate numerical maps for each element were composited into a single numerical map using a classification system that ranked the numbers into areas of good , fair, and poor recharge potential. Most of the Santa Cruz coastal area and the Norht-central area have a poor recharge potential, and much of the Soquel-Aptos area has a good to fair recharge potential. (Kosco-USGS)

Muir, K. S.; Johnson, Michael J.

1979-01-01

378

Electrolyte for use in high energy lithium based rechargeable electrochemical cell and rechargeable electrochemical cell including the electrolyte  

Microsoft Academic Search

The general object of this invention is to provide a lithium based rechargeable electrochemical cell having an improved capacity. A more specific object of the invention is to provide an electrolyte for such a cell. A still further object of the invention is to provide such a cell. A still further object of the invention is to provide such a

R. J. Mammone; M. Binder

1986-01-01

379

The spatial and temporal variability of groundwater recharge in a forested basin in northern Wisconsin  

USGS Publications Warehouse

Recharge varies spatially and temporally as it depends on a wide variety of factors (e.g. vegetation, precipitation, climate, topography, geology, and soil type), making it one of the most difficult, complex, and uncertain hydrologic parameters to quantify. Despite its inherent variability, groundwater modellers, planners, and policy makers often ignore recharge variability and assume a single average recharge value for an entire watershed. Relatively few attempts have been made to quantify or incorporate spatial and temporal recharge variability into water resource planning or groundwater modelling efforts. In this study, a simple, daily soil-water balance model was developed and used to estimate the spatial and temporal distribution of groundwater recharge of the Trout Lake basin of northern Wisconsin for 1996-2000 as a means to quantify recharge variability. For the 5 years of study, annual recharge varied spatially by as much as 18 cm across the basin; vegetation was the predominant control on this variability. Recharge also varied temporally with a threefold annual difference over the 5-year period. Intra-annually, recharge was limited to a few isolated events each year and exhibited a distinct seasonal pattern. The results suggest that ignoring recharge variability may not only be inappropriate, but also, depending on the application, may invalidate model results and predictions for regional and local water budget calculations, water resource management, nutrient cycling, and contaminant transport studies. Recharge is spatially and temporally variable, and should be modelled as such. Copyright ?? 2009 John Wiley & Sons, Ltd.

Dripps, W. R.; Bradbury, K. R.

2010-01-01

380

Groundwater Recharge In Semi-Arid Regions Of India: An Overview Of Results Obtained Using Tracers  

NASA Astrophysics Data System (ADS)

Natural direct groundwater recharge was measured in the semi-arid/arid regions of India using techniques that employ environmental, geochemical, and artificial tracers. India is a sub-continent and has diverse hydrogeological and hydrometeorological conditions, including monsoon-type rainfall. Various geologic units were investigated, including unconsolidated, semiconsolidated, and consolidated materials and crystalline granitic/gneissic rocks. In the arid sands of Western Rajasthan and the semi-arid alluvial tracts of Gujarat, recharge rate is 3-10 percent (20-50 mm) of local average annual rainfall, whereas in the alluvial tracts of Uttar Pradesh, Punjab, and Haryana, recharge rates are about 12-20 percent (120-200 mm). The coastal semiconsolidated sandstone aquifers of Pondicherry and Neyveli have an average recharge rate of about 15-25 percent (200-300 mm). The consolidated aquifers, consisting of the basaltic and granitic-gneissic complexes, have a natural recharge rate of 3-15 percent (20-100 mm). Low values of recharge in Rajasthan and Gujarat are primarily due to arid conditions. The relatively high values of recharge to coastal aquifers are due to favourable hydrogeologic and climatic conditions. The weathered granitic and gneissic complexes of southern India have neither hydrogeological nor hydrometeorological factors in their favour, which accounts for their small recharge rates. The basaltic regions have intermediate recharge values (8-12 percent). Limited natural rainfall recharge and increased water use throughout the sub-continent calls for conservation as well as augmentation by artificial recharge techniques.

Sukhija, B. S.; Nagabhushanam, P.; Reddy, D. V.

1996-03-01

381

Hydrometeorological daily recharge assessment model (DREAM) for the Western Mountain Aquifer, Israel: Model application and effects of temporal patterns  

Microsoft Academic Search

Recharge is a critical issue for water management. Recharge assessment and the factors affecting recharge are of scientific and practical importance. The purpose of this study was to develop a daily recharge assessment model (DREAM) on the basis of a water balance principle with input from conventional and generally available precipitation and evaporation data and demonstrate the application of this

N. A. Sheffer; E. Dafny; H. Gvirtzman; S. Navon; A. Frumkin; E. Morin

2010-01-01

382

Transient, spatially-varied recharge for groundwater modeling  

NASA Astrophysics Data System (ADS)

This study is aimed at producing spatially and temporally varying groundwater recharge for transient groundwater modeling in a pilot watershed in the North Okanagan, Canada. The recharge modeling is undertaken by using a Richard's equation based finite element code (HYDRUS-1D) [Simunek et al., 2002], ArcGISTM [ESRI, 2011], ROSETTA [Schaap et al., 2001], in situ observations of soil temperature and soil moisture and a long term gridded climate data [Nielsen et al., 2010]. The public version of HYDUS-1D [Simunek et al., 2002] and another beta version with a detailed freezing and thawing module [Hansson et al., 2004] are first used to simulate soil temperature, snow pack and soil moisture over a one year experimental period. Statistical analysis of the results show both versions of HYDRUS-1D reproduce observed variables to the same degree. Correlation coefficients for soil temperature simulation were estimated at 0.9 and 0.8, at depths of 10 cm and 50 cm respectively; and for soil moisture, 0.8 and 0.6 at 10 cm and 50 cm respectively. This and other standard measures of model performance (root mean square error and average error) showed a promising performance of the HYDRUS-1D code in our pilot watershed. After evaluating model performance using field data and ROSETTA derived soil hydraulic parameters, the HYDRUS-1D code is coupled with ArcGISTM to produce spatially and temporally varying recharge maps throughout the Deep Creek watershed. Temporal and spatial analysis of 25 years daily recharge results at various representative points across the study watershed reveal significant temporal and spatial variations; average recharge estimated at 77.8 ± 50.8mm /year. This significant variation over the years, caused by antecedent soil moisture condition and climatic condition, illustrates the common flaw of assigning a constant percentage of precipitation throughout the simulation period. Groundwater recharge modeling has previously been attempted in the Okanagan Basin and other parts of Canada by using the HELP code. However, HELP has known limitations related with boundary conditions as well as spatial and temporal discretization options, and thus cannot simulate highly variable fluxes near boundaries. The limitations are even more pronounced in semi-arid areas like the Okanagan Basin where upward fluxes can be high, because HELP assumes that water below evaporative zone simply drains to the base of a soil column without accounting for upward fluxes. In addition to these limitations, previous studies that used HELP for recharge estimation, [Towes and Allen, 2009; Jyrkama and Sykes, 2007], did not attempt to verify model performance in their study area. The study here presents an integrated procedure that can help address some of these often neglected modelling challenges. The significance of the method in transient groundwater modeling is demonstrated by applying the spatially and temporally varying recharge boundary condition to a saturated zone groundwater model, MIKESHE [DHI, 2009a]. The water table simulated using this method is found to be within 0.6 m of the observed values, whereas the water levels estimated using uniform recharge boundary condition can fluctuate by as much as 1.6 m. Root mean square errors were estimated at 0.3 and 0.94 respectively.

Assefa, K.; Woodbury, A. D.

2012-12-01

383

Monitoring induced denitrification in an artificial aquifer recharge system.  

NASA Astrophysics Data System (ADS)

As demands on groundwater increase, artificial recharge is becoming a common method for enhancing groundwater supply. The Llobregat River is a strategic water supply resource to the Barcelona metropolitan area (Catalonia, NE Spain). Aquifer overexploitation has leaded to both a decrease of groundwater level and seawater intrusion, with the consequent deterioration of water quality. In the middle section of the aquifer, in Sant Vicenç del Horts, decantation and infiltration ponds recharged by water from the Llobregat River (highly affected from wastewater treatment plant effluents), were installed in 2007, in the framework of the ENSAT Life+ project. At the bottom of the infiltration pond, a vegetal compost layer was installed to promote the growth of bacteria, to induce denitrification and to create favourable conditions for contaminant biodegradation. This layer consists on a mixture of compost, aquifer material, clay and iron oxide. Understanding the fate of contaminants, such as nitrate, during artificial aquifer recharge is required to evaluate the impact of artificial recharge in groundwater quality. In order to distinguish the source of nitrate and to evaluate the capability of the organic reactive layer to induce denitrification, a multi-isotopic approach coupled with hydrogeochemical data was performed. Groundwater samples, as well as river samples, were sampled during artificial and natural recharge periods. The isotopic analysis included: ?15N and ?18O of dissolved nitrate, ?34S and ?18O of dissolved sulphate, ?13C of dissolved inorganic carbon, and ?2H and ?18O of water. Dissolved nitrate isotopic composition (?15NNO3 from +9 to +21 o and ?18ONO3 from +3 to +16 ) demonstrated that heterotrophic denitrification induced by the reactive layer was taking place during the artificial recharge periods. An approximation to the extent of nitrate attenuation was calculated, showing a range between 95 and 99% or between 35 and 45%, by using the extreme literature ?N values of -4o and -22o respectively (Aravena and Robertson, 1998; Pauwels et al., 2000). Ongoing denitrification batch experiments will allow us to determine the specific nitrogen and oxygen isotopic fractionation induced by the organic reactive layer, in order to estimate more precisely the extent of denitrification during artificial aquifer recharge. These results confirmed that the reactive layer induces denitrification in the recharge ponds area, proving the usefulness of an isotopic approach to characterize water quality improvement occurring during artificial aquifer recharge. References 1. Aravena, R., Robertson, W.D., 1998. Use of multiple isotope tracers to evaluate denitrification in ground water: Study of nitrate from a large-flux septic system plume. Ground Water, 36(6): 975-982. 2. Pauwels, H., J.C., Kloppmann, W., 2000. Denitrification and mixing in a schist aquifer: Influence on water chemistry and isotopes. Chemical Geology, 168(3-4): 307-324. Acknowledgment This study was supported by the projects CGL2011-29975-C04-01 from the Spanish Government, 2009SGR-00103 from the Catalan Government and ENPI/2011/280-008 from the European Commission. Please fill in your abstract text.

