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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

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

4

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

5

Lithium insertion into manganese dioxide electrode in MnO 2/Zn aqueous battery . Part III. Electrochemical behavior of ?-MnO 2 in aqueous lithium hydroxide electrolyte  

NASA Astrophysics Data System (ADS)

The electrochemical behavior of ?-MnO 2 in lithium hydroxide (LiOH) and potassium hydroxide (KOH) aqueous media has been studied using slow-scan cyclic voltammetry (25 ?V s -1) in conjunction with X-ray analysis (XRD) and scanning electron microscopy (SEM). The reduction of ?-MnO 2 in aqueous LiOH results in intercalation of Li + forming a new phase of lithium intercalated MnO 2 (Li xMnO 2). The process is found to be reversible. In this regard, the reduction of ?-MnO 2 in LiOH is quite different from that in aqueous KOH, which is irreversible and no lithium intercalation occurs. This difference in behavior is explained in terms of the relative ionic sizes of Li + and K +. The Li xMnO 2 lattice is stable only for Li + because Li + and Mn 4+ are of approximately the same size whereas K xMnO 2 is not stable because K + has almost double the size.

Minakshi, Manickam; Singh, Pritam; Issa, Touma B.; Thurgate, Stephen; De Marco, Roland

6

Oxidative Transformation of 17?-estradiol by MnO 2 in Aqueous Solution  

Microsoft Academic Search

17?-Estradiol (E2) is known as a natural endocrine disruptor and often found in municipal sewage. Batch experiments were conducted\\u000a to assess the oxidative transformation of E2 in aqueous solutions by MnO2 and the probable degradation pathway. The results suggested that E2 could be degraded by MnO2, and the oxidation reaction deviated from pseudo-first-order kinetics due to the accumulation of reaction

Liying Jiang; Cheng Huang; Jianmeng Chen; Xiao Chen

2009-01-01

7

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

8

?-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

9

Discharge characteristics of chemically prepared MnO 2 and electrolytic MnO 2 in non-aqueous electrolytes  

NASA Astrophysics Data System (ADS)

The discharge performance of chemically prepared MnO 2 (CMD) and electrolytic MnO 2 (EMD) is investigated in various electrolytes. LiPF 6, LiCF 3SO 3, and LiBF 4 are used as lithium salts in a mixed solvent of ethylene carbonate, propylene carbonate, and 1,2-dimethoxyethane (DME). The size and crystal structure of MnO 2 particles is observed by scanning electron microscope and X-ray diffraction, respectively. The particle size of CMD is smaller than that of EMD, but the crystal structures of the two materials are similar. The concentration of dissolved manganese ions from CMD and EMD particles is 148 and 23 mg l -1 in the same electrolyte, respectively. The interfacial electrochemistry of test cells is analyzed by impedance spectroscopy. The discharge performance is poor in the electrolyte containing LiCF 3SO 3 salt. The specific discharge capacity of CMD is superior to that of EMD at high discharge rate.

Kim, Hyung-Sun; Kim, Hyun-Joong; Cho, Won-Il; Cho, Byung-Won; Ju, Jeh-Beck

10

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

11

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

12

Lithium insertion into manganese dioxide electrode in MnO 2/Zn aqueous battery . Part I. A preliminary study  

NASA Astrophysics Data System (ADS)

The discharge characteristics of manganese dioxide (?-MnO 2 of electrolytic manganese dioxide (EMD) type) as a cathode material in a Zn-MnO 2 battery containing saturated aqueous LiOH electrolyte have been investigated. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data on the discharged material indicate that lithium is intercalated into the host structure of EMD without the destruction of its core structure. The XPS data show that a layer of insoluble material, possibly Li 2CO 3, is deposited on the cathode, creating a barrier to H 2O, thus preventing the formation of Mn hydroxides, but allowing the migration of Li ions into the MnO 2 structure. The cell could be reversibly charged with 83% of voltaic efficiency at 0.5 mA/cm 2 current density to a 1.9 V cutoff voltage. The percentage utilization of the cathode material during discharge was 56%.

Manickam, Minakshi; Singh, Pritam; Issa, Touma B.; Thurgate, Stephen; De Marco, Roland

13

TEM investigation of MnO 2 cathode containing TiS 2 and its influence in aqueous lithium secondary battery  

Microsoft Academic Search

The discharge characteristics of manganese dioxide (MnO2) cathode in the presence of small amounts (1, 3 and 5wt.%) of TiS2 additive has been investigated in an alkaline cell using aqueous lithium hydroxide as the electrolyte. The incorporation of small amounts of TiS2 additives into MnO2 was found to improve the battery discharge capacity from 150 to 270mAh\\/g. However, increasing the

Minakshi Manickam; David R. G. Mitchell; Pritam Singh

2007-01-01

14

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

15

Development of a 4.2 V aqueous hybrid electrochemical capacitor based on MnO2 positive and protected Li negative electrodes  

NASA Astrophysics Data System (ADS)

An aqueous hybrid electrochemical capacitor consisting of a capacitive manganese oxide (MnO2) positive electrode and a water-stable, protected Li negative electrode in near-neutral aqueous electrolyte (1.0 M Li2SO4, pH = 5.5) is demonstrated. Galvanostatic charge/discharge cycling tests were conducted with pouched cells, offering a cell voltage of 4.2 V with maximum specific energy of 753 W h kg-1 based on the positive electrode. The combination of a pseudocapacitive MnO2 positive and a Li negative electrode offers high specific charge and cell voltage, resulting in an aqueous hybrid electrochemical capacitor having exceptionally high specific energy.

Shimizu, Wataru; Makino, Sho; Takahashi, Keita; Imanishi, Nobuyuki; Sugimoto, Wataru

2013-11-01

16

Rechargeable Lithium Batteries with Aqueous Electrolytes  

Microsoft Academic Search

Rechargeable lithium-ion batteries that use an aqueous electrolyte have been developed. Cells with LiMn_2O_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 nickel-cadmium and lead-acid batteries on the basis of stored energy per unit of weight.

Wu Li; J. R. Dahn; D. S. Wainwright

1994-01-01

17

Rechargeable lithium batteries with aqueous electrolytes  

Microsoft Academic Search

Rechargeable lithium-ion batteries that use an aqueous electrolyte have been developed. Cells with LiMnâOâ and VOâ(B) as electrodes and 5 M LiNOâ 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.

Wu Li; J. R. Dahn; D. S. Wainwright

1994-01-01

18

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

19

Non-aqueous, rechargeable electrochemical cell  

SciTech Connect

Non-aqueous rechargeable electrochemical cell is described comprising a negative electrode, a positive electrode containing an active material and an electrolyte solution into which said electrodes are immersed; said negative electrode comprising lithium; said electrolyte solution comprising sulfur dioxide (SO[sub 2]) as solvent and at least one solute which is a lithium salt with an anion of a group 3A element halide; and said positive electrode comprising a lithium cobalt oxide as the active material.

Heitbaum, J.; Hambitzer, G.

1993-05-25

20

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

21

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

22

The aqueous and non-aqueous electrochemistry of polyacetylene: Application in high power density rechargeable batteries  

NASA Astrophysics Data System (ADS)

Polyacetylene can be doped either chemically or electrochemically in aqueous solution to the metallic regime. The characteristics of selected rechargeable batteries employing (CH) x electrodes in non-aqueous electrolytes are described.

MacDiarmid, A. G.; Kaner, R. B.; Mammone, R. J.; Heeger, A. J.

1983-01-01

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

REE(III) adsorption onto Mn dioxide (?-MnO 2) and Fe oxyhydroxide: Ce(III) oxidation by ?-MnO 2  

Microsoft Academic Search

The adsorption experiments of rare-earth elements (REE) onto ?-MnO2 and Fe oxyhydroxide precipitates suspended in aqueous NaCl solutions have been conducted. The distribution coefficients, Kd(REE: precipitate\\/solution) between suspended ?-MnO2 and solutions show extremely large positive Ce anomalies unlike those between Fe oxyhydroxide precipitates and solutions. The iodometric titration of ?-MnO2 precipitates containing different amounts of scavenged Ce reveals that Ce(III)

Atsuyuki Ohta; Iwao Kawabe

2001-01-01

25

REE(III) adsorption onto Mn dioxide (?-MnO 2) and Fe oxyhydroxide: Ce(III) oxidation by ?-MnO 2  

NASA Astrophysics Data System (ADS)

The adsorption experiments of rare-earth elements (REE) onto ?-MnO 2 and Fe oxyhydroxide precipitates suspended in aqueous NaCl solutions have been conducted. The distribution coefficients, Kd(REE: precipitate/solution) between suspended ?-MnO 2 and solutions show extremely large positive Ce anomalies unlike those between Fe oxyhydroxide precipitates and solutions. The iodometric titration of ?-MnO 2 precipitates containing different amounts of scavenged Ce reveals that Ce(III) is oxidized to Ce(IV) by ?-MnO 2. A convex tetrad effect observed in the series variations of log Kd(REE) between suspending ?-MnO 2 and solutions becomes conspicuous with increasing pH in the range of 4.8 < pH < 6.8. This reflects the changing ratio of hydroxyl ion to water molecule coordinating REE(III) adsorbed on ?-MnO 2 suspensions with increasing experimental pH in the solution.

Ohta, Atsuyuki; Kawabe, Iwao

2001-03-01

26

Redox Active Layer-by-Layer Structures containing MnO2 Nanoparticles  

SciTech Connect

Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications. This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathode materials in rechargeable Li batteries. Our recent work has focused on synthesizing MnO2 nanoparticles and using these in layer-by-layer (LbL) structures to probe the redox properties of the nanoparticles. We show that the aqueous colloidal nanoparticles produced by butanol reduction of tetramethylammonium permanganate can be trapped in thin films using a layer-by-layer deposition approach, and that these films are both redox active and exhibit kinetically facile electrochemical responses. We show cyclic voltammetry of MnO2 colloidal nanoparticles entrapped in a LbL thin film at an ITO electrode surface using poly(diallyldimethylammonium chloride) (PDDA). CV experiments demonstrate that Li+ insertion accompanies Mn(IV) reduction in LiClO4 supporting electrolytes, and that reduction is hindered in supporting electrolytes containing only tetrabutylammonium cations. We also show that electron propagation through multilayer films is facile, suggesting that electrons percolate through the films via electron exchange between nanoparticles.

Bazito, Fernanda; O'Brien, Robert; Buttry, Daniel A.

2005-02-01

27

Evidence for covalent bonding of aryl groups to MnO2 nanorods from diazonium-based grafting.  

PubMed

We show here that the surface of MnO2 nanorods can be modified with aryl groups by grafting from aqueous and non-aqueous solutions of aryldiazonium salts. X-ray photoelectron spectroscopy provides direct evidence for covalent bonding of aryl groups to MnO2 through surface oxygens. PMID:25247262

Bell, K J; Brooksby, P A; Polson, M I J; Downard, A J

2014-10-14

28

Catalytic characteristics of MnO2 nanostructures for the O2 reduction process  

NASA Astrophysics Data System (ADS)

Nanorods with an ? type MnO2 structure and a diameter ranging from 25 to 40 nm, along with tipped needles with a ? MnO2 structure and a diameter of 100 nm were obtained. The 25 nm diameter ? MnO2 nanorods showed the best catalytic activity for dissociation of HO2 - formed during oxygen reduction in a KOH solution. The MnO2 nanostructures preferably followed a two-electron oxygen reduction mechanism in a LiOH solution. The size of the catalyst also affected the specific capacities of the non-aqueous Li/O2 batteries fabricated using the MnO2 based air electrode. The highest specific capacity of 1917 mA h g - 1 was obtained for an ? MnO2 nanorod catalyst having a diameter of 25 nm. The cation present in the MnO2 nanostructures appears to determine the catalytic activity of MnO2.

Kalubarme, Ramchandra S.; Cho, Min-Seung; Yun, Kwi-Sub; Kim, Tae-Sin; Park, Chan-Jin

2011-09-01

29

Quantitative correlation between Li absorption and H content in manganese oxide spinel ?-MnO 2  

Microsoft Academic Search

In the present paper, the composition of several spinel-type ?-MnO2 samples (which absorb lithium ions with a high selectivity in an aqueous solution) is analyzed and the correlation between the composition and the absorption capacity of lithium is investigated experimentally. Then samples of ?-MnO2 with different hydrogen contents are prepared, and each lithium absorption capacity is measured. The results indicate

Hideki Koyanaka; Osamu Matsubaya; Yoshio Koyanaka; Natsuo Hatta

2003-01-01

30

An aqueous rechargeable lithium battery based on doping and intercalation mechanisms  

Microsoft Academic Search

An aqueous rechargeable lithium battery (ARLB) using an electroactive polymer, polypyrrole (PPy), as a negative electrode;\\u000a a lithium ion intercalation compound LiCoO2 as a positive electrode; and Li2SO4 aqueous solution as an electrolyte and its working mechanism are described. The charge\\/discharge process is associated with\\u000a the doping\\/un-doping of anions at the negative electrode and intercalation\\/deintercalation of lithium ions at the

G. J. Wang; L. C. Yang; Q. T. Qu; B. Wang; Y. P. Wu; R. Holze

2010-01-01

31

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

32

Synthesis and characterization of different MnO2 morphologies for lithium-air batteries  

NASA Astrophysics Data System (ADS)

Manganese dioxide (MnO2) was synthesized in the forms of nanorods, nanoparticles, and mesoporous structures and the characteristics of these materials were investigated. Crystallinities were studied by x-ray diffraction and morphologies by scanning and transmission electron microscopy. Average pore sizes and specific surface areas were analyzed using the Barret-Joyner-Halenda and Brunauer-Emmett-Teller methods, respectively. Samples were also studied by cyclic voltammetry using 1M aqueous KOH solution saturated with either O2 or N2 as electrolytes to investigate their ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) activities. Of the samples produced, mesoporous MnO2 exhibited the highest ORR and OER catalytic activities. Mesoporous MnO2 supported on a gas diffusion layer was also used as a catalyst on the air electrode (cathode) of a lithium-air battery in organic electrolyte. The charge-discharge behavior of mesoporous MnO2 was investigated at a current density 0.2 mAcm-2 in a pure oxygen environment. Mesoporous MnO2 electrodes showed stable cycleability up to 65 cycles at a cell capacity of 700 mAhg-1.

Choi, Hyun-A.; Jang, Hyuk; Hwang, Hyein; Choi, Mincheol; Lim, Dongwook; Shim, Sang Eun; Baeck, Sung-Hyeon

2014-09-01

33

Electrochemical instability of LiV 3O 8 as an electrode material for aqueous rechargeable lithium batteries  

Microsoft Academic Search

We demonstrate the unsuitability of LiV3O8 as an electrode material for aqueous rechargeable lithium batteries on simple but solid grounds: the compound is unstable under typical battery operation conditions, where it slowly dissolves as reflected in the yellow color acquired by the electrolyte. This can be the origin of the poor performance of the aqueous batteries based on this compound.

A. Caballero; J. Morales; O. A. Vargas

2010-01-01

34

An aqueous rechargeable formate-based hydrogen battery driven by heterogeneous pd catalysis.  

PubMed

The formate-based rechargeable hydrogen battery (RHB) promises high reversible capacity to meet the need for safe, reliable, and sustainable H2 storage used in fuel cell applications. Described herein is an additive-free RHB which is based on repetitive cycles operated between aqueous formate dehydrogenation (discharging) and bicarbonate hydrogenation (charging). Key to this truly efficient and durable H2 handling system is the use of highly strained Pd nanoparticles anchored on graphite oxide nanosheets as a robust and efficient solid catalyst, which can facilitate both the discharging and charging processes in a reversible and highly facile manner. Up to six repeated discharging/charging cycles can be performed without noticeable degradation in the storage capacity. PMID:25382034

Bi, Qing-Yuan; Lin, Jian-Dong; Liu, Yong-Mei; Du, Xian-Long; Wang, Jian-Qiang; He, He-Yong; Cao, Yong

2014-12-01

35

An Aqueous Rechargeable Lithium Battery Using Coated Li Metal as Anode  

PubMed Central

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

36

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

37

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

38

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

39

MnO2/CeO2 for catalytic ultrasonic degradation of methyl orange.  

PubMed

Catalytic ultrasonic degradation of aqueous methyl orange was studied in this paper. Heterogeneous catalyst MnO2/CeO2 was prepared by impregnation of manganese oxide on cerium oxide. Morphology and specific surface area of MnO2/CeO2 catalyst were characterized and its composition was determined. Results showed big differences between fresh and used catalyst. The removal efficiency of methyl orange by MnO2/CeO2 catalytic ultrasonic process was investigated. Results showed that ultrasonic process could remove 3.5% of methyl orange while catalytic ultrasonic process could remove 85% of methyl orange in 10 min. The effects of free radical scavengers were studied to determine the role of hydroxyl free radical in catalytic ultrasonic process. Results showed that methyl orange degradation efficiency declined after adding free radical scavengers, illustrating that hydroxyl free radical played an important role in degrading methyl orange. Theoretic analysis showed that the resonance size of cavitation bubbles was comparable with the size of catalyst particles. Thus, catalyst particles might act as cavitation nucleus and enhance ultrasonic cavitation effects. Measurement of H2O2 concentration in catalytic ultrasonic process confirmed this hypothesis. Effects of pre-adsorption on catalytic ultrasonic process were examined. Pre-adsorption significantly improved methyl orange removal. The potential explanation was that methyl orange molecules adsorbed on catalysts could enter cavitation bubbles and undergo stronger cavitation. PMID:24369902

Zhao, He; Zhang, Guangming; Zhang, Quanling

2014-05-01

40

Nanochain LiMn 2O 4 as ultra-fast cathode material for aqueous rechargeable lithium batteries  

Microsoft Academic Search

Nanochain LiMn2O4 was prepared by a starch-assisted sol–gel method. Its electrochemical behavior as a cathode material for aqueous rechargeable lithium batteries (ARLBs) was characterized by cyclic voltaammograph, capacity measurement and cycling test. Results show that the nanochain LiMn2O4 has an ultra-fast charge capability. It presents a reversible capacity of 110mAh\\/g at 4.5C and 95mAh\\/g even at 91C in 0.5mol\\/l Li2SO4

W. Tang; S. Tian; L. L. Liu; L. Li; H. P. Zhang; Y. B. Yue; Y. Bai; Y. P. Wu; K. Zhu

2011-01-01

41

Electrochemical properties of rechargeable aqueous lithium ion batteries with an olivine-type cathode and a Nasicon-type anode  

Microsoft Academic Search

Rechargeable aqueous lithium ion batteries have been developed by using olivine LiMn0.05Ni0.05Fe0.9PO4 as cathode material, Nasicon LiTi2(PO4)3 as anode material, and saturated Li2SO4 solution as electrolyte. The cycling performance and rate capability of these batteries have been investigated. At a current density of 0.2mA\\/cm2, the initial discharge capacity of the battery was approximately 103.9mAh\\/g, and the potential plateau was located

Xiao-Hong Liu; Taishi Saito; Takayuki Doi; Shigeto Okada; Jun-ichi Yamaki

2009-01-01

42

LiMn2O4 nanotube as cathode material of second-level charge capability for aqueous rechargeable batteries.  

PubMed

LiMn2O4 nanotube with a preferred orientation of (400) planes is prepared by using multiwall carbon nanotubes as a sacrificial template. Because of the nanostructure and preferred orientation, it shows a superfast second-level charge capability as a cathode for aqueous rechargeable lithium battery. At the charging rate of 600C (6 s), 53.9% capacity could be obtained. Its reversible capacity can be 110 mAh/g, and it also presents excellent cycling behavior due to the porous tube structure to buffer the strain and stress from Jahn-Teller effects. PMID:23537381

Tang, Wei; Hou, Yuyang; Wang, Faxing; Liu, Lili; Wu, Yuping; Zhu, Kai

2013-05-01

43

Highly selective lithium recovery from brine using a ?-MnO2-Ag battery.  

PubMed

The demand for lithium has greatly increased with the rapid development of rechargeable batteries. Currently, the main lithium resource is brine lakes, but the conventional lithium recovery process is time consuming, inefficient, and environmentally harmful. Rechargeable batteries have been recently used for lithium recovery, and consist of lithium iron phosphate as a cathode. These batteries feature promising selectivity between lithium and sodium, but they suffer from severe interference from coexisting magnesium ions, an essential component of brine, which has prompted further study. This study reports on a highly selective and energy-efficient lithium recovery system using a rechargeable battery that consists of a ?-MnO2 positive electrode and a chloride-capturing negative electrode. This system can be used to recover lithium from brine even in the presence of magnesium ions as well as other dissolved cations. In addition, lithium recovery from simulated brine is successfully demonstrated, consuming 1.0 W h per 1 mole of lithium recovered, using water similar to that from the artificial brine, which contains various cations (mole ratio: Na/Li ? 15.7, K/Li ? 2.2, Mg/Li ? 1.9). PMID:23595419

Lee, Jaehan; Yu, Seung-Ho; Kim, Choonsoo; Sung, Yung-Eun; Yoon, Jeyong

2013-05-28

44

Investigation of the rechargeability of Li–O 2 batteries in non-aqueous electrolyte  

Microsoft Academic Search

To understand the limited cycle life performance and poor energy efficiency associated with rechargeable lithium–oxygen (Li–O2) batteries, the discharge products of primary Li–O2 cells at different depths of discharge (DOD) were systematically analyzed using XRD, FTIR and Ultra-high field MAS NMR. When discharged to 2.0V, the reaction products of Li–O2 cells include a small amount of Li2O2 along with Li2CO3

Jie Xiao; Jianzhi Hu; Deyu Wang; Dehong Hu; Wu Xu; Gordon L. Graff; Zimin Nie; Jun Liu; Ji-Guang Zhang

2011-01-01

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

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

47

High cycling stability of zinc-anode/conducting polymer rechargeable battery with non-aqueous electrolyte  

NASA Astrophysics Data System (ADS)

A non-aqueous zinc-polyaniline secondary battery was fabricated with polyaniline Emeraldine base as cathode and zinc metal as anode in an electrolyte consisting of 0.3 M zinc-bis(trifluoromethyl-sulfonyl)imide Zn(TFSI)2 dissolved in propylene carbonate. We observed that the formation of the battery required a prerequisite condition to stabilize the interfaces in order to maintain a stable capacity. The battery suffered from Zn dissolution which induces a competition between concurrent Zn dissolution and plating when the battery is in charge mode, and thus inefficient cycles are obtained. The capacity and coulombic efficiency of the battery depends on the charge-discharge rates. We propose cycling protocols at different rates to determine the steady-state rates of competing reactions. When the cell is cycled at ?1 C rate, the coulombic efficiency improves. The maximum capacity and energy densities of the battery are 148 mAhg-1 and 127 mWhg-1, respectively for discharge at C/2. The battery was successively charged/discharged at constant current densities (1C rate), and high cycling stability was obtained for more than 1700 cycles at 99.8% efficiency. Zinc dissolution and self discharge of the battery were investigated after 24 h of standby. The investigation showed that the battery experiences a severe self-discharge of 48% per day.

Guerfi, A.; Trottier, J.; Boyano, I.; De Meatza, I.; Blazquez, J. A.; Brewer, S.; Ryder, K. S.; Vijh, A.; Zaghib, K.

2014-02-01

48

MnO2 spontaneously coated on carbon nanotubes for enhanced water oxidation.  

PubMed

?-MnO2/o-MWCNTs were synthesized by coating MnO2 spontaneously on oxidized multi-walled carbon nanotubes via simple immersion of the o-MWCNTs into KMnO4 solution. This catalyst comprising the outer region of catalytic MnO2 and the inner region of highly conductive o-MWCNTs enhanced photocatalytic water oxidation activity. PMID:25162068

Wei, Jie; Liu, Yan; Ding, Yong; Luo, Chao; Du, Xiaoqiang; Lin, Junqi

2014-10-14

49

Lithiation of ramsdellite-pyrolusite MnO 2; NMR, XRD, TEM and electrochemical investigation of the discharge mechanism  

NASA Astrophysics Data System (ADS)

Electrolytic manganese dioxide (EMD) is made in aqueous sulfuric acid and neutralized or ion exchanged with aqueous lithium hydroxide before use in Li batteries. Solid state Li NMR studies show that Li is present on surface and vacancy sites and migrates into Mn (III) related sites after heat treatment to remove water. During heat treatment the MnO 2 rearranges from ramsdellite/pyrolusite intergrowth EMD to a defect pyrolusite heat-treated manganese dioxide (HEMD). EMD exhaustively treated with lithium hydroxide solution has 40-50% of the protons in EMD exchanged for Li ions to produce a structurally unchanged ?-MnO 2. Li magic angle spinning (MAS) NMR reveals that this lithiated material contains lithium in cation vacancy and Mn (III) related sites in the MnO 2 lattice in addition to ionic Li on the surface. During heat treatment, the vacancy lithium content prevents the ramsdellite to pyrolusite rearrangement in HEMD formation. Instead, an ordered ramsdellite/pyrolusite intergrowth of lithiated manganese dioxide (LiMD) is formed with an approximate composition of 50% ramsdellite and 50% pyrolusite. Li MAS NMR of LiMD shows Li resonances near 280 and 560 ppm, consistent with Li transition from surface and cation vacancy sites into the ramsdellite lattice. LiMD discharged against lithium shows two processes, one near 3.1 V, the other about 2.8 V. Li MAS NMR studies show the initial reduction results a lithium resonance near 560 ppm associated with Li near a mixed valence Mn (III/IV) environment followed by appearance of a resonance near 100 ppm consistent with a Li environment near Mn (III). TEM studies of the reduced material show initial expansion of the ramsdellite lattice accompanied by a loss in crystallinity in the 3.1 V discharge process followed by disappearance of the pyrolusite content via conversion to ramsdellite in the second discharge process.

Bowden, W.; Grey, C. P.; Hackney, S.; Wang, F.; Paik, Y.; Iltchev, N.; Sirotina, R.

50

Energetic aqueous rechargeable sodium-ion battery based on Na2 CuFe(CN)6 -NaTi2 (PO4 )3 intercalation chemistry.  

PubMed

Aqueous rechargeable sodium-ion batteries have the potential to meet growing demand for grid-scale electric energy storage because of the widespread availability and low cost of sodium resources. In this study, we synthesized a Na-rich copper hexacyanoferrate(II) Na2 CuFe(CN)6 as a high potential cathode and used NaTi2 (PO4 )3 as a Na-deficient anode to assemble an aqueous sodium ion battery. This battery works very well with a high average discharge voltage of 1.4 V, a specific energy of 48 Wh kg(-1) , and an excellent high-rate cycle stability with approximately 90 % capacity retention over 1000 cycles, achieving a new record in the electrochemical performance of aqueous Na-ion batteries. Moreover, all the anode, cathode, and electrolyte materials are low cost and naturally abundant and are affordable for widespread applications. PMID:24464957

Wu, Xian-Yong; Sun, Meng-Ying; Shen, Yi-Fei; Qian, Jiang-Feng; Cao, Yu-Liang; Ai, Xin-Ping; Yang, Han-Xi

2014-02-01

51

Adsorption of REE(III)-humate complexes onto MnO 2: Experimental evidence for cerium anomaly and lanthanide tetrad effect suppression  

Microsoft Academic Search

Experiments were conducted to evaluate the impact of organic complexation on the development of Ce anomalies and the lanthanide tetrad effect during the adsorption of rare-earth elements (REE) onto MnO2. Two types of aqueous solutions—NaCl and NaNO3—were tested at pH 5 and 7.5. Time-series experiments indicate that a steady-state is reached within less than 10 h when REE occur as

Mélanie Davranche; Olivier Pourret; Gérard Gruau; Aline Dia; Martine Le Coz-Bouhnik

2005-01-01

52

?-MnO 2 nano-sieve membrane: preparation, characterization and reaction studies  

NASA Astrophysics Data System (ADS)

?-MnO 2 nano-sieve membrane was synthesized using ?-MnO 2 nanometer powders by suspending particles sintering method. The results of BET, AFM, and SEM indicate that ?-MnO 2 nano-sieve membrane with a thickness of about 2 ?m is porous (pore size 4 nm), and has a smooth surface. The results of XRD and TPR exhibit that the phase transformation which can be suppressed at La/Mn = 0.15, and the activity of oxygen center of ?-MnO 2 nano-sieve membrane (La/Mn = 0.15) is slightly lower than that of ?-MnO 2 nanometer powders. ?-MnO 2 nano-sieve membrane shows a higher separation factor of H 2/Ar in the range of 50-300 °C. In addition, the ?-MnO 2 nano-sieve membrane was applied to the membrane reactor for cyclohexane oxidative dehydrogenation, and the effect of temperature on cyclohexane conversion was investigated. The result shows that cyclohexane conversion in the ?-MnO 2 nano-sieve membrane reactor is higher than that in the conventional packed bed reactor.

Zhao, Lili; Wang, Rongshu

2004-09-01

53

Electrochemical behavior of spherical LiNi 1\\/3 Co 1\\/3 Mn 1\\/3 O 2 as cathode material for aqueous rechargeable lithium batteries  

Microsoft Academic Search

Spherical LiNi1\\/3Co1\\/3Mn1\\/3O2 powders have been synthesized from co-precipitated spherical metal hydroxide. The electrochemical performances of the LiNi1\\/3Co1\\/3Mn1\\/3O2 electrodes in 1 M LiNO3, 5 M LiNO3, and saturated LiNO3 aqueous electrolytes have been studied using cyclic voltammetry and ac impedance tests in this work. The results show that\\u000a LiNi1\\/3Co1\\/3Mn1\\/3O2 electrode in saturated LiNO3 electrolyte exhibits the best electrochemical performance. An aqueous rechargeable lithium

Li Liu; Fanghua Tian; Xingyan Wang; Zhenhua Yang; Quanqi Chen; Xianyou Wang

54

Balance the reaction MnO4 (aq) MnO2(s) + SO4  

E-print Network

Balance the reaction MnO4 Ð (aq) + SO3 2Ð (aq) MnO2(s) + SO4 2Ð (aq) in basic solution Oxidation +4) and S gets oxidized (+4 +6) 1) Write down the half reactions (incomplete) : MnO4 Ð MnO2 (a) SO3 + 2H2O 5) Balance charge by adding electrons MnO4 Ð + 4H + + 3e Ð MnO2 + 2H2O 6) Convert to basic

Peterson, Kirk A.