Grau-Martinez, Alba; Torrentó, Clara; Folch, Albert; Domènech, Cristina; Otero, Neus; Soler, Albert

2014-05-01

384

Geophysical Methods for Improved Understanding of Managed Aquifer Recharge (Invited)  

NASA Astrophysics Data System (ADS)

Managed aquifer recharge is increasingly being used as a means of augmenting groundwater supplies. With the increased use, questions arise regarding the suitability of sites for such operations, as well as the operational efficiency of these systems. In this work we specifically look at MAR using an artificial recharge pond. There are two operational challenges commonly faced in artificial recharge ponds: 1) A decrease in infiltration rate of water into the subsurface during operating; this limits the amount of stored water. 2) Low recovery rates of the stored water. Addressing both of these challenges requires sufficient information about the spatial and temporal variation in governing hydrologic properties and processes. Geophysical methods provide a novel way of obtaining such information from the region beneath a recharge pond. A study of the Harkins Slough Recharge Pond, near Watsonville California, presented a unique opportunity to develop and test geophysical methods, specifically for improved understanding off MAR. At this site we deployed a series of geophysical sensors aimed at addressing the two operational challenges at the site. We first addressed the question: What is controlling the decrease in filtration rate? The development and installation of electrical conductivity probes beneath the pond allowed us to monitor changes in the top ~1 m over a 4-month period. This dataset revealed that clogging in the top ~10 cm was responsible for the decreased infiltration rate. These 1D data were augmented by a time-lapse 2D ERT dataset that shows significant lateral variability in infiltration at the site. The second question we addressed was: Why is the recovery rate so low? Using a combination of cone-penetrometer testing and seismic reflection data, we developed a subsurface model that suggested there was a thin clay layer that may be impeding the flow of water to the recovery wells. To further understand this, we developed electrical conductivity probes, containing pore pressure transducers, to monitor changes in electrical conductivity and fluid pressure to a depth of 30 m. The data acquired with these probes clearly showed that the subsurface clay layer was impeding flow to the screened zone of the recovery wells. The findings at the site demonstrate the value of geophysics obtaining information regarding the siting and operation of artificial recharge ponds.

Pidlisecky, A.; Nenna, V.; Knight, R. J.

2013-12-01

385

Aqueous Inorganic Sonochemistry  

NASA Astrophysics Data System (ADS)

This chapter discusses the effect of ultrasound propagation in water and aqueous solutions, in the atmosphere of inert and reactive gases. Sonochemical studies of aqueous solutions of divalent and trivalent metal ions and their salts have been reviewed and the precipitation behaviour of hydroxides of metal ions has been discussed. Synthesis of nanoparticles of many metals using ultrasound and in aqueous solutions has also been discussed briefly. Besides, the nephelometric and conductometric studies of sonicated solutions of these metal ions have been reported.

Pankaj

386

Prussian blue containing Nafion composite film as rechargeable battery  

SciTech Connect

A solid-state thin film rechargeable battery has been prepared using a novel efficient technique of ''surface complexation method'' by which a thin layer of Prussian blue (PB) can be overlaid on a solid polymer electrolyte of Nafion (NF) as matrix. An electrochemical cell made of the composite PB-Nf film sandwiched with supporting electrodes was examined on i-V curves in solid state and for characteristics as a rechargeable battery. The resulting PB-Nf battery showed good durability in repetitive cycles of charging and discharging and gave the following results: open-circuit voltage of the unit cell per 160 ..mu..m 0.68V, short-circuit current 0.2-2 mA/cm/sup 2/ depending upon the water content of the Nf matrix, and an energy density of about 50 Wh/kg.

Honda, K.; Hayashi, H.

1987-06-01

387

Zinc electrode and rechargeable zinc-air battery  

DOEpatents

An improved zinc electrode is disclosed for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed which utilizes the improved zinc electrode and further includes an alkaline electrolyte within said battery circulating through the passageways in the zinc electrode and an external electrolyte circulation means which has an electrolyte reservoir external to the battery case including filter means to filter solids out of the electrolyte as it circulates to the external reservoir and pump means for recirculating electrolyte from the external reservoir to the zinc electrode.

Ross, Jr., Philip N. (Kensington, CA)

1989-01-01

388

Electronic structure and optical spectra of novel rechargeable lithium batteries  

Microsoft Academic Search

Electronic spectra of promising materials for rechargeable lithium batteries, LiC6 and LiMn2O4, have been studied. Theoretical calculations in combination with experiments for the pi*0 and sigma* x-ray absorption edges are reported for the pure graphite and the graphite intercalation compound, LiC6. The anisotropy of the absorption spectra is due to the difference in the optical matrix elements for two different

Gennadiy E. Grechnev; Rajeev Ahuja; Jinghua Guo; Olle Eriksson

2004-01-01

389

Templated Nanocarbon Black Nanocomposite Electrodes for Rechargeable Lithium Batteries  

Microsoft Academic Search

In this work, the fabrication of high energy density electrode materials for solid-state rechargeable batteries via block copolymer templating schemes was investigated. Atom transfer radical polymerization was used to synthesize the copolymer template poly((oligooxyethylene) methacrylate)-block-poly(butyl methacrylate), POEM-b-PBMA. Continuous, nanoscale phases of vanadium oxide were subsequently grown within the POEM domains of the microphase-separating block copolymer using sol-gel synthesis from a

Ozge Akbulut; Elsa A. Olivetti; Donald R. Sadoway; Anne M. Mayes

2006-01-01

390

Scale effects of hydrostratigraphy and recharge zonation on base flow  

USGS Publications Warehouse

Uncertainty regarding spatial variations of model parameters often results in the simplifying assumption that parameters are spatially uniform. However, spatial variability may be important in resource assessment and model calibration. In this paper, a methodology is presented for estimating a critical basin size, above which base flows appear to be relatively less sensitive to the spatial distribution of recharge and hydraulic conductivity, and below which base flows are relatively more sensitive to this spatial variability. Application of the method is illustrated for a watershed that exhibits distinct infiltration patterns and hydrostratigraphic layering. A ground water flow model (MODFLOW) and a parameter estimation code (UCODE) were used to evaluate the influence of recharge zonation and hydrostratigraphic layering on base flow distribution. Optimization after removing spatial recharge variability from the calibrated model altered base flow simulations up to 53% in watersheds smaller than 40 km2. Merging six hydrostratigraphic units into one unit with average properties increased base flow residuals up to 83% in basins smaller than 50 km2. Base flow residuals changed <5% in watersheds larger than 40 and 50 km2 when recharge and hydrostratigraphy were simplified, respectively; thus, the critical basin size for the example area is ???40 to 50 km2. Once identified for an area, a critical basin size could be used to guide the scale of future investigations. By ensuring that parameter discretization needed to capture base flow distribution is commensurate with the scope of the investigation, uncertainty caused by overextending uniform parameterization or by estimating extra parameter values is reduced. ?? 2006 National Ground Water Association.

Juckem, P. F.; Hunt, R. J.; Anderson, M. P.

2006-01-01

391

Virus fate and transport during artificial recharge with recycled water  

Microsoft Academic Search

A field-scale experiment was conducted at a research site using bacterial viruses (bacteriophage) MS2 and PRD1 as surrogates for human viruses, bromide as a conservative tracer, and tertiary-treated municipal wastewater (recycled water) to investigate the fate and transport of viruses during artificial recharge. Observed virus concentrations were fitted using a mathematical model that simulates virus transport in one-dimensional, homogeneous, water-saturated

Robert Anders; C. V. Chrysikopoulos

2005-01-01

392

Evaluation of Recharge Potential at Crater U5a (WISHBONE)  

SciTech Connect

Radionuclides are present both below and above the water table at the Nevada Test Site (NTS), as the result of underground nuclear testing. Mobilization and transport of radionuclides from the vadose zone is a complex process that is influenced by the solubility and sorption characteristics of the individual radionuclides, as well as the soil water flux. On the NTS, subsidence craters resulting from testing underground nuclear weapons are numerous, and many intercept surface water flows. Because craters collect surface water above the sub-surface point of device detonation, these craters may provide a mechanism for surface water to recharge the groundwater aquifer system underlying the NTS. Given this situation, there is a potential for the captured water to introduce contaminants into the groundwater system. Crater U5a (WISHBONE), located in Frenchman Flat, was selected for study because of its potentially large drainage area, and significant erosional features, which suggested that it has captured more runoff than other craters in the Frenchman Flat area. Recharge conditions were studied in subsidence crater U5a by first drilling boreholes and analyzing the collected soil cores to determine the soil properties and moisture conditions. This information, coupled with a 32-year precipitation record, was used to conduct surface and vaodse zone modeling. Surface water modeling predicted that approximately 13 ponding events had occurred during the life of the crater. Vadose zone modeling indicated that since the crater's formation approximately 5,900 m3 of water were captured by the crater. Of this total, approximately 5,200 m3 of potential recahrge may have occurred, and the best estimates of annual average potential recharge rates lie between 36 and 188 cm of water per year. The term potential is used here to indicate that the water is not technically recharged because it has not yet reached the water table.

Richard H. French; Samuel L. Hokett

1998-11-01

393

Changes in vegetation diversity caused by artificial recharge  

USGS Publications Warehouse

Efforst to increase the rate of artificial recharge through basins often necessitates scrapping and ditching before and during operations. Such operations can result in more or less drastic changes in vegetation (depending on what was there before), characterized by diminisched numbers of species and lowered diversity. Two examples, one from Texas and one from the Netherlands are presented showing how similar treatments cause similar changes in two completely difference plant communities. ?? 1979 Dr. W. Junk b.v. - Publishers.

van, Hylckama, T. E. A.

1979-01-01

394

Heat as a Tracer for Estimating Ground-water Recharge  

NASA Astrophysics Data System (ADS)

Temperature profiles above the water table may be analyzed to estimate ground-water recharge (or discharge). Depending on depth, sediment temperature profiles are established by meteorological conditions and/or the geothermal gradient, and modified by the direction and rate of ground-water fluxes through the sediments. For shallow water tables (less than 30 m), the combined effects of meteorological boundary conditions and ground-water fluxes generally determine sediment temperature profiles, while for deeper water tables, the combined effects of the geothermal gradient and ground-water fluxes determine vertical temperature profiles. Three approaches are presented to demonstrate the manner in which recharge rates may be estimated by matching predicted temperatures with measured temperatures above the water table. For the case of a shallow water table beneath a streambed, a variably saturated heat and water (liquid-only) transport simulation code, VS2DH, was used with an optimization procedure to inversely fit simulated temperatures to measured temperatures for several Southwestern stream channels. In some cases, temperature-based estimates of vertical flux were compared to surface-water measurements of streamflow loss. For the case of a deep water table, two different approaches were examined. An analytical solution with limitations on stratigraphic complexity was compared to measured temperature profiles beneath Yucca Flat, NV. A simulation code, TOUGH2, was used to match simulated to measured temperatures profiles beneath washes near Beatty, NV. Hypothetical results using the analytical solution generated a linear vertical temperature gradient for no-flow conditions, a concave upward gradient for groundwater recharge, and a concave downward gradient for groundwater discharge. TOUGH2 simulation results were capable of matching the complex temperature profiles in the deep, highly layered unsaturated material underlying the wash sites. Best-fit analytical and simulation temperature profiles yielded estimates of ground-water recharge for the Yucca Flat and wash sites, which reflected their dissimilar hydrological settings.

Constantz, J. E.; Tyler, S. W.; Kwicklis, E.

2001-12-01

395

Optimized zinc electrode for the rechargeable zinc–air battery  

Microsoft Academic Search

For the development of a long-lived, electrically rechargeable zinc–air battery the structure and wettability of pasted zinc electrodes were optimized. Pasted zinc electrodes containing 1 to 10% cellulose but having almost the same nominal capacities were prepared and tested in zinc\\/oxygen cells. The effect of discharge rate on cell voltage and delivered capacity, as well as the maximum power, were

S. Müller; F. Holzer; O. Haas

1998-01-01

396

Rechargeable zinc air batteries market and technology overview  

Microsoft Academic Search

AER Energy Resources is a US-based technology company that has developed a rechargeable zinc-air battery system. The advantage of the AER Energy Technology Battery is that it's energy density on a weight basis is three times that of nickel-cadmium, nickel metal hydride and lead-acid batteries, and almost twice that of currently available lithium-ion batteries. This new battery technology can enable

M. Schimpf

1993-01-01

397

Advanced materials for electrodes and electrolyte in rechargeable lithium batteries  

Microsoft Academic Search

The lithium-ion (Li-ion) battery possesses many outstanding advantages over the well known rechargeable battery systems, in particularly higher energy density and longer shelf life, as well as not suffering from the memory effect problems of Ni-MH batteries. Those advantages are making it the greatest energy source of choice for the portable electronic market. Graphite and LiCoO2 are commonly used in

Sau yen Chew

2009-01-01

398

Seismicity induced by seasonal groundwater recharge at Mt. Hood, Oregon  

NASA Astrophysics Data System (ADS)

Groundwater recharge at Mt. Hood, Oregon, is dominated by spring snow melt which provides a natural large-amplitude and narrow-width pore-fluid pressure signal. Time delays between this seasonal groundwater recharge and seismicity triggered by groundwater recharge can thus be used to estimate large-scale hydraulic diffusivities and the state of stress in the crust. We approximate seasonal variations in groundwater recharge with discharge in runoff-dominated streams at high elevations. We interpolate the time series of number of earthquakes, N, seismic moment, Mo, and stream discharge, Q, and determine cross-correlation coefficients at equivalent frequency bands between Q and both N and Mo. We find statistically significant correlation coefficients at a mean time lag of about 151 days. This time lag and a mean earthquake depth of about 4.5 km are used in the solution to the pressure diffusion equation, under periodic (1 year) boundary conditions, to estimate a hydraulic diffusivity of ??10 -1 m 2/s, a hydraulic conductivity of about Kh?10 -7 m/s, and a permeability of about k?10 -15 m 2. Periodic boundary conditions also allow us to determine a critical pore-fluid pressure fraction, P'/ P0?0.1, of the applied near-surface pore-fluid pressure perturbation, P0?0.1 MPa, that has to be reached at the mean earthquake depth to cause hydroseismicity. The low magnitude of P'?0.01 MPa is consistent with other studies that propose 0.01? P'?0.1 MPa and suggests that the state of stress in the crust near Mt. Hood could be near critical for failure. Therefore, we conclude that, while earthquakes occur throughout the year at Mt. Hood, elevated seismicity levels along pre-existing faults south of Mt. Hood during summer months are hydrologically induced by a reduction in effective stress.

Saar, Martin O.; Manga, Michael

2003-09-01

399

Long cycle life rechargeable lithium\\/titanium disulfide cells  

Microsoft Academic Search

Lithium\\/titanium disulfide (Li\\/TiS2) cells are being developed for long life rechargeable applications. The effects of cathode thickness, packing density, percent carbon, electrolyte type, and anode type on cycle life were evaluated. Cathode thickness was found to have the most dramatic effect on cycle life, followed by cathode packing density and electrolyte type. The cycle life of AA Li\\/TiS2 cells increased

C. J. Post; E. S. Takeuchi

1992-01-01

400

Computer simulations of the impedance response of lithium rechargeable batteries  

Microsoft Academic Search

A mathematical model is developed to simulate the impedance response of a wide range of lithium rechargeable battery systems. The mathematical model is a macroscopic model of a full-cell sandwich utilizing porous electrode theory to treat the electrode region and concentrated solution theory for transport processes in solution. Insertion processes are described with charge-transfer kinetic expressions and solid-phase diffusion of

Marc Doyle; Jeremy P. Meyers; John Newman

2000-01-01

401

Electrochemical impedance spectroscopy of lithium-titanium disulfide rechargeable cells  

Microsoft Academic Search

The two-terminal alternating current impedance of Li\\/TiS2 rechargeable cells was studied as a function of frequency, state-of-charge, and extended cycling. Analysis based on a plausible equivalent circuit model for the Li\\/TiS2 cell leads to evaluation of kinetic parameters for the various physicochemical processes occurring at the electrode\\/electrolyte interfaces. To investigate the causes of cell degradation during extended cycling, the parameters

S. R. Narayanan; D. H. Shen; S. Surampudi; A. I. Attia; G. Halpert

1993-01-01

402

Electrochemical impedance spectroscopy of lithium-titanium disulfide rechargeable cells  

Microsoft Academic Search

The two-terminal alternating current impedance of lithium-titanium disulfide (Li\\/TiS[sub 2]) rechargeable cells has been studies as a function of frequency, state-of-charge, and extended cycling. Analysis based on a plausible equivalent circuit model for the Li\\/TiS[sub 2] cell leads to evaluation of kinetic parameters for the various physicochemical processes occurring at the electrode\\/electrolyte interfaces. To investigate the causes of cell degradation

S. R. Narayanan; D. H. Shen; S. Surampudi; A. I. Attia; G. Halpert

1993-01-01

403

12-Crown-4 Ether Improves Rechargeable Lithium Cells  

NASA Technical Reports Server (NTRS)

Experiments show addition of 12-crown-4 ether (12Cr4) to thin film of polyethylene oxide (PEO) and LiBF4 reduces charge-transfer resistance of film and enhances performance of electrochemical cell in which film is electrolyte, anode is lithium, and cathode is LixCoO2. By increasing conductivity of the electrolyte, 12Cr4 reduces polarization loss; enabling cell to sustain higher current. Result is new type of rechargeable lithium cell.

Nagasubramanian, Ganesan; Attia, Alan I.