55

Growth and characterization of carbon-supported MnO 2 nanorods for supercapacitor electrode  

Microsoft Academic Search

Preparation of carbon-supported nano-MnO2 composite (MnO2\\/C) by microemulsion process is reported. As evidenced by high-resolution transmission electron microscopy (HR-TEM) micrographs, highly dispersed MnO2 nanorods over carbon surface with clear inter-phase boundaries are obtained. X-ray diffraction results of as grown composite powder confirm the ?MnO2 phase of manganese oxide that on annealing at elevated temperatures undergo oxidative transformation to Mn3O4 and

Raj Kishore Sharma; Hyung-Suk Oh; Yong-Gun Shul; Hansung Kim

2008-01-01

56

Adsorption of REE(III)-humate complexes onto MnO 2: Experimental evidence for cerium anomaly and lanthanide tetrad effect suppression  

NASA Astrophysics Data System (ADS)

Experiments were conducted to evaluate the impact of organic complexation on the development of Ce anomalies and the lanthanide tetrad effect during the adsorption of rare-earth elements (REE) onto MnO 2. Two types of aqueous solutions—NaCl and NaNO 3—were tested at pH 5 and 7.5. Time-series experiments indicate that a steady-state is reached within less than 10 h when REE occur as free inorganic species, whereas steady state is not reached before 10 d when REE occur as REE-humate complexes. The distribution coefficients (K dREE) between suspended MnO 2 and solution show no or only very weak positive Ce anomaly or lanthanide tetrad effect when REE occur as humate complexes, unlike the results obtained in experiments with REE occurring as free inorganic species. Monitoring of dissolved organic carbon (DOC) concentrations show that log K dREE organic/K dDOC ratios are close to 1.0, implying that the REE and humate remain bound to each other upon adsorption. Most likely, the Ce anomaly reduction/suppression in the organic experiments arises from a combination of two processes: (i) inability of MnO 2 to oxidize Ce(III) because of shielding of MnO 2 surfaces by humate molecules and (ii) Ce(IV) cannot be preferentially removed from solution due to quantitative complexation of the REE by organic matter. We suggest that the lack of lanthanide tetrad effect arises because the adsorption of REE-humate complexes onto MnO 2 occurs dominantly via the humate side of the complexes (anionic adsorption), thereby preventing expression of the differences in Racah parameters for 4f electron repulsion between REE and the oxide surface. The results presented here explain why, despite the development of strongly oxidizing conditions and the presence of MnO 2 in the aquifer, no (or insignificant) negative Ce anomalies are observed in organic-rich waters. The present study demonstrates experimentally that the Ce anomaly cannot be used as a reliable proxy of redox conditions in organic-rich waters or in precipitates formed at equilibrium with organic-rich waters.

Davranche, Mélanie; Pourret, Olivier; Gruau, Gérard; Dia, Aline; Le Coz-Bouhnik, Martine

2005-10-01

57

Dielectric SiO2 Planarization Using MnO2 Slurry  

NASA Astrophysics Data System (ADS)

MnO2 slurry can polish SiO2 film faster and planarize wide feature steps (2 ×2 mm2) to a lower height than conventional silica slurry. A comparison of Gibbs free energies indicates that the MnO2 abrasive directly reacts on the SiO2 film. In post-Chemical mechanical polishing (CMP), the MnO2 abrasive can be completely removed by dipping it in mixed solutions of inorganic acids and H2O2 followed by scrubbing and dipping in HF solution. A comparison of Gibbs free energies clarifies that the MnO2 abrasive on the wafer is easily dissolved in a mixed solution of an inorganic acid and H2O2.

Kishii, Sadahiro; Nakamura, Ko; Hanawa, Kenzo; Watanabe, Satoru; Arimoto, Yoshihiro; Kurokawa, Syuhei; Doi, Toshiro K.

2012-01-01

58

MnO 2-coated Ni nanorods: Enhanced high rate behavior in pseudo-capacitive supercapacitor  

Microsoft Academic Search

Ni nanorods prepared by electrochemical growth through an anodized aluminium oxide membrane were used as substrate for the electrodeposition of MnO2 either in potentiostatic mode or by a pulsed method. Electrochemical deposition parameters were chosen for an homogeneous deposit onto Ni nanorods. Resulting Ni supported MnO2 electrodes were tested for electrochemical performances as nanostructured negative electrodes for supercapacitors. They exhibited

Y. Lei; B. Daffos; P. L. Taberna; P. Simon; F. Favier

2010-01-01

59

An economical and environmentally friendly oxidative biaryl coupling promoted by activated MnO2.  

PubMed

An activated manganese dioxide (MnO2)-BF3·OEt2 oxidation system was developed to efficiently mediate the intramolecular as well as intermolecular biaryl coupling. The oxidative coupling proceeds smoothly at ambient temperature to deliver the corresponding five- to eight-membered tricyclic products in good to excellent yields. The employment of the combination of MnO2 and BF3·OEt2 is attractive on the basis of economical and environmental issues. PMID:25144866

Yang, Jingjing; Sun, Shutao; Zeng, Ziyu; Zheng, Hongbo; Li, Wei; Lou, Hongxiang; Liu, Lei

2014-10-21

60

Synthesis of nano-grained MnO2 thin films by laser ablation  

Microsoft Academic Search

Manganese dioxide (MnO2) is considered as one of the most attractive compound among the manganese oxide phases due to its fundamental chemical and physical properties, its use in energy-storage devices, electrochemical applications, and biosensors. There have been limited attempts to grow high quality MnO2 thin films where high pressure and low substrate temperature are targeted to promote the formation of

Malek Tabbal; Maya Abi-Akl; Samih Isber; Elisar Majdalani; Theodore Christidis

2009-01-01

61

Evolving microstructure in MnO 2 using amorphisation and recrystallisation  

Microsoft Academic Search

The electrochemical properties of ?-MnO2 are governed by the rich and complex microstructure it accommodates. However, characterisation, at the atomistic level, of this material is difficult experimentally; rather the materials are typified by their X-ray diffraction (XRD) patterns. Here, we use an evolutionary simulation—amorphisation and recrystallisation (A&R)—to generate atomistic models for ?-MnO2, which include microstructural detail. These models conform to

Thi X. T. Sayle; C. Richard A. Catlow; R. Rapella. Maphanga; Phuti E. Ngoepe; Dean C. Sayle

2006-01-01

62

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

63

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

64

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

65

How accurate are 234Th measurements in seawater based on the MnO2-impregnated cartridge technique?  

Microsoft Academic Search

In the past decade, a MnO2-impregnated cartridge technique has been widely used to extract 234Th from seawater. One of the inherent assumptions associated with this technique is that all Th species in the dissolved phase are subject to extraction by the MnO2 cartridges. In this study, an intercalibration between the cartridge technique and a small-volume MnO2 coprecipitation technique was carried

Pinghe Cai; Minhan Dai; Dongwei Lv; Weifang Chen

2006-01-01

66

Uncoupled surface spin induced exchange bias in ?-MnO2 nanowires.  

PubMed

We have studied the microstructure, surface states, valence fluctuations, magnetic properties, and exchange bias effect in MnO2 nanowires. High purity ?-MnO2 rectangular nanowires were synthesized by a facile hydrothermal method with microwave-assisted procedures. The microstructure analysis indicates that the nanowires grow in the [0 0 1] direction with the (2 1 0) plane as the surface. Mn(3+) and Mn(2+) ions are not found in the system by X-ray photoelectron spectroscopy. The effective magnetic moment of the manganese ions fits in with the theoretical and experimental values of Mn(4+) very well. The uncoupled spins in 3d(3) orbitals of the Mn(4+) ions in MnO6 octahedra on the rough surface are responsible for the net magnetic moment. Spin glass behavior is observed through magnetic measurements. Furthermore, the exchange bias effect is observed for the first time in pure ?-MnO2 phase due to the coupling of the surface spin glass with the antiferromagnetic ?-MnO2 matrix. These ?-MnO2 nanowires, with a spin-glass-like behavior and with an exchange bias effect excited by the uncoupled surface spins, should therefore inspire further study concerning the origin, theory, and applicability of surface structure induced magnetism in nanostructures. PMID:25319531

Li, Wenxian; Zeng, Rong; Sun, Ziqi; Tian, Dongliang; Dou, Shixue

2014-01-01

67

Uncoupled surface spin induced exchange bias in ?-MnO2 nanowires  

NASA Astrophysics Data System (ADS)

We have studied the microstructure, surface states, valence fluctuations, magnetic properties, and exchange bias effect in MnO2 nanowires. High purity ?-MnO2 rectangular nanowires were synthesized by a facile hydrothermal method with microwave-assisted procedures. The microstructure analysis indicates that the nanowires grow in the [0 0 1] direction with the (2 1 0) plane as the surface. Mn3+ and Mn2+ ions are not found in the system by X-ray photoelectron spectroscopy. The effective magnetic moment of the manganese ions fits in with the theoretical and experimental values of Mn4+ very well. The uncoupled spins in 3d3 orbitals of the Mn4+ ions in MnO6 octahedra on the rough surface are responsible for the net magnetic moment. Spin glass behavior is observed through magnetic measurements. Furthermore, the exchange bias effect is observed for the first time in pure ?-MnO2 phase due to the coupling of the surface spin glass with the antiferromagnetic ?-MnO2 matrix. These ?-MnO2 nanowires, with a spin-glass-like behavior and with an exchange bias effect excited by the uncoupled surface spins, should therefore inspire further study concerning the origin, theory, and applicability of surface structure induced magnetism in nanostructures.

Li, Wenxian; Zeng, Rong; Sun, Ziqi; Tian, Dongliang; Dou, Shixue

2014-10-01

68

Uncoupled surface spin induced exchange bias in ?-MnO2 nanowires  

PubMed Central

We have studied the microstructure, surface states, valence fluctuations, magnetic properties, and exchange bias effect in MnO2 nanowires. High purity ?-MnO2 rectangular nanowires were synthesized by a facile hydrothermal method with microwave-assisted procedures. The microstructure analysis indicates that the nanowires grow in the [0 0 1] direction with the (2 1 0) plane as the surface. Mn3+ and Mn2+ ions are not found in the system by X-ray photoelectron spectroscopy. The effective magnetic moment of the manganese ions fits in with the theoretical and experimental values of Mn4+ very well. The uncoupled spins in 3d3 orbitals of the Mn4+ ions in MnO6 octahedra on the rough surface are responsible for the net magnetic moment. Spin glass behavior is observed through magnetic measurements. Furthermore, the exchange bias effect is observed for the first time in pure ?-MnO2 phase due to the coupling of the surface spin glass with the antiferromagnetic ?-MnO2 matrix. These ?-MnO2 nanowires, with a spin-glass-like behavior and with an exchange bias effect excited by the uncoupled surface spins, should therefore inspire further study concerning the origin, theory, and applicability of surface structure induced magnetism in nanostructures. PMID:25319531

Li, Wenxian; Zeng, Rong; Sun, Ziqi; Tian, Dongliang; Dou, Shixue

2014-01-01

69

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

2013-10-01

70

Charge tunneling and trapping in Er stabilized ?-MnO2 films for memory applications  

NASA Astrophysics Data System (ADS)

Recently, the memory effect was observed in Er stabilized ?-MnO2 metal oxide semiconductor structure. In this work, the electric properties and mechanism of charge tunneling and trapping are studied by combining frequency-dependent capacitance-voltage curves, variable sweep range capacitance-voltage curves, and current-voltage curves. The charge traps are identified to be deep donors in ?-MnO2. The deep donor level is close to the valance band, which results in the asymmetric enlargement in variable sweep range capacitance-voltage curves. Resonant tunneling and Fowler-Nordheim tunneling mechanisms are observed at low and high voltages, respectively. All these phenomena can be explained by the proposed model as a whole. The experimental evidence shows that Er-stabilized ?-MnO2 is a good candidate charge storage material in nonvolatile memory devices.

Cui, Jian; Ji, Ting; Nie, Tianxiao; Jiang, Zuimin

2014-06-01

71

Facile synthesis of hierarchical hollow ?-MnO2 spheres and their application in supercapacitor electrodes  

NASA Astrophysics Data System (ADS)

The hierarchical hollow microspheres of ?-MnO2 have been synthesized through a facile chemical method at room temperature followed by selective removal of manganese carbonate structures with HCl. The microstructure and morphologies of the resulting materials are investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results indicate that the product obtained by simple reaction for 3 min has a porous shell with excellent permeability and uniform pore-size distribution. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge and impedance spectra. As a result, the hierarchical hollow ?-MnO2 showed the specific capacitance of 115 F g-1 at 0.5 A g-1. These results demonstrate that the ?-MnO2 as electrode materials have potential application for high-performance supercapacitors.

Han, Dandan; Jing, Xiaoyan; Xu, Pengcheng; Ding, Yuansheng; Liu, Jingyuan

2014-10-01

72

Controlled growth of hierarchical nanostructured MnO2/carbon hybrids  

NASA Astrophysics Data System (ADS)

An exceptional hierarchical nanostructured MnO2/carbon hybrid was in situ generated by a mild wet chemical pre-treatment and then hydrothermal method. The thickness of the representative petal-like nanosheet was measured below 5 nm. Growth mechanism of the achieved hierarchical hybrid is associated with simultaneously occurred redox and oxidation-intercalation reactions. The surface layers of carbon black (XC-72) were partly exfoliated, and redox reaction between KMnO4 and hydroxyl group occurred on the both side of these layers, resulting in the hierarchical hybrid of MnO2/carbon.

Chen, Ying; Xie, Bingqiao; Luo, Shiyu; Zhang, Yong

2013-11-01

73

Nanoporous LiNi(1/3)Co(1/3)Mn(1/3)O2 as an ultra-fast charge cathode material for aqueous rechargeable lithium batteries.  

PubMed

Nanoporous LiNi1/3Co1/3Mn1/3O2 (NP-NCM) was synthesized by using vapour grown carbon fibers (VGCFs) as templates. It exhibits excellent electrochemical performance as a cathode material for aqueous rechargeable lithium batteries, especially with ultra-fast charge capability, and 72 mA h g(-1) can be achieved at a charge time of 20 s. PMID:23998182

Wang, Faxing; Xiao, Shiying; Chang, Zheng; Yang, Yaqiong; Wu, Yuping

2013-10-14

74

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

75

Graphene-wrapped MnO2 -graphene nanoribbons as anode materials for high-performance lithium ion batteries.  

PubMed

A facile and cost-effective approach for the fabrication of a hierarchical nanocomposite material of graphene-wrapped MnO2 -graphene nanoribbons (GMG) is developed. The resulting composite has a high specific capacity and an excellent cycling stability owing to the synergistic combination of the electrically conductive graphene, graphene nanoribbons, and MnO2 . PMID:23996876

Li, Lei; Raji, Abdul-Rahman O; Tour, James M

2013-11-20

76

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

77

Rutile (?-)MnO2 surfaces and vacancy formation for high electrochemical and catalytic performance.  

PubMed

MnO2 is a technologically important material for energy storage and catalysis. Recent investigations have demonstrated the success of nanostructuring for improving the performance of rutile MnO2 in Li-ion batteries and supercapacitors and as a catalyst. Motivated by this we have investigated the stability and electronic structure of rutile (?-)MnO2 surfaces using density functional theory. A Wulff construction from relaxed surface energies indicates a rod-like equilibrium morphology that is elongated along the c-axis, and is consistent with the large number of nanowire-type structures that are obtainable experimentally. The (110) surface dominates the crystallite surface area. Moreover, higher index surfaces than considered in previous work, for instance the (211) and (311) surfaces, are also expressed to cap the rod-like morphology. Broken coordinations at the surface result in enhanced magnetic moments at Mn sites that may play a role in catalytic activity. The calculated formation energies of oxygen vacancy defects and Mn reduction at key surfaces indicate facile formation at surfaces expressed in the equilibrium morphology. The formation energies are considerably lower than for comparable structures such as rutile TiO2 and are likely to be important to the high catalytic activity of rutile MnO2. PMID:24446882

Tompsett, David A; Parker, Stephen C; Islam, M Saiful

2014-01-29

78

Ultrathin MnO(2) 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

2014-07-25

79

Microstructure and Phase Transition of MnO2-Doped Bismuth Layered-Structure Ferroelectrics  

NASA Astrophysics Data System (ADS)

The effects of MnO2 doping on the microstructure and phase transition of ferroelectric CaBi4Ti4O15 (CBT) ceramics with x mol % of MnO2 (CBT-xM x = 0, 1, 3) have been studied. The single-phase crystal structure and the plate-like grain morphology are clearly observed for all compositions, while extended grains are observed with x = 3. The dielectric permittivity and dielectric loss show that the Mn2+ and Mn3+ ions are preferentially incorporated into the A- and B-sites, respectively, up to a limiting extent of approximately x = 2. The ac conductivity decreases and the activation energy increases with increasing Mn content owing to the decrease in the number of conducting carriers and increase in covalence, respectively. The Curie temperature TC is independent of MnO2 doping within the experimental accuracy, and the dielectric constant satisfies the Curie-Weiss law above TC. The temperature dependence of the soft mode with x = 0 and 1 shows a significant softening towards T1˜TC + 113 °C (at T1, the square of the soft mode frequency ?s2?0). ?s2 is approximately proportional to T - T1. These findings indicate that the displacive nature of the phase transition is not affected by MnO2 doping, at least below x = 3.

Saidul Islam, Md.; Kano, Jun; Tsukada, Shinya; Yin, Qingrui; Kojima, Seiji

2009-09-01

80

Microstructure and Phase Transition of MnO2-Doped Bismuth Layered-Structure Ferroelectrics  

NASA Astrophysics Data System (ADS)

The effects of MnO2 doping on the microstructure and phase transition of ferroelectric CaBi4Ti4O15 (CBT) ceramics with x mol % of MnO2 (CBT-xM; x = 0, 1, 3) have been studied. The single-phase crystal structure and the plate-like grain morphology are clearly observed for all compositions, while extended grains are observed with x = 3. The dielectric permittivity and dielectric loss show that the Mn2+ and Mn3+ ions are preferentially incorporated into the A- and B-sites, respectively, up to a limiting extent of approximately x = 2. The ac conductivity decreases and the activation energy increases with increasing Mn content owing to the decrease in the number of conducting carriers and increase in covalence, respectively. The Curie temperature TC is independent of MnO2 doping within the experimental accuracy, and the dielectric constant satisfies the Curie-Weiss law above TC. The temperature dependence of the soft mode with x = 0 and 1 shows a significant softening towards T1˜ TC + 113 °C (at T1, the square of the soft mode frequency ?s{}2? 0). ?s{}2 is approximately proportional to T - T1. These findings indicate that the displacive nature of the phase transition is not affected by MnO2 doping, at least below x = 3.

Islam, Md. Saidul; Kano, Jun; Tsukada, Shinya; Yin, Qingrui; Kojima, Seiji

2009-09-01

81

Bacteriology of Manganese Nodules. Iv. Induction of an MNO2-Reductase System in a Marine Bacillus.  

National Technical Information Service (NTIS)

Bacillus 29, isolated from a ferromanganese nodule from the Atlantic Ocean, was shown to possess an MnO2-reductase system which is induced in the presence of manganous ion. Maximal activity of the enzyme system was induced in about 5 hr in the presence of...

R. B. Trimble, H. L. Ehrlich

1970-01-01

82

?-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

83

Advanced Small Rechargeable Batteries  

NASA Technical Reports Server (NTRS)

Lithium-based units offer highest performance. Paper reviews status of advanced, small rechargeable batteries. Covers aqueous systems including lead/lead dioxide, cadmium/nickel oxide, hydrogen/nickel oxide, and zinc/nickel oxide, as well as nonaqueous systems. All based on lithium anodes, nonaqueous systems include solid-cathode cells (lithium/molybdenum disulfide, lithium/titanium disulfide, and lithium/vanadium oxide); liquid-cathode cells (lithium/sulfur dioxide cells); and new category, lithium/polymer cells.

Halpert, Gerald

1989-01-01

84

Mild Synthesis Route to Nanostructured ?-MnO2 as Electrode Materials for Electrochemical Energy Storage  

NASA Astrophysics Data System (ADS)

?-MnO2 electrode materials with sphere-, rod- and flower-like nanostructures were for the first time fabricated by a redox reaction between KMnO4 and NaHSO3 in chemical bath. Crystal structure and morphology of the as-crystallized samples were characterized by X-ray diffraction and scanning electron microscopy. The influence of reaction temperature and H+ concentration on both morphology and crystalline nature was investigated. Their electrochemical behaviors were investigated by cycling voltammetry and galvanostatic charge/discharge measurements in a three-electrode glass cell. Depending upon different synthesis conditions of ?-MnO2 electrodes, their specific capacitance values varied in the range of 43 to 197 F g-1 at the current density of 1 A g-1. Moreover, their specific capacitance values decrease with increasing crystallinity and particle size. In this work, we conclude that the energy storage mechanism is closely related to the particle aggregation state of electrode materials.

Zhang, Yuanjian; Xue, Dongfeng

2012-09-01

85

Acid-leached ?-MnO2 nanowires for electrochemical energy storage  

NASA Astrophysics Data System (ADS)

We present synthesis, acid-leaching, characterization and electrochemistry of ?-MnO2 nanowires with tunnel crystal structure. This material is used as a matrix for lithium ions intercalation to provide insights into the effects of postsynthesis treatment on charge storage properties. Hydrothermal treatment of precursors produced 20 - 200 nm thick and tens of microns long nanowires. Acid leaching was carried out in the concentrated nitric acid at room temperature and resulted in the change of material composition and surface area. Original ?-MnO2 nanowires showed initial discharge specific capacity of 96 mAh/g, while acid-leached material exhibited higher capacity values. This work forms the basis for future study aimed at understanding of correlation between crystal structure, composition and morphology of the "host" matrix and nature of the "guest" ions for beyond lithium electrochemical energy storage. In addition, we demonstrate single nanowire electrochemical cells for the study of electrochemically-correlated mechanical properties of the nanowires.

Byles, Bryan; Subramanian, Arunkumar; Pomerantseva, Ekaterina

2014-09-01

86

First-principles Study of Magnetism in Spinel MnO_2  

Microsoft Academic Search

First-principles electronic structure methods using the generalized gradient approximation have been used to calculate the magnetic groundstate, transition temperature, and thermodynamic properties in spinel MnO_2. This system is of interest because it has both competing ferromagnetic and antiferromagnetic contributions to the exchange coupling and because it is geometrically frustrated. The magnetic interactions were mapped onto a classical Heisenberg model whose

Dane Morgan; Billie Wang; Gerbrand Ceder

2001-01-01

87

Process dependent graphene-wrapped plate-like MnO2 nanospheres for high performance supercapacitor  

NASA Astrophysics Data System (ADS)

Two kinds of MnO2/graphene nanocomposites (M1 and M2) were synthesized by two different reaction procedures. M1 was synthesized as follows: the plate-like MnO2/graphene nanocomposite was obtained by using hydrazine reduction of MnO2/graphene oxide. M2 was formed as follows: the plate-like MnO2 nanospheres was synthesized on the graphene nanosheet which was reduced by hydrazine reduction of graphene oxide. The M1 have a good electrochemical performance and the average capacitance is as high as 250.6 F g-1 at 1 A g-1 in 1 mol L-1 Na2SO4 electrolyte, which is higher than that of the M2 (206.8 F g-1).

Liu, Chunliang; Gui, Dayong; Liu, Jianhong

2014-10-01

88

Facile synthesis of graphene-wrapped honeycomb MnO2 nanospheres and their application in supercapacitors.  

PubMed

Graphene-wrapped MnO(2) nanocomposites were first fabricated by coassembly between honeycomb MnO(2) nanospheres and graphene sheets via electrostatic interaction. The materials were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and thermogravimetric analysis. The novel MnO(2)/graphene hybrid materials were used for investigation of electrochemical capacitive behaviors. The hybrid materials displayed enhanced capacitive performance (210 F/g at 0.5 A/g). Additionally, over 82.4% of the initial capacitance was retained after repeating the cyclic voltammetry test for 1000 cycles. The improved electrochemical performance might be attributed to the combination of the pesudocapacitance of MnO(2) nanospheres with the honeycomb-like "opened" structure and good electrical conductivity of graphene sheets. PMID:22329919

Zhu, Jiayi; He, Junhui

2012-03-01

89

Rationally designed hierarchical MnO2-shell/ZnO-nanowire/carbon-fabric for high-performance supercapacitor electrodes  

NASA Astrophysics Data System (ADS)

High-performance supercapacitor electrodes with a novel hierarchical structure of MnO2/ZnO/carbon-fabric were rationally designed, and prepared by a simple three-step-solution method. The design comprises ZnO nanowires radially grown on each micron-size fiber of a carbon-fabric electrode, with a thin MnO2 shell on each ZnO nano-core. This multi-scale hierarchical structure yields: (a) high specific area of pseudo-capacitive MnO2 to maximize specific capacitance; (b) effective MnO2-electrolyte interface to facilitate fast charging/discharging; and (c) conductive MnO2-ZnO-electrode path to reduce energy loss. In addition, the overall capacitor performance is optimized by choosing proper thickness of MnO2 shell and aspect ratio of ZnO nano-core. The design was realized and validated with the development of a simple three-step-solution method: (a) radial deposition of nano-ZnO on carbon fabric; (b) coating ZnO by a thin layer of carbon; and (c) reduction of MnO4- and replacement of this carbon overlayer by MnO2. With this design and method, high specific capacitance of 886 F g-1 was found from electrodes with 5 nm MnO2 on ZnO having an average diameter of 50 nm and aspect ratio of 30. These samples showed specific energy of 16 Wh kg-1 and specific power of 27 kW kg-1 at current density of 20 mA cm-2, and good long-term cycling stability.

Yang, Q.; Zhang, X. T.; Zhang, M. Y.; Gao, Y.; Gao, H.; Liu, X. C.; Liu, H.; Wong, K. W.; Lau, W. M.

2014-12-01

90

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

91

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

92

Facile preparation of three-dimensional multilayer porous MnO2/reduced graphene oxide composite and its supercapacitive performance  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) multilayer porous MnO2/reduced graphene oxide composites are coated on a nickel foam substrate (denoted as MnO2/R-GO@Ni-foam) by a facile and scalable spray method following by low temperature annealing. The composite electrodes are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The content of MnO2 in the MnO2/R-GO@Ni-foam composites is determined by thermal gravimetric analysis. The supercapacitive performance of the composite electroides is investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The results show that the MnO2/R-GO@Ni-foam composite displays a high specific capacitance of 267 F g-1 at 0.25 A g-1 and excellent capacitance retention of 89.5% after 1000 cycles. This study provides a facile way for the preparation of composite electrodes for high-performance supercapacitor.

Li, Yiju; Wang, Guiling; Ye, Ke; Cheng, Kui; Pan, Yue; Yan, Peng; Yin, Jinling; Cao, Dianxue

2014-12-01

93

Oxygen Vacancy Formation and Reduction Properties of ?-MnO2 Grain Boundaries and the Potential for High Electrochemical Performance.  

PubMed

In recent years, the nanostructuring of rutile (?-)MnO2 has been shown to vastly improve its properties and performance in a number of technological applications. The contrast between the strong electrochemical properties of the nanostructured material and the bulk material that shows limited Li intercalation and electrochemical capacitance is not yet fully understood. In this work, we investigate the structure, stability and catalytic properties of four tilt grain boundaries in ?-MnO2 using interatomic potential methods. By considering the ?-surfaces of each of the grain boundaries, we are able to find the lowest energy configurations for each grain boundary structure. For each grain boundary, we observe a significant decrease in the oxygen vacancy energies in and around the grain boundaries compared to bulk ?-MnO2 and also the bulk-like structures in the grain boundary cells. The reduction of Mn(4+) to Mn(3+) is also considered and again is shown to be preferable at the boundaries. These energies suggest a potentially higher catalytic activity at the grain boundaries of ?-MnO2. The results are also placed into context with recent calculations of ?-MnO2 surfaces to produce a more detailed understanding into this important phenomenon. PMID:25247793

Dawson, James A; Tanaka, Isao

2014-10-22

94

Hierarchical MnO2/SnO2 heterostructures for a novel free-standing ternary thermite membrane.  

PubMed

We report the synthesis of a novel hierarchical MnO2/SnO2 heterostructures via a hydrothermal method. Secondary SnO2 nanostructure grows epitaxially on the surface of MnO2 backbones without any surfactant, which relies on the minimization of surface energy and interfacial lattice mismatch. Detailed investigations reveal that the cover density and morphology of the SnO2 nanostructure can be tailored by changing the experimental parameter. Moreover, we demonstrate a bottom-up method to produce energetic nanocomposites by assembling nanoaluminum (n-Al) and MnO2/SnO2 hierarchical nanostructures into a free-standing MnO2/SnO2/n-Al ternary thermite membrane. This assembled approach can significantly reduce diffusion distances and increase their intimacy between the components. Different thermite mixtures were investigated to evaluate the corresponding activation energies using DSC techniques. The energy performance of the ternary thermite membrane can be manipulated through different components of the MnO2/SnO2 heterostructures. Overall, our work may open a new route for new energetic materials. PMID:23905515

Yang, Yong; Zhang, Zhi-Cheng; Wang, Peng-Peng; Zhang, Jing-Chao; Nosheen, Farhat; Zhuang, Jing; Wang, Xun

2013-08-19

95

Synthesis and characterization of hierarchically structured mesoporous MnO 2 and Mn 2O 3  

NASA Astrophysics Data System (ADS)

Hierarchically structured mesoporous MnO 2 with high surface area was prepared by a facile precursor route. Well-defined morphological manganese oxalate, synthesized by adding L-lysine via a hydrothermal method, was used as precursor. Mesoporous amorphous MnO 2 with high Brunauer-Emmett-Teller (BET) surface area (340 m 2/g) and mesoporous Mn 2O 3 composed of nano-crystals (BET surface area 188 m 2/g) were obtained by selective calcination of the oxalate precursor at 330 °C and 400 °C, respectively. Thermogravimetric and differential thermal analyses (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2-sorption analysis and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and property of products. Cyclic voltammetry (CV) and charge-discharge measurements were used to preliminarily study the electrochemical performance of the products. The range of pH value (about 5.0-7.0) in the synthesis process is apt to prepare the hierarchical structured manganese dioxide. Other types of amino acids were also employed as the crystallization modifiers and different morphologies of manganese dioxides were obtained.

Liu, Mi; Zhang, Gui-Jun; Shen, Zhu-Rui; Sun, Ping-Chuan; Ding, Da-Tong; Chen, Tie-Hong

2009-01-01

96

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

97

MnO2 -Modified Persistent Luminescence Nanoparticles for Detection and Imaging of Glutathione in Living Cells and In Vivo.  