1992-01-01

404

Recent developments and future prospects for lithium rechargeable batteries  

Microsoft Academic Search

Possible future developments of lithium rechargeable batteries are discussed. Lithium ion liquid electrolyte batteries are now well established, with energy densities of up to around 150Whkg?1. There are prospects of increases in the energy density to perhaps 200–250Whkg?1 by using new cathode materials (lithium nickel cobalt oxide) and light weight construction. High power cells make it possible for these batteries

A. G. Ritchie

2001-01-01

405

Hysteresis in Thin-Film Rechargeable Lithium Batteries  

SciTech Connect

Discharge - charge cycling of thin-film rechargeable lithium batteries with an amorphous or nanocrystalline LiXMn2.Y04 cathode reveals evidence for a true hysteresis in the lithium insertion reaction. This is compared with an apparent hysteresis attributed to a kinetically hindered phase transition near 3 V for batteries with either a crystalline or a nanocrystalline LiJ@Yo4 cathode.

Bates, J.B.; Dudney, N.J.; Evans, C.D.; Hart, F.X.

1999-04-25

406

Development of Carbon Anode for Rechargeable Lithium Cells  

NASA Technical Reports Server (NTRS)

Conventionally, rechargeable lithium cells employ a pure lithium anode. To overcome problems associated with the pure lithium electrode, it has been proposed to replace the conventional electrode with an alternative material having a greater stability with respect to the cell electrolytes. For this reason, several graphitic and coke based carbonaceous materials were evaluated as candidate anode materials...In this paper, we summarize the results of the studies on Li-ion cell development.

Huang, C. -K.; Surampudi, S.; Halpert, G.

1994-01-01

407

AC impedance study of Li\\/SO2 rechargeable cells  

Microsoft Academic Search

The kinetics of lithium passivation and the development of the impedance of carbon electrodes and LiGaCl4 and LiAlCl4 non-solvate electrolytes in rechargeable Li\\/SO2 cells have been studied using the AC impedance technique. The effects of cycling and depth of discharge (DOD) on impedance parameters and the effects of electrolyte concentration on cell performance and open circuit voltage (OCV) are discussed.

T. J. Lee; G. T. K. Fey

1990-01-01

408

Performance of lithium-sulfur dioxide rechargeable cells  

Microsoft Academic Search

The lithium-sulfur dioxide rechargeable system has been investigated with LiAlCl4 electrolyte in hermetically sealed experimental cells. Over 50 cells were tested at 1-5 mA\\/cm2 discharge and 0.5-2 mA\\/cm2 charge rates using carbon cathode material to evaluate cycle life and capacity at ambient (21°C) and low (-30°C) temperatures. Most of the cells delivered excellent cycle life with significantly higher capacity than

Sohrab Hossain; Peter Harris; Robert McDonald; Franz Goebel

1990-01-01

409

Characterization of ether electrolytes for rechargeable lithium cells. Technical report  

Microsoft Academic Search

2Methyl-tetrahydrofuran (2Me-THF)\\/LiAsFâ and several diethyl ether (DEE)\\/LiAsFâ-based electrolytes have been characterized for their usefulness in rechargeable Li\\/TiSâ cells. This characterization has involved extended room temperature cell cycling at various depths of discharge, evaluation of rate\\/capacity behavior of cells at 25C and -10C, and storage of cells at 50C for up to one month with subsequent cycling. The thermal stability of

K. M. Abraham; J. L. Goldman; D. L. Natwig

1982-01-01

410

Electrochemically Stable Cathode Current Collectors for Rechargeable Magnesium Batteries  

SciTech Connect

Rechargeable Mg batteries are attractive energy storage systems and could bring cost-effective energy solutions. Currently, however, no practical cathode current collectors that can withstand high voltages in Mg2+ electrolytes has been identified and therefore cathode research is greatly hindered. Here we identified that two metals, Mo and W, are electrochemically stable through formation of surface passive layers. The presented results could have significant impacts on the developments of high voltage Mg batteries.

Cheng, Yingwen; Liu, Tianbiao L.; Shao, Yuyan; Engelhard, Mark H.; Liu, Jun; Li, Guosheng

2014-01-01

411

Inorganic electrolyte solutions and gels for rechargable lithium batteries  

Microsoft Academic Search

A class of inorganic oxychloride compounds have been evaluated for use as electrolytic solvents in rechargeable lithium batteries. Compared with SOâ-based electrolytes, these showed much improved safety while maintaining room temperature conductivities of 10⁻³--10⁻² S\\/cm and electrochemical voltage windows of 4.5--5.5 vs. Li{sup +}\\/Li and supporting reversible lithium metal deposition\\/stripping. With the addition of 2 â¼ 5% polymer, the solutions

Kang Xu; N. D. Day; C. A. Angell

1996-01-01

412

Estimation of groundwater recharge parameters by time series analysis.  

USGS Publications Warehouse

A model is proposed that relates water level fluctuations in a Dupuit aquifer to effective precipitation at the top of the unsaturated zone. Effective precipitation, defined herein as that portion of precipitation which becomes recharge, is related to precipitation measured in a nearby gage by a two-parameter function. A second-order stationary assumption is used to connect the spectra of effective precipitation and water level fluctuations.-from Authors

Naff, R. L.; Gutjahr, A. L.

1983-01-01

413

Movement of water infiltrated from a recharge basin to wells  

USGS Publications Warehouse

Local surface water and stormflow were infiltrated intermittently from a 40-ha basin between September 2003 and September 2007 to determine the feasibility of recharging alluvial aquifers pumped for public supply, near Stockton, California. Infiltration of water produced a pressure response that propagated through unconsolidated alluvial-fan deposits to 125 m below land surface (bls) in 5 d and through deeper, more consolidated alluvial deposits to 194 m bls in 25 d, resulting in increased water levels in nearby monitoring wells. The top of the saturated zone near the basin fluctuates seasonally from depths of about 15 to 20 m. Since the start of recharge, water infiltrated from the basin has reached depths as great as 165 m bls. On the basis of sulfur hexafluoride tracer test data, basin water moved downward through the saturated alluvial deposits until reaching more permeable zones about 110 m bls. Once reaching these permeable zones, water moved rapidly to nearby pumping wells at rates as high as 13 m/d. Flow to wells through highly permeable material was confirmed on the basis of flowmeter logging, and simulated numerically using a two-dimensional radial groundwater flow model. Arsenic concentrations increased slightly as a result of recharge from 2 to 6 ?g/L immediately below the basin. Although few water-quality issues were identified during sample collection, high groundwater velocities and short travel times to nearby wells may have implications for groundwater management at this and at other sites in heterogeneous alluvial aquifers.

O'Leary, David R.; Izbicki, John A.; Moran, Jean E.; Meeth, Tanya; Nakagawa, Brandon; Metzger, Loren; Bonds, Chris; Singleton, Michael J.

2012-01-01

414

Identification of priority organic compounds in groundwater recharge of China.  

PubMed

Groundwater recharge using reclaimed water is considered a promising method to alleviate groundwater depletion, especially in arid areas. Traditional water treatment systems are inefficient to remove all the types of contaminants that would pose risks to groundwater, so it is crucial to establish a priority list of organic compounds (OCs) that deserve the preferential treatment. In this study, a comprehensive ranking system was developed to determine the list and then applied to China. 151 OCs, for which occurrence data in the wastewater treatment plants were available, were selected as candidate OCs. Based on their occurrence, exposure potential and ecological effects, two different rankings of OCs were established respectively for groundwater recharge by surface infiltration and direct aquifer injection. Thirty-four OCs were regarded as having no risks while the remaining 117 OCs were divided into three groups: high, moderate and low priority OCs. Regardless of the recharge way, nonylphenol, erythromycin and ibuprofen were the highest priority OCs; their removal should be prioritized. Also the database should be updated as detecting technology is developed. PMID:24960229

Li, Zhen; Li, Miao; Liu, Xiang; Ma, Yeping; Wu, Miaomiao

2014-09-15

415

Impact of climate change on groundwater recharge in arid areas  

NASA Astrophysics Data System (ADS)

Groundwater recharge in arid areas is critical for water resources management and for contaminant transport from waste deposit sites located in these areas. However, the impact of climate change on groundwater in arid areas is not well understood at this point, because of difficulties in accurately measuring soil-water flow processes under arid conditions and in quantifying complex interactions among climate, soil water, and vegetation in these areas. The purpose of this exploratory study is to develop an innovative approach to assessing the impact of climate change on soil-water dynamics in arid areas. The approach is based on a new hypothesis that in arid areas, temporally averaged soil-water saturation will not be affected by climate change during growing seasons as a result of the naturally occurring optimization processes for vegetation growth. Arid-area soil-water dynamics in growing seasons is important because precipitation and groundwater recharge mainly occur during these seasons. The hypothesis is supported by results from a comprehensive literature survey of published data. Stochastic models are developed based on the hypotheses to determine impacts of climate changes on groundwater recharge in arid areas. Modeling results show that the impacts are largely buffered by the associated vegetation dynamics.

Liu, H.; Zhang, K.

2009-12-01

416

Natural recharge and localization of fresh ground water in Kuwait  

USGS Publications Warehouse

Fresh ground water (200 parts per million total dissolved solids and upwards) occurs in portions of Pleistocene sandstone aquifers beneath basins and wadis in north Kuwait where the mean rainfall is about five inches per year. The fresh water is surrounded and underlain by brackish water (> 4000 ppm TDS). Drilling and testing show that fresh water saturation is restricted to wadis and basin areas; in Rawdatain basin it attains a maximum thickness of about 110 feet and a lateral extent of about seven miles. The fresh ground water represents recharge localized, during infrequent, torrential rain storms, in areas of concentrated runoff where sediments in the vadose zone are moderately permeable and depth to the water table is generally less than a hundred feet. Concentration of runoff appears to be the primary control in the localization of recharge. The fresh water percolates downward to the ground-water reservoir following rare storms, then flows in the direction of hydraulic gradient and gradually becomes brackish. Theoretical delineation of the recharge area and ground-water flow pattern in Rawdatain was confirmed by tritium and C14 dating of the water. Brackish ground-water conditions prevail from water table downward in areas where rainfall infiltrates essentially where it falls, permeability of sediments in the vadose zone is low, or the water table is several hundred feet below land surface. In these areas, rainfall is retained and lost within the soil zone or becomes mineralized during deep percolation. ?? 1964.

Bergstrom, R. E.; Aten, R. E.

1965-01-01

417

Ions in Aqueous Solution  

NSDL National Science Digital Library

This 11-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include the aqueous behavior of ions based on their size and charge, the meaning of activity of ions in aqueous solution, the equilibrium constant, complexation of ions and hydrolysis of cations. Also included are informative illustrations, diagrams and equations.

Sherman, David M.; Bristol, University O.

418

Simulation of ground-water level fluctuations using recharge estimated by field infiltrometer measurements  

USGS Publications Warehouse

An infiltrometer was used at multiple locations at a site in Lee County, Fl. to define the spatial variability in infiltration parameters. Water-level data from a well at this site were collected hourly and used to determine the temporal variability in recharge. These results were used to define recharge in a representative stochastic numerical model of the aquifer. Model results without recharge compare well with existing analytical solutions for spatial head variability. Simulations with representative recharge events indicate that recharge produces a significant to dominant effect on head variability, which creates dispersion of contaminants, and that small-scale spatial and temporal recharge variations are the predominant mechanism causing the head variations.

Swain, E. D.

1997-01-01

419

Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA  

Microsoft Academic Search

Lysimeter-percolate and well-hydrograph analyses were combined to evaluate recharge for the Masser Recharge Site (central\\u000a Pennsylvania, USA). In humid regions, aquifer recharge through an unconfined low-porosity fractured-rock aquifer can cause\\u000a large magnitude water-table fluctuations over short time scales. The unsaturated hydraulic characteristics of the subsurface\\u000a porous media control the magnitude and timing of these fluctuations. Data from multiple sets of

Christopher S. Heppner; John R. Nimmo; Gordon J. Folmar; William J. Gburek; Dennis W. Risser

2007-01-01

420

Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA  

Microsoft Academic Search

Lysimeter-percolate and well-hydrograph analyses were combined to evaluate recharge for the Masser Recharge Site (central Pennsylvania, USA). In humid regions, aquifer recharge through an unconfined low-porosity fractured-rock aquifer can cause large magnitude water-table fluctuations over short time scales. The unsaturated hydraulic characteristics of the subsurface porous media control the magnitude and timing of these fluctuations. Data from multiple sets of

Christopher S. Heppner; John R. Nimmo; Gordon J. Folmar; William J. Gburek; Dennis W. Risser

2007-01-01

421

Estimation of groundwater recharge using the soil moisture budget method and the base-flow model  

Microsoft Academic Search

Estimation of groundwater recharge is extremely important for proper management of groundwater systems. Many different approaches\\u000a exist for estimating recharge. The main purpose of this paper is to apply a water balance concept with two methods to estimate\\u000a the groundwater recharge in the Ching-Shui watershed, Taiwan. First, a soil moisture budget method is established to estimate\\u000a the infiltration, runoff, evapotranspiration,

Cheng-Haw Lee; Hsin-Fu Yeh; Jin-Fa Chen

2008-01-01

422

Mountain-block recharge, present and past, in the eastern Española Basin, New Mexico, USA  

Microsoft Academic Search

Noble gas recharge temperatures (NGTs) and radiocarbon ages were determined for 43 groundwater samples collected in the eastern\\u000a Española Basin, New Mexico (USA), to identify mountain-block recharge in waters <10 thousand years (ka) old and to evaluate\\u000a possible changes in mountain-block recharge over the past ?35 ka. For Holocene samples from the southeastern area, NGTs are\\u000a dominantly 2–4° cooler than the

Andrew H. Manning

2011-01-01

423

Effect of land development on groundwater recharge determined from non-steady chloride profiles  

NASA Astrophysics Data System (ADS)

The effect of clearing and subsequent crop and pasture growth on recharge to ground waters was investigated in three experimental catchments in the brigalow ( Acacia harpophylla) lands of north-eastern Australia. Recharge was calculated from soil chloride data, using a simple transient solute mass balance model. Clearing had a substantial initial effect on groundwater recharge, with average recharge rates of 29 to 70 mm year -1 in two cleared catchments, compared with 7 mm year -1 in an uncleared catchment. These results were attributed to record high rains that fell while both cleared catchments were bare of vegetation, before crops or pastures were established. The effect was only short lived, however, with no significant recharge occurring in any of the three catchments during the period in which crops and pastures were fully established. This lack of recharge was contrary to the general belief that clearing and establishment of crops or pastures causes a sustained increase in groundwater recharge. The low recharge rates at this site were attributed to the slowly permeable soils and the climate of the study site, where potential evaporation exceeds average rainfall in all months, and to the water use characteristic of brigalow. Brigalow is shallow-rooted, and at this site generated lower soil water deficits than either crops or pastures. Clearing is unlikely to result in high water-tables in these soils under pastures or opportunity cropping systems under the average climatic conditions of the region. The simple transient solute mass balance model used to estimate recharge rates gave important and significant differences in recharge when compared with a more commonly used steady-state model. All recharge rates calculated with the steady-state model were ? 1.8 mm year -1 (most < 0.3 mm year -1), and so this model could not identify the gross short-term recharge response to clearing at this site.

Thorburn, Peter J.; Cowie, Bruce A.; Lawrence, Paul A.

1991-04-01

424

Using CRD method for quantification of groundwater recharge in the Gaza Strip, Palestine  

Microsoft Academic Search

Rainfall is the main source of groundwater recharge in the Gaza Strip area in Palestine. The area is located in the semi-arid\\u000a zone and there is no source of recharge other than rainfall. Estimation of groundwater recharge from rainfall is not an easy\\u000a task since it depends on many uncertain parameters. The cumulative rainfall departure (CRD) method, which depends on

Husam Baalousha

2005-01-01

425

Comparison of recharge estimates at a small watershed in east-central Pennsylvania, USA  

Microsoft Academic Search

The common recommendation that recharge should be estimated from multiple methods is sound, but the inherent differences of\\u000a the methods make it difficult to assess the accuracy of differing results. In this study, four methods for estimating groundwater\\u000a recharge and two methods for estimating base flow (as a proxy for recharge) are compared at two hydrologic research sites\\u000a in east-central

Dennis W. Risser; William J. Gburek; Gordon J. Folmar

2009-01-01

426

A generalized estimate of ground-water-recharge rates in the Lower Peninsula of Michigan  

USGS Publications Warehouse

Ground-water recharge rates were estimated by analysis of streamflow, precipitation, and basin-characteristics data. Streamflow data were partitioned into ground-water-discharge and surface-water-runoff components. Regression equations relate ground-water discharge to precipitation at each basin. Basin-characteristics and long-term precipitation data were used to aid in the interpolation of recharge characteristics within gaged and ungaged areas. A multiple regression equation was developed to estimate spatial variation of recharge. The generalized estimate provides a consistent method for approximating recharge rates in the Lower Peninsula of Michigan.

Holtschlag, David J.

1997-01-01

427

Use of soil moisture probes to estimate ground water recharge at an oil spill site  

USGS Publications Warehouse

Soil moisture data collected using an automated data logging system were used to estimate ground water recharge at a crude oil spill research site near Bemidji, Minnesota. Three different soil moisture probes were tested in the laboratory as well as the field conditions of limited power supply and extreme weather typical of northern Minnesota: a self-contained reflectometer probe, and two time domain reflectometry (TDR) probes, 30 and 50 cm long. Recharge was estimated using an unsaturated zone water balance method. Recharge estimates for 1999 using the laboratory calibrations were 13 to 30 percent greater than estimates based on the factory calibrations. Recharge indicated by the self-contained probes was 170 percent to 210 percent greater than the estimates for the TDR probes regardless of calibration method. Results indicate that the anomalously large recharge estimates for the self-contained probes are not the result of inaccurate measurements of volumetric moisture content, but result from the presence of crude oil, or bore-hole leakage. Of the probes tested, the 50 cm long TDR probe yielded recharge estimates that compared most favorably to estimates based on a method utilizing water table fluctuations. Recharge rates for this probe represented 24 to 27 percent of 1999 precipitation. Recharge based on the 30 cm long horizontal TDR probes was 29 to 37 percent of 1999 precipitation. By comparison, recharge based on the water table fluctuation method represented about 29 percent of precipitation. (JAWRA) (Copyright ?? 2005).

Delin, G. N.; Herkelrath, W. N.

2005-01-01

428

Estimated ground-water recharge from streamflow in Fortymile Wash near Yucca Mountain, Nevada  

SciTech Connect

The two purposes of this report are to qualitatively document ground-water recharge from stream-flow in Fortymile Wash during the period 1969--95 from previously unpublished ground-water levels in boreholes in Fortymile Canyon during 1982--91 and 1995, and to quantitatively estimate the long-term ground-water recharge rate from streamflow in Fortymile Wash for four reaches of Fortymile Wash (Fortymile Canyon, upper Jackass Flats, lower Jackass Flats, and Amargosa Desert). The long-term groundwater recharge rate was estimated from estimates of the volume of water available for infiltration, the volume of infiltration losses from streamflow, the ground-water recharge volume from infiltration losses, and an analysis of the different periods of data availability. The volume of water available for infiltration and ground-water recharge in the four reaches was estimated from known streamflow in ephemeral Fortymile Wash, which was measured at several gaging station locations. The volume of infiltration losses from streamflow for the four reaches was estimated from a streamflow volume loss factor applied to the estimated streamflows. the ground-water recharge volume was estimated from a linear relation between infiltration loss volume and ground-water recharge volume for each of the four reaches. Ground-water recharge rates were estimated for three different periods of data availability (1969--95, 1983--95, and 1992--95) and a long-term ground-water recharge rate estimated for each of the four reaches.