PubMed

Persistent luminescence nanoparticles (PLNPs) hold great promise for the detection and imaging of biomolecules. Herein, we have demonstrated a novel nanoprobe, based on the manganese dioxide (MnO2 )-modified PLNPs, that can detect and image glutathione in living cells and in vivo. The persistent luminescence of the PLNPs can be efficiently quenched by the MnO2 nanosheets. In the presence of glutathione (GSH), MnO2 was reduced to Mn(2+) and the luminescence of PLNPs can be restored. The persistent luminescence property can allow detection and imaging without external excitation and avoid the background noise originating from the in situ excitation. This strategy can offer a promising platform for detection and imaging of reactive species in living cells or in vivo. PMID:25352246

Li, Na; Diao, Wei; Han, Yaoyao; Pan, Wei; Zhang, Tingting; Tang, Bo

2014-12-01

98

Simultaneous recovery of Zn and MnO2 from used batteries, as raw materials, by electrolysis.  

PubMed

High purity electrolytic manganese dioxide (EMD) is the main raw material used for manufacturing of zinc and manganese based portable batteries (alkaline with manganese AlMn and zinc carbon Zn-C). Lately, due to the progressive depletion of MnO(2) natural resources, the quantity of artificially electrolytic produced MnO(2) has started to increase to satisfy the demand. This paper describes an electrolytic process for the simultaneous production of the following components:The electrolysis process was conducted in a specialized laboratory facility. The study was particularly focused on the following electrolysis process parameters: PMID:23731699

Buzatu, Mihai; S?ceanu, Simona; Ghica, Valeriu Gabriel; Iacob, Gheorghe; Buzatu, Traian

2013-08-01

99

The rate of sulfide oxidation by ?MnO 2 in seawater  

NASA Astrophysics Data System (ADS)

The rate of oxidation of hydrogen sulfide by manganese dioxide in seawater was determined as a function of pH (2.0-9.0), temperature (5-45°C), and ionic strength (0-4 M). The overall rate constant, k, in seawater at pH = 8.17 was found to be first order with respect to both sulfide and manganese dioxide: - d[H 2S] T/dt = k[H 2S] ?[MnO 2] . The rate constant, k, for seawater (S = 35.8, pH = 8.17) at 25°C was found to be 436 M -1 min -1, or 0.0244 m -2 1 min -1 when [MnO 2] is expressed in surface area (m 2/L). The energies of activation were found to be 14 ± 1 KJ mol -1 and 10 ± 1 KJ mol -1, respectively, for pH = 8.2 and pH = 5.0 in seawater (S = 35). The rate increased from pH 2.0 to a maximum at a pH of about 5.0 and decreased at higher pH. This pH dependence was attributed to formation of a surface complex between >MnO - and H 2S. As the concentration of HS - increases above pH = 5 the rate of the reaction decreases. The rate of sulfide oxidation by MnO 2 is not strongly dependent on ionic strength. The rates in 0.57 M NaCl were found to be slightly higher than the rates in seawater. Measurements made in solutions of the major sea salts indicated that Ca 2+ and Mg 2+ caused the rates to decrease, apparently by absorbing on the surface of manganese dioxide. Measurements made in artificial seawater (Na +, Mg 2+, Ca 2+, Cl -, and SO 2-4) were found to be in good agreement with the measurements in actual seawater. Phosphate was found to inhibit the reaction significantly.

Yao, Wensheng; Millero, Frank J.

1993-07-01

100

Microstructure and ferroelectric properties of MnO2-doped bismuth-layer ,,Ca,Sr...Bi4Ti4O15 ceramics  

E-print Network

inside the grains, which hinders domain-wall movements. The reduction of domain-wall mobility producesMicrostructure and ferroelectric properties of MnO2-doped bismuth-layer ,,Ca,Sr...Bi4Ti4O15 September 2005 We have studied the microstructures and ferroelectric properties of MnO2-doped bismuth

Cao, Wenwu

101

Stable Isotope Fractionation during Chromium(III) Oxidation by ?-MnO2  

NASA Astrophysics Data System (ADS)

Hexavalent chromium is a highly mobile anthropogenic pollutant, and reduction of Cr(VI) to the less-soluble Cr(III) is the most important natural process involved in contamination attenuation. Earlier work has shown a preferential reduction of lighter Cr stable isotopes attributed to a kinetically-controlled mechanism, and isotope ratio measurements may be used as indicators of Cr(VI) reduction [1]. Recent work has detected no significant isotope exchange between dissolved Cr(III) and Cr(VI) over a period of days to weeks, and has suggested that complex bidirectional reactions control fractionation during Cr(III) oxidation by H2O2 [2]. Previous studies on oxidation by pyrolusite (?-MnO2) have reported ?53/52Cr up to approximately +1.1‰ in the Cr(VI) product [3]. However, laboratory investigations of fractionation during Cr(III) oxidation by birnessite (?-MnO2) have been inconclusive, and oxidation mechanisms remain unclear [4]. In order to fully exploit stable isotope fractionation during redox reactions of Cr in groundwater as an indicator of Cr attenuation, the effect of Cr(III) oxidation on isotope ratios must be better understood. We will report the latest measurements of isotope fractionation during oxidation on birnessite under varying pH and MnO2 and Cr(III) concentrations. Our preliminary findings (at initial Cr(III) and ?-MnO2 concentrations of 10 mg/L and 100 mg/L, respectively) show the Cr(VI) product shifted by -0.5‰ to +0.0‰ relative to the reactant at pH ? 4.5. The reaction is incomplete and plateaus within 60 min. Unlike that observed with pyrolusite, fractionation during Cr oxidation on birnessite is much smaller or absent. These initial results suggest that kinetic effects are either very small or are negated by back reaction or equilibration in the multi-step oxidation mechanism. Alternatively, in our experiments, a step involving little isotope fractionation may be rate-limiting; thus, the final magnitude of isotope fractionation during oxidation on birnessite could vary if the rate-limiting step changes. Additional experiments at different conditions will aid in the elucidation of fractionating mechanisms during Cr(III) oxidation. [1] Ellis, A. S.; Johnson, T. M.; Bullen, T. D. (2002) Science, 295(5562), 2060 [2] Zink, S.; Schoenberg, R.; Staubwasser, M. (2010) Geochim. Cosmochim. Acta, in press [3] Ellis, A. S.; Johnson, T. M.; Villalobos-Aragon, A.; Bullen, T. D. (2008) Eos Trans. AGU, 89(53), Fall Meet. Suppl., Abstract H53F-08 [4] Bain, D. J.; Bullen, T. D. (2005) Geochim. Cosmochim. Acta, 69(10), Suppl. 1, A212

Wang, D. T.; Fregoso, D. C.; Ellis, A. S.; Johnson, T. M.; Bullen, T. D.

2010-12-01

102

Growth and memory effect of Er-stabilized ?-MnO2 films grown on Si substrates  

NASA Astrophysics Data System (ADS)

A memory effect is reported for Er-stabilized ?-MnO2 films made of highly orientation-aligned textured nanocrystals. The films are composed of nanocrystals with a size of about 20 nm. The crystalline direction along the growth direction is almost along ?-MnO2 < 100> , but the one in the plane is disordered. Er doping can effectively enhance the thermal stability of ?-MnO2 up to 850 {}^\\circ C, which is essential for its future application in industry. A memory effect has been observed for both as-grown and annealed samples. The mechanism of the memory effect was found by analysis to be charge trapping by carrier injection, from either the bottom or the top electrode. For the annealed sample, a low leakage current was achieved, which is about 5 orders of magnitude smaller than that of the as-grown sample. The results show that ?-MnO2 is a promising candidate material for nonvolatile memory applications.

Cui, Jian; Ji, Ting; Nie, Tianxiao; Lv, Yi; Yang, Sheng; Yang, Xinju; Jiang, Zuimin; Zou, Jin

2014-09-01

103

Aqueous rechargeable lithium battery (ARLB) based on LiV 3O 8 and LiMn 2O 4 with good cycling performance  

Microsoft Academic Search

Crystalline LiV3O8 and LiMn2O4 were prepared by conventional solid-state reaction and characterized by X-ray diffraction analysis. Cyclic voltammetry technique was employed to evaluate the electrochemical behaviors of LiV3O8 and LiMn2O4 in 2mol\\/l Li2SO4 aqueous solution, and the results show that both LiV3O8 and LiMn2O4 are very stable in this aqueous electrolyte and can be used as the negative and positive

G. J. Wang; H. P. Zhang; L. J. Fu; B. Wang; Y. P. Wu

2007-01-01

104

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 13 min at pH 2.2, 9 min at pH 6.0, 8 min at pH 9.3, respectively. PMID:24793308

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

2014-09-01

105

Hierarchically structured MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors  

NASA Astrophysics Data System (ADS)

We report a hierarchical Ni@MnO2 structure consisting of MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors. The Ni@MnO2 structure, which was prepared via a facile electrodeposition method, is highly porous and appears like a forest of pine trees grown vertically on a substrate. At a MnO2 mass loading of 0.35 mg cm-2, the Ni@MnO2 electrode demonstrated a specific capacitance of 1125 F g-1 that is close to the theoretical value. In addition, a remarkable high-rate performance (766 F g-1 at a discharge current density of 100 A g-1) was achieved. Electrochemical tests in a two-electrode configuration for the Ni@MnO2 structure with a high MnO2 loading of 3.6 mg cm-2 showed a low equivalent series resistance (ESR) of 1 ? and a high specific power of 72 kW kg-1. This superior performance can be attributed to the highly porous and hierarchical structure of Ni@MnO2 that favors rapid diffusion of an electrolyte, highly conductive pathway for electron transport, and efficient material utilization.We report a hierarchical Ni@MnO2 structure consisting of MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors. The Ni@MnO2 structure, which was prepared via a facile electrodeposition method, is highly porous and appears like a forest of pine trees grown vertically on a substrate. At a MnO2 mass loading of 0.35 mg cm-2, the Ni@MnO2 electrode demonstrated a specific capacitance of 1125 F g-1 that is close to the theoretical value. In addition, a remarkable high-rate performance (766 F g-1 at a discharge current density of 100 A g-1) was achieved. Electrochemical tests in a two-electrode configuration for the Ni@MnO2 structure with a high MnO2 loading of 3.6 mg cm-2 showed a low equivalent series resistance (ESR) of 1 ? and a high specific power of 72 kW kg-1. This superior performance can be attributed to the highly porous and hierarchical structure of Ni@MnO2 that favors rapid diffusion of an electrolyte, highly conductive pathway for electron transport, and efficient material utilization. Electronic supplementary information (ESI) available: More TEM and SEM images, digital photo, XPS, and XRD of the samples. See DOI: 10.1039/c3nr00209h

Sun, Zhipeng; Firdoz, Shaik; Ying-Xuan Yap, Esther; Li, Lan; Lu, Xianmao

2013-05-01

106

In situ investigation of the discharge of alkaline Zn -MnO2 batteries with synchrotron x-ray and neutron tomographies  

NASA Astrophysics Data System (ADS)

Zn -MnO2 alkaline batteries were investigated in situ at different stages of electric discharge by synchrotron tomography with monochromatic x rays and by neutron tomography. The spatial distribution and the changes in the morphology of different components of a battery caused by the reduction of MnO2, the dissolution of Zn, and the nucleation and growth of ZnO are investigated with high spatial resolution around several micrometers with x rays. Neutron tomography is used to monitor the changes in the spatial distribution of hydrogen in the MnO2 matrix and provides complementary information about the process.

Manke, I.; Banhart, J.; Haibel, A.; Rack, A.; Zabler, S.; Kardjilov, N.; Hilger, A.; Melzer, A.; Riesemeier, H.

2007-05-01

107

Square coordinated MnO(2)-units in BiMn(7)O(12).  

PubMed

Room temperature high-resolution synchrotron X-ray diffraction (HRSXRD) measurements were carried out on polycrystalline samples of BiMn(7)O(12) and LaMn(7)O(12). Rietveld refinements of HRSXRD data describe the crystal structures of both compounds in the monoclinic space group I2/m. The maximum entropy method-based pattern fitting (MPF) method inversion of HRSXRD data was utilized to obtain the spatial electron density (ED) distribution. Obtained results show clear differences in ED distributions around Mn-O bonds between isomorphic BiMn(7)O(12) and LaMn(7)O(12). The scheme of ED distributions in BiMn(7)O(12) indicates the presence of orbital ordering in the MnO(2) planar arrangement that appears as prominent features in very distorted MnO(12) and MnO(6) polyhedrons in the perovskite related structure of [BiMn(3)](A-site)[Mn(4)](B-site)O(12). PMID:20799716

Okamoto, Hiroshi; Imamura, Naoki; Karppinen, Maarit; Yamauchi, Hisao; Fjellvåg, Helmer

2010-10-01

108

Oxidation of benzyl alcohol and carbon monoxide using gold nanoparticles supported on MnO2 nanowire microspheres.  

PubMed

MnO2 was synthesised as a catalyst support material using a hydrothermal method. This involved reacting MnSO4?H2O and (NH4)2S2O8 at 120?°C for a range of crystallisation times, which affords control over the morphology and phase composition of the MnO2 formed. Gold was deposited on these supports using sol-immobilisation, impregnation and deposition precipitation methods, and the resultant materials were used for the oxidation of benzyl alcohol and carbon monoxide. The effect of the support morphology on the dispersion of the gold nanoparticles and the consequent effect on the catalytic performance is described and discussed. PMID:24402974

Alhumaimess, Mosaed; Lin, Zhongjie; He, Qian; Lu, Li; Dimitratos, Nickolaos; Dummer, Nicholas F; Conte, Marco; Taylor, Stuart H; Bartley, Jonathan K; Kiely, Christopher J; Hutchings, Graham J

2014-02-01

109

Inhibition of charge disproportionation of MnO2 electrocatalysts for efficient water oxidation under neutral conditions.  

PubMed

The development of Mn-oxide electrocatalysts for the oxidation of H(2)O to O(2) has been the subject of intensive researches not only for their importance as components of artificial photosynthetic systems, but also as O(2)-evolving centers in photosystem II. However, limited knowledge of the mechanisms underlying this oxidation reaction hampers the ability to rationally design effective catalysts. Herein, using in situ spectroelectrochemical techniques, we demonstrate that the stabilization of surface-associated intermediate Mn(3+) species relative to charge disproportionation is an effective strategy to lower the overpotential for water oxidation by MnO(2). The formation of N-Mn bonds via the coordination of amine groups of poly(allylamine hydrochloride) to the surface Mn sites of MnO(2) electrodes effectively stabilized the Mn(3+) species, resulting in an ~500-mV negative shift of the onset potential for the O(2) evolution reaction at neutral pH. PMID:23088413

Takashima, Toshihiro; Hashimoto, Kazuhito; Nakamura, Ryuhei

2012-11-01

110

Enhanced low-temperature capacitance of MnO2 nanorods in a redox-active electrolyte  

NASA Astrophysics Data System (ADS)

The negative effect of low temperature on the capacitive behavior of MnO2 nanorods in 4 M KOH is studied by cyclic voltammetry, constant current charge/discharge and electrochemical impedance techniques. The results show the discharge specific capacitance reduces from 270 to 80 F g-1 at 0.2 A g-1 as the temperature decreases from 20 to -20 °C due to the faded mass transportation and charge transfer processes at low temperature. After introducing p-phenylenediamine (PPD) in the electrolyte, the specific capacitance reaches to 156 F g-1 at 2 A g-1. The improvement on low-temperature capacitance is thought to come from the synergic effect of PPD and MnO2 by combining two pseudocapacitance charge-storage mechanisms taking place in the electrode and electrolyte together.

Su, Linghao; Gong, Liangyu; Lü, Haitao; Xü, Qiang

2014-02-01

111

A kinetic study of electrochemical lithium insertion in nanosized rutile ?-MnO 2 by impedance spectroscopy  

Microsoft Academic Search

The kinetics of the electrochemical lithium insertion reaction in nano-sized rutile ?-MnO2 has been investigated using ac impedance spectroscopy. The experimental kinetic data are obtained for a rutile compound synthesized by ball-milling the powder produced from the heat treatment of manganese nitrate salts. The results are discussed as a function of the Li content for 0

S. Bach; J. P. Pereira-Ramos; P. Willmann

2011-01-01

112

Capture and release of cancer cells based on sacrificeable transparent MnO2 nanospheres thin film.  

PubMed

A CTCs detection assay using transparent MnO2 nanospheres thin films to capture and release of CTCs is reported. The enhanced local topography interaction between extracellular matrix scaffolds and the antibody-coated substrate leads to improved capture efficiency. CTCs captured from artificial blood sample can be cultured and released, represent a new functional material capable of CTCs isolation and culture for subsequent studies. PMID:24652776

Huang, Qinqin; Chen, Bolei; He, Rongxiang; He, Zhaobo; Cai, Bo; Xu, Junhua; Qian, Weiyi; Chan, Helen Laiwa; Liu, Wei; Guo, Shishang; Zhao, Xing-Zhong; Yuan, Jikang

2014-09-01

113

Determination of elastic properties of a MnO2 coating by surface acoustic wave velocity dispersion analysis  

NASA Astrophysics Data System (ADS)

MnO2 is a material of interest in the development of high energy-density batteries, specifically as a coating material for internal 3D structures, thus ensuring rapid energy deployment. Its electrochemical properties have been mapped extensively, but there are, to the best of the authors' knowledge, no records of the elastic properties of thin film MnO2. Impulsive stimulated thermal scattering (ISTS), also known as the heterodyne diffraction or transient grating technique, was used to determine the Young's modulus (E) and porosity (?) of a 500 nm thick MnO2 coating on a Si(001) substrate. ISTS is an all optical method that is able to excite and detect surface acoustic waves (SAWs) on opaque samples. From the measured SAW velocity dispersion, the Young's modulus and porosity were determined to be E = 25 ± 1 GPa and ? = 42 ± 1 %, respectively. These values were confirmed by independent techniques and determined by a most-squares analysis of the carefully fitted SAW velocity dispersion. This study demonstrates the ability of the presented technique to determine the elastic parameters of a thin, porous film on an anisotropic substrate.

Sermeus, J.; Sinha, R.; Vanstreels, K.; Vereecken, P. M.; Glorieux, C.

2014-07-01

114

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

115

Surface modification of spinel ?-MnO2 and its lithium adsorption properties from spent lithium ion batteries  

NASA Astrophysics Data System (ADS)

Spinel ?-MnO2 ion-sieves are promising materials because of their high selectivity toward lithium ions, and this can be applied to the recovery of lithium from spent lithium ion batteries. However, manganese dissolution loss during the delithiation of LiMn2O4 causes a decrease in adsorption capacity and poor cycling stability for these ion-sieves. To improve the lithium adsorption properties of ?-MnO2 ion-sieves, surface modification with a CeO2 coating was studied using hydrothermal-heterogeneous nucleation. The structure, morphology and composition of the synthesized materials were determined by XRD, SEM, TEM and EDS. The effect of hydrothermal synthesis conditions and the amount of CeO2 coating on the adsorption performance of ?-MnO2 were also investigated. A 0.5 wt.% CeO2-coated ion-sieve was synthesized by heating at 120 °C for 3 h and it had better adsorption properties than the bare samples. The effect of ultrasonic treatment on the lithium extraction ratio from LiMn2O4 upon acid treatment at various temperatures was studied and the results were compared with conventional mechanical stirring. We found that ultrasonic treatment at lower temperature gave almost the same maximum lithium extraction ratio and was more efficient and economic.

Li, Li; Qu, Wenjie; Liu, Fang; Zhao, Taolin; Zhang, Xiaoxiao; Chen, Renjie; Wu, Feng

2014-10-01

116

Nano-LiCoO 2 as cathode material of large capacity and high rate capability for aqueous rechargeable lithium batteries  

Microsoft Academic Search

Crystalline nanoparticles of LiCoO2 are prepared by a sol–gel method at 550°C and characterized by X-ray diffraction. Their electrochemical behaviors were characterized by cyclic voltammograms, capacity measurement and cycling performance. Results show that the reversible capacity of the nano-LiCoO2 can be up to 143mAh\\/g at 1000mA\\/g and still be 133mAh\\/g at 10,000mA\\/g (about 70C) in 0.5mol\\/l Li2SO4 aqueous electrolyte. In

W. Tang; L. L. Liu; S. Tian; L. Li; Y. B. Yue; Y. P. Wu; S. Y. Guan; K. Zhu

2010-01-01

117

WASHINGTON UNIVERSITY RECHARGE CENTERS  

E-print Network

9/1/2005 1 WASHINGTON UNIVERSITY RECHARGE CENTERS revised July 1, 2005 A. SCOPE Recharge centers in charges to federal and nonfederal grants and contracts. In connection with Washington University's receipt recharge centers. This policy helps assure that Washington University consistently applies sound cost

Subramanian, Venkat

118

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

2014-07-11

119

Hierarchically Porous MnO2 Microspheres Doped with Homogeneously Distributed Fe3O4 Nanoparticles for Supercapacitors.  

PubMed

Hierarchically porous yet densely packed MnO2 microspheres doped with Fe3O4 nanoparticles are synthesized via a one-step and low-cost ultrasound assisted method. The scalable synthesis is based on Fe(2+) and ultrasound assisted nucleation and growth at a constant temperature in a range of 25-70 °C. Single-crystalline Fe3O4 particles of 3-5 nm in diameter are homogeneously distributed throughout the spheres and none are on the surface. A systematic optimization of reaction parameters results in isolated, porous, and uniform Fe3O4-MnO2 composite spheres. The spheres' average diameter is dependent on the temperature, and thus is controllable in a range of 0.7-1.28 ?m. The involved growth mechanism is discussed. The specific capacitance is optimized at an Fe/Mn atomic ratio of r = 0.075 to be 448 F/g at a scan rate of 5 mV/s, which is nearly 1.5 times that of the extremely high reported value for MnO2 nanostructures (309 F/g). Especially, such a structure allows significantly improved stability at high charging rates. The composite has a capacitance of 367.4 F/g at a high scan rate of 100 mV/s, which is 82% of that at 5 mV/s. Also, it has an excellent cycling performance with a capacitance retention of 76% after 5000 charge/discharge cycles at 5 A/g. PMID:25255299

Zhu, Jian; Tang, Shaochun; Xie, Hao; Dai, Yuming; Meng, Xiangkang

2014-10-22

120

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

121

Multicopper Oxidase Involvement in Both Mn(II) and Mn(III) Oxidation during Bacterial Formation of MnO2  

PubMed Central

Global cycling of environmental manganese requires catalysis by bacteria and fungi for MnO2 formation, since abiotic Mn(II) oxidation is slow under ambient conditions. Genetic evidence from several bacteria implicates multicopper oxidases (MCOs) as being required for MnO2 formation. However, MCOs catalyze one-electron oxidations, whereas conversion of Mn(II) to MnO2 is a two-electron process. Trapping experiments with pyrophosphate (PP), a Mn(III) chelator, have demonstrated that Mn(III) is an intermediate in Mn(II) oxidation when mediated by exosporium from the Mn-oxidizing bacterium Bacillus SG-1. The reaction of Mn(II) depends on O2 and is inhibited by azide, consistent with MCO catalysis. We show that the subsequent conversion of Mn(III) to MnO2 also depends on O2 and is inhibited by azide. Thus, both oxidation steps appear to be MCO-mediated, likely by the same enzyme, indicated by genetic evidence to be the MnxG gene product. We propose a model of how the manganese oxidase active site may be organized to couple successive electron transfers to the formation of polynuclear Mn(IV) complexes as precursors to MnO2 formation. PMID:22892957

Soldatova, Alexandra V.; Butterfield, Cristina; Oyerinde, Oyeyemi F.; Tebo, Bradley M.; Spiro, Thomas G.

2013-01-01

122

In situ spectroscopic and solution analyses of the reductive dissolution of MnO2 by Fe(II).  

PubMed

The reductive dissolution of MnO2 by Fe(II) under conditions simulating acid mine drainage (pH 3, 100 mM SO4(2-)) was investigated by utilizing a flow-through reaction cell and synchrotron X-ray absorption spectroscopy. This configuration allows collection of in situ, real-time X-ray absorption near-edge structure (XANES) spectra and bulk solution samples. Analysis of the solution chemistry suggests that the reaction mechanism changed (decreased reaction rate) as MnO2 was reduced and Fe(III) precipitated, primarily as ferrihydrite. Simultaneously, we observed an additional phase, with the local structure of jacobsite (MnFe2O4), in the Mn XANES spectra of reactants and products. The X-ray absorbance of this intermediate phase increased during the experiment, implying an increase in concentration. The presence of this phase, which probably formed as a surface coating, helps to explain the reduced rate of dissolution of manganese(IV) oxide. In natural environments affected by acid mine drainage, the formation of complex intermediate solid phases on mineral surfaces undergoing reductive dissolution may likewise influence the rate of release of metals to solution. PMID:11347928

Villinski, J E; O'Day, P A; Corley, T L; Conklin, M H

2001-03-15

123

Synthesis and electrochemical properties of Li0.33MnO2 nanorods as positive electrode material for 3 V lithium batteries.  

PubMed

In this study, one-dimensional Li0.33MnO2 nanorods were synthesized by a solid state reaction using gamma-MnO2 as a precursor. Gamma-MnO2 was prepared under different reaction times by a redox process. The HR-TEM results showed that the diameter and length of the Li0.33MnO2 nanorods are 5-20 nm and about 200 nm, respectively. The Li0.33MnO2 nanorods delivered a discharge capacity of 157 mA h g(-1) at 1 C, and retained 97% of their initial capacity over 30 cycles. Good rate performance was also observed, with discharge capacities of 201 and 133 mA h g(-1) at 0.1 C and 2 C, respectively. The morphology of the nanorods could increase their electrochemical properties, resulting in higher capacity and rate performance. PMID:24205628

Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Lee, Chul-Tae; Roh, Kwang Chul

2013-09-01

124

Microstructure and ferroelectric properties of MnO2-doped bismuth-layer (Ca,Sr)Bi4Ti4O15 ceramics  

NASA Astrophysics Data System (ADS)

We have studied the microstructures and ferroelectric properties of MnO2-doped bismuth-layered (Ca,Sr)Bi4Ti4O15 (CSBTM). The piezoelectric coefficient, dielectric loss, mechanical quality factor, and the P-E hysteresis loop measurements indicate that Mn ions entered both the A and B sites of the pseudoperovskite-layered structure, creating ``soft'' and ``hard'' doping effects simultaneously. Scanning electron microscopy and energy dispersion spectroscopy showed that the platelike grains in CSBTM ceramics become larger with the increase of MnO2 additive, and Mn ions are found inside the grains as well as in the grain boundaries. The lattice parameter, room-temperature dielectric constant, and the Curie temperature do not vary with MnO2 additive. We conclude that the Mn3+ ions play a critical role in the effects of soft and hard behaviors since it can enter both the A and B sites of the perovskite structure.

Li, Gurong; Zheng, Liaoying; Yin, Qingrui; Jiang, Bei; Cao, Wenwu

2005-09-01

125

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

NASA Astrophysics Data System (ADS)

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 MnO2-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.

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

2009-04-01

126

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

127

Break-up of Two-Dimensional MnO2 Nanosheets Promotes Ultrasensitive pH-Triggered Theranostics of Cancer.  

PubMed

Chemically exfoliated two-dimensional MnO2 nanosheets are successfully modified with amino-polyethylene glycol as a theranostic platform for ultrasensitive stimuli-responsive theranostics of cancer. The highly dispersed MnO2 nanosheets exhibit a unique break-up in the mildly acidic microenvironment of tumor tissues, which could substantially enhance their in vitro and in vivo performances in T1 -weighted magnetic resonance imaging. Such a pH-triggered breaking-up behavior could further promote the fast release of loaded anticancer drugs for concurrent pH-responsive drug release and circumvent the multidrug resistance of cancer cells. PMID:25156250

Chen, Yu; Ye, Delai; Wu, Meiying; Chen, Hangrong; Zhang, Linlin; Shi, Jianlin; Wang, Lianzhou

2014-11-01

128

The versatility of MnO2 for lithium battery applications  

Microsoft Academic Search

Manganese dioxide has for many years found widespread use as a cathode material in aqueous Leclanche, zinc chloride and alkaline cells and, more recently, in nonaqueous lithium cells. However, despite the large number of polymorphic structures that exist in the manganese dioxide family, the battery industry has used y-MnOz exclusively as the positive electrode in these cells. With the advent

M. M. Thackeray; M. H. Rossouw; A. de Kock; A. P. de la Harpe; R. J. Gummow; K. Pearce; D. C. Liles

1993-01-01

129

Estimating groundwater recharge  

USGS Publications Warehouse

Groundwater recharge is the entry of fresh water into the saturated portion of the subsurface part of the hydrologic cycle, the modifier "saturated" indicating that the pressure of the pore water is greater than atmospheric.

Stonestrom, David A.

2011-01-01

130

Porous MnO2 for use in a high performance supercapacitor: replication of a 3D graphene network as a reactive template.  

PubMed

Graphene oxide hydrogel is used as a reactive template to prepare nanoporous materials with a 3D microstructure. The as-prepared porous MnO2 shows a capacitance retention of ~70.6% at a current density as high as 15 A g(-1), resulting from the 3D interconnected ion transport channel replicated from the graphene oxide hydrogel. PMID:24141912

Xie, Xiaoying; Zhang, Chen; Wu, Ming-Bo; Tao, Ying; Lv, Wei; Yang, Quan-Hong

2013-12-01

131

PVP-Assisted ZrO2 coating on LiMn2O4 spinel cathode nanoparticles prepared by MnO2 nanowire templates  

E-print Network

where the electrolyte and manganese surface atoms are in contact (at the spinel/electrolyte interface metal oxide coatings have been reported, studies to improve both the rate capabilities of spinel LiMn2O4PVP-Assisted ZrO2 coating on LiMn2O4 spinel cathode nanoparticles prepared by MnO2 nanowire

Cho, Jaephil

132

Facile synthesis of hierarchical Co3O4@MnO2 core-shell arrays on Ni foam for asymmetric supercapacitors  

NASA Astrophysics Data System (ADS)

Hierarchical Co3O4@MnO2 core-shell arrays on Ni foam have been fabricated by a facile hydrothermal approach and further investigated as the electrode for high-performance supercapacitors. Owing to the high conductivity of the well-defined mesoporous Co3O4 nanowire arrays in combination with the large surface area provided by the ultrathin MnO2 nanosheets, the unique designed Co3O4@MnO2 core-shell arrays on Ni foam have exhibited a high specific capacitance (560 F g-1 at a current density of 0.2 A g-1), good rate capability, and excellent cycling stability (95% capacitance retention after 5000 cycles). An asymmetric supercapacitor with Co3O4@MnO2 core-shell nanostructure as the positive electrode and activated microwave exfoliated graphite oxide activated graphene (MEGO) as the negative electrode yielded an energy density of 17.7 Wh kg-1 and a maximum power density of 158 kW kg-1. The rational design of the unique core-shell array architectures demonstrated in this work provides a new and facile approach to fabricate high-performance electrode for supercapacitors.