Savard, C.S.

1998-10-01

429

Mountain-block recharge present and past in the eastern Española Basin, New Mexico, USA  

USGS Publications Warehouse

Noble gas recharge temperatures (NGTs) and radiocarbon ages were determined for 43 groundwater samples collected in the eastern Española Basin, New Mexico (USA), to identify mountain-block recharge in waters <10 thousand years (ka) old and to evaluate possible changes in mountain-block recharge over the past ~35 ka. For Holocene samples from the southeastern area, NGTs are dominantly 2-4° cooler than the measured water-table temperature near the mountain front. Computed minimum mountain-block recharge fractions are dominantly 0.2-0.5, consistent with previous large mountain-block recharge estimates. NGTs do not display the distinct low during the last glacial maximum observed in other paleorecharge studies; samples recharged 15-25 ka ago are on average only 1.3° cooler than Holocene samples. Instead, samples with the coldest NGTs were recharged 25-35 ka ago. A proposed explanation is that higher precipitation rates during the last glacial maximum resulted in a lower mean recharge elevation for the basin, essentially buffering the effect of the lower mean annual air temperature and producing NGTs similar to the Holocene. In the period preceding the last glacial maximum, precipitation rates more like today’s resulted in Holocene-like mountain-block recharge fractions, producing a mean NGT ~5° cooler than the Holocene, as expected.

Manning, Andrew H.

2011-01-01

430

Indirect and direct recharges in a tropical forested watershed: Mule Hole, India  

NASA Astrophysics Data System (ADS)

SummaryIt is commonly accepted that forest plays role to modify the water cycle at the watershed scale. However, the impact of forest on aquifer recharge is still discussed: some studies indicate that infiltration is facilitated under forest while other studies suggest a decrease of recharge. This paper presents an estimate of recharge rates to groundwater in a humid forested watershed of India. Recharge estimates are based on the joint use of several methods: chloride mass balance, water table fluctuation, geophysics, groundwater chemistry and flow analysis. Two components of the recharge (direct and indirect) are estimated over 3 years of monitoring (2003-2006). The direct and localized recharges resulting from rainfall over the entire watershed surface area is estimated to 45 mm/yr while the indirect recharge occurring from the stream during flood events is estimated to 30 mm/yr for a 2 km-long stream. Calculated recharge rates, rainfall and runoff measurements are then combined in a water budget to estimate yearly evapotranspiration which ranges from 80% to 90% of the rainfall, i.e. 1050 mm/y as an average. This unexpected high value for a deciduous forest is nevertheless in agreement with the forest worldwide relationship between rainfall and evapotranspiration. The large evapotranspiration from the forest cover contributes to decrease the recharge rate which leads to a lowering of the water table. This is the reason why the stream is highly ephemeral.

Maréchal, Jean-Christophe; Varma, Murari R. R.; Riotte, Jean; Vouillamoz, Jean-Michel; Kumar, M. S. Mohan; Ruiz, Laurent; Sekhar, M.; Braun, Jean-Jacques

2009-01-01

431

Potential for, and possible effects of, artificial recharge in Carson Valley, Douglas County, Nevada  

USGS Publications Warehouse

Rapid population growth in Carson Valley, west- central Nevada, requires a dependable municipal water source. Artificial recharge of aquifers using available flow of the Carson River is one way to increase the amount of water in underground storage and maintain a dependable ground-water supply. Ground water can be artificially recharged by routing excess surface water or, after proper treatment, routing wastewater to infiltration basins or injection wells. Withdrawal wells would remove stored water when needed. As a first step, maps showing areas in Carson Valley with high, low, moderate and unknown potential for artificial recharge were developed on the basis of the distribution of geologic units, depth to water, specific yield, infiltration rate, and location of natural recharge and discharge. For recharge by means of infiltration, areas totaling 5,700 acres have high potential, 23,900 acres have moderate potential, and 6,200 acres have low potential. For recharge through injection, areas totaling 7,800 acres have high potential and 43,500 acres have moderate potential; 23,000 acres have unknown potential because data are lacking on subsurface conditions. A ground-water-flow model was used to assess the possible results of artificial recharge. Simulations with no accompanying ground-water withdrawal show that, when recharge by injection is simulated near the valley floor, heads in the semiconfined aquifer increase over much of the valley, floor; only about 20 percent of the recharged water is stored in the aquifer after 5 years and as much as 80 percent is lost to streamflow and evapotranspiration. When recharge is simulated on the eastern side of the valley, 80 percent of the recharged water remains in storage after 5 years. When recharge is simulated near the valley floor, more water is lost to discharge than when recharge is on the eastern side of the valley. When recharge is applied for long periods without accompanying withdrawal, recharged water moves downgradient to discharge areas. The recharge water that discharges to the surface-water system could in turn replenish base flow of the Carson River and benefit downstream users.

Maurer, Douglas K.; Peltz, Lorri A.

1994-01-01

432

SWB-A modified Thornthwaite-Mather Soil-Water-Balance code for estimating groundwater recharge  

USGS Publications Warehouse

A Soil-Water-Balance (SWB) computer code has been developed to calculate spatial and temporal variations in groundwater recharge. The SWB model calculates recharge by use of commonly available geographic information system (GIS) data layers in combination with tabular climatological data. The code is based on a modified Thornthwaite-Mather soil-water-balance approach, with components of the soil-water balance calculated at a daily timestep. Recharge calculations are made on a rectangular grid of computational elements that may be easily imported into a regional groundwater-flow model. Recharge estimates calculated by the code may be output as daily, monthly, or annual values.

Westenbroek, S. M.; Kelson, V. A.; Dripps, W. R.; Hunt, R. J.; Bradbury, K. R.

2010-01-01

433

Hydrological functions of sinkholes and characteristics of point recharge in groundwater basins  

NASA Astrophysics Data System (ADS)

Karstic limestone aquifers are hydrologically and hydrochemically extremely heterogeneous and point source recharge via sinkholes and fissures is a common feature. We studied three groundwater systems in karstic settings dominated by point source recharge in order to assess the relative contributions to total recharge from point sources using chloride and ?18O relations. Preferential groundwater flows were observed through an inter-connected network of highly conductive zones with groundwater mixing along flow paths. Measurements of salinity and chloride indicated that fresh water pockets exist at point recharge locations. A measurable fresh water plume develops only when a large quantity of surface water enters the aquifer as a point recharge source. The difference in chloride concentrations in diffuse and point recharge zones decreases as aquifer saturated thickness increases and the plumes become diluted through mixing. The chloride concentration in point recharge fluxes crossing the watertable plane can remain at or near surface runoff chloride concentrations, rather than in equilibrium with groundwater chloride. In such circumstances the conventional chloride mass balance method that assumes equilibrium of recharge water chloride with groundwater requires modification to include both point and diffuse recharge mechanisms.

Somaratne, N.; Smettem, K.; Lawson, J.; Nguyen, K.; Frizenschaf, J.

2013-09-01

434

Artificial-recharge investigation near Aurora, Nebraska: 2-year progress report  

USGS Publications Warehouse

This report presents the results of the first 2 years of a 4-year investigation of potential for artificial recharge and recharge methods that might be used to mitigate excessive aquifer depletion in Nebraska. A Quaternary sand-and-gravel aquifer near Aurora, Nebr., was recharged by injecting water through a well at a rate of approximately 730 gallons per minute for nearly 6 months. Total recharge was 530 acre-feet. Recharge was intermittent during the first 2 months, but was virtually continuous during the last 4 months. Buildup of the water level in the recharge well was 17 feet. The rate of buildup indicates that the well could have accepted water by gravity flow at more than 3,000 gallons per minute for at least 1 year. The cause of a continuing slow rise in water levels in the recharge well in contrast to nearly stable water levels in observation wells as close as 10 feet from the recharge well is as yet uncertain. The recharge water and the native ground water appeared to be chemically compatible. Infiltration rates from 24-foot-diameter surface impoundments ranged from 0.04 to 0.66 feet per day. The higher rates may have resulted in part from leakage down incompletely sealed holes that were drilled to install monitoring equipment. The investigation, including a report on the entire project, is scheduled for completion by 1980.

Lichtler, William F.; Stannard, David I.; Kouma, Edwin

1979-01-01

435

Rechargeable silver-modified mercuric oxide-zinc cell for cardiac pacemakers.  

PubMed

Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere (mua) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. In 6.4 ma discharge tests on 24 cells, recharging once every 8 days of simulated pacing, only 1 cell in 24 failed after an equivalent of more than 500 years of pacing (actual time 2 years). In tests on 13 cells pacing at a 200 mua drain without recharging, the simulated mean duration of pacing before total discharge was 4.8 years. Seven other cells at a 200 mua drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 mua drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources. PMID:983958

Tyers, G F; Hughes, H C; Brownlee, R R; Manley, N J; Gorman, I N

1976-11-01

436

Sources and mechanisms of recharge for ground water in the west-central Amargosa Desert, Nevada; a geochemical interpretation  

USGS Publications Warehouse

Ground water in the west-central Amargosa Desert, Nevada, was recharged primarily by overland flow of snowmelt in or near the present-day stream channels, rather than by subsurface flow from highland recharge areas to the north. Geochemical arguments, including reaction mechanisms, are used to support these findings. Carbon-, hydrogen-, and oxygen-isotope data show that much of the recharge in the area occurred during late Wisconsin time. Absence of ground-water recharge prior to late Pleistocene is considered to indicate that either climatic conditions were unfavorable for recharge or that ground-water velocities were such that they transported this earlier recharge away from the study aea. (USGS)

Claassen, H. C.

1983-01-01

437

Simulation of runoff and recharge and estimation of constituent loads in runoff, Edwards aquifer recharge zone (outcrop) and catchment area, Bexar County, Texas, 1997-2000  

USGS Publications Warehouse

The U.S. Geological Survey developed a watershed model (Hydrological Simulation Program?FORTRAN) to simulate runoff and recharge and to estimate constituent loads in surface-water runoff in the Edwards aquifer recharge zone (outcrop) and catchment area in Bexar County, Texas. Rainfall and runoff data collected during 1970?98 from four gaged basins in the outcrop and catchment area were used to calibrate and test the model. The calibration parameters were applied in simulations of the four calibration basins and six ungaged basins that compose the study area to obtain runoff and recharge volumes for 4 years, 1997?2000. In 1997, simulated runoff from the study area was 5.62 inches. Simulated recharge in the study area was 7.85 inches (20 percent of rainfall). In 1998, simulated runoff was 11.05 inches; simulated recharge was 10.99 inches (25 percent of rainfall). In 1999, simulated runoff was 0.66 inch; simulated recharge was 3.03 inches (19 percent of rainfall). In 2000, simulated runoff was 5.29 inches; simulated recharge was 7.19 inches (21 percent of rainfall). During 1997?2000, direct infiltration of rainfall accounted for about 56 percent of the total Edwards aquifer recharge in Bexar County. Streamflow losses contributed about 37 percent of the recharge; flood impoundment contributed 7 percent. The simulated runoff volumes were used with event-mean-concentration data from basins in the study area and from other Bexar County basins to compute constituent loads and yields for various land uses. Annual loads for suspended solids, dissolved solids, dissolved nitrite plus nitrate nitrogen, and total lead were consistently largest from undeveloped land and smallest from commercial land or transportation corridors. Annual loads and yields varied with rainfall, with the maximum loads produced in the wettest year (1998) and the minimum loads produced in the driest year (1999).

Ockerman, Darwin J.

2002-01-01

438

Kinetics of the formation of gas bubbles during polarization of copper and graphite electrodes in electrolytic aqueous solutions  

Microsoft Academic Search

The adsorption and kinetic processes of the formation of gas bubbles passivating the surface during polarization of copper\\u000a and graphite electrodes in 1% aqueous solution of sulfuric acid have been investigated. Three stages of the process related\\u000a to the recharging of the double electric layer—adsorption accumulation of the gas escaping from the surface, the critical\\u000a nucleation of the gas bubbles,

A. M. Orlov; I. O. Yavtushenko; M. V. Churilov

2010-01-01

439

A 65 Ah rechargeable lithium molybdenum disulfide battery  

NASA Technical Reports Server (NTRS)

A rechargeable lithium molybdenum disulfide battery which has a number of superior performance characteristics which includes a high energy density, a high power density, and a long charge retention time was developed. The first cell sizes developed included a C size cell and an AA size cell. Over the last two years, a project to demonstrate the feasibility of the scale up to this technology to a BC size cell with 65 Ah capacity was undertaken. The objective was to develop, build, and test a .6 kWh storage battery consisting of 6 BC cells in series.

Brandt, K.

1986-01-01

440

A sealed rechargeable metal-oxygen battery for traction purposes  

NASA Astrophysics Data System (ADS)

A prototype of a sealed, rechargeable iron-oxygen battery that is based on a new oxygen electrode design is described, noting that the electrode design has made it possible to considerably simplify construction. It is pointed out that the oxygen electrode can be described as a self-breathing oxygen pocket electrode. It reaches 2 cm above the electrolyte in the battery and is fed with oxygen at the top of the battery by virtue of the pressure difference between the top of the electrode and the bottom.

Bursell, M.

441

High pressure water electrolysis for space station EMU recharge  

NASA Technical Reports Server (NTRS)

A high pressure oxygen recharge system (HPORS), is being developed for application on board the Space Station. This electrolytic system can provide oxygen at up to 6000 psia without a mechanical compressor. The Hamilton standard HPORS based on a solid polymer electrolyte system is an extension of the much larger and succesful 3000 psia system of the U.S. Navy. Cell modules have been successfully tested under conditions beyond which spacecraft may encounter during launch. The control system with double redundancy and mechanical backups for all electronically controlled components is designed to ensure a safe shutdown.

Lance, Nick; Puskar, Michael; Moulthrop, Lawrence; Zagaja, John

1988-01-01

442

Downstream of downtown: urban wastewater as groundwater recharge  

NASA Astrophysics Data System (ADS)

Wastewater infiltration is often a major component of overall recharge to aquifers around urban areas, especially in more arid climates. Despite this, such recharge still represents only an incidental (or even accidental) byproduct of various current practices of sewage effluent handling and wastewater reuse. This topic is reviewed through reference to certain areas of detailed field research, with pragmatic approaches being identified to reduce the groundwater pollution hazard of these practices whilst attempting to retain their groundwater resource benefit. Since urban sewage effluent is probably the only `natural resource' whose global availability is steadily increasing, the socioeconomic importance of this topic for rapidly developing urban centres in the more arid parts of Asia, Africa, Latin America and the Middle East will be apparent. L'infiltration des eaux usées est souvent la composante essentielle de toute la recharge des aquifères des zones urbaines, particulièrement sous les climats les plus arides. Malgré cela, une telle recharge ne constitue encore qu'un sous-produit incident, ou même accidentel, de pratiques courantes variées du traitement de rejets d'égouts et de réutilisation d'eaux usées. Ce sujet est passé en revue en se référant à certaines régions étudiées en détail, par des approches pragmatiques reconnues pour permettre de réduire les risques de pollution des nappes dues à ces pratiques tout en permettant d'en tirer profit pour leur ressource en eau souterraine. Puisque les effluents d'égouts urbains sont probablement la seule « ressource naturelle » dont la disponibilité globale va croissant constamment, l'importance socio-économique de ce sujet est évidente pour les centres urbains à développement rapide de l'Asie, de l'Afrique, de l'Amérique latine et du Moyen-Orient. La infiltración de aguas residuales es a menudo un componente principal de la recarga total en acuíferos ubicados en torno a zonas urbanas, especialmente en los climas más áridos. A pesar de ello, dicho componente todavía es una consecuencia secundaria (o incluso accidental) de diversas prácticas asociadas con la manipulación de las aguas residuales y con la reutilitzación de aguas depuradas. Este tema se revisa mediante referencias a ciertas áreas en las que existen investigación detallada de campo, identificando enfoques pragmáticos con el fin de reducir el riesgo de contaminación de las aguas subterráneas por tales prácticas, a la vez tratando de conservar los beneficios para los recursos del acuífero. Dado que los efluentes de aguas residuales urbanas son probablemente la única `fuente natural' cuya disponibilidad global se halla en del aumento, la importancia socioeconómica de este tema será evidente para los centros urbanos de rápido desarrollo en Asia, Latinoamérica y Oriente Medio.

Foster, S. S. D.; Chilton, P. J.

443

Chemical lithium extraction from manganese oxides for lithium rechargeable batteries  

Microsoft Academic Search

Chemical lithium extraction has been carried out on the following manganese oxides: the spinel-type compounds LiMn2O4 and Li(4\\/3)Mn(5\\/3)O4, and the rocksalt-related compound Li2MnO3. Lithium can be partially removed chemically from these compounds without destroying the host framework. Some compounds obtained by this method have been tested as cathodic materials in rechargeable lithium cells. Electrochemical results and X-ray diffraction patterns of

F. Lubin; A. Lecerf; M. Broussely; J. Labat

1991-01-01

444

RISING beamline (BL28XU) for rechargeable battery analysis  

PubMed Central

The newly installed BL28XU beamline at SPring-8 is dedicated to in situ structural and electronic analysis of rechargeable batteries. It supports the time range (1?ms to 100?s) and spatial range (1?µm to 1?mm) needed for battery analysis. Electrochemical apparatus for battery charging and discharging are available in experimental hutches and in a preparation room. Battery analysis can be carried out efficiently and effectively using X-ray diffraction, X-ray absorption fine-structure analysis and hard X-ray photoelectron spectroscopy. Here, the design and performance of the beamline are described, and preliminary results are presented.

Tanida, H.; Fukuda, K.; Murayama, H.; Orikasa, Y.; Arai, H.; Uchimoto, Y.; Matsubara, E.; Uruga, T.; Takeshita, K.; Takahashi, S.; Sano, M.; Aoyagi, H.; Watanabe, A.; Nariyama, N.; Ohashi, H.; Yumoto, H.; Koyama, T.; Senba, Y.; Takeuchi, T.; Furukawa, Y.; Ohata, T.; Matsushita, T.; Ishizawa, Y.; Kudo, T.; Kimura, H.; Yamazaki, H.; Tanaka, T.; Bizen, T.; Seike, T.; Goto, S.; Ohno, H.; Takata, M.; Kitamura, H.; Ishikawa, T.; Ohta, T.; Ogumi, Z.