Huang, Ming; Zhang, Yuxin; Li, Fei; Zhang, Lili; Wen, Zhiyu; Liu, Qing

2014-04-01

133

Oxidation of As(III) by MnO 2 in the absence and presence of Fe(II) under acidic conditions  

NASA Astrophysics Data System (ADS)

Oxidation of As(III) by natural manganese (hydr)oxides is an important geochemical reaction mediating the transformation of highly concentrated As(III) in the acidic environment such as acid mine drainage (AMD) and industrial As-contaminated wastewater, however, little is known regarding the presence of dissolved Fe(II) on the oxidation process. In this study, oxidation of As(III) in the absence and presence of Fe(II) by MnO 2 under acidic conditions was investigated. Kinetic results showed that the presence of Fe(II) significantly inhibited the removal of As(III) (including oxidation and sorption) by MnO 2 in As(III)-Fe(II) simultaneous oxidation system even at the molar ratio of Fe(II):As(III) = 1/64:1, and the inhibitory effects increased with the increasing ratios of Fe(II):As(III). Such an inhibition could be attributed to the formation of Fe(III) compounds covering the surface of MnO 2 and thus preventing the oxidizing sites available to As(III). On the other hand, the produced Fe(III) compounds adsorbed more As(III) and the oxidized As(V) on the MnO 2 surface with an increasing ratio of Fe(II):As(III) as demonstrated in kinetic and XPS results. TEM and EDX results confirmed the formation of Fe compounds around MnO 2 particles or separated in solution in Fe(II) individual oxidation system, Fe(II) pre-treated and simultaneous oxidation processes, and schwertmannite was detected in Fe(II) individual and Fe pre-treated oxidation processes, while a new kind of mineral, probably amorphous FeOHAs or FeAsO 4 particles were detected in Fe(II)-As(III) simultaneous oxidation process. This suggests that the mechanisms are different in Fe pre-treated and simultaneous oxidation processes. In the Fe pre-treated and MnO 2-mediated oxidation pathway, As(III) diffused through a schwertmannite coating formed around MnO 2 particles to be oxidized. The newly formed As(V) was adsorbed onto the schwertmannite coating until its sorption capacity was exceeded. Arsenic(V) then diffused out of the coating and was released into the bulk solution. The diffusion into the schwertmannite coating and the oxidation of As(III) and sorption of both As(V) and As(III) onto the coating contributed to the removal of total As from the solution phase. In the simultaneous oxidation pathway, the competitive oxidation of Fe(II) and As(III) on MnO 2 occurred first, followed by the formation of FeOHAs or FeAsO 4 around MnO 2 particles, and these poorly crystalline particles of FeOHAs and FeAsO 4 remained suspended in the bulk solution to adsorb As(III) and As(V). The present study reveals that the formation of Fe(III) compounds on mineral surfaces play an important role in the sorption and oxidation of As(III) by MnO 2 under acidic conditions in natural environments, and the mechanisms involved in the oxidation of As(III) depend upon how Fe(II) is introduced into the As(III)-MnO 2 system.

Han, Xu; Li, Yi-Liang; Gu, Ji-Dong

2011-01-01

134

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

135

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

136

Hybrid MnO(2)-disordered mesoporous carbon nanocomposites: synthesis and characterization as electrochemical pseudocapacitor electrodes  

SciTech Connect

MnO{sub 2}-mesoporous carbon hybrid nanocomposites were synthesized to achieve high values of redox pseudocapacitance at scan rates of 100 mV s{sup -1}. High-resolution transmission electron microscopy (HRTEM) along with energy dispersive X-ray spectroscopy (EDX) demonstrated that {approx}1 nm thick MnO{sub 2} nanodomains, resembling a conformal coating, were uniformly distributed throughout the mesoporous carbon structure. HRTEM and X-ray diffraction (XRD) showed formation of MnO{sub 2} nanocrystals with lattice planes corresponding to birnessite. The electrochemical redox pseudocapacitance of these composite materials in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte containing as little as 2 wt% MnO{sub 2} exhibited a high gravimetric MnO{sub 2} pseudocapacitance (C{sub MnO{sub 2}}) of 560 F g{sub MnO{sub 2}}{sup -1}. Even for 30 wt% MnO{sub 2}, a high C{sub MnO{sub 2}} of 137 F g{sub MnO{sub 2}}{sup -1} was observed at 100 mV s{sup -1}. Sodium ion diffusion coefficients on the order of 10{sup -9} to 10{sup -10} cm{sup 2} s{sup -1} were measured using chronoamperometry. The controlled growth and conformal coating of redox-active MnO{sub 2}-mesoporous carbon composites offer the potential for achieving high power energy storage with low cost materials.

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

2010-01-01

137

Rechargeable Lithium Batteries  

Microsoft Academic Search

Much of materials electrochemistry represents a fusion of solid-state chemistry and electrochemistry. The commercial success of the world's first rechargeable lithium battery, introduced recently by Sony, is a triumph of materials electrochemistry. By developing radically new anodes, cathodes and electrolytes, a cell has been produced which can store three times the energy per unit weight and volume compared with conventional

Peter G. Bruce

1996-01-01

138

The effect of Na0.44MnO2 formation in Na+-modified spinel LiMn2O4  

NASA Astrophysics Data System (ADS)

Na0.44MnO2 impure phase is formed during the synthetic process of Na+-modified spinel LiMn2O4 by solid state reaction which is confirmed by x-ray diffraction analysis. Scanning electron microscopy, transmission electron microscopy and galvanostatic charge-discharge measurements are carried out to investigate the effect of the formation of Na0.44MnO2 impurity on the morphology and electrochemical properties of the spinel material. The results show that the spinel material with impure phase exhibits improved cyclability compared to that of the pristine LiMn2O4. The improved electrochemical performance is mainly ascribed to the improved crystallinity of the spinel particles, enhanced stability of the spinel structure and good electronic conductivity of the composite.

Xiong, Lilong; Xu, Youlong; Wu, Weiguo; Lei, Pei; Tao, Tao; Dong, Xin

2014-07-01

139

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

140

Fluoride removal from water using activated and MnO 2-coated Tamarind Fruit ( Tamarindus indica) shell: Batch and column studies  

Microsoft Academic Search

The present work is concerned with the defluoridation capacities of activated (ATFS) and MnO2-coated Tamarind Fruit Shell (MTFS), using batch and column sorption techniques. In the batch technique, the dynamics of fluoride sorption, with respect to pH, [F]o and sorbent dose, was studied. The applicability of pseudo-first order for ATFS and Ritchie-second order for MTFS was observed. The kinetics data

V. Sivasankar; T. Ramachandramoorthy; A. Chandramohan

2010-01-01

141

Influence of the route of administration and the chemical form (MnCl2, MnO2) on the absorption and cerebral distribution of manganese in rats  

Microsoft Academic Search

The absorption and cerebral distribution of manganese (Mn) have been studied with respect to the route of administration\\u000a and the chemical form of the Mn compound. Different groups of adult male rats received either MnCl2???4H2O or MnO2 once a week for 4 weeks at a dose of 24.3 mg Mn\\/kg body wt. (b.w.) by oral gavage (g.) or 1.22 mg

H. Roels; G. Meiers; M. Delos; I. Ortega; R. Lauwerys; J. P. Buchet; D. Lison

1997-01-01

142

Preparation of ultrafine MnO 2 powders by the solid state method reaction of KMnO 4 with Mn(II) salts at room temperature  

Microsoft Academic Search

A novel route was used to prepare ultrafine powders of MnO2, i.e. the solid state reaction of KMnO4 with manganese acetate or manganese chloride at or near room temperature. The results of XPS and chemical analysis revealed that the main valence state of synthesized manganese oxides was 4. TEM and XRD showed that the average particle sizes were in the

Qingwen Li; Guoan Luo; Juan Li; Xi Xia

2003-01-01

143

Effect of MnO2 Addition on Sintering Properties of 18NiO-NiFe2O4 Composite Ceramics: Preliminary Results  

NASA Astrophysics Data System (ADS)

NiFe2O4 samples with small amounts of MnO2 were prepared via ball-milling process and two-step sintering process from commercial powders. Sintered density, average grain size, and microstructure of Mn-doped 18NiO-NiFe2O4 composite ceramics have been investigated by means of x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Bending strength was measured by three-point method. The results show that the crystalline structures of the ceramic matrix are still NiFe2O4 spinel structure and Mn ions homogeneously distribute in both the grains interiors and the grain boundaries. When 1 wt.% MnO2 was added, the values of relative density and bending strength of composite ceramics reached their respective maximum of 93.6% and 38.75 MPa, respectively. It is preliminarily found that MnO2 can reduce the sintering temperature obviously because of partial substitution of Fe3+ with Mn4+ in NiFe2O4 lattice.

Du, Jinjing; Liu, Yihan; Yao, Guangchun; Zhang, Zhigang

2012-09-01

144

Multifunctional MnO2 nanosheet-modified Fe3O4@SiO2/NaYF4:Yb, Er nanocomposites as novel drug carriers.  

PubMed

We report on a novel drug carrier which is based on the combination of magnetic and upconversion (UC) emission of Fe3O4@SiO2/NaYF4:Yb, Er (MSU) hybrids modified with MnO2 nanosheets (MSU/MnO2). The MSU hybrids were fabricated by covalently linking amino-modified Fe3O4@SiO2 particles with carboxyl-functionalized NaYF4:Yb, Er particles. The Fe3O4 core and the NaYF4:Yb, Er shell functioned successfully for magnetic targeting and fluorescence imaging, respectively. MnO2 nanosheets served as drug carriers and UC luminescence quenchers. The drug can be released by introducing glutathione (GSH) which reduces MnO2 to Mn(2+), and at the same time, UC luminescence can be turned on. These results clearly show that these MSU/MnO2 nanocomposites are promising platforms which can be applied to construct a smart drug delivery system with magnetic targeting and GSH-stimulation, as well as tracking by UC luminescence. PMID:24065169

Zhao, Peng; Zhu, Yihua; Yang, Xiaoling; Shen, Jianhua; Jiang, Xin; Zong, Jie; Li, Chunzhong

2014-01-14

145

All-solid-state electrochemical capacitors using MnO2 electrode/SiO2-Nafion electrolyte composite prepared by the sol-gel process  

NASA Astrophysics Data System (ADS)

Electrode-electrolyte composites of MnO2 active material, acetylene black (AB), and SiO2-Nafion solid electrolyte were prepared using the sol-gel process to form good solid-solid interfaces. The composites were obtained by the addition of MnO2 and AB into a sol of hydrolyzed tetraethoxysilane with Nafion, and successive solidification of the precursor sol. Scanning electron microscope and energy dispersive X-ray spectroscopy measurements show that good solid-solid interface is formed between electrodes and solid electrolytes in the composites. All-solid-state hybrid capacitors were fabricated using the composites or the hand-grinding mixture of MnO2, AB and SiO2-Nafion powder as positive electrodes, activated carbon powder as a negative electrode, and phosphosilicate gel as a solid electrolyte. The all-solid-state hybrid capacitors using the composites exhibit larger capacitances and better rate performance than the capacitors using the electrode prepared by hand-mixing of powders. Specific discharge capacitances of the capacitor with the composite are 85 F g-1 for the one with the composite electrode and 48 F g-1 for the one with the hand-mixed electrode, at 1 mA cm-2. Moreover, the all-solid-state capacitors using the composite electrode can be operated at temperatures between -30 °C and 60 °C.

Shimamoto, Kazushi; Tadanaga, Kiyoharu; Tatsumisago, Masahiro

2014-02-01

146

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

147

Aqueous-based chemical route toward ambient preparation of multicomponent core-shell nanotubes.  

PubMed

Room-temperature synthesized V2O5@MnO2 core-shell nanotubes with tunable tunnel dimensions via a facile aqueous-based method are presented. The rational-designed tubular morphology endows them with good permeability of electrolyte ions for maximum utilization of the electroactive sites, while the epitaxial-grown MnO2 imposes mechanical support to V2O5 against structural collapse upon long-term cycling. Hence, specific capacitance as high as 694 F g(-1) is achieved at 1 A g(-1) accompanied by excellent cycling stability (preserved 92% of its initial specific capacitance after 5000 cycles). In addition, functionalization of the V2O5@MnO2 nanotubes with other transition metal oxides results in ternary composites, V2O5@MnO2/M nanotubes (M = Fe2O3, Co2O3/Co(OH)2, Ni(OH)2). The versatility of this synthetic protocol provides a platform to fabricate complex ternary nanocomposites in a more benign way. PMID:24645828

Tan, Hui Teng; Rui, Xianhong; Yu, Hong; Liu, Weiling; Xu, Chen; Xu, Zhichuan; Hng, Huey Hoon; Yan, Qingyu

2014-04-22

148

Long-term cycling behavior of asymmetric activated carbon\\/MnO 2 aqueous electrochemical supercapacitor  

Microsoft Academic Search

Activated carbon–MnO2 hybrid electrochemical supercapacitor cells have been assembled and characterized in K2SO4 aqueous media. A laboratory cell achieved 195,000 cycles with stable performance. The maximal cell voltage was 2V associated with 21±2Fg?1 of total composite electrode materials (including activated carbon and MnO2, binder and conductive additive) and an equivalent serie resistance (ESR) below 1.3?cm2. Long-life cycling was achieved by

Thierry Brousse; Pierre-Louis Taberna; Olivier Crosnier; Romain Dugas; Philippe Guillemet; Yves Scudeller; Yingke Zhou; Frédéric Favier; Daniel Bélanger; Patrice Simon

2007-01-01

149

Kinetics for the Oxygen Evolution Reaction and Application of the Ti\\/SnO 2 ?+?RuO 2 ?+?MnO 2 Electrode  

Microsoft Academic Search

A Ti\\/SnO2?+?RuO2?+?MnO2 electrode was prepared by thermal decomposition of their salts. Results from SEM and XPS analyses, respectively, indicate\\u000a that the coating layer exhibits a compact structure and the oxidation state of Mn in the coating layer is +IV. The experimental\\u000a activation energy for the oxygen evolution reaction, which increased linearly with increasing overpotential, is about 8 kJ?mol?1 at the equilibrium

Zhenhai Liang; Yanfa Sun; Caimei Fan; Xiaogang Hao; Yanping Sun

2009-01-01

150

Nanomedicine: Break-up of Two-Dimensional MnO2 Nanosheets Promotes Ultrasensitive pH-Triggered Theranostics of Cancer (Adv. Mater. 41/2014).  

PubMed

Exfoliated 2D MnO2 nanosheets described by J. Shi, L. Wang, and co-workers on page 7019, show a unique break-up nature in mild acidic microenvironment of tumor tissues, which could substantially enhance the in vitro and in vivo performances of T1 -weighted magnetic resonance imaging. Such a pH-triggered break-up nature can also promote the fast release of loaded anticancer drugs for concurrent pH-responsive theranostics of cancer. PMID:25363881

Chen, Yu; Ye, Delai; Wu, Meiying; Chen, Hangrong; Zhang, Linlin; Shi, Jianlin; Wang, Lianzhou

2014-11-01

151

Study on immunosensor based on gold nanoparticles\\/chitosan and MnO 2 nanoparticles composite membrane\\/Prussian blue modified gold electrode  

Microsoft Academic Search

A novel and convenient immunosensor, based on the electrostatic adsorption characteristics between the positively charged\\u000a MnO2 nanoparticles (nano-MnO2) and chitosan (CS) composite membrane (nano-MnO2 + CS) and the negatively charged prussian blue (PB), was prepared for the detection of carcinoembryonic antigen (CEA). Firstly,\\u000a PB was electro-deposited on the surface of the gold electrode in the constant potential, and then nano-MnO2 + CS was adsorbed

Shujuan Ling; Ruo Yuan; Yaqin Chai; Tingting Zhang

2009-01-01

152

A new type rechargeable lithium battery based on a Cu-cathode  

Microsoft Academic Search

In present work, we report a new type rechargeable lithium battery, in which a Cu-cathode in aqueous electrolyte and a Li-anode in non-aqueous electrolyte are united together by a lithium super-ionic conductor glass film (LISICON) through which only lithium-ions can pass. During the charge–discharge process, combining with the dissolution–deposition of metallic Cu (or Li) electrode, lithium ions transfer between aqueous

Yonggang Wang; Haoshen Zhou

2009-01-01

153

Improved rechargeable lithium electrode  

SciTech Connect

The goals of the research were (1) to demonstrate that a synthetically generated lithium-ion-conducting interphase could extend the cycle life of the lithium electrode; and (2) to determine whether an organic solvent's stability toward lithium is intrinsic or simply due to mediating surface films. The presence of superoxide ion was found to quadruple the life of LiAlCl4/tetrahydrofuran electrolyte and to allow lithium to be cycled to LiAlCl4/2-methyl tetrahydrofuran. The discovery that 2-methyl tetrahydrofuran is more stable toward lithium-mercury amalgam than is tetrahydrofuran suggests that structural features of a solvent molecule may be manipulated so as to decrease its propensity for reduction by lithium metal. These results are said to provide a basis upon which solvents and the lithium solvent interface may be modified, leading to a practical secondary lithium electrode for use in rechargeable high-energy-density batteries.

Koch, V.R.

1983-04-01

154

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

155

Alkaline composite film as a separator for rechargeable lithium batteries  

Microsoft Academic Search

We report a new type of separator film for application in rechargeable lithium and lithium-ion batteries. The films are made\\u000a of mainly alkaline calcium carbonate (CaCO3) and a small amount of polymer binder. Owing to porosity and capillarity, the composite films show excellent wettability\\u000a with non-aqueous liquid electrolytes. Typically, the composite films composed of CaCO3 and Teflon and wetted with

S. S. Zhang; K. Xu; T. R. Jow

2003-01-01

156

Removal of NO2 and O3 generated from corona discharge in indoor air cleaning with MnO2 catalyst  

NASA Astrophysics Data System (ADS)

The production rules and removal efficiency of harmful byproducts such as NO2 and O3 generated from DC corona discharge in indoor air cleaning were investigated. The production behaviours of NO2 and O3 and the relationship between the amount of catalyst (MnO2) and the removal rate of harmful byproducts were experimentally studied. Further, indoor application tests were carried out in a closed room with 90 m3. The results showed that the concentrations of NO2 and O3 produced by corona discharge linearly increased with discharge time. The NO2 yield is larger than O3 by almost one order of magnitude under the same discharge power. To satisfy the demand of Standard of Indoor Air Quality (GB/T18883-2002), the power consumption of unit volume should be less than 1 W m-3 and the catalyst MnO2 consumptions in positive-negative corona discharge were 200 cm3 W-1 and 100 cm3 W-1, respectively.

Ge, H.; Yu, R.; Mi, D.; Zhu, Y. M.

2013-03-01

157

Facile Synthesis of Hierarchically Structured Magnetic MnO2/ZnFe2O4 Hybrid Materials and Their Performance in Heterogeneous Activation of Peroxymonosulfate.  

PubMed

In heterogeneous catalysis for water treatment, feasible recovery of nanocatalysts is crucial to make the process cost-effective and environmentally benign. In this study, we applied two strategies, for example, magnetic separation and hierarchical structure of solid catalysts, to ensure manganese catalysts are readily separable, meanwhile their catalytic performance was retained by the nanosized structure of MnO2 nanosheets or nanorods. ZnFe2O4 was used as the magnetic core and MnO2 corolla-like sphere consisting of nanosheets, and sea-urchin shaped structure made of nanorods, were fabricated by a hydrothermal method at 100 and 140 °C, respectively. Crystalline structure, morphology and textural property of the materials were investigated. The prepared catalysts were able to effectively activate peroxymonosulfate (PMS) to generate sulfate radicals for catalytic oxidation of a typical organic pollutant of phenol. After the heterogeneous catalysis, the catalysts were easily recovered by applying an external magnetic field. The effects of temperature and repeated use on the degradation efficiencies were evaluated. The generation and evolution of sulfate radicals and phenol oxidation were studied using both competitive radical tests and electron paramagnetic resonance (EPR). PMID:25350938

Wang, Yuxian; Sun, Hongqi; Ang, Ha Ming; Tadé, Moses O; Wang, Shaobin

2014-11-26

158

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

159

Prototype systems for rechargeable magnesium batteries.  

PubMed

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 hindered by two problems. First, owing to the chemical activity of Mg, only solutions that neither donate nor accept protons are suitable as electrolytes; but most of these solutions allow the growth of passivating surface films, which inhibit any electrochemical reaction. Second, the choice of cathode materials has been limited by the difficulty of intercalating Mg ions in many hosts. Following previous studies of the electrochemistry of Mg electrodes in various non-aqueous solutions, and of a variety of intercalation electrodes, we have now developed rechargeable Mg battery systems that show promise for applications. The systems comprise electrolyte solutions based on Mg organohaloaluminate salts, and Mg(x)Mo3S4 cathodes, into which Mg ions can be intercalated reversibly, and with relatively fast kinetics. We expect that further improvements in the energy density will make these batteries a viable alternative to existing systems. PMID:11048714

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

2000-10-12

160

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

161

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

162

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

163

Choosing appropriate techniques for quantifying groundwater recharge  

USGS Publications Warehouse

Various techniques are available to quantify recharge; however, choosing appropriate techniques is often difficult. Important considerations in choosing a technique include space/time scales, range, and reliability of recharge estimates based on different techniques; other factors may limit the application of particular techniques. The goal of the recharge study is important because it may dictate the required space/time scales of the recharge estimates. Typical study goals include water-resource evaluation, which requires information on recharge over large spatial scales and on decadal time scales; and evaluation of aquifer vulnerability to contamination, which requires detailed information on spatial variability and preferential flow. The range of recharge rates that can be estimated using different approaches should be matched to expected recharge rates at a site. The reliability of recharge estimates using different techniques is variable. Techniques based on surface-water and unsaturated-zone data provide estimates of potential recharge, whereas those based on groundwater data generally provide estimates of actual recharge. Uncertainties in each approach to estimating recharge underscore the need for application of multiple techniques to increase reliability of recharge estimates.

Scanlon, B.R.; Healy, R.W.; Cook, P.G.

2002-01-01

164

Reusable Energy and Power Sources: Rechargeable Batteries  

ERIC Educational Resources Information Center

Rechargeable batteries are very popular within consumer electronics. If one uses a cell phone or portable electric tool, she/he understands the need to have a reliable product and the need to remember to use the recharging systems that follow a cycle of charge/discharge. Rechargeable batteries are being called "green" energy sources. They are a…

Hsiung, Steve C.; Ritz, John M.

2007-01-01

165

Revised 06-2011 Rechargeable  

E-print Network

Waste Label (see separate instructions). Step 4: Bag It Insert a battery or cell phone in a provided bagRevised 06-2011 Rechargeable Battery And Cell Phone Recycling Program Guidelines University. For big batteries, or if no bag is available, cover terminals with non- conductive tape. Step 5: Seal

Taylor, Jerry

166

Unsteady Climate, Groundwater Recharge, and Human Influence  

NASA Astrophysics Data System (ADS)

Recharge is arguably the starting point of the groundwater hydrologic cycle. It marries above-ground hydrologic and climatic processes -runoff, precipitation, evapotranspiration- with groundwater flow and biochemical dynamics. This paper focuses on unsteady climate and ground water recharge linkages. Unsteady climate by virtue of its seasonal and inter-annual fluctuations or by shifts in the earth-atmosphere's radiative budget caused by secular forcing. Recharge is primarily caused by spatially diffuse percolation or by streamflow seepage. These two mechanisms are briefly reviewed. Examples of regional recharge governed by unsteady climate and affected by unsteady population are presented. Questions are raised about climate-recharge-human feebacks, and adaptation possibilities are proposed.

Loaiciga, H. A.

2007-12-01

167

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

168

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

169

Fluoride removal from water using activated and MnO2-coated Tamarind Fruit (Tamarindus indica) shell: batch and column studies.  

PubMed

The present work is concerned with the defluoridation capacities of activated (ATFS) and MnO(2)-coated Tamarind Fruit Shell (MTFS), using batch and column sorption techniques. In the batch technique, the dynamics of fluoride sorption, with respect to pH, [F](o) and sorbent dose, was studied. The applicability of pseudo-first order for ATFS and Ritchie-second order for MTFS was observed. The kinetics data were found to fit well with Temkin isotherm for ATFS and Langmuir for MTFS. The interaction of co-ions in the defluoridation capacity of the sorbent was studied. Column experiments were carried out under a constant fluoride concentration of 2mg/l, flow rate and different bed depths. The capacities of the breakthrough and exhaustion points increased with increase in the bed depth for ATFS unlike MTFS. The Thomson model was applied to the column experimental results. The characterization of the sorbents, ATFS and MTFS, was done using the FTIR, SEM and XRD techniques. PMID:20071077

Sivasankar, V; Ramachandramoorthy, T; Chandramohan, A

2010-05-15

170

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

171

Synthesis of TiO(2)/WO(3)/MnO(2) composites and high-throughput screening for their photoelectrical properties.  

PubMed

On the basis of the idea of equilateral ingredient triangle, a material library of the TiO(2)/WO(3)/MnO(2) composite material system was designed, which consisted of 66 ingredient points. Each point in the library corresponded with a device. To fabricate the device, the technology of screen printing was used. The pastes which were suitable for this technology were prepared by ball milling. After we printed the pastes onto the alumina substrate which had been preprinted with Au interdigital electrodes, these printed samples were sintered at 550 degrees C for 2 h in air. The photocurrent of each device under different light sources was measured respectively using a high-throughput screening system. The largest photocurrent was observed when the mole ratio of TiO(2)/WO(3) was 2/8 in the composite system. X-ray diffraction (XRD) was used to investigate the phase structure of the powder which had excellent photoelectric response. PMID:20225882

Zou, Zhijun; Liu, Yuan; Li, Huayao; Liao, Yichuan; Xie, Changsheng

2010-05-10

172

Electrically rechargeable REDOX flow cell  

NASA Technical Reports Server (NTRS)

A bulk energy storage system is designed with an electrically rechargeable reduction-oxidation (REDOX) cell divided into two compartments by a membrane, each compartment containing an electrode. An anode fluid is directed through the first compartment at the same time that a cathode fluid is directed through the second compartment. Means are provided for circulating the anode and cathode fluids, and the electrodes are connected to an intermittent or non-continuous electrical source, which when operating, supplies current to a load as well as to the cell to recharge it. Ancillary circuitry is provided for disconnecting the intermittent source from the cell at prescribed times and for circulating the anode and cathode fluids according to desired parameters and conditions.

Thaller, L. H. (inventor)

1976-01-01

173

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

174

A new thermal battery for powering borehole equipment: The discharge performance of Li-Mg-B alloy/LiNO3-KNO3/MnO2 cells at high temperatures  

NASA Astrophysics Data System (ADS)

There is interest in developing a suitable battery system that can be used at temperatures of 250 °C or less to power instrumentation used in oil/gas and geothermal boreholes. The discharge performance of MnO2 cathodes with Li-Mg-B alloy anodes is examined using the LiNO3-KNO3 eutectic electrolyte over a temperature range of 150 °C-300 °C at current densities from 10 to 30 mA cm-2. In this study, we find that the cell can be activated at 150 °C and operate within the desired temperature range without any indication of possible hazards. However, we did observe that temperature and current density significantly affected cell capacity and voltage. Overall, the Li-Mg-B alloy/LiNO3-KNO3/MnO2 system shows great potential for powering instrumentation used in oil/gas and geothermal boreholes.

Niu, Yongqiang; Wu, Zhu; Du, Junlin; Duan, Weiyuan

2014-01-01

175

Groundwater recharge and agricultural contamination  

USGS Publications Warehouse

Agriculture has had direct and indirect effects on the rates and compositions of groundwater recharge and aquifer biogeochemistry. Direct effects include dissolution and transport of excess quantities of fertilizers and associated materials and hydrologic alterations related to irrigation and drainage. Some indirect effects include changes in water-rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agrilcultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3-, N2, Cl, SO42-, H+, P, C, K, Mg, Ca, Sr, Ba, Ra, and As, as well a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3-, a combination of chemical, isotopic, and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. Groundwater records derived from multi-component hydrostratigraphic data can be used to quantify recharge rates and residence times of water and dissolved contaminants, document past variations in recharging contaminant loads, and identify natural contaminant-remediation processes. These data indicate that many of the world's surficial aquifers contain transient records of changing agricultural contamination from the last half of the 20th century. The transient agricultural groundwater signal has important implications for long-term trends and spatial heterogeneity in discharge.

Böhlke, J.K.

2002-01-01

176

Dielectric behavior of ternary mixtures: epoxy resin plus titanates (MgTiO3, CaTiO3 or BaTiO3) associated to oxides (CaO, MnO2 or ZnO)  

NASA Astrophysics Data System (ADS)

In the present work, we study the dielectric behavior of various ternary mixtures composed of epoxy resin (RE), of one of three different titanates (barium titanate, BaTiO3; calcium titanate, CaTiO3; magnesium titanate, MgTiO3) respectively with one of three oxides (calcium oxide, CaO; manganese dioxide, MnO2; zinc oxide, ZnO) using time domain reflectometry (TDR). The different composites are mixed at room temperature in different volume fractions keeping the epoxy resin at a constant volume fraction. Several mixture combinations are studied to see the oxides influence on the titanates dielectric behavior in the range from DC to 10 GHz. This is done through the experimental determination of the dielectric constant ?s. A noticeable effect has been recorded at the low frequency and which consists of an increase of this dielectric permittivity when growing the volume fraction of manganese dioxide. One meaningful point of this study is the lowest static conductivity value (8.017 × 10-3/(?m)) being reached with an incursion of 7.5% of MnO2 in a ternary mixture composed of RE, MgTiO3 and MnO2. In addition, the behavior obtained experimentally has been validated by the Lichtenecker modified model. This study interest lies on an application of these materials in microelectronics and particularly in telecommunication components manufacturing.

Bourouba, Nacerdine; Lalla, Khalfa; Martinez Jimenez, Juan Pablo; Bouzit, Nacerdine

2014-01-01

177

Rechargeable lithium battery technology - A survey  

NASA Astrophysics Data System (ADS)

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

178

Micro windmills to recharge your mobile phone  

E-print Network

0Tweet 0 Micro windmills to recharge your mobile phone Discussion in 'Other Engineering Trades be hosted on your mobile phone and used to charge your mobile phone on the go. Rao's work has seen a greatMicro windmills to recharge your mobile phone | CrazyEngineers 1/19/2014http://www.crazyengineers.com/threads/micro-windmills-to-recharge-your-mobile-phone

Chiao, Jung-Chih

179

Ground Water Recharge through Pits and Wells.  

National Technical Information Service (NTIS)

Well water was successfully recharged to the Meade formation in Southcentral Kansas through a pit and a well. However, when surface runoff water was recharged, the surface of the pit became sealed over for all practical purposes and the specific capacity ...

H. L. Manges

1973-01-01

180

Recharge at the Hanford Site: Status report  

SciTech Connect

A variety of field programs designed to evaluate recharge and other water balance components including precipitation, infiltration, evaporation, and water storage changes, have been carried out at the Hanford Site since 1970. Data from these programs have indicated that a wide range of recharge rates can occur depending upon specific site conditions. Present evidence suggests that minimum recharge occurs where soils are fine-textured and surfaces are vegetated with deep-rooted plants. Maximum recharge occurs where coarse soils or gravels exist at the surface and soils are kept bare. Recharge can occur in areas where shallow-rooted plants dominate the surface, particularly where soils are coarse-textured. Recharge estimates have been made for the site using simulation models. A US Geological Survey model that attempts to account for climate variability, soil storage parameters, and plant factors has calculated recharge values ranging from near zero to an average of about 1 cm/yr for the Hanford Site. UNSAT-H, a deterministic model developed for the site, appears to be the best code available for estimating recharge on a site-specific basis. Appendix I contains precipitation data from January 1979 to June 1987. 42 refs., 11 figs., 11 tabs.

Gee, G.W.

1987-11-01

181

High power rechargeable batteries Paul V. Braun  

E-print Network

High power rechargeable batteries Paul V. Braun , Jiung Cho, James H. Pikul, William P. King storage Secondary batteries High energy density High power density Lithium ion battery 3D battery of rechargeable (second- ary) batteries, as this is critical for most applications. As the penetration

Braun, Paul

182

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

183

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

184

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

185

Rechargeable lead-acid batteries.  

PubMed

Batteries used in medical equipment, like their counterparts in consumer products, attract little attention until they fail to function effectively. In some applications, such as in emergency medical devices, battery failure can have fatal consequences. While modern batteries are usually quite reliable, ECRI has received 53 written problem reports and countless verbal reports or questions related to battery problems in hospitals during the past five years. This large number of reports is due, at least in part, to the enormous quality of batteries used to operate or provide backup power in contemporary hospital equipment. As part of an ongoing evaluation of rehabilitation assistive equipment, ECRI has been studying the performance of 12 V rechargeable deep-cycle lead-acid batteries used in powered wheelchairs. During the course of this evaluation, it has become apparent that many professionals, both clinical and industrial, regard batteries as "black box" devices and know little about proper care and maintenance--and even less about battery selection and purchase. Because equipment performance and reliability can be strongly influenced by different battery models, an understanding of battery characteristics and how they affect performance is essential when selecting and purchasing batteries. The types of rechargeable batteries used most commonly in hospitals are lead-acid and nickel-cadmium (nicad), which we compare below; however, the guidance we provide in this article focuses on lead-acid batteries. While the examples given are for high-capacity 12 V deep-cycle batteries, similar analyses can be applied to smaller lead-acid batteries of different voltages. PMID:2211174

1990-09-01

186

Improved cycling performance of bismuth-modified amorphous manganese oxides as cathodes for rechargeable lithium batteries  

Microsoft Academic Search

Bismuth-modified amorphous manganese oxides were synthesized via a room temperature aqueous route. They were galvanostatically tested as intercalation cathodes for rechargeable lithium batteries at 1mAcm?2 between 1.5 and 4.3V. In sharp contrast to severe capacity fading of unmodified amorphous manganese oxide synthesized by the same route, a stable cycling performance of the bismuth-modified amorphous manganese oxide was observed. After an

Jingsi Yang; Terrill B Atwater; Jun John Xu

2005-01-01

187

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

188

Design of an AUV recharging system  

E-print Network

The utility of present Autonomous Underwater Vehicles (AUVs) is limited by their on-board energy storage capability. Research indicates that rechargeable batteries will continue to be the AUV power source of choice for at ...

Gish, Lynn Andrew

2004-01-01

189

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

190

Theory of the generalized chloride mass balance method for recharge estimation in groundwater basins characterised by point and diffuse recharge  

NASA Astrophysics Data System (ADS)

Application of the conventional chloride mass balance (CMB) method to point recharge dominant groundwater basins can substantially under-estimate long-term average annual recharge by not accounting for the effects of localized surface water inputs. This is because the conventional CMB method ignores the duality of infiltration and recharge found in karstic systems, where point recharge can be a contributing factor. When point recharge is present in groundwater basins, recharge estimation is unsuccessful using the conventional CMB method with, either unsaturated zone chloride or groundwater chloride. In this paper we describe a generalized CMB that can be applied to groundwater basins with point recharge. Results from this generalized CMB are shown to be comparable with long-term recharge estimates obtained using the watertable fluctuation method, groundwater flow modelling and Darcy flow calculations. The generalized CMB method provides an alternative, reliable long-term recharge estimation method for groundwater basins characterised by both point and diffuse recharge.

Somaratne, N.; Smettem, K. R. J.

2014-01-01

191

Doped lanthanum nickelates with a layered perovskite structure as bifunctional cathode catalysts for rechargeable metal-air batteries.  

PubMed

Rechargeable metal-air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction-evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La2NiO4) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium-air and zinc-air batteries assembled with these catalysts exhibit remarkably reduced discharge-charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling. PMID:24053465

Jung, Kyu-Nam; Jung, Jong-Hyuk; Im, Won Bin; Yoon, Sukeun; Shin, Kyung-Hee; Lee, Jong-Won

2013-10-23

192

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

193

Rechargeable 3 V Li cells using hydrated lamellar manganese oxide  

SciTech Connect

The synthesis and the electrochemical features of hydrated lamellar manganese oxides are reported. The authors use the reduction of aqueous permanganate solution by fumaric acid and the oxidation of manganese hydroxide by an aqueous permanganate solution to obtain sol-gel birnessite and classical X-exchanged birnessites (X = Li, Al, Na), respectively. The high oxidation state of Mn associated with the 2D character of the hot lattice allows high specific capacities (150 to 200 Ah/kg) available in the potential range of 4 to 2 V. Interlayer water provides the structural stability of the host lattice required for long cycling. Rechargeable two-electrode Li cells using starved or flooded electrolytes were built with the cathodic materials. The batteries exhibit a satisfactory behavior with a specific capacity of 160 Ah/kg recovered after 30 cycles at the C/20 discharge-charge rate for the sol-gel birnessite. This paper demonstrates an interest in cathodic materials based on oxides containing structural water for use in secondary Li batteries.

Bach, S.; Pereira-Ramos, J.P. [CNRS, Thiais (France). Electrochimie, Catalyse et Synthese Organique; Baffier, N. [CNRS, Paris (France). Chimie Appliquee de l`Etat Solide

1996-11-01

194

A bi-functional device for self-powered electrochromic window and self-rechargeable transparent battery applications  

NASA Astrophysics Data System (ADS)

Electrochromic smart windows are regarded as a good choice for green buildings. However, conventional devices need external biases to operate, which causes additional energy consumption. Here we report a self-powered electrochromic window, which can be used as a self-rechargeable battery. We use aluminium to reduce Prussian blue (PB, blue in colour) to Prussian white (PW, colourless) in potassium chloride electrolyte, realizing a device capable of self-bleaching. Interestingly, the device can be self-recovered (gaining blue appearance again) by simply disconnecting the aluminium and PB electrodes, which is due to the spontaneous oxidation of PW to PB by the dissolved oxygen in aqueous solution. The self-operated bleaching and colouration suggest another important function of the device: a self-rechargeable transparent battery. Thus the PB/aluminium device we report here is bifunctional, that is, it is a self-powered electrochromic window as well as a self-rechargeable transparent battery.

Wang, Jinmin; Zhang, Lei; Yu, Le; Jiao, Zhihui; Xie, Huaqing; Lou, Xiong Wen (David); Wei Sun, Xiao

2014-09-01

195

A bi-functional device for self-powered electrochromic window and self-rechargeable transparent battery applications.  

PubMed

Electrochromic smart windows are regarded as a good choice for green buildings. However, conventional devices need external biases to operate, which causes additional energy consumption. Here we report a self-powered electrochromic window, which can be used as a self-rechargeable battery. We use aluminium to reduce Prussian blue (PB, blue in colour) to Prussian white (PW, colourless) in potassium chloride electrolyte, realizing a device capable of self-bleaching. Interestingly, the device can be self-recovered (gaining blue appearance again) by simply disconnecting the aluminium and PB electrodes, which is due to the spontaneous oxidation of PW to PB by the dissolved oxygen in aqueous solution. The self-operated bleaching and colouration suggest another important function of the device: a self-rechargeable transparent battery. Thus the PB/aluminium device we report here is bifunctional, that is, it is a self-powered electrochromic window as well as a self-rechargeable transparent battery. PMID:25247385

Wang, Jinmin; Zhang, Lei; Yu, Le; Jiao, Zhihui; Xie, Huaqing; Lou, Xiong Wen David; Wei Sun, Xiao

2014-01-01

196

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

197

Computer Program for Predicting Recharge with a Master Recession Curve.  

National Technical Information Service (NTIS)

Water-table fluctuations occur in unconfined aquifers owing to ground-water recharge following precipitation and infiltration, and ground-water discharge to streams between storm events. Ground-water recharge can be estimated from well hydrograph data usi...

C. S. Heppner, J. R. Nimmo

2005-01-01

198

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.

199

Melt-Formable Block Copolymer Electrolytes for Lithium Rechargeable Batteries  

E-print Network

conductivity in polymer electrolytes for solid-state rechargeable lithium batteries. However, due to the strong in solid-state rechargeable lithium batteries. Yet, technical obstacles to their commercialization derive

Sadoway, Donald Robert

200

Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte  

Microsoft Academic Search

Aqueous lithium-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. But all reported aqueous lithium-ion battery systems have shown poor stability: the capacity retention is typically less than 50% after 100 cycles.

Jia-Yan Luo; Wang-Jun Cui; Ping He; Yong-Yao Xia

2010-01-01

201

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

202

Spatial and temporal variations in seepage during managed aquifer recharge  

Microsoft Academic Search

Managed aquifer recharge (MAR) is an increasingly important means of supplementing fresh water resources and helping to limit ground water overdraft. Many MAR systems are operated above a vadose zone and usually recharge rapidly during an initial phase of diversion. Recharge typically slows considerably within subsequent weeks to months as sedimentation, biofouling, soil compaction, drainage at the base of the

A. J. Racz; A. T. Fisher; C. M. Schmidt; B. S. Lockwood; M. Los Huertos

2009-01-01

203

Heat transport in the vicinity of an artificial recharge site  

Microsoft Academic Search

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

Alexander Vandenbohede; Emmanuel van Houtte; Luc Lebbe

2010-01-01

204

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

205

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

206

Rechargeable metal hydrides for spacecraft application  

Microsoft Academic Search

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

J. L. Perry

1988-01-01

207

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

208

Self-Recharging Virtual Currency David Irwin  

E-print Network

or starve. We outline the design and rationale for self-recharging currency in Cereus, a system for market to discourage fraudulent behav- ior. Currency transactions in Cereus are accountable: offline third-party audits use in Cereus1 , a system for service-oriented util- ity computing. The Cereus system is based

Shenoy, Prashant

209

Rechargeable solid polymer electrolyte battery cell  

DOEpatents

A rechargeable battery cell comprising first and second electrodes sandwiching a solid polymer electrolyte comprising a layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte adjacent said polymer blend and a layer of dry solid polymer electrolyte adjacent said layer of polymer blend and said second electrode.

Skotheim, Terji (East Patchoque, NY)

1985-01-01

210

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

211

Design considerations for rechargeable lithium batteries  

NASA Technical Reports Server (NTRS)

Viewgraphs of a discussion of design considerations for rechargable lithium batteries. The objective is to determine the influence of cell design parameters on the performance of Li-TiS2 cells. Topics covered include cell baseline design and testing, cell design and testing, cell design parameters studies, and cell cycling performance.

Shen, D. H.; Huang, C.-K.; Davies, E.; Perrone, D.; Surampudi, S.; Halpert, Gerald

1993-01-01

212

An approach to identify urban groundwater recharge  

NASA Astrophysics Data System (ADS)

Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, ...). The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i) Identification of potential recharge sources, (ii) Selection of tracers, (iii) Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv) Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%), the sewage network losses (30%), rainfall, concentrated in the non-urbanized areas (17%), from runoff infiltration (20%), and the Besòs River (11%). Regarding species, halogens (chloride, fluoride and bromide), sulfate, total nitrogen, and stable isotopes (18O, 2H, and 34S) behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations.

Vázquez-Suñé, E.; Carrera, J.; Tubau, I.; Sánchez-Vila, X.; Soler, A.

2010-10-01

213

An approach to identify urban groundwater recharge  

NASA Astrophysics Data System (ADS)

Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, ...). The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i) Identification of potential recharge sources, (ii) Selection of tracers, (iii) Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv) Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%), the sewage network losses (30%), rainfall, concentrated in the non-urbanized areas (17%), from runoff infiltration (20%), and the Besòs River (11%). Regarding species, halogens (chloride, fluoride and bromide), sulfate, total nitrogen, and stable isotopes (18O2H, and 34S) behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations.

Vázquez-Suñé, E.; Carrera, J.; Tubau, I.; Sánchez-Vila, X.; Soler, A.

2010-04-01

214

Improving the treatment of non-aqueous phase TCE in low permeability zones with permanganate.  

PubMed

Treating dense non-aqueous phase liquids (DNAPLs) embedded in low permeability zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate (MnO4(-)) into LPZs to treat high concentrations of TCE. This was accomplished by conducting transport experiments that quantified the penetration of various permanganate flooding solutions into a LPZ that was spiked with non-aqueous phase (14)C-TCE. The treatments we evaluated included permanganate paired with: (i) a shear-thinning polymer (xanthan); (ii) stabilization aids that minimized MnO2 rind formation and (iii) a phase-transfer catalyst. In addition, we quantified the ability of these flooding solutions to improve TCE destruction under batch conditions by developing miniature LPZ cylinders that were spiked with (14)C-TCE. Transport experiments showed that MnO4(-) alone was inefficient in penetrating the LPZ and reacting with non-aqueous phase TCE, due to a distinct and large MnO2 rind that inhibited the TCE from further oxidant contact. By including xanthan with MnO4(-), the sweeping efficiency increased (90%) but rind formation was still evident. By including the stabilization aid, sodium hexametaphosphate (SHMP) with xanthan, permanganate penetrated 100% of the LPZ, no rind was observed, and the percentage of TCE oxidized increased. Batch experiments using LPZ cylinders allowed longer contact times between the flooding solutions and the DNAPL and results showed that SHMP+MnO4(-) improved TCE destruction by ?16% over MnO4(-) alone (56.5% vs. 40.1%). These results support combining permanganate with SHMP or SHMP and xanthan as a means of treating high concentrations of TCE in low permeable zones. PMID:24491441

Chokejaroenrat, Chanat; Comfort, Steve; Sakulthaew, Chainarong; Dvorak, Bruce

2014-03-15

215

Doping effects on structure and electrode performance of K-birnessite-type manganese dioxides for rechargeable lithium battery  

Microsoft Academic Search

The potassium birnessites doped with Al, Ni, and Co were prepared by calcination and aqueous treatment, which showed that single phase products were obtained with Ni and Al up to 5at.% and Co up to 25at.% addition to strating KMnO4. The discharge–recharge capacities and capacity retentions in an aprotic Li cell were not improved by the Ni and Al dopings,

A. Ogata; S. Komaba; R. Baddour-Hadjean; J.-P. Pereira-Ramos; N. Kumagai

2008-01-01

216

Manganese oxide cathodes for rechargeable batteries  

NASA Astrophysics Data System (ADS)

Manganese oxides are considered as promising cathodes for rechargeable batteries due to their low cost and low toxicity as well as the abundant natural resources. In this dissertation, manganese oxides have been investigated as cathodes for both rechargeable lithium and alkaline batteries. Nanostructured lithium manganese oxides designed for rechargeable lithium cells have been synthesized by reducing lithium permanganate with methanol or hydrogen in various solvents followed by firing at moderate temperatures. The samples have been characterized by wet-chemical analyses, thermal methods, spectroscopic methods, and electron microscopy. It has been found that chemical residues in the oxides such as carboxylates and hydroxyl groups, which could be controlled by varying the reaction medium, reducing agents, and additives, make a significant influence on the electrochemical properties. The Li/Mn ratio in the material has also been found to be a critical factor in determining the rechargeability of the cathodes. The optimized samples exhibit a high capacity of close to 300 mAh/g with good cyclability and charge efficiency. The high capacity with a lower discharge voltage may make these nanostructured oxides particularly attractive for lithium polymer batteries. The research on the manganese oxide cathodes for alkaline batteries is focused on an analysis of the reaction products generated during the charge/discharge processes or by some designed chemical reactions mimicking the electrochemical processes. The factors influencing the formation of Mn3O4 in the two-electron redox process of delta-MnO2 have been studied with linear sweep voltammetry combined with X-ray diffraction. The presence of bismuth, the discharge rate, and the microstructure of the electrodes are found to affect the formation of Mn3O4, which is known to be electrochemically inactive. A faster voltage sweep and a more intimate mixing of the manganese oxide and carbon in the cathode are found to suppress the formation of Mn3O4. Bismuth has also been found to be beneficial in the one-electron process of gamma-MnO 2 when incorporated into the cathode. The results of a series of chemical reactions reveal that bismuth is blocking some reaction paths leading to the unwanted birnessite or Mn3O4. Barium is also found to play a similar role, but it is less effective than bismuth for the same amount of additive. Optimization of the additives has the potential to make the rechargeable alkaline cells based on manganese oxides to successfully compete with other rechargeable systems due to their low cost, environmental friendliness, and excellent safety features.

Im, Dongmin

217

Assessing controls on diffuse groundwater recharge using unsaturated flow modeling  

NASA Astrophysics Data System (ADS)

Understanding climate, vegetation, and soil controls on recharge is essential for estimating potential impacts of climate variability and land use/land cover change on recharge. Recharge controls were evaluated by simulating drainage in 5-m-thick profiles using a one-dimensional (1-D) unsaturated flow code (UNSAT-H), climate data, and vegetation and soil coverages from online sources. Soil hydraulic properties were estimated from STATSGO/SSURGO soils data using pedotransfer functions. Vegetation parameters were obtained from the literature. Long-term (1961-1990) simulations were conducted for 13 county-scale regions representing arid to humid climates and different vegetation and soil types, using data for Texas. Areally averaged recharge rates are most appropriate for water resources; therefore Geographic Information Systems were used to determine spatial weighting of recharge results from 1-D models for the combination of vegetation and soils in each region. Simulated 30-year mean annual recharge in bare sand is high (51-709 mm/yr) and represents 23-60% (arid-humid) of mean annual precipitation (MAP). Adding vegetation reduced recharge by factors of 2-30 (humid-arid), and soil textural variability reduced recharge by factors of 2-11 relative to recharge in bare sand. Vegetation and soil textural variability both resulted in a large range of recharge rates within each region; however, spatially weighted, long-term recharge rates were much less variable and were positively correlated with MAP (r2 = 0.85 for vegetated sand; r2 = 0.62 for variably textured soils). The most realistic simulations included vegetation and variably textured soils, which resulted in recharge rates from 0.2 to 118 mm/yr (0.1-10% of MAP). Mean annual precipitation explains 80% of the variation in recharge and can be used to map recharge.

Keese, K. E.; Scanlon, B. R.; Reedy, R. C.

2005-06-01

218

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. PMID:20940361

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

2010-01-01

219

Rechargeable batteries and battery management systems design  

Microsoft Academic Search

Estimated worldwide sales for rechargeable batteries, was around US$36 billion in 2008 and this is expected to grow towards US$51 billion by 2013. As per market reports, US demand for primary and secondary batteries will increase by 2.5% annually to 16.8 billion in 2012, while primary batteries will account for 5.8 billion with a growth rate of 3%. The insatiable

N. Kularatna

2010-01-01

220

Ampere-Hour Meter For Rechargeable Battery  

NASA Technical Reports Server (NTRS)

Low-power analog/digital electronic circuit meters discharge of storage battery in ampere-hours. By metering discharge, one obtains indication of state of charge of battery and avoids unnecessary recharging, maintaining capacity of battery and prolonging life. Because of its small size and low power consumption, useful in such applications as portable video cameras, communication equipment on boats, portable audio equipment, and portable medical equipment.

Tripp, John S.; Schott, Timothy D.; Tcheng, Ping

1993-01-01

221

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

222

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

223

Oxidative removal of aqueous steroid estrogens by manganese oxides.  

PubMed

This study investigated the oxidative removal of steroid estrogens from water by synthetic manganese oxide (MnO2) and the factors influencing the reactions. Using 1 x 10(-5)M MnO2 at pH 4, estrone (E1), 17beta-estradiol (E2), estriol (E3) and 17alpha-ethinylestradiol (EE2), all at 4 x 10(-6)M, were rapidly removed within 220 min, indicating the effectiveness of MnO2 as an oxidizing agent towards estrogens. E2 removal increased with decreasing pH over the tested range of 4-8, due most likely to increased oxidizing power of MnO2 and a cleaner reactive surface in acidic solutions. Coexisting metal ions of 0.01 M (Cu(II), Zn(II), Fe(III) and Mn(II)) and Mn(II) released from MnO2 reduction competed with E2 for reactive sites leading to reduced E2 removal. Observed differential suppression on E2 removal may be related to different speciations of metals, as suggested by the MINTEQ calculations, and hence their different adsorptivities on MnO2. By suppressing the metal effect, humic acid substantially enhanced E2 removal. This was attributed to complexation of humic acid with metal ions. With 0.01 M ZnCl2 in solutions containing 1 mg l(-1) humic acid, the binding of humic acid for Zn(II) was determined at 251 mmol g(-1). An in vitro assay using human breast carcinoma MCF-7 cells indicated a near elimination of estrogenic activities without secondary risk of estrogen solutions treated with MnO2. Synthetic MnO2 is therefore a promising chemical agent under optimized conditions for estrogen removal from water. Metal chelators recalcitrant to MnO2 oxidation may be properly used to further enhance the MnO2 performance. PMID:18929389

Xu, Lei; Xu, Chao; Zhao, Meirong; Qiu, Yuping; Sheng, G Daniel

2008-12-01

224

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

225

Assessing controls on diffuse groundwater recharge using unsaturated flow modeling  

Microsoft Academic Search

Understanding climate, vegetation, and soil controls on recharge is essential for estimating potential impacts of climate variability and land use\\/land cover change on recharge. Recharge controls were evaluated by simulating drainage in 5-m-thick profiles using a one-dimensional (1-D) unsaturated flow code (UNSAT-H), climate data, and vegetation and soil coverages from online sources. Soil hydraulic properties were estimated from STATSGO\\/SSURGO soils

K. E. Keese; B. R. Scanlon; R. C. Reedy

2005-01-01

226

Climatic controls on diffuse groundwater recharge across Australia  

NASA Astrophysics Data System (ADS)

Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical modelling for a range of Köppen-Geiger climate types (tropical, arid and temperate) to investigate the effect of climate variables on recharge for different soil and vegetation types. For the majority of climate types, the correlation between the modelled recharge and total annual rainfall is weaker than the correlation between recharge and the annual rainfall parameters reflecting rainfall intensity. Under similar soil and vegetation conditions for the same annual rainfall, annual recharge in regions with winter-dominated rainfall is greater than in regions with summer-dominated rainfall. The importance of climate parameters other than rainfall in recharge estimation is highest in the tropical climate type. Mean annual values of solar radiation and vapour pressure deficit show a greater importance in recharge estimation than mean annual values of the daily mean temperature. Climate parameters have the lowest relative importance in recharge estimation in the arid climate type (with cold winters) and the temperate climate type. For 75% of all soil, vegetation and climate types investigated, recharge elasticity varies between 2 and 4 indicating a 20% to 40% change in recharge for a 10% change in annual rainfall. Understanding how climate controls recharge under the observed historical climate allows more informed choices of analogue sites if they are to be used for climate change impact assessments.

Barron, O. V.; Crosbie, R. S.; Dawes, W. R.; Charles, S. P.; Pickett, T.; Donn, M. J.

2012-12-01

227

Using noble gases to investigate mountain-front recharge  

Microsoft Academic Search

Mountain-front recharge is a major component of recharge to inter-mountain basin-fill aquifers. The two components of mountain-front recharge are (1) subsurface inflow from the mountain block (subsurface inflow), and (2) infiltration from perennial and ephemeral streams near the mountain front (stream seepage). The magnitude of subsurface inflow is of central importance in source protection planning for basin-fill aquifers and in

Andrew H Manning; D. Kip Solomon

2003-01-01

228

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

229

The national collection and recycling program for nickel-cadmium rechargeable batteries  

SciTech Connect

This presentation discusses the effort of the rechargeable battery and rechargeable consumer products industries to form and implement a national collection program for rechargeable batteries in the US. Many states have mandatory labeling and collection requirements for rechargeable batteries. A national rechargeable battery management program to collect and recycle batteries throughout the US is discussed.

England, C.N. [Portable Rechargeable Battery Association, Atlanta, GA (United States)

1995-07-01

230

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

231

Recycling of used Ni-MH rechargeable batteries  

SciTech Connect

The Ni-MH (nickel metal hydride) rechargeable battery was developed several years ago. Its higher electrochemical capacity and greater safety compared with the Ni-Cd rechargeable battery have resulted in very rapid increase in its production. The Ni-MH rechargeable battery consists of Ni, Co and rare earth metals, so that recycling is important to recover these valuable mineral resources. In this study, a basic recycling process for used Ni-MH rechargeable batteries has been developed, in which the Ni, Co and rare earth elements are recovered through a combination of mechanical processing and hydrometallurgical processing.

Yoshida, T.; Ono, H.; Shirai, R. [Mitsui Mining and Smelting Co., Ltd., Ageo, Saitama (Japan). Corporate R and D Center

1995-12-31

232

Climatic controls on diffuse groundwater recharge across Australia  

NASA Astrophysics Data System (ADS)

Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical modeling for a range of Köppen-Geiger climate types (tropical, arid and temperate) to investigate the effect of climate variables on recharge for different soil and vegetation types. For the majority of climate types the total annual rainfall had a weaker correlation with recharge than the rainfall parameters reflecting rainfall intensity. In regions with winter-dominated rainfall, annual recharge under the same annual rainfall, soils and vegetation conditions is greater than in regions with summer-dominated rainfall. The relative importance of climate parameters other than rainfall is higher for recharge under annual vegetation, but overall is highest in the tropical climate type. Solar radiation and vapour pressure deficit show a greater relative importance than mean annual daily mean temperature. Climate parameters have lowest relative importance in the arid climate type (with cold winters) and the temperate climate type. For 75% of all considered cases of soil, vegetation and climate types recharge elasticity varies between 2 and 4, indicating a 20% to 40% change in recharge for a 10% change in annual rainfall Understanding how climate controls recharge under the observed historical climate allows more informed choices of analogue sites if they are to be used for climate change impact assessments.

Barron, O. V.; Crosbie, R. S.; Pollock, D.; Dawes, W. R.; Charles, S. P.; Pickett, T.; Donn, M.

2012-05-01

233

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

234

Lattice vibrations of materials for lithium rechargeable batteries III. Lithium manganese oxides  

Microsoft Academic Search

Structural features of several lithiated manganese oxides are studied using Raman scattering (RS) spectroscopy. This local probe is capable to analyse directly the near-neighbour environment of oxygen coordination around manganese and lithium cations. The samples include: orthorhombic and monoclinic LiMnO2, spinel LiMn2O4, monoclinic Li2MnO3, lithiated-spinel Li2Mn2O4, Li-birnessite, LT- and HT-Li0.52MnO2.1, spinel Li4Mn5O12, and Li0.33MnO2. Thus, as a first approach, we

C. M. Julien; M. Massot

2003-01-01

235

PALEO-CHANNELS IN LOW ALLUVIAL PLAINS: INDIRECT RECHARGE PATHWAYS AND OPPORTUNITIES FOR INDUCING MORE RECHARGE  

Microsoft Academic Search

The paper deals with description of a continuous monitoring scheme implemented in a sandy aquifer complex recharged by the Po river in low Padana plain near Ferrara (Italy). The aquifer actually is formed by two distinct sandy lithosomes: Holocenic paleo-channels (shallow unconfined aquifer) and Upper Pleistocenic sands (confined aquifer). The lithosomes are separated by a clayey aquitard but locally they

236

Glossary of testing terminology for rechargeable batteries  

SciTech Connect

The Battery Test Working Task Force was formed in 1983 for the purpose of coordinating the evaluation of development rechargeable batteries by DOE-funded labs. The Task Force developed this glossary of testing terminology to improve the accuracy of communication and to permit meaningful comparisons of test results. It consists of a section of technical terms and a separate section of programmatic phrases and acronyms. The glossary emphasizes terms related to electric vehicle batteries due to the significant development and testing activities in this area. 8 refs.

Butler, P.C.