2014-01-01

445

Glyme-based nonaqueous electrolytes for rechargeable lithium cells  

Microsoft Academic Search

Poly(ethylene glycol)dimethyl ethers [(CH3O(CH2CH2O)nCH3, n = 1, 2, 3, and 4)] are generally known as “glymes”. This study examines the conductivity, lithium ion solvation state and charge–discharge cycling efficiency of lithium metal anodes in glyme-based electrolytes for rechargeable lithium cells. 1M (M: moll?1) LiPF6 was used as the solute. The properties of the glymes were investigated by using a ternary

S. Tobishima; H. Morimoto; M. Aoki; Y. Saito; T. Inose; T. Fukumoto; T. Kuryu

2004-01-01

446

Characterization of ether electrolytes for rechargeable lithium cells  

Microsoft Academic Search

2Methyl-tetrahydrofuran(2Me-THF)\\/LiAsFâ and several diethyl ether (DEE)\\/LiAsFâ-based electrolytes have been characterized for their usefulness in rechargeable Li\\/TiSâ cells. This characterization has involved extended room temperature cell cycling at various depths of discharge, evaluation of rate\\/capacity behavior of cells at 25° and -10°C, and storage of cells at 50°C for up to one month with subsequent cycling. The thermal stability of the

K. M. Abraham; J. L. Goldman; D. L. Natwig

1982-01-01

447

Using 14C and 3H to understand groundwater flow and recharge in an aquifer window  

NASA Astrophysics Data System (ADS)

Knowledge of groundwater residence times and recharge locations are vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge and recharge from the Gellibrand River. To determine recharge patterns and groundwater flowpaths, environmental isotopes (3H, 14C, ?13C, ?18O, ?2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. Despite the water table fluctuating by 0.9-3.7 m annually producing estimated recharge rates of 90 and 372 mm yr-1, residence times of shallow (11-29 m) groundwater determined by 14C ages are between 100 and 10 000 years. 3H activities are negligible in most of the groundwater and groundwater electrical conductivity in individual areas remains constant over the period of study. Although diffuse local recharge is evident, the depth to which it penetrates is limited to the upper 10 m of the aquifer. Rather, groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High, and acts as a regional discharge zone where upward head gradients are maintained annually, limiting local recharge. Additionally, the Gellibrand River does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10 000 years BP to the present day are interpreted to indicate an increase in recharge rates on the Barongarook High.

Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

2014-06-01

448

Absorption from Aqueous Solution.  

National Technical Information Service (NTIS)

A model based on material balance concepts and second-order reaction kinetics is presented for prediction of the performance of expanded-bed adsorption systems for treatment of complex mixtures of dissolved organic materials in aqueous solution. The model...

W. J. Weber P. J. Usinowics

1974-01-01

449

Reflectance of Aqueous Solutions.  

National Technical Information Service (NTIS)

The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning ext...

M. R. Querry

1972-01-01

450

Reflectance of aqueous solutions  

NASA Technical Reports Server (NTRS)

The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.

Querry, M. R.

1972-01-01

451

Reconnaissance Estimates of Recharge Based on an Elevation-dependent Chloride Mass-balance Approach  

SciTech Connect

Significant uncertainty is associated with efforts to quantity recharge in arid regions such as southern Nevada. However, accurate estimates of groundwater recharge are necessary to understanding the long-term sustainability of groundwater resources and predictions of groundwater flow rates and directions. Currently, the most widely accepted method for estimating recharge in southern Nevada is the Maxey and Eakin method. This method has been applied to most basins within Nevada and has been independently verified as a reconnaissance-level estimate of recharge through several studies. Recharge estimates derived from the Maxey and Eakin and other recharge methodologies ultimately based upon measures or estimates of groundwater discharge (outflow methods) should be augmented by a tracer-based aquifer-response method. The objective of this study was to improve an existing aquifer-response method that was based on the chloride mass-balance approach. Improvements were designed to incorporate spatial variability within recharge areas (rather than recharge as a lumped parameter), develop a more defendable lower limit of recharge, and differentiate local recharge from recharge emanating as interbasin flux. Seventeen springs, located in the Sheep Range, Spring Mountains, and on the Nevada Test Site were sampled during the course of this study and their discharge was measured. The chloride and bromide concentrations of the springs were determined. Discharge and chloride concentrations from these springs were compared to estimates provided by previously published reports. A literature search yielded previously published estimates of chloride flux to the land surface. {sup 36}Cl/Cl ratios and discharge rates of the three largest springs in the Amargosa Springs discharge area were compiled from various sources. This information was utilized to determine an effective chloride concentration for recharging precipitation and its associated uncertainty via Monte Carlo simulations. Previously developed isohyetal maps were utilized to determine the mean and standard deviation of precipitation within the area. A digital elevation model was obtained to provide elevation information. A geologic model was obtained to provide the spatial distribution of alluvial formations. Both were used to define the lower limit of recharge. In addition, 40 boreholes located in alluvial sediments were drilled and sampled in an attempt to support the argument that the areal distribution of alluvial sediments can be used to define a zone of negligible recharge. The data were compiled in a geographic information system and used in a Monte Carlo analysis to determine recharge occurring within the study area. Results of the analysis yielded estimates of the mean and standard deviation of recharge occurring within the study area (28.168 x 10{sup 6} m{sup 3} yr{sup -1} and 7.008 x 10{sup 6} m{sup 3} yr{sup -1}, and 26.838 x 10{sup 6} m{sup 3} yr{sup -1} and 6.928 x 10{sup 6} m{sup 3} yr{sup -1}) for two sets of simulations using alternate definitions of the lower limit of recharge. A sensitivity analysis determined the recharge estimates were most sensitive to uncertainty associated with the chloride concentration of the spring discharge. The second most sensitive parameter was the uncertainty associated with the mean precipitation within the recharge areas. Comparison of the analysis to previously published estimates of recharge revealed mixed results with the recharge estimates derived during the course of this project generally greater relative to previously published estimates.

Charles E. Russell; Tim Minor

2002-08-31

452

Recharge Rates and Chemistry Beneath Playas of the High Plains Aquifer - A Literature Review and Synthesis  

USGS Publications Warehouse

Playas are ephemeral, closed-basin wetlands that are important zones of recharge to the High Plains (or Ogallala) aquifer and critical habitat for birds and other wildlife in the otherwise semiarid, shortgrass prairie and agricultural landscape. The ephemeral nature of playas, low regional recharge rates, and a strong reliance on ground water from the High Plains aquifer has prompted many questions regarding the contribution of recharge from playas to the regional aquifer. To address these questions and concerns, the U.S. Geological Survey, in cooperation with the Playa Lakes Joint Venture, present a review and synthesis of the more than 175 publications about recharge rates and chemistry beneath playas and interplaya settings. Although a number of questions remain regarding the controls on recharge rates and chemistry beneath playas, the results from most published studies indicate that recharge rates beneath playas are substantially (1 to 2 orders of magnitude) higher than recharge rates beneath interplaya settings. The synthesis presented here supports the conceptual model that playas are important zones of recharge to the High Plains aquifer and are not strictly evaporative pans. The major findings of this synthesis yield science-based implications for the protection and management of playas and ground-water resources of the High Plains aquifer and directions for future research.

Gurdak, Jason J.; Roe, Cassia D.

2009-01-01

453

Probabilistic Analysis of Rechargeable Batteries in a Photovoltaic Power Supply System  

Microsoft Academic Search

We developed a model for the probabilistic behavior of a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. Stochastic and deterministic models are created to simulate the behavior of the system component;. The components are the solar resource, the photovoltaic power supply system, the rechargeable battery, and a load. Artificial neural networks are incorporated

P. Barney; D. Ingersoll; R. Jungst; C. OGorman; T. L. Paez; A. Urbina

1998-01-01

454

Application of a Genetic Algorithm for Estimating Recharge Potential of the Choushui Rover Alluvial Fan  

Microsoft Academic Search

As groundwater resources are vital to the regional water supply, protection of groundwater resources have become important issues. A systematic approach to locating high recharge areas is the first step in protection of groundwater. In a previous study proposed by the Central Geological Survey (CGS), the CGS used a factor-based approach to determine the spatial distribution of recharge potential (RP).

S. Yang; L. Chang; Y. Chen; C. Jung; C. Huang; J. Chen; P. J. Tsai

2010-01-01

455

PROSPECTS FOR ENHANCED GROUNDWATER RECHARGE VIA INFILTRATION OF URBAN STORMWATER RUNOFF: A CASE STUDY  

EPA Science Inventory

The rain garden is an urban storm water best management practice that is used to infiltrate runoff close to its source, thereby disconnecting impervious area while providing an avenue for groundwater recharge. Groundwater recharge may provide additional benefits to aquatic ecosys...

456

Air, ground, and groundwater recharge temperatures in an alpine setting, Brighton Basin, Utah  

NASA Astrophysics Data System (ADS)

Noble gases are useful tracers for constraining groundwater recharge temperature and elevation, critical in determining source areas of groundwater recharge in mountainous terrain. A monitoring network in the alpine Brighton Basin in the Wasatch Mountains of northern Utah, USA, was established to examine the relationship between air temperatures, ground temperatures, and noble gas groundwater recharge temperatures. Maximum noble gas groundwater recharge temperatures computed using the closed-system equilibration model from 25 samples collected over the 2 year perio