1988-10-01

237

2/24/2014 Micro-Windmills to Recharge Cell Phones http://www.jadecadelina.com/innovation/micro-windmills-recharge-phones/ 1/2  

E-print Network

2/24/2014 Micro-Windmills to Recharge Cell Phones http://www.jadecadelina.com/innovation/micro-windmills-recharge-phones & Technology Search this site... R ECEN T P OSTS welcome Micro-Windmills to Recharge Cell Phones Super Ty phoon (required) Micro-Windmills to Recharge Cell Phones January 16, 2014 · by mr.jade · in Energy, Innovation

Chiao, Jung-Chih

238

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

239

Artificial recharge of groundwater and its role in water management  

USGS Publications Warehouse

This paper summarizes and discusses the various aspects and methods of artificial recharge with particular emphasis on its uses and potential role in water management in the Arabian Gulf region. Artificial recharge occurs when man's activities cause more water to enter an aquifer, either under pumping or non-pumping conditions, than otherwise would enter the aquifer. Use of artificial recharge can be a practical means of dealing with problems of overdraft of groundwater. Methods of artificial recharge may be grouped under two broad types: (a) water spreading techniques, and (b) well-injection techniques. Successful use of artificial recharge requires a thorough knowledge of the physical and chemical characteristics of the aquifier system, and extensive onsite experimentation and tailoring of the artificial-recharge technique to fit the local or areal conditions. In general, water spreading techniques are less expensive than well injection and large quantities of water can be handled. Water spreading can also result in significant improvement in quality of recharge waters during infiltration and movement through the unsaturated zone and the receiving aquifer. In comparison, well-injection techniques are often used for emplacement of fresh recharge water into saline aquifer zones to form a manageable lens of fresher water, which may later be partially withdrawn for use or continue to be maintained as a barrier against salt-water encroachment. A major advantage in use of groundwater is its availability, on demand to wells, from a natural storage reservoir that is relatively safe from pollution and from damage by sabotage or other hostile action. However, fresh groundwater occurs only in limited quantities in most of the Arabian Gulf region; also, it is heavily overdrafted in many areas, and receives very little natural recharge. Good use could be made of artificial recharge by well injection in replenishing and managing aquifers in strategic locations if sources of freshwater could be made available for the artificial-recharge operations. ?? 1989.

Kimrey, J. O.

1989-01-01

240

Probabilistic analysis of the effects of climate change on groundwater recharge  

E-print Network

[1] Groundwater recharge is likely to be affected by climate change. In semiarid regions where groundwater resources are often critical, annual recharge rates are typically small and most recharge occurs episodically. Such ...

Ng, Gene-Hua Crystal

241

Lithium-ion cells with aqueous electrolytes  

SciTech Connect

The electrochemical intercalation of lithium can occur in aqueous electrolytes provided that the host material, the Li{sup +} ion concentration and the pH, are carefully selected. Therefore, rechargeable cells with aqueous electrolytes based on the intercalation of lithium in both electrodes can be made. Here the authors describe some examples of these cells including Li{sub 1{minus}x}Mn{sub 2}O{sub 4}/Li{sub 1+x}Mn{sub 2}O{sub 4}, Li{sub 1{minus}x}Mn{sub 2}O{sub 4}/{gamma}-Li{sub 0.36}MnO{sub 2}, and LiMn{sub 2}O{sub 4}/VO{sub 2}(B) using several aqueous electrolytes. The voltage vs. charge relation for these aqueous cells predicted from the difference of the voltages of Li/LiMn{sub 2}O{sub 4}, Li/{gamma}-Li{sub 0.36}MnO{sub 2}, and Li/VO{sub 2}(B) nonaqueous cells is in excellent agreement with experiment, proving that lithium intercalation is occurring in the cells with aqueous electrolytes. The cells have poor cycle life (approximately 25 cycles) for reasons that are not yet understood.

Li, W.; Dahn, J.R. [Simon Fraser Univ., Burnaby, British Columbia (Canada). Dept. of Physics

1995-06-01

242

Electrochemical behavior of LiCoO 2 as aqueous lithium-ion battery electrodes  

Microsoft Academic Search

Despite the large number of studies on the behavior of LiCoO2 in organic electrolytes and its recent application as a positive electrode in rechargeable water battery prototypes, a little information is available about the lithium intercalation reaction in this layered compound in aqueous electrolytes. This work shows that LiCoO2 electrodes can be reversibly cycled in LiNO3 aqueous electrolytes for tens

Riccardo Ruffo; Colin Wessells; Robert A. Huggins; Yi Cui

2009-01-01

243

Comparing groundwater recharge and storage variability from GRACE satellite observations with observed water levels and recharge model simulations  

NASA Astrophysics Data System (ADS)

Sustainable management of groundwater resources, particularly in water stressed regions, requires estimates of groundwater recharge. This study in southern Mali, Africa compares approaches for estimating groundwater recharge and understanding recharge processes using a variety of methods encompassing groundwater level-climate data analysis, GRACE satellite data analysis, and recharge modelling for current and future climate conditions. Time series data for GRACE (2002-2006) and observed groundwater level data (1982-2001) do not overlap. To overcome this problem, GRACE time series data were appended to the observed historical time series data, and the records compared. Terrestrial water storage anomalies from GRACE were corrected for soil moisture (SM) using the Global Land Data Assimilation System (GLDAS) to obtain monthly groundwater storage anomalies (GRACE-SM), and monthly recharge estimates. Historical groundwater storage anomalies and recharge were determined using the water table fluctuation method using observation data from 15 wells. Historical annual recharge averaged 145.0 mm (or 15.9% of annual rainfall) and compared favourably with the GRACE-SM estimate of 149.7 mm (or 14.8% of annual rainfall). Both records show lows and peaks in May and September, respectively; however, the peak for the GRACE-SM data is shifted later in the year to November, suggesting that the GLDAS may poorly predict the timing of soil water storage in this region. Recharge simulation results show good agreement between the timing and magnitude of the mean monthly simulated recharge and the regional mean monthly storage anomaly hydrograph generated from all monitoring wells. Under future climate conditions, annual recharge is projected to decrease by 8% for areas with luvisols and by 11% for areas with nitosols. Given this potential reduction in groundwater recharge, there may be added stress placed on an already stressed resource.

Allen, D. M.; Henry, C.; Demon, H.; Kirste, D. M.; Huang, J.

2011-12-01

244

ESTIMATION OF GROUND WATER RECHARGE USING SOIL MOISTURE BALANCE APPROACH  

E-print Network

ESTIMATION OF GROUND WATER RECHARGE USING SOIL MOISTURE BALANCE APPROACH C. P. Kumar* ABSTRACT is the principal means for replenishment of moisture in the soil water system and recharge to ground water at the upper boundary, the antecedent soil moisture conditions, the water table depth and the soil type

Kumar, C.P.

245

Autonomous Battery Recharging for Indoor Mobile Robots Seungjun Oh  

E-print Network

1 Autonomous Battery Recharging for Indoor Mobile Robots Seungjun Oh Australian National University the batteries on a mobile robot. The robot used in this project is the Nomadic Technologies? Nomad XR4000 mobile robot. The battery recharging system was implemented using the robot's built-in sensors to control

246

Transcutaneous Battery Recharging By Volume Conduction and its Circuit Modeling  

Microsoft Academic Search

Many implantable devices require large capacity batteries implanted in the body. Transcutaneous battery recharging can effectively maintain the longevity of these implants. Based on this consideration we have developed a transcutaneous battery recharging circuit unit which takes advantages of skin volume conduction. This unit is able to pass 2.8 mA from the outside to the inside of pig skin with

Zhide Tang; R. J. Sclabassi; C. Sun; S. A. Hackworth; Jun Zhao; X. T. Cui; M. Sun

2006-01-01

247

Probabilistic estimation and prediction of groundwater recharge in a semi-arid environment  

E-print Network

Quantifying and characterizing groundwater recharge are critical for water resources management. Unfortunately, low recharge rates are difficult to resolve in dry environments, where groundwater is often most important. ...

Ng, Gene-Hua Crystal

2009-01-01

248

Global synthesis of groundwater recharge in semiarid and arid regions  

NASA Astrophysics Data System (ADS)

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 (40-374 000 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 Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977-1998) relative to periods dominated by La Niñas (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.

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

2006-10-01

249

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

2014-01-01

250

Lithium electronic environments in rechargeable battery electrodes  

NASA Astrophysics Data System (ADS)

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 reactivity. Experimental techniques were established to minimize sample contamination and control electron beam damage to studied compounds. Lithium hydroxide was found to be the most common product of beam damaged lithium alloys. Under an intense electron beam, halogen atoms desorbed by radiolysis in lithium halides. EELS spectra from a number of standard lithium compounds were obtained in order to identify the variety of spectra encountered in lithium rechargeable battery electrodes. Lithium alloys all displayed characteristically broad Li K-edge spectra, consistent with transitions to continuum states. Transitions to bound states were observed in the Li K and oxygen K-edge spectra of lithium oxides. Lithium halides were distinguished by their systematic chemical shift proportional to the anion electronegativity. Good agreement was found with measured lithium halide spectra and electron structure calculations using a self-consistant multiscattering code. The specific electrode environments of LiC6, LiCoO2, and Li-SnO were investigated. Contrary to published XPS predictions, lithium in intercalated graphite was determined to be in more metallic than ionic. We present the first experimental evidence of charge compensation by oxygen ions in deintercalated LiCoO2. Mossbauer studies on cycled Li-SnO reveal severely defective structures on an atomic scale. Metal hydride systems are presented in the appendices of this thesis. The mechanical alloying of immiscible Fe and Mg powders resulted in single-phase bcc alloys of less than 20 at% Mg. Kinetic studies on LaNi5-xSn x alloys proved that the mass transfer of hydrogen through these alloys was not hindered with increasing Sn substitutions for Ni. Collaborations with Energizer(c) found LanNi4.7Sn0.3 alloys to possess limited utility in rechargeable nickel-metal-hydride sealed-cell batteries.

Hightower, Adrian

251

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

252

Unlinkable Priced Oblivious Transfer with Rechargeable Wallets  

NASA Astrophysics Data System (ADS)

We present the first truly unlinkable priced oblivious transfer protocol. Our protocol allows customers to buy database records while remaining fully anonymous, i.e., (1) the database does not learn who purchases a record, and cannot link purchases by the same customer; (2) the database does not learn which record is being purchased, nor the price of the record that is being purchased; (3) the customer can only obtain a single record per purchase, and cannot spend more than his account balance; (4) the database does not learn the customer's remaining balance. In our protocol customers keep track of their own balances, rather than leaving this to the database as done in previous protocols. Our priced oblivious transfer protocol is also the first to allow customers to (anonymously) recharge their balances. Finally, we prove our protocol secure in the standard model (i.e., without random oracles).

Camenisch, Jan; Dubovitskaya, Maria; Neven, Gregory

253

Rechargeable metal hydrides for spacecraft application  

NASA Astrophysics Data System (ADS)

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.

1988-09-01

254

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

255

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

256

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

257

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

258

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 W h/kg theoretical). Energy densities in excess of 180 W h/kg have been realized in practical batteries. More recently, cathodes other than sulfur are being evaluated. Various new cathode materials are presently being evaluated 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, the studies have focussed on alternative metal chlorides such as CuCl2 and organic cathode materials such as TCNE.

Di Stefano, S.; Ratnakumar, B. V.; Bankston, C. P.

1990-01-01

259

Advances in development of rechargeable mitochondrial antioxidants.  

PubMed

It has been about 15 years since the introduction of the rechargeable mitochondria-targeted antioxidants (RMA). Two major groups have been developing RMA of the MitoQ and SkQ types independently, and many additional trials have been done by other researchers. This has provided solid preclinical evidence of RMA efficacy in various models. Human trials of systemic MitoQ were not followed by further advances, but the safety of MitoQ and, most likely, other RMA in humans has been demonstrated. A prooxidant effect at higher concentrations of RMA was described. For RMA of the SkQ type, a large window between anti- and prooxidant concentrations was observed, which makes SkQs promising as potential medicines. Significant RMA-induced improvements in many diseases that do not have an accepted treatment have been described. This justifies further clinical trials of RMA. PMID:25149221

Lukashev, Alexander N; Skulachev, Maxim V; Ostapenko, Victoria; Savchenko, Alla Yu; Pavshintsev, V V; Skulachev, Vladimir P

2014-01-01

260

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

261

Synthesis and electrochemical characterizations of nano-scaled Zn doped LiMn 2O 4 cathode materials for rechargeable lithium batteries  

Microsoft Academic Search

The LiZnxMn2?xO4 (x=0.00–0.15) cathode materials for rechargeable lithium-ion batteries were synthesized by simple sol–gel technique using aqueous solutions of metal nitrates and succinic acid as the chelating agent. The gel precursors of metal succinates were dried in vacuum oven for 10h at 120°C. After drying, the gel precursors were ground and heated at 900°C. The structural characterization was carried out

D. Arumugam; G. Paruthimal Kalaignan; Kumaran Vediappan; Chang Woo Lee

2010-01-01

262

Synthesis and electrochemical characterizations of nano size Ce doped LiMn 2O 4 cathode materials for rechargeable lithium batteries  

Microsoft Academic Search

LiCexMn2?xO4 (x=0.00–0.10) cathode materials for rechargeable lithium-ion batteries were synthesized by simple sol–gel technique using aqueous solutions of metal nitrates and succinic acid as the chelating agent. The gel precursors of metal succinates were dried in vacuum oven for 10h at 120°C. After drying, the gel precursors were ground and heated at 900°C. The structural characterization was carried out by

D. Arumugam; G. Paruthimal Kalaignan

2010-01-01

263

A new NASICON-type polyanion, Li x Ni 2(MoO 4) 3 as 3-V class positive electrode material for rechargeable lithium batteries  

Microsoft Academic Search

This paper presents our success in synthesizing a new framework type LixNi2(MoO4)3 (0?x?4) polyanion compound by adopting a novel aqueous soft-combustion process. The annealed powders exhibited a single-phase structure as confirmed by X-ray diffraction (XRD) and were characterized by electrochemical techniques in order to elucidate the suitability of this new material as positive electrode material in rechargeable lithium-containing batteries. The

K. M. Begam; Y. H. Taufiq-Yap; M. S. Michael; S. R. S. Prabaharan

2004-01-01

264

Using atmospheric tracers to reduce uncertainty in groundwater recharge areas.  

PubMed

A Monte Carlo-based approach to assess uncertainty in recharge areas shows that incorporation of atmospheric tracer observations (in this case, tritium concentration) and prior information on model parameters leads to more precise predictions of recharge areas. Variance-covariance matrices, from model calibration and calculation of sensitivities, were used to generate parameter sets that account for parameter correlation and uncertainty. Constraining parameter sets to those that met acceptance criteria, which included a standard error criterion, did not appear to bias model results. Although the addition of atmospheric tracer observations and prior information produced similar changes in the extent of predicted recharge areas, prior information had the effect of increasing probabilities within the recharge area to a greater extent than atmospheric tracer observations. Uncertainty in the recharge area propagates into predictions that directly affect water quality, such as land cover in the recharge area associated with a well and the residence time associated with the well. Assessments of well vulnerability that depend on these factors should include an assessment of model parameter uncertainty. A formal simulation of parameter uncertainty can be used to delineate probabilistic recharge areas, and the results can be expressed in ways that can be useful to water-resource managers. Although no one model is the correct model, the results of multiple models can be evaluated in terms of the decision being made and the probability of a given outcome from each model. PMID:21416662

Starn, J Jeffrey; Bagtzoglou, Amvrossios C; Robbins, Gary A

2010-01-01

265

Effects of artificial recharge on the Ogallala aquifer, Texas  

USGS Publications Warehouse

Four recharge tests were conducted by injecting water from playa lakes through wells into the Ogallala Formation. Injection was by gravity flow and by pumping under pressure. At one site, 34-acre feet of water was injected by gravity and produced a significant increase in yield of the well. At a second site, gravity injection of only 0.58 acre-foot caused a significant decrease in permeability due to plugging by suspended sediment. At two other sites, injection by pumping 6 and 14 acre-feet respectively, resulted in discharge of water at the surface and in perching of water above the water table. Differences in success of recharge were largely due to aquifer lithology and, therefore, the type of permeability; the concentration of suspended solids in the recharge water; and the injection technique. The injection technique can be controlled and the concentration of suspended solids can be minimized by treatment, but the site for well recharge will accept water most rapidly if it is selected on the basis of a favorable geohydrologic environment. Geophysical logs were used to study the effect of aquifer lithology on recharge and to understand the movement of injected water. Temperature logs were particularly useful in tracing the movement of recharged water. Natural-gamma, gamma-gamma, and neutron logs provided important data on lithology and porosity in the aquifer and changes in porosity and water distribution resulting from recharge. Effective recharge of the Ogallala Formation, using water from playa lakes, is possible where geohydrologic conditions are favorable and the recharge system is properly constructed.

Brown, Richmond Flint; Keys, W. S.

1985-01-01

266

Ground-water recharge from streamflow data, NW Florida  

USGS Publications Warehouse

Annual base flows of streams draining Okaloosa County and adjacent areas in northwest Florida were determined through hydrograph separation and correlation techniques for purposes of evaluating variations in ground-water recharge rates. Base flows were least in the northern part of the county and greatest in the southern part. Topographic and soils data were then superimposed on the distribution of base flow by subbasin to produce a map showing distribution of ground-water recharge throughout the county. The highest recharge rate occurs in the southern part of the county where relatively flat upland areas underlain by excessively drained sandy soils result in minimal storm runoff and evapotranspiration.

Vecchioli, John; Bridges, W. C.; Rumenik, R. P.; Grubbs, J. W.

1991-01-01

267

A new synthesis route to electrode materials for rechargeable lithium batteries  

SciTech Connect

An increasing demand for light-weight, compact power sources has led to the development of several insertion compounds as cathodes for rechargeable lithium batteries. The battery performance and cyclability of these cathodes are partly influenced by their microstructure, which in turn is controlled by the methods of synthesis and processing used. A novel approach involving the reduction of aqueous alkali metal metallate A{sub x}(MO{sub 4}){sub y} (A = Na or K and M = V, Mo, W or Mn) solutions with aqueous alkali metal borohydrides ABH{sub 4} (A = Na or K) at ambient temperatures has been developed to obtain amorphous or nanocrystalline transition metal oxide electrodes. The electrochemical performance of MoO{sub 2}, MnO{sub 2} and a metastable form of VO{sub 2} obtained by this approach is discussed. In addition, insertion of Li into MnO{sub 2} at ambient temperature followed by heat treatment at moderate temperatures to obtain the high surface area LiMn{sub 2}O{sub 4} spinel cathode and its battery performance are discussed. This aqueous solution-based approach is inexpensive and has the potential to offer new electrode materials as well.

Manthiram, A.; Dananjay, A.; Tsang, C. [Univ. of Texas, Austin, TX (United States)

1996-12-31

268

Evaluating Climate, Vegetation, and Soil Controls on Groundwater Recharge Using Unsaturated Flow Modeling  

Microsoft Academic Search

Understanding the relative importance of climate, vegetation, and soils in controlling groundwater recharge is critical for estimating recharge rates and for assessing the importance of these factors in controlling aquifer vulnerability to contamination. Understanding the role of climate and vegetation in controlling recharge will also be valuable in determining impacts of climate change and land use change on recharge. Numerical

K. E. Keese; B. R. Scanlon; R. C. Reedy

2003-01-01

269

Spatial Variability of Groundwater Recharge and its Effect on Shallow Groundwater Quality in Southern New Jersey  

Microsoft Academic Search

to the percentage of well-drained soils near wells. Spatial patterns of and topographic data to determine whether recharge recharge estimates, exceedance probabilities, and clay content indicate could be accurately predicted from landscape character- that sediment texture controls recharge in the study area. Relations with land elevation and a topographic wetness index were statistically istics. Finally, recharge estimates were compared with

Bernard T. Nolan; Arthur L. Baehr; Leon J. Kauffman

2003-01-01

270

Chemical routes to synthesize lithium cobalt oxide powders for rechargeable lithium batteries  

SciTech Connect

Lithium cobalt oxide (LiCoO{sub 2}) is known to be a good cathode material for high voltage (4V) rechargeable Li-ion batteries. New chemical routes based on aqueous solution chemistry have been developed to synthesize molecularly mixed precursors that transform to form LiCoO{sub 2} at temperatures as low as 400{degrees}C. The resultant oxide powders are nanocrystalline ({approx} 20-40 nm) and exhibit unique morphologies and microstructures depending on the molecular environment of the ions in solution. Cathodes fabricated from the oxide powders and tested in {open_quote}hockey-puck{close_quote} test cells exhibited specific capacities of about 135 mAh/g with a reversible range close to 0.5 Li ions. Results of the phase evolution and microstructural analysis are discussed in relation to the electrochemical performance of the cathodes.

Gallet, D.; Waghray, A.; Kumta, P.N. [Carnegie Mellon Univ., Pittsburgh, PA (United States)] [and others

1996-12-31

271

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); Amine, Khalil (Downers Grove, IL)

2008-01-01

272

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

273

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

274

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

275

Energy Storage with Ambient Temperature Rechargeable Lithium Batteries.  

National Technical Information Service (NTIS)

An ambient temperature rechargeable lithium battery with characteristics suitable for load-levelling and electric vehicle applications was developed. The battery was to use an organic electrolyte and a dissolved depolarizer. Studies were made of transitio...

S. B. Brummer, F. W. Dampier, V. R. Koch, R. D. Rauh, T. F. Reise

1978-01-01

276

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

277

Remote sensing of soil moisture: implications for groundwater recharge  

Microsoft Academic Search

.   Remote sensing provides information on the land surface. Therefore, linkages must be established if these data are to be\\u000a used in groundwater and recharge analyses. Keys to this process are the use of remote sensing techniques that provide information\\u000a on soil moisture and water-balance models that tie these observations to the recharge. Microwave remote sensing techniques\\u000a are used to

Thomas J. Jackson

2002-01-01

278

Recharge signal identification based on groundwater level observations.  

PubMed

This study applied a method of the rotated empirical orthogonal functions to directly decompose the space-time groundwater level variations and determine the potential recharge zones by investigating the correlation between the identified groundwater signals and the observed local rainfall records. The approach is used to analyze the spatiotemporal process of piezometric heads estimated by Bayesian maximum entropy method from monthly observations of 45 wells in 1999-2007 located in the Pingtung Plain of Taiwan. From the results, the primary potential recharge area is located at the proximal fan areas where the recharge process accounts for 88% of the spatiotemporal variations of piezometric heads in the study area. The decomposition of groundwater levels associated with rainfall can provide information on the recharge process since rainfall is an important contributor to groundwater recharge in semi-arid regions. Correlation analysis shows that the identified recharge closely associates with the temporal variation of the local precipitation with a delay of 1-2 months in the study area. PMID:22016042

Yu, Hwa-Lung; Chu, Hone-Jay

2012-10-01

279

Quantifying groundwater recharge from floods in semi-arid environments  

NASA Astrophysics Data System (ADS)

Floods represent an important aquifer recharge component in semi-arid environment. Changes in land use and the creation of artificial barriers to protect land from inundation can considerably influence the amount of aquifer recharge. Despite their importance, mechanisms that control flood recharge are poorly understood. Moreover, groundwater flow models rarely incorporate these processes with an appropriate physics based approach. In this study, we use a fully integrated surface subsurface fluid flow model to quantify changes in flood recharge induced by changes in land use. First, the flow simulations are performed on a synthetic aquifer to understand first order controls on flood recharge. Later, the simulations are extended to a real aquifer located in the lower Namoi aquifer, New South Wales, Australia. The long term groundwater monitoring hydrographs are used to calibrate the aquifer model. Satellite and aero-photographic surveys available both before and after changes in land use enable the comparison of flood extent to groundwater hydrograph response. The results show that the volume of water provided by the floods can represent a significant fraction of the aquifer water balance, and that changes in land use have a considerable effect on it. In addition, the results highlight the importance of treating flood recharge as a non-linear process.

Comunian, A.; Ajami, H.; Kelly, B. F.

2013-12-01

280

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

281

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

282

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 were realized in practical batteries. Other technological advantages include its chemical simplicity, absence of self-discharge, and long cycle life possibility. More recently, other high temperature sodium batteries have come into the spotlight. These systems can be described as follow: Na/Beta Double Prime-Al2O3/NaAlCl4/Metal Dichloride Sodium/metal dichloride systems are colloquially known as the zebra system and are currently being developed for traction and load leveling applications. The sodium-metal dichloride systems appear to offer many of the same advantages of the Na/S system, especially in terms of energy density and chemical simplicity. The metal dichloride systems offer increased safety and good resistance to overcharge and operate over a wide range of temperatures from 150 to 400 C with less corrosion problems.

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

1989-01-01

283

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

284

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 are being investigated and developed. Candidate support materials were drawn from transition metal carbides, borides, nitrides and oxides which have high conductivity (greater than 1 ohm/cm). Candidate catalyst materials were selected largely from metal oxides of the form ABO sub x (where A = Pb, Cd, Mn, Ti, Zr, La, Sr, Na, and B = Pt, Pd, Ir, Ru, Ni (Co) which were investigated and/or developed for one function only, O2 reduction or O2 evolution. The electrical conductivity requirement for catalysts may be lower, especially if integrated with a higher conductivity support. All candidate materials of acceptable conductivity are subjected to corrosion testing. Materials that survive chemical testing are examined for electrochemical corrosion activity. For more stringent corrosion testing, and for further evaluation of electrocatalysts (which generally show significant O2 evolution at at 1.4 V), samples are held at 1.6 V or 0.6 V for about 100 hours. The surviving materials are then physically and chemically analyzed for signs of degradation. To evaluate the bifunctional oxygen activity of candidate catalysts, Teflon-bonded electrodes are fabricated and tested in a floating electrode configuration. Many of the experimental materials being studied have required development of a customized electrode fabrication procedure. In advanced development, the goal is to reduce the polarization to about 300 to 350 mV. Approximately six support materials and five catalyst materials were identified to date for further development. The test results will be described.

Swette, L.; Kackley, N.

1989-01-01

285

Design and simulation of lithium rechargeable batteries  

SciTech Connect

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 solution theory to describe the transport processes in the solution phase. The insertion process itself is treated with a charge-transfer process at the surface obeying Butler-Volmer kinetics, followed by diffusion of the lithium ion into the host structure. These models are used to explore the phenomena that occur inside of lithium cells under conditions of discharge, charge, and during periods of relaxation. Also, in order to understand the phenomena that limit the high-rate discharge of these systems, we focus on the modeling of a particular system with well-characterized material properties and system parameters. The system chosen is a lithium-ion cell produced by Bellcore in Red Bank, NJ, consisting of a lithium-carbon negative electrode, a plasticized polymer electrolyte, and a lithium-manganese-oxide spinel positive electrode. This battery is being marketed for consumer electronic applications. The system is characterized experimentally in terms of its transport and thermodynamic properties, followed by detailed comparisons of simulation results with experimental discharge curves. Next, the optimization of this system for particular applications is explored based on Ragone plots of the specific energy versus average specific power provided by various designs.

Doyle, C.M.

1995-08-01

286

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

287

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

288

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

289

Crab Burrows are Important Conduits for Groundwater Recharge in Bangladesh  

NASA Astrophysics Data System (ADS)

Recent research suggests that recharge from man-made ponds may stimulate arsenic mobilization within Bangladeshi aquifers. Man-made ponds are widespread throughout Bangladesh and are generally underlain by low permeability clays that could potentially limit flow to the sandy aquifer below if they are not compromised by preferential flow paths. Animal borrows are one common type of preferential flow path through surface clays. Across the Ganges Delta, terrestrial crabs dig borrows, sometimes as long as 10 meters. In our study pond in Munshiganj, Bangladesh we found crab burrows extending through the surficial clays and down into the shallow aquifer spaced approximately every meter. We use these field observations along with a novel, coupled isotope and water balance model to quantify the fluxes into and out of the pond. We show that nearly all of the aquifer recharge from the pond is through crab burrows which have enhanced the hydraulic conductivity of the surficial sediments by several orders of magnitude. In addition we show that the recharging pond water is shifting the solute composition of water beneath the pond. We suggest that, as a result of crab burrows, young ponds may contribute large fluxes of recharge water whereas older ponds may contribute little recharge to the aquifer. All terrestrial crabs have gills that must remain moist to allow for respiration. So, to ensure an uninterrupted water source, their borrows must reach the maximum depth that the water table drops to seasonally after irrigation ceases and before the onset of the monsoon. Once a pond is installed crabs living within the sediments that now make up the new pond bottom would no longer need to construct burrows to ensure a constant supply of water. Over time, burrows that existed prior to pond construction can clog. Water balance data for an old pond at our study site indicates that this pond contributes less recharge than our newly constructed pond.

Stahl, M.; Tarek, M. H.; Yeo, D. C.; Badruzzaman, A.; Harvey, C. F.

2013-12-01

290

Focused Ground-Water Recharge in the Amargosa Desert Basin  

USGS Publications Warehouse

The Amargosa River is an approximately 300-kilometer long regional drainage connecting the northern highlands on the Nevada Test Site in Nye County, Nev., to the floor of Death Valley in Inyo County, Calif. Streamflow analysis indicates that the Amargosa Desert portion of the river is dry more than 98 percent of the time. Infiltration losses during ephemeral flows of the Amargosa River and Fortymile Wash provide the main sources of ground-water recharge on the desert-basin floor. The primary use of ground water is for irrigated agriculture. The current study examined ground-water recharge from ephemeral flows in the Amargosa River by using streamflow data and environmental tracers. The USGS streamflow-gaging station at Beatty, Nev., provided high-frequency data on base flow and storm runoff entering the basin during water years 1998?2001. Discharge into the basin during the four-year period totaled 3.03 million cubic meters, three quarters of which was base flow. Streambed temperature anomalies indicated the distribution of ephemeral flows and infiltration losses within the basin. Major storms that produced regional flow during the four-year period occurred in February 1998, during a strong El Ni?o that more than doubled annual precipitation, and in July 1999. The study also quantified recharge beneath undisturbed native vegetation and irrigation return flow beneath irrigated fields. Vertical profiles of water potential and environmental tracers in the unsaturated zone provided estimates of recharge beneath the river channel (0.04?0.09 meter per year) and irrigated fields (0.1?0.5 meter per year). Chloride mass-balance estimates indicate that 12?15 percent of channel infiltration becomes ground-water recharge, together with 9?22 percent of infiltrated irrigation. Profiles of potential and chloride beneath the dominant desert-shrub vegetation suggest that ground-water recharge has been negligible throughout most of the basin since at least the early Holocene. Surface-based electrical-resistivity imaging provided areal extension of borehole information from sampled profiles. These images indicate narrowly focused recharge beneath the Amargosa River channel, flanked by large tracts of recharge-free basin floor.

Stonestrom, David A.; Prudic, David E.; Walvoord, Michelle A.; Abraham, Jared D.; Stewart-Deaker, Amy E.; Glancy, Patrick A.; Constantz, Jim; Laczniak, Randell J.; Andraski, Brian J.

2007-01-01

291

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

292

Modelling of recharge and pollutant fluxes to urban groundwaters.  

PubMed

Urban groundwater resources are of considerable importance to the long-term viability of many cities world-wide, yet prediction of the quantity and quality of recharge is only rarely attempted at anything other than a very basic level. This paper describes the development of UGIf, a simple model written within a GIS, designed to provide estimates of spatially distributed recharge and recharge water quality in unconfined but covered aquifers. The following processes (with their calculation method indicated) are included: runoff and interception (curve number method); evapotranspiration (Penman-Grindley); interflow (empirical index approach); volatilization (Henry's law); sorption (distribution coefficient); and degradation (first order decay). The input data required are: meteorological data, landuse/cover map with event mean concentration attributes, geological maps with hydraulic and geochemical attributes, and topographic and water table elevation data in grid form. Standard outputs include distributions of: surface runoff, infiltration, potential recharge, ground level slope, interflow, actual recharge, pollutant fluxes in surface runoff, travel times of each pollutant through the unsaturated zone, and the pollutant fluxes and concentrations at the water table. The process of validation has commenced with a study of the Triassic Sandstone aquifer underlying Birmingham, UK. UGIf predicts a similar average recharge rate for the aquifer as previous groundwater flow modelling studies, but with significantly more spatial detail: in particular the results indicate that recharge through paved areas may be more important than previously thought. The results also highlight the need for more knowledge/data on the following: runoff estimation; interflow (including the effects of lateral flow and channelling on flow times and therefore chemistry); evapotranspiration in paved areas; the nature of unsaturated zone flow below paved areas; and the role of the pipe network. Although considerably more verification is needed, UGIf shows promise for use: in providing input for regional groundwater solute transport models; in identifying gaps in knowledge and data; in determining which processes are the most important influences on urban groundwater quantity and quality; in evaluating existing recharge models; in planning, for example in investigation of the effects of landuse or climate change; and in assessing groundwater vulnerability. PMID:16325236

Thomas, Abraham; Tellam, John

2006-05-01

293

78 FR 16031 - Twelfth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...  

Federal Register 2010, 2011, 2012, 2013

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2013-03-13

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

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2012-02-14

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78 FR 38093 - Thirteenth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...  

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2013-06-25

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2012-04-05

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2011-07-01

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2011-04-20

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76 FR 6180 - First Meeting: RTCA Special Committee 225: Rechargeable Lithium Batteries and Battery Systems...  

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2011-02-03

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78 FR 55773 - Fourteenth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...  

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2013-09-11

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78 FR 6845 - Eleventh Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...  

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2013-01-31

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77 FR 39321 - Eighth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...  

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2012-07-02

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76 FR 54527 - Fourth Meeting: RTCA Special Committee 225: Rechargeable Lithium Batteries and Battery Systems...  

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2011-09-01

304

Nickel hydroxide and other nanophase cathode materials for rechargeable batteries  

NASA Astrophysics Data System (ADS)

The staff of US Nanocorp, Inc. are developing unique nanostructured materials for a wide range of applications in the areas of energy storage (batteries and ultracapacitors) and energy conversion (fuel cells and thermoelectric) devices. Many of the preparations of these materials exploit a wet synthesis process (patent pending) that is scaleable to large volume manufacturing and anticipated to be low in cost. Specifically, both the ?-form of nickel hydroxide and the hollandite form of manganese dioxide have been synthesized. The hexagonal Ni(OH) 2 is anticipated to significantly boost energy densities in nickel-alkaline batteries, including nickel/cadmium, nickel/metal hydride and nickel/zinc. The nanophase MnO 2 microstructure exhibits an unusual tunnelled tubular geometry within a 'bird's nest' superstructure, and is expected to be of interest as an intercalation cathode material in lithium-ion systems as well as a catalyst for fuel cells. Characterization of these materials has been by the techniques of high resolution SEM and TEM, as well as XRD. Both Hg porosimetry and BET surface measurements for conventional and spherical nickel hydroxides are summarized. Pore distribution and electrochemical activity for the nanophase materials will be examined in the future.

Reisner, David E.; Salkind, Alvin J.; Strutt, Peter R.; Xiao, T. Danny

305

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

306

Climate change impacts on groundwater recharge uncertainty, shortcomings, and the way forward?  

Microsoft Academic Search

An integrated approach to assessing the regional impacts of climate and socio-economic change on groundwater recharge is described from East Anglia, UK. Many factors affect future groundwater recharge including changed precipitation and temperature regimes, coastal flooding, urbanization, woodland establishment, and changes in cropping and rotations.Important sources of uncertainty and shortcomings in recharge estimation are discussed in the light of the

I. P. Holman

2006-01-01

307

Estimated Recharge Rates From Groundwater Temperatures In The Nara Basin, Japan  

Microsoft Academic Search

Groundwater recharge rates to the sandy aquifer in the Nara basin, Japan, were determined by using a theory that describes the simultaneous transfer of heat and water in a porous medium. Seasonal changes in temperatue-depth profiles were used to estimate the recharge rates in a relatively shallow aquifer. Estimations of the recharge rates were done by fitting a dimensionless parameter

Makoto Taniguchi

1994-01-01

308

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

309

PRINCIPALS OF ORGANIC CONTAMINANT BEHAVIOR DURING ARTIFICIAL RECHARGE  

EPA Science Inventory

The behavior of a variety of organic contaminants having low molecular weight has been observed during groundwater recharge with reclaimed water. The evidence is site-specific, but is believed to have broader implications regarding the general behavior of organic contaminants in ...

310

Potential for Recharge in Agricultural Soils of the Mississippi Delta  

NASA Astrophysics Data System (ADS)

Ground water models predict that 5 percent or less of precipitation in the Mississippi Delta region recharges the heavily-used alluvial aquifer; however the presence of agricultural chemicals in ground water suggests more substantial recharge. In a preliminary assessment of the potential for aerial recharge through the agricultural soils of the Bogue Phalia basin in the Mississippi Delta, we applied a method for rapidly measuring field- saturated hydraulic conductivity (Kfs) in 26 locations in cotton and soybean fields. The technique makes use of a portable falling-head, small-diameter, single-ring infiltrometer and an analytical formula for Kfs that compensates both for falling head and for subsurface radial spreading. Soil samples were also collected at the surface and at about 6 cm depth at each location for particle size analysis. Kfs values are generally higher than anticipated and vary over more than three orders of magnitude from 1x10-2 to 5x10-6 cm/s. There is also a correlation between Kfs and mean particle size which may prove useful in generalizing recharge rates over larger areas. A 2-m ring infiltration test is planned that will include the use of tracers and subsurface instruments for measuring water content and matric potential from the near surface to about 5 m to evaluate flow and transport below the root zone.

Perkins, K. S.; Nimmo, J. R.; Coupe, R. H.; Rose, C. E.; Manning, M. A.

2007-12-01

311

Separation composition evaluation in model rechargeable silver-zinc cells  

Microsoft Academic Search

In previous reports, the evaluation of Viskase sausage casings (SCs) in a variety of configurations for silver\\/zinc rechargeable cells has been reported. The conclusions have been that several layers of SC, while providing improved resistance to silver migration acid zinc dendrite growth compared to standard cellophane film, also impart increased internal impedance which leads to faster capacity loss in comparison

H. Lewis; S. Henderson; T. Danko

2001-01-01

312

High power, rechargeable, pile type silver zinc battery  

Microsoft Academic Search

This patent describes a high rate rechargeable silver-zinc pile type battery including a plurality of bipolar electrodes which are assembled into a full scale multi-cell pile. Each of bipolar electrodes includes a positive side having a porous silver matrix attached to silver foil and a negative side having a porous zinc structure vapor deposited on silver foil. A separator including

L. R. Erisman; R. A. Marsh

1978-01-01

313

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

314

Technology uses micro-windmills to recharge cell phones  

E-print Network

Technology uses micro-windmills to recharge cell phones A micro-windmill is pictured on the face designed a micro-windmill that generates wind energy and may become an innovative solution to cell phone be embedded in a sleeve for a cell phone. Wind, created by waving the cell phone in air or holding it up

Chiao, Jung-Chih

315

Interdisciplinary Institute for Innovation Optimal Recharging Strategy for  

E-print Network

while the Spanish government has committed to having 1 million electric or hybrid cars on Spanish roads price differentials in electricity tariffs are designed to dissuade car owners from recharging for Electric Vehicles in France Margaret Armstrong Charles El Hajj Moussa Jérôme Adnot Alain Galli Philippe

Paris-Sud XI, Université de

316

Carbon materials for lithium-ion rechargeable batteries  

Microsoft Academic Search

The recent development of lithium rechargeable batteries results from the use of carbon materials as lithium reservoir at the negative electrode. Reversible intercalation, or insertion, of lithium into the carbon host lattice avoids the problem of lithium dendrite formation and provides large improvement in terms of cycleability and safety. This paper reviews the main achievements on performance and understanding of

S. Flandrois; B. Simon

1999-01-01

317

Rechargeable lithium batteries in the Navy -- Policy and protocol  

SciTech Connect

Rechargeable lithium batteries are an emerging technology that is finding widespread use in myriad 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 for this technology range from propulsion power for autonomous unmanned vehicles to power sources for exercise mines. Current battery chemistries that might eventually be replaced by rechargeable lithium batteries include silver-zinc batteries, lithium-thionyl chloride batteries, and possibly lithium thermal batteries. The Navy is developing and implementing a universal test protocol for evaluating the safety characteristics of rechargeable lithium power sources, as discussed by Winchester et al (1995). Test plans based on this protocol are currently being used to evaluate both commercially available and developmental products. In this paper the authors will review the testing protocol that has been developed for evaluating the safety of rechargeable lithium batteries. Relevant data from current test programs will be presented.

Banner, J.A.; Winchester, C.S. [Naval Surface Warfare Center, Silver Spring, MD (United States). Carderock Div.

1996-12-31

318

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

319

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.

1990-01-01

320

Cops and Robber Game Without Recharging Fedor V. Fomin  

E-print Network

study of such games has a long history, tracing back to the work of Pierre Bouguer, who in 1732 studied applications reaching from law enforcement to video games and thus were studied within different disciplinesCops and Robber Game Without Recharging Fedor V. Fomin Petr A. Golovach Daniel Lokshtanov Abstract

Fomin, Fedor V.

321

Cops and Robber Game Without Recharging Fedor V. Fomin  

E-print Network

- ematical study of such games has a long history, tracing back to the work of Pierre Bouguer, who in 1732 applications reaching from law enforcement to video games and thus were studied within differ- ent disciplinesCops and Robber Game Without Recharging Fedor V. Fomin Petr A. Golovach Daniel Lokshtanov Abstract

Fomin, Fedor V.

322

Effects of recharge wells and flow barriers on seawater intrusion.  

PubMed

The installation of recharge wells and subsurface flow barriers are among several strategies proposed to control seawater intrusion on coastal groundwater systems. In this study, we performed laboratory-scale experiments and numerical simulations to determine the effects of the location and application of recharge wells, and of the location and penetration depth of flow barriers, on controlling seawater intrusion in unconfined coastal aquifers. We also compared the experimental results with existing analytical solutions. Our results showed that more effective saltwater repulsion is achieved when the recharge water is injected at the toe of the saltwater wedge. Point injection yields about the same repulsion compared with line injection from a screened well for the same recharge rate. Results for flow barriers showed that more effective saltwater repulsion is achieved with deeper barrier penetration and with barriers located closer to the coast. When the flow barrier is installed inland from the original toe position however, saltwater intrusion increases with deeper barrier penetration. Saltwater repulsion due to flow barrier installation was found to be linearly related to horizontal barrier location and a polynomial function of the barrier penetration depth. PMID:20533955

Luyun, Roger; Momii, Kazuro; Nakagawa, Kei

2011-01-01

323

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

324

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

325

Spatial and Temporal Infiltration Dynamics during Managed Aquifer Recharge  

E-print Network

to catchment runoff.19 Introduction and Project Motivation20 Groundwater is essential for meeting fresh water to the environment and water supply associated with overdraft, artificial38 recharge of groundwater is gaining, Santa Cruz, Santa Cruz, California 95064 2 Pajaro Valley Water Management Agency, Watsonville

Fisher, Andrew

326

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

327

Advanced traction rechargeable battery system for cableless mobile robot  

Microsoft Academic Search

Mobile robot often relies on a battery system as its power supply and such kind of mobile robot is called cableless mobile robot. In the past years, while there are many researches on automation and control techniques, mechanical and sensor designs of mobile robot, very little systematic and comprehensive work has been done in the design of rechargeable battery power

Chenghui Cai; Dong Du; Zhiyu Liu

2003-01-01

328

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...

329

Synthesis and electrochemical studies of manganese oxides with spinel structure in aqueous electrolyte (9 M KOH)  

Microsoft Academic Search

Oxides with spinel structure have received widespread attention as being suitable electrode materials for rechargeable Li-ion batteries. So far they have mostly been synthesized at relatively high temperatures of between 700 and 800 °C. Here, we describe a new synthesis route to LiMn2O4 and manganese dioxides with spinel structure based on the freeze-drying of aqueous solutions and allowing the preparation

H. Schlörb; M. Bungs; W. Plieth

1997-01-01

330

Climate change effects on vegetation characteristics and groundwater recharge  

NASA Astrophysics Data System (ADS)

Climate change is among the most pressing issues of our time. Increase in temperature, a decrease in summer precipitation and increase in reference evapotranspiration might affect the water balance, freshwater availability and the spatial distribution and type of vegetation. Precipitation and evapotranspiration (ET) largely determine groundwater recharge. Therefore, climate change likely affects both the spatial and temporal freshwater availability for nature conservation, agriculture and drinking water supply. Moreover, in the coastal (dune) areas, the groundwater recharge is crucial to the maintenance of the freshwater bell and the dynamics of the fresh - salt interface. Current knowledge, however, is insufficient to estimate reliably the effects of climate change on future freshwater availability. Future groundwater recharge, the driving force of the groundwater system, can only be assessed if we understand how vegetation responds to changing climatic conditions, and how vegetation feedbacks on groundwater recharge through altered actual ET. Although the reference ET (i.e. the ET of a reference vegetation, defined as a short grassland completely covering the soil and optimally provided by water) is predicted to increase, the future actual ET (i.e. the ET of the actual ‘real' vegetation under the ‘real' moisture conditions) is highly unknown. It is the dynamics in the actual ET, however, through which the vegetation feeds back on the groundwater recharge. In an earlier study we showed that increased atmospheric CO2 raises the water use efficiency of plants, thus reducing ET. Here we demonstrate another important vegetation feedback in dune systems: the fraction of bare soil and non-rooting species (lichens and mosses) in the dune vegetation will increase when, according to the expectations, summers become drier. From our calculations it appeared that on south slopes of dunes, which receive more solar radiation and are warmer than north facing surfaces, the fraction of vascular plants may drop from 70 to 20 percent in the future (2050) climate due to increased moisture deficits. ET of bare soil and non-rooting species is much lower than that of vascular plants and thus the vegetation composition feeds back on the soil moisture conditions. Knowledge on such feedback mechanisms is indispensable in the analysis of climate change effects on the future groundwater recharge. Important questions are how, in the course of time, climate change will affect both groundwater table depth and dynamics, and how water management could adapt to these changes. We pursue a dynamic modeling approach that takes account of the interacting processes in the soil-plant-atmosphere system, including feedback mechanisms of the vegetation. This allows us to analyze climate change effects on groundwater recharge and thus future freshwater availability.

(Flip) Witte, J. P. M.; (Ruud) Bartholomeus, R. P.; (Gijsbert) Cirkel, D. G.

2010-05-01

331

Climate change effects on vegetation characteristics and groundwater recharge  

NASA Astrophysics Data System (ADS)

Climate change is among the most pressing issues of our time. Increase in temperature, a decrease in summer precipitation and increase in reference evapotranspiration might affect the water balance, freshwater availability and the spatial distribution and type of vegetation. Precipitation and evapotranspiration (ET) largely determine groundwater recharge. Therefore, climate change likely affects both the spatial and temporal freshwater availability for nature conservation, agriculture and drinking water supply. Moreover, in the coastal (dune) areas, the groundwater recharge is crucial to the maintenance of the freshwater bell and the dynamics of the fresh - salt interface. Current knowledge, however, is insufficient to estimate reliably the effects of climate change on future freshwater availability. Future groundwater recharge, the driving force of the groundwater system, can only be assessed if we understand how vegetation responds to changing climatic conditions, and how vegetation feedbacks on groundwater recharge through altered actual ET. Although the reference ET (i.e. the ET of a reference vegetation, defined as a short grassland completely covering the soil and optimally provided by water) is predicted to increase, the future actual ET (i.e. the ET of the actual ‘real’ vegetation under the ‘real’ moisture conditions) is highly unknown. It is the dynamics in the actual ET, however, through which the vegetation feeds back on the groundwater recharge. In an earlier study we showed that increased atmospheric CO2 raises the water use efficiency of plants, thus reducing ET. Here we demonstrate another important vegetation feedback in dune systems: the fraction of bare soil and non-rooting species (lichens and mosses) in the dune vegetation will increase when, according to the expectations, summers become drier. From our calculations it appeared that on south slopes of dunes, which receive more solar radiation and are warmer than north facing surfaces, the fraction of vascular plants may drop from 70 to 20 percent in the future (2050) climate due to increased moisture deficits. ET of bare soil and non-rooting species is much lower than that of vascular plants and thus the vegetation composition feeds back on the soil moisture conditions. Knowledge on such feedback mechanisms is indispensable in the analysis of climate change effects on the future groundwater recharge. Important questions are how, in the course of time, climate change will affect both groundwater table depth and dynamics, and how water management could adapt to these changes. We pursue a dynamic modeling approach that takes account of the interacting processes in the soil-plant-atmosphere system, including feedback mechanisms of the vegetation. This allows us to analyze climate change effects on groundwater recharge and thus future freshwater availability.

Bartholomeus, R.; Voortman, B.; Witte, J.

2010-12-01

332

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

333

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

334

1/14/14 Technologyuses micro-windmills to recharge cell phones www.rdmag.com/news/2014/01/technology-uses-micro-windmills-recharge-cell-phones 1/10  

E-print Network

/01/technology-uses-micro-windmills-recharge-cell-phones 1/10 ADVERTISEMENT LOG IN REGISTERFIND MY COMPANY News ADVERTISEMENT Technology uses micro-windmills to recharge cell phones Mon, 01/13/2014 - 9:06am Get today's R micro-windmills to recharge cell phones www.rdmag.com/news/2014/01/technology-uses-micro-windmills-recharge-cell-phones

Chiao, Jung-Chih

335

1/14/14 Technologyuses micro-windmills to recharge cell phones www.rdmag.com/print/news/2014/01/technology-uses-micro-windmills-recharge-cell-phones 1/3  

E-print Network

1/14/14 Technologyuses micro-windmills to recharge cell phones www.rdmag.com/print/news/2014/01/technology-uses-micro-windmills-recharge-cell-phones 1/3 One of Smitha Rao's micro- windmills is placed here uses micro-windmills to recharge cell phones Technology uses micro-windmills to recharge cell phones

Chiao, Jung-Chih

336

3/4/2014 Mini Windmills Can Recharge Cell Phones http://www.cemag.us/news/2014/01/mini-windmills-can-recharge-cell-phones#.UxY6ePldWa8 1/9  

E-print Network

3/4/2014 Mini Windmills Can Recharge Cell Phones http://www.cemag.us/news/2014/01/mini-windmills-can-recharge-cell-phones'S GUIDE LOG IN REGISTERFIND MY COMPANY News Mini Windmills Can Recharge Cell Phones ADVERTISEMENT Mon, 01 energy and may become an innovative solution to cell phone batteries constantly in need of recharging

Chiao, Jung-Chih

337

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

338

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

339

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, Kibreab; Woodbury, Allan

2013-04-01

340

On the modified inverse spinel-LiCo(PO 4 ) x (VO 4 ) 1? x as cathode for rechargeable lithium batteries  

Microsoft Academic Search

The structural and electrochemical behavior of a modified and unmodified inverse spinel phases with general formula, LiCo(PO4)\\u000a x\\u000a (VO4)1???x\\u000a [with x?=?0.0 and 0.1] for the possible application as cathodes in rechargeable lithium batteries have been investigated. The modified\\u000a and unmodified phases, represented as LiCoP0.1V0.9O4 and LiCoVO4 have been synthesized by an aqueous route at 700 °C. Both the phases have been

Kalyani Palanichamy

2011-01-01

341

Synthesis and electrochemical characterizations of La doped nano-size LiCo0.2Ni0.8O2 cathode materials for rechargeable lithium batteries  

Microsoft Academic Search

The LiLaxCo0.20-xNi0.80O2, where x = 0.00, 0.01, 0.03, 0.05 and 0.10 cathode materials for rechargeable lithium ion batteries were synthesized by simple sol-gel technique using aqueous solutions of metal nitrates and polyvinyl alcohol. The gel precursors were dried in vacuum oven for 12 h at 120 °C. After drying, the gel precursors were ground and heated at 800 °C. The

D. Arumugam; G. Paruthimal Kalaignan; K. Vediappan; C. W. Lee

2010-01-01

342

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

343

Ag nanoparticles-anchored reduced graphene oxide catalyst for oxygen electrode reaction in aqueous electrolytes and also a non-aqueous electrolyte for Li-O2 cells.  

PubMed

Silver nanoparticles-anchored reduced graphene oxide (Ag-RGO) is prepared by simultaneous reduction of graphene oxide and Ag(+) ions in an aqueous medium by ethylene glycol as the reducing agent. Ag particles of average size of 4.7 nm were uniformly distributed on the RGO sheets. Oxygen reduction reaction (ORR) is studied on Ag-RGO catalyst in both aqueous and non-aqueous electrolytes by using cyclic voltammetry and rotating disk electrode techniques. As the interest in non-aqueous electrolyte is to study the catalytic performance of Ag-RGO for rechargeable Li-O2 cells, these cells are assembled and characterized. Li-O2 cells with Ag-RGO as the oxygen electrode catalyst are subjected to charge-discharge cycling at several current densities. A discharge capacity of 11?950 mA h g(-1) (11.29 mA h cm(-2)) is obtained initially at low current density. Although there is a decrease in the capacity on repeated discharge-charge cycling initially, a stable capacity is observed for about 30 cycles. The results indicate that Ag-RGO is a suitable catalyst for rechargeable Li-O2 cells. PMID:25242373

Kumar, Surender; Selvaraj, C; Scanlon, L G; Munichandraiah, N

2014-10-01

344

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

345

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

346

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

347

Managed aquifer recharge: rediscovering nature as a leading edge technology.  

PubMed

Use of Managed Aquifer Recharge (MAR) has rapidly increased in Australia, USA, and Europe in recent years as an efficient means of recycling stormwater or treated sewage effluent for non-potable and indirect potable reuse in urban and rural areas. Yet aquifers have been relied on knowingly for water storage and unwittingly for water treatment for millennia. Hence if 'leading edge' is defined as 'the foremost part of a trend; a vanguard', it would be misleading to claim managed aquifer recharge as a leading edge technology. However it has taken a significant investment in scientific research in recent years to demonstrate the effectiveness of aquifers as sustainable treatment systems to enable managed aquifer recharge to be recognised along side engineered treatment systems in water recycling. It is a 'cross-over' technology that is applicable to water and wastewater treatment and makes use of passive low energy processes to spectacularly reduce the energy requirements for water supply. It is robust within limits, has low cost, is suitable from village to city scale supplies, and offers as yet almost untapped opportunities for producing safe drinking water supplies where they do not yet exist. It will have an increasingly valued role in securing water supplies to sustain cities affected by climate change and population growth. However it is not a universal panacea and relies on the presence of suitable aquifers and sources of water together with effective governance to ensure human health and environment protection and water resources planning and management. This paper describes managed aquifer recharge, illustrates its use in Australia, outlining economics, guidelines and policies, and presents some of the knowledge about aquifer treatment processes that are revealing the latent value of aquifers as urban water infrastructure and provide a driver to improving our understanding of urban hydrogeology. PMID:21076220

Dillon, P; Toze, S; Page, D; Vanderzalm, J; Bekele, E; Sidhu, J; Rinck-Pfeiffer, S

2010-01-01

348

A specialized ROV for cleaning groundwater recharge basins  

Microsoft Academic Search

In 1998, Harbor Branch Oceanographic Institution's (HBOI) Engineering Division completed the design and development of a precision dredge vehicle for Orange County Water District in Anaheim, California. The prototype vehicle-referred to as the basin cleaning vehicle (BCV)-is designed to remove the silt-clogging layer from the District's natural, sand-bottom, groundwater recharge lakes. The vehicle functions like a swimming pool cleaner to

Donna M. Kocak; Jerry W. Neely; John Holt; M. Miyake

1999-01-01

349

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

350

Natural groundwater recharge and water balance at the Hanford Site  

SciTech Connect

The purpose of this report is to present water-balance data collected in 1988 and 1989 from the 300 Area Buried Waste Test Facility and Grass Site, and the 200 East Area closed-bottom lysimeter. This report is an annual update of previous recharge status reports by Gee, Rockhold, and Downs, and Gee. Data from several other lysimeter sites are included for comparison. 43 refs., 28 figs., 7 tabs.

Rockhold, M.L.; Fayer, M.J.; Gee, G.W.; Kanyid, M.J.

1990-01-01

351

Scale effects of hydrostratigraphy and recharge zonation on base flow.  

PubMed

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 km(2). Merging six hydrostratigraphic units into one unit with average properties increased base flow residuals up to 83% in basins smaller than 50 km(2). Base flow residuals changed <5% in watersheds larger than 40 and 50 km(2) when recharge and hydrostratigraphy were simplified, respectively; thus, the critical basin size for the example area is approximately 40 to 50 km(2). 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. PMID:16681517

Juckem, Paul F; Hunt, Randall J; Anderson, Mary P

2006-01-01

352

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

353

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

354

Impacts of Decreasing Recharge Rates on Sustainable Groundwater Management  

Microsoft Academic Search

\\u000a Groundwater is a vital resource for living and food security for at least two billion people worldwide. Ever increasing demand\\u000a on groundwater has led to overexploitation of the aquifers and degradation of groundwater quality. Climate change will exacerbate\\u000a these problems by producing reduced recharge rates in some areas, more reliance on groundwater resources due to decrease in\\u000a reliability of surface

Hasan Yazicigil; Koray K. Yilmaz; Burcu Unsal Erdemli; Ozlem Yagbasan

355

Molten Air -- A new, highest energy class of rechargeable batteries  

E-print Network

This study introduces the principles of a new class of batteries, rechargeable molten air batteries, and several battery chemistry examples are demonstrated. The new battery class uses a molten electrolyte, are quasi reversible, and have amongst the highest intrinsic battery electric energy storage capacities. Three examples of the new batteries are demonstrated. These are the iron, carbon and VB2 molten air batteries with respective intrinsic volumetric energy capacities of 10,000, 19,000 and 27,000 Wh per liter.

Licht, Stuart

2013-01-01

356

The MOLICEL(R) rechargeable lithium system: Multicell battery aspects  

NASA Technical Reports Server (NTRS)

MOLICEL rechargeable lithium cells were cycled in batteries using series, parallel, and series/parallel connections. The individual cell voltages and branch currents were measured to understand the cell interactions. The observations were interpreted in terms of the inherent characteristics of the Li/MoS2 system and in terms of a singular cell failure mode. The results confirm that correctly configured multicell batteries using MOLICELs have performance characteristics comparable to those of single cells.

Fouchard, D.; Taylor, J. B.

1987-01-01

357

Ground-Water Recharge from Small Intermittent Streams in the Western Mojave Desert, California  

USGS Publications Warehouse

Population growth has impacted ground-water resources in the western Mojave Desert, where declining water levels suggest that recharge rates have not kept pace with withdrawals. Recharge from the Mojave River, the largest hydrographic feature in the study area, is relatively well characterized. In contrast, recharge from numerous smaller streams that convey runoff from the bounding mountains is poorly characterized. The current study examined four representative streams to assess recharge from these intermittent sources. Hydraulic, thermal, geomorphic, chemical, and isotopic data were used to study recharge processes, from streamflow generation and infiltration to percolation through the unsaturated zone. Ground-water movement away from recharge areas was also assessed. Infiltration in amounts sufficient to have a measurable effect on subsurface temperature profiles did not occur in every year in instrumented study reaches. In addition to streamflow availability, results showed the importance of sediment texture in controlling infiltration and eventual recharge. Infiltration amounts of about 0.7 meters per year were an approximate threshold for the occurrence of ground-water recharge. Estimated travel times through the thick unsaturated zones underlying channels reached several hundred years. Recharging fluxes were influenced by stratigraphic complexity and depositional dynamics. Because of channel meandering, not all water that penetrates beneath the root zone can be assumed to become recharge on active alluvial fans. Away from study washes, elevated chloride concentrations and highly negative water potentials beneath the root zone indicated negligible recharge from direct infiltration of precipitation under current climatic conditions. In upstream portions of washes, generally low subsurface chloride concentrations and near-zero water potentials indicated downward movement of water toward the water table, driven primarily by gravity. Recharging conditions did not extend to the distal ends of all washes. Where urbanization had concentrated spatially distributed runoff into a small number of fixed channels, enhanced infiltration induced recharging conditions, mobilizing accumulated chloride. Estimated amounts of ground-water recharge from the studied reaches were small. Extrapolating on the basis of drainage areas, the estimated aggregate recharge from small intermittent streams is minor compared to recharge from the Mojave River. Recharge is largely controlled by streamflow availability, which primarily reflects precipitation patterns. Precipitation in the Mojave Desert is strongly controlled by topography. Cool moist air masses from the Pacific Ocean are mostly blocked from entering the desert by the high mountains bordering its southern edge. Storms do, however, readily enter the region through Cajon Pass. These storms generate flow in the Mojave River that often reaches Afton Canyon, more than 150 kilometers downstream. The isotopic composition of ground water reflects the localization of recharge beneath the Mojave River. Similar processes occur near San Gorgonio Pass, 75 kilometers southeast from Cajon Pass along the bounding San Andreas Fault.

Izbicki, John A.; Johnson, Russell U.; Kulongoski, Justin; Predmore, Steven

2007-01-01

358

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

359

Movement of water infiltrated from a recharge basin to wells.  

PubMed

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 µg/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. PMID:21740423

O'Leary, David R; Izbicki, John A; Moran, Jean E; Meeth, Tanya; Nakagawa, Brandon; Metzger, Loren; Bonds, Chris; Singleton, Michael J

2012-01-01

360

Issue and challenges facing rechargeable thin film lithium batteries  

SciTech Connect

New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. Technological improvements in rechargeable solid-state batteries are being driven by an ever-increasing demand for portable electronic devices. Lithium batteries are the systems of choice, offering high energy density, flexible, lightweight design and longer lifespan than comparable battery technologies. We present a brief historical review of the development of lithium-based thin film rechargeable batteries highlight ongoing research strategies and discuss the challenges that remain regarding the discovery of nanomaterials as electrolytes and electrodes for lithium batteries also this article describes the possible evolution of lithium technology and evaluates the expected improvements, arising from new materials to cell technology. New active materials under investigation and electrode process improvements may allow an ultimate final energy density of more than 500 Wh/L and 200 Wh/kg, in the next 5-6 years, while maintaining sufficient power densities. A new rechargeable battery technology cannot be foreseen today that surpasses this. This report will provide key performance results for thin film batteries and highlight recent advances in their development.

Patil, Arun; Patil, Vaishali; Shin, Dong Wook; Choi, Ji-Won; Paik, Dong-Soo [Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Yoon, Seok-Jin [Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)], E-mail: sjyoon@kist.re.kr

2008-08-04

361

Evaluating Climate, Vegetation, and Soil Controls on Groundwater Recharge Using Unsaturated Flow Modeling  

NASA Astrophysics Data System (ADS)

Understanding the relative importance of climate, vegetation, and soils in controlling groundwater recharge is critical for estimating recharge rates and for assessing the importance of these factors in controlling aquifer vulnerability to contamination. Understanding the role of climate and vegetation in controlling recharge will also be valuable in determining impacts of climate change and land use change on recharge. Numerical modeling is a valuable tool for assessing controls on recharge and for developing a predictive understanding of recharge processes. Unsaturated flow modeling was used to simulate recharge for a range of climate (arid - humid), vegetation (shrub, grass, forest, crops), and soils (fine - coarse grained, monolithic - layered) using data from Texas. Data from 10 meteorological stations in the state provided long-term (30 yr) climate forcing ranging from arid to humid conditions. Spatial distribution of dominant vegetation associations provided by the USGS was used to assign vegetation parameters using GIS and including fractional vegetation coverage, leaf area index, root depth, and root length density. Varying levels of soils data were used in the simulations ranging from simple monolithic sand profiles to complex layered soil profiles from the SSURGO database and pedotransfer functions were used to translate soils data to hydraulic parameters for the simulations. The effect of climate was evaluated using monolithic sand profiles without vegetation. Recharge rates varied from 54 mm/yr in arid west Texas to 720 mm/yr in humid east Texas, correlating positively with precipitation (R=0.99, slope = 0.69). These recharge rates represent 24 to 61 percent of long-term average precipitation. High potential recharge rates in monolithic sand profiles indicate that climate is not the limiting factor controlling recharge and that vegetation and soil texture are important in reducing recharge. Addition of vegetation to the monolithic sand profiles reduced recharge rates for most cases by factors ranging from 2 to 11. Soil profile layering reduced recharge rates in most cases relative to recharge rates based on monolithic sand profiles by factors ranging from 2 to 10. Recharge estimates based on nonvegetated, layered soil profiles were quite variable locally depending on soil texture and sequence of layers. However, aerially weighted average recharge rates for the counties analyzed in this study were much less variable and were positively correlated with precipitation (R=0.79; slope = 0.19). The final simulations included vegetation and layered soil profiles and resulted in recharge rates ranging from 0 to 328 mm/yr which represent reductions from potential recharge by factors ranging from 6 to 380. Unsaturated flow modeling proved to be a useful tool in evaluating the effects of climate, soil, and vegetation on recharge because these factors could be isolated in different simulations. Modeling results indicate that long-term average precipitation can be used as a predictor of recharge, but is not the limiting factor; vegetation and soil texture are important in reducing recharge. The results of this study have important implications for estimating recharge and indicate that the role of vegetation and soil texture in reducing recharge could significantly impact aquifer vulnerability to contamination.

Keese, K. E.; Scanlon, B. R.; Reedy, R. C.

2003-12-01

362

Ponds and Rice Fields: The Hydrology and Chemistry of Aquifer Recharge in Bangladesh  

NASA Astrophysics Data System (ADS)

The shallow aquifer in Bangladesh, which provides drinking water for millions and irrigation water for innumerable rice fields, is severely contaminated with naturally occurring arsenic. Water balance calculations show that surface ponds and irrigated rice fields are the primary sources of recharge to this contaminated aquifer. Recharge from an individual rice field is both temporally and spatially heterogeneous, whereas flow from a pond is more constant and uniform through the pond sediments. Rice field recharge is focused through bunds (the berms surrounding the field), and depends on irrigation intervals. Field flow patterns are controlled by cracks and the development of an unsaturated zone. The water chemistry of these two recharge sources is distinctly different. Compared to the rice fields, ponds contribute recharge with a higher organic carbon load and increased concentrations of solutes associated with anoxic microbial respiration. The differences in the recharge behavior and solute loads of these two sources may explain the spatial patterns of groundwater chemistry that control arsenic concentrations.

Neumann, R. B.; Harvey, C. F.

2007-12-01

363

Novel aqueous dual-channel aluminum-hydrogen peroxide battery  

NASA Astrophysics Data System (ADS)

A dual-channel aluminum hydrogen peroxide battery is introduced with an open-circuit voltage of 1.9 volts, polarization losses of 0.9 mV cm(exp 2) mA(exp -1), and power densities of 1 W/cm(exp 2). Catholyte and anolyte cell compartments are separated by an Ir/Pd modified porous nickel cathode. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode. The battery is expressed by aluminum oxidation and aqueous solution phase hydrogen peroxide reduction for an overall battery discharge consisting of 2Al + 3H2O2 + 2OH(-) yields 2AlO2(-) + 4H2O E = 2.3 V. The search for electrical propulsion sources which fit the requirements for electrically powered vehicles has blurred the standard characteristics associated with electrochemical storage systems. Presently, electrochemical systems comprised of mechanically rechargeable primary batteries, secondary batteries, and fuel cells are candidates for electrochemical propulsion sources. While important advances in energy and power density continue for nonaqueous and molten electrolytes, aqueous electrolyte batteries often have an advantage in simplicity, conductivity, cost effectiveness, and environmental impact. Systems coupling aluminum anodes and aqueous electrolytes have been investigated. These systems include: aluminum/silver oxide, aluminum/manganese dioxide, aluminum air, aluminum/hydrogen peroxide aqueous batteries, and the recently introduced aluminum/ferricyanide and aluminum sulfur aqueous batteries. Conventional aqueous systems such as the nickel cadmium and lead-acid batteries are characterized by their relatively low energy densities and adverse environmental impact. Other systems have substantially higher theoretical energy capacities. While aluminum-silver oxide has demonstrated the highest steady-state power density, its high cost is an impediment for widespread utilization for electric propulsion.

Marsh, Catherine; Licht, Stuart

1994-06-01

364

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

365

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 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

Andrew H. Manning

2011-01-01

366

Synthesis of layered LiMnO2 as an electrode for rechargeable lithium batteries  

Microsoft Academic Search

RECHARGEABLE lithium batteries can store more than twice as much energy per unit weight and volume as other rechargeable batteries1,2. They contain lithium ions in an electrolyte, which shuttle back and forth between, and are intercalated by, the electrode materials. The first commercially successful rechargeable lithium battery3, introduced by the Sony Corporation in 1990, consists of a carbon-based negative electrode,

A. Robert Armstrong; Peter G. Bruce

1996-01-01

367

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

368

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

369

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

370

Groundwater-recharge estimation in the Ordos Plateau, China: comparison of methods  

Microsoft Academic Search

Groundwater recharge is a key factor in water-balance studies, especially in (semi-)arid areas. In this study, multiple methods\\u000a were used to estimate groundwater recharge in the Ordos Plateau (China), including reference to water-table fluctuation, Darcy’s\\u000a law and the water budget. The mean annual recharge rates found were: water-table-fluctuation method (46–109 mm\\/yr); saturated-zone\\u000a Darcian method (17–54 mm\\/yr); and water-budget method (21–109 mm\\/yr). Generally, groundwater-recharge

Lihe Yin; Guangcheng Hu; Jinting Huang; Dongguang Wen; Jiaqiu Dong; Xiaoyong Wang; Hongbo Li

371

Hydrologic and hydraulic assessment of artificial recharge in the Sparta Aquifer of Union County, Arkansas .  

E-print Network

??Groundwater pumping from the Sparta aquifer in Union County, Arkansas, has long exceeded natural recharge, threatening the regional water supply. An alternative water-supply project, completed… (more)

Sowby, Robert B

2013-01-01

372

Modeling spatiotemporal impacts of hydroclimatic extremes on groundwater recharge at a Mediterranean karst aquifer  

NASA Astrophysics Data System (ADS)

aquifers provide large parts of the water supply for Mediterranean countries, though climate change is expected to have a significant negative impact on water availability. Recharge is therefore a key variable that has to be known for sustainable groundwater use. In this study, we present a new approach that combines two independent methods for karst recharge estimation. The first method derives spatially distributed information of mean annual recharge patterns through GIS analysis. The second is a process-based karst model that provides spatially lumped but temporally distributed information about recharge. By combining both methods, we add a spatial reference to the lumped simulations of the process-based model. In this way, we are able to provide spatiotemporal information of recharge and subsurface flow dynamics also during varying hydroclimatic conditions. We find that there is a nonlinear relationship between precipitation and recharge rates resulting in strong decreases of recharge following even moderate decreases of precipitation. This is primarily due to almost constant actual evapotranspiration amounts despite varying hydroclimatic conditions. During the driest year in the record, almost the entire precipitation was consumed as actual evapotranspiration and only little diffuse recharge took place at the high altitudes of our study site. During wettest year, recharge constituted a much larger fraction of precipitation and occurred at the entire study site. Our new method and our findings are significant for decision makers in similar regions that want to prepare for possible changes of hydroclimatic conditions in the future.

Hartmann, Andreas; Mudarra, Matías; Andreo, Bartolomé; Marín, Ana; Wagener, Thorsten; Lange, Jens

2014-08-01

373

Synthesis and characterization of nanostructured cathode materials for rechargeable lithium/lithium ion batteries  

NASA Astrophysics Data System (ADS)

The rapidly increasing markets of portable electronic devices and electric/hybrid vehicles have raised worldwide R&D efforts in developing high-energy rechargeable lithium and lithium ion batteries. High performance intercalation cathodes are key to the success of these batteries. The nanotechnology has endowed the electrode materials with a variety of improved features as well as unique characteristics. Synthesis approaches were designed in this thesis work to utilize these advantages and investigate the exceptional phenomena raised by the nanostructured materials. A novel sol-gel method was designed for the synthesis of carbon-coated phase-pure lithium iron phosphate with submicron particle sizes and uniform size distribution. The surface carbon coating was formed in-situ through pyrolysis of the precursor gel, which improved the apparent electronic conductivity of the as prepared material to 10-2 S/cm compared with 10-9-10-10 S/cm of the pristine LiFePO 4. The favorable physical characteristics of the synthesized LiFePO 4 particles and the improved electronic conductivity through the carbon coating led to electrochemical properties comparable to the best performances reported so far. Amorphous manganese oxide cryogels with nanoarchitecture were obtained by freeze-drying Mn (IV) oxide hydrogels. The combination of the advantages of the amorphous structure and the nano-architecture of the materials gave high capacities and excellent rate capabilities. This work led to the finding of a nanocrystalline Li2MnO3-like compound with a surprising electrochemical activity, which is in sharp contrast to the microcrystalline rock-salt Li2MnO3 that has been known to be electrochemically inactive. The study highlights the possibility of qualitative difference in intercalation behavior of nanostructured intercalation compounds compared with their microcrystalline counterparts. Bismuth and copper modified amorphous manganese oxides were synthesized by aqueous coprecipitation methods and investigated as intercalation hosts for rechargeable lithium batteries. The results suggest the promise of achieving high performance intercalation electrodes by enhancing amorphous manganese oxides through cation modification.

Yang, Jingsi

374

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

375

New aqueous magnetic fluids  

Microsoft Academic Search

New aqueous magnetic fluids constituted of nickel-zinc ferrite particles are synthesized using a soft chemical approach. Ferrofluids and solid particles are characterized using several techniques : chemical analysis, X-ray diffraction, transmission electron microscopy, infrared spectroscopy, and magnetization measurements.The stability of the aqueous magnetic fluids is studied as a function of pH and their magnetization is measured as a function of

D. Zins; V. Cabuil; R. Massart

1999-01-01

376

Artificial recharge through a thick, heterogeneous unsaturated zone.  

PubMed

Thick, heterogeneous unsaturated zones away from large streams in desert areas have not previously been considered suitable for artificial recharge from ponds. To test the potential for recharge in these settings, 1.3 x 10(6) m(3) of water was infiltrated through a 0.36-ha pond along Oro Grande Wash near Victorville, California, between October 2002 and January 2006. The pond overlies a regional pumping depression 117 m below land surface and is located where thickness and permeability of unsaturated deposits allowed infiltration and saturated alluvial deposits were sufficiently permeable to allow recovery of water. Because large changes in water levels caused by nearby pumping would obscure arrival of water at the water table, downward movement of water was measured using sensors in the unsaturated zone. The downward rate of water movement was initially as high as 6 m/d and decreased with depth to 0.07 m/d; the initial time to reach the water table was 3 years. After the unsaturated zone was wetted, water reached the water table in 1 year. Soluble salts and nitrate moved readily with the infiltrated water, whereas arsenic and chromium were less mobile. Numerical simulations done using the computer program TOUGH2 duplicated the downward rate of water movement, accumulation of water on perched zones, and its arrival at the water table. Assuming 10 x 10(6) m(3) of recharge annually for 20 years, a regional ground water flow model predicted water level rises of 30 m beneath the ponds, and rises exceeding 3 m in most wells serving the nearby urban area. PMID:18194322

Izbicki, John A; Flint, Alan L; Stamos, Christina L

2008-01-01

377

Artificial recharge through a thick, heterogeneous unsaturated zone  

USGS Publications Warehouse

Thick, heterogeneous unsaturated zones away from large streams in desert areas have not previously been considered suitable for artificial recharge from ponds. To test the potential for recharge in these settings, 1.3 ?? 10 6 m3 of water was infiltrated through a 0.36-ha pond along Oro Grande Wash near Victorville, California, between October 2002 and January 2006. The pond overlies a regional pumping depression 117 m below land surface and is located where thickness and permeability of unsaturated deposits allowed infiltration and saturated alluvial deposits were sufficiently permeable to allow recovery of water. Because large changes in water levels caused by nearby pumping would obscure arrival of water at the water table, downward movement of water was measured using sensors in the unsaturated zone. The downward rate of water movement was initially as high as 6 m/d and decreased with depth to 0.07 m/d; the initial time to reach the water table was 3 years. After the unsaturated zone was wetted, water reached the water table in 1 year. Soluble salts and nitrate moved readily with the infiltrated water, whereas arsenic and chromium were less mobile. Numerical simulations done using the computer program TOUGH2 duplicated the downward rate of water movement, accumulation of water on perched zones, and its arrival at the water table. Assuming 10 ?? 10 6 m3 of recharge annually for 20 years, a regional ground water flow model predicted water level rises of 30 m beneath the ponds, and rises exceeding 3 m in most wells serving the nearby urban area.

Izbicki, J. A.; Flint, A. L.; Stamos, C. L.

2008-01-01

378

Indian Ocean Dipole interpreted in terms of Recharge Oscillator Theory  

NASA Astrophysics Data System (ADS)

The Indian Ocean Dipole (IOD) is a year-to-year fluctuation with significant impacts on regional patterns of weather variability and ocean biogeochemical cycles. The IOD originates through ocean-atmosphere interactions and large scale ocean dynamics similar to those that characterize El Niño and the Southern Oscillation (ENSO) in the Pacific. In this presentation we use observations and a linear analytical wind forced model to address the question of whether variations in upper ocean heat content are a necessary precondition for the development of IOD events as they are for ENSO in the Pacific. High quality satellite altimetry data, which are a proxy for thermocline depth and upper ocean heat content, are used both to describe IOD variability over the period 1993-2011 and to validate the dynamical model. Results are interpreted in terms of Recharge Oscillator theory, which was originally developed to explain ENSO in the Pacific but can be applied to the IOD since similar processes are at work in both oceans on interannual time scales. As in the Pacific, the dominant modes of variability in the Indian Ocean include an east-west thermocline tilting mode, which is approximately in phase with zonal wind stress and SST gradients along the equator, and a zonally coherent recharge mode that leads the tilting mode by about four months. However, the maximum correlation between these two modes, which occurs when the recharge mode in boreal summer (JJA) leads the titling mode in boreal fall (SON), is very weak and not statistically significant. These spatial patterns and lead-lag correlations are found both in observations and the analytical model. These results suggest that, unlike for ENSO, heat content is of marginal value as a predictor in the equatorial Indian Ocean for the development of IOD events. We conclude that other factors, such as ENSO forcing from the Pacific, are more important in initiating IOD events than preconditioning of upper ocean heat content along the equator.

McPhaden, M. J.; Nagura, M.

2012-12-01

379

A 65 Ah rechargeable lithium molybdenum disulfide battery  

NASA Astrophysics Data System (ADS)

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.

1986-09-01

380

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. PMID:24365948

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

381

Tracers in recharge — Effects of partitioning in soils  

NASA Astrophysics Data System (ADS)

Partitioning among mobile and stationary water phases in a soil measurably reduces movement of a tracer relative to the mobile water phase. The quantity of water infiltrating the soil, however, still follows from the product of the distance travelled by the tracer and average moisture content of the soil over that distance. Partitioning between surface and water phases in a soil by proton and protium exchange has only a small effect on the retention of isotopically labelled water. Partitioning between surface, water and gas phases in a soil, however, strongly decreases diffusive movement of isotopically labelled water in the gas phase. In sandy soils with moisture contents less than 5%, the effective diffusion coefficient in the gas phase can be reduced by a factor between 50 and 5000. As a soil dries out, diffusive movement of 18O labelled water will become larger than of HDO and HTO. Negative charges on soil surfaces repel chloride and bromide. The effect of charge exclusion on movement of Cl - and Br - relative to HDO was measured in small columns for a number of soils from the southwest of Western Australia. Data from these experiments show that in the unsaturated zone of sandy soils, charge exclusion can reduce the pore volume available to Cl - and Br - in the water phase at field capacity by > 20%. Recharge to ground water, if calculated from the position of Cl - or Br - tracers and average moisture in the soil profile, must then be reduced by the same percentage. The effect of charge exclusion in soils on the calculation of recharge from profile data, was evaluated for a practical situation. Significant amounts of bromide from car exhaust gases accumulate in soils in urban areas and can be used to trace water movement. A site was chosen in metropolitan Perth on a sparsely vegetated calcareous sand near the junction of two busy roads. A seasonal effect on bromide accumulation in the soil profile at this site was clearly visible from data on the soil solution. The distribution of bromide in the soil profile appears to correspond to 93% of rainfall recharging ground water. Correcting the data for charge exclusion, results in a calculated recharge of ? 70% of annual rainfall.

Gerritse, Robert G.; Adeney, John A.

1992-02-01

382

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

383

Lithiated manganese oxide cathodes for rechargeable lithium batteries  

Microsoft Academic Search

Lithiated manganese oxides LixMnyO2 prepared at the low temperature of 400-450°C exhibited significantly different electrochemical properties than the spinel phase, LiMn2O4, formed at 650-850°C. The former was nonstoichiometric and yielded a capacity of ~0.7 LiMn2 unit at ~2.8 V in polymer electrolyte-based Li cells. Its excellent rechargeability was demonstrated by more than 100 charge\\/discharge cycles. Spinel Li2Mn4 was formed by

K. M. Abraham; D. M. Pasquariello; T. H. Hguyen; Z. Jiang; D. Peramunage

1996-01-01

384

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.

385

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

386

Numerical assessment of ASR recharge using small-diameter wells and surface basins  

NASA Astrophysics Data System (ADS)

Aquifer storage and recovery (ASR) methods are increasingly used to overcome the temporal imbalance between water demand and availability. Common ASR recharge methods utilize large-diameter injection wells or surface infiltration basins and trenches, and can be costly to implement. A new low-cost ASR recharge method is currently being developed. This approach is based on recharge via gravity in small-diameter wells installed with direct-push (DP) technology. Numerical modeling is used here to assess the potential of this new approach under conditions commonly faced in field settings. The primary objective is to investigate if a battery of small-diameter DP wells can serve as a viable alternative to a surface basin under typical field conditions, while the secondary objective is to assess which subsurface parameters have the greatest control on DP well performance. Simulation results indicate that gravity recharge via small-diameter wells appears to have a distinct advantage over recharge via surface infiltration basins. For example, two 0.05-m shallow vadose-zone wells with 9-m screens can recharge water at a greater rate than a 60 m2 basin. Also, results reveal that, contrary to an infiltration basin, the recharge rate in a DP well has a much stronger dependence on the horizontal component of hydraulic conductivity than on the vertical component. Moreover, near-surface layers of low hydraulic conductivity, which can significantly reduce the recharge capacity of a surface basin, have a relatively small impact on the recharge capacity of a well as long as a significant portion of the well screen is installed below those layers. Given that installation and operation costs can be low in comparison to common ASR recharge methods, this new approach appears to have great potential for recharging good quality water in shallow unconsolidated aquifers. A field investigation has recently been initiated to follow up the findings of this simulation assessment.

Händel, Falk; Liu, Gaisheng; Dietrich, Peter; Liedl, Rudolf; Butler, James J.

2014-09-01

387

Ground-water recharge in Escambia and Santa Rosa Counties, Florida  

USGS Publications Warehouse

Ground water is a major component of Florida's water resources, accounting for 90 percent of all public-supply and self-supplied domestic water withdrawals, and 58 percent of self-supplied commercial-industrial and agricultural withdrawals of freshwater (Marella, 1992). Ground-water is also an important source of water for streams, lakes, and wetlands in Florida. Because of their importance, a good understanding of these resources is essential for their sound development, use, and protection. One area in which our understanding is lacking is in characterizing the rate at which ground water in aquifers is recharged, and how recharge rates vary geographically. Ground-water recharge (recharge) is the replenishment of ground water by downward infiltration of water from rainfall, streams, and other sources (American Society of Civil Engineers, 1987, p. 222). The recharge rates in many areas of Florida are unknown, of insufficient accuracy, or mapped at scales that are too coarse to be useful. Improved maps of recharge rates will result in improved capabilities for managing Florida's ground-water resources. In 1989, the U.S. Geological Survey, in cooperation with the Florida Department of Environmental Regulation, began a study to delineate high-rate recharge areas in several regions of Florida (Vecchioli and others, 1990). This study resulted in recharge maps that delineated areas of high (greater than 10 inches per year) and low (0 to 10 inches per year) recharge in three counties--Okaloosa, Pasco, and Volusia Counties--at a scale of 1:100,000. This report describes the results of a similar recharge mapping study for Escambia and Santa Rosa Counties (fig. 1), in which areas of high- and low-rates of recharge to the sand-and-gravel aquifer and Upper Floridan aquifer are delineated. The study was conducted in 1992 and 1993 by the U.S. Geological Survey in cooperation with the Florida Department of Environmental Protection.

Grubbs, J. W.

1995-01-01

388

Tritium tracer test to estimate aquifer recharge under irrigated conditions  

NASA Astrophysics Data System (ADS)

Environmental tracers, as tritium, have been generally used to estimate aquifer recharge under natural conditions. A tritium tracer test to estimate recharge under semi-arid and irrigated conditions is presented. The test was carried out in an experimental plot under drip irrigation, located in SE Spain, with annual row crops (rotation lettuce and melon), following common agricultural practices in open air. Tritiated water was applied as an irrigation pulse, soil cores were taken at different depths and a liquid scintillation analyzer was used to measure the concentration of tritium in soil samples. Transport of tritium was simulated with SOLVEG code, a one-dimensional numerical model for simulating transport of heat, water and tritiated water in liquid and gas phase, which has been modified and adapted for this experience, including ground cover, root growth and root water uptake. One crop has been used to calibrate the modeling approach and other three crops to validate it. Results of flow and transport modelling show a good agreement between observed and estimated tritium concentration profile. For the period October 2007-September 2008, total drainage obtained value was 441 mm.

Jimenez-Martinez, J.; Tamoh, K.; Candela, L.

2009-12-01

389

Feasibility of groundwater recharge dam projects in arid environments  

NASA Astrophysics Data System (ADS)

A new method for determining feasibility and prioritizing investments for agricultural and domestic recharge dams in arid regions is developed and presented. The method is based on identifying the factors affecting the decision making process and evaluating these factors, followed by determining the indices in a GIS-aided environment. Evaluated parameters include results from field surveys and site visits, land cover and soils data, precipitation data, runoff data and modeling, number of beneficiaries, domestic irrigation demand, reservoir objectives, demography, reservoirs yield and reliability, dam structures, construction costs, and operation and maintenance costs. Results of a case study on more than eighty proposed dams indicate that assessment of reliability, annualized cost/demand satisfied and yield is crucial prior to investment decision making in arid areas. Irrigation demand is the major influencing parameter on yield and reliability of recharge dams, even when only 3 months of the demand were included. Reliability of the proposed reservoirs as related to their standardized size and net inflow was found to increase with increasing yield. High priority dams were less than 4% of the total, and less priority dams amounted to 23%, with the remaining found to be not feasible. The results of this methodology and its application has proved effective in guiding stakeholders for defining most favorable sites for preliminary and detailed design studies and commissioning.

Jaafar, H. H.

2014-05-01

390

Rechargeable LI2O2 electrode for lithium batteries.  

PubMed

Rechargeable lithium batteries represent one of the most important developments in energy storage for 100 years, with the potential to address the key problem of global warming. However, their ability to store energy is limited by the quantity of lithium that may be removed from and reinserted into the positive intercalation electrode, Li(x)CoO(2), 0.5 < x < 1 (corresponding to 140 mA.h g(-1) of charge storage). Abandoning the intercalation electrode and allowing Li to react directly with O(2) from the air at a porous electrode increases the theoretical charge storage by a remarkable 5-10 times! Here we demonstrate two essential prerequisites for the successful operation of a rechargeable Li/O(2) battery; that the Li(2)O(2) formed on discharging such an O(2) electrode is decomposed to Li and O(2) on charging (shown here by in situ mass spectrometry), with or without a catalyst, and that charge/discharge cycling is sustainable for many cycles. PMID:16433559

Ogasawara, Takeshi; Débart, Aurélie; Holzapfel, Michael; Novák, Petr; Bruce, Peter G

2006-02-01

391

Natural water purification and water management by artificial groundwater recharge  

PubMed Central

Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth’s surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages. The contamination of infiltrated river water will be reduced by natural attenuation. Clay minerals, iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save. PMID:18357624

Balke, Klaus-Dieter; Zhu, Yan

2008-01-01

392

Clogging in Managed Aquifer Recharge: Hydrodynamics and Geochemistry  

NASA Astrophysics Data System (ADS)

Managed aquifer recharge (MAR) is the engineered process by which water is delivered into an aquifer for storage, transmission, or treatment. Perhaps the most significant technical challenge in MAR is clogging, a detrimental reduction of permeability in the aquifer porous media. This presentation describes research from the allied fields of water treatment, soil science, and petrology, each of which sheds light on the mechanisms by which hydrodynamics and geochemistry influence clogging in MAR. The primary focus is clogging by suspended solids, especially clay colloids, which are ubiquitous in natural porous media. When colloids deposit in aquifers, they reduce the effective porosity and alter the pore space geometry, both of which can inhibit the flow of groundwater. Management of clogging is complicated by the complexity inherent in this system, in which hydrodynamics, geochemistry, clay mineralogy, and colloidal effects each play a role. This presentation will briefly review colloid filtration, mobilization, and clogging models, then highlight the key physical and chemical variables that control clogging. It will be argued that clogging in managed aquifer recharge is analogous to clogging in soils or hydrocarbon reservoirs, rather than to clogging in granular media filters used for water treatment. Based on this analogy, the presentation will conclude with several recommendations to prevent or manage clogging in MAR.

Mays, D. C.

2013-12-01

393

Recycling rechargeable lithium ion batteries: Critical analysis of natural resource savings  

Microsoft Academic Search

Rechargeable Li-ion battery applications in consumer products are fastly growing, resulting in increasing resources demand: it is for example estimated that battery applications account for nearly 25% of the worldwide cobalt demand in 2007. It is obvious that recycling of batteries may help saving natural resources. However, it is not straightforward to quantify to what extent rechargeable battery recycling saves

Jo Dewulf; Geert Van der Vorst; Kim Denturck; Herman Van Langenhove; Wouter Ghyoot; Jan Tytgat; Kurt Vandeputte

2010-01-01

394

www.VadoseZoneJournal.org | 6622011, Vol. 10 Groundwater Recharge through  

E-print Network

groundwater recharge, including water quantity and quality. Soil core samples (0­11-m depth) from six recharge fluxes and to test matrix vs. preferential flow hypotheses. Water contents under irrigated Cropland vs. Natural Land, Israel Land use change from natural ecosystems to cropland influences

Scanlon, Bridget R.

395

Promoting the Market for Plug-in Hybrid and Battery Electric Vehicles: Role of Recharge Availability  

SciTech Connect

Much recent attention has been drawn to providing adequate recharge availability as a means to promote the battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) market. The possible role of improved recharge availability in developing the BEV-PHEV market and the priorities that different charging options should receive from the government require better understanding. This study reviews the charging issue and conceptualizes it into three interactions between the charge network and the travel network. With travel data from 3,755 drivers in the National Household Travel Survey, this paper estimates the distribution among U.S. consumers of (a) PHEV fuel-saving benefits by different recharge availability improvements, (b) range anxiety by different BEV ranges, and (c) willingness to pay for workplace and public charging in addition to home recharging. With the Oak Ridge National Laboratory MA3T model, the impact of three recharge improvements is quantified by the resulting increase in BEV-PHEV sales. Compared with workplace and public recharging improvements, home recharging improvement appears to have a greater impact on BEV-PHEV sales. The impact of improved recharging availability is shown to be amplified by a faster reduction in battery cost.

Lin, Zhenhong [ORNL; Greene, David L [ORNL

2012-01-01

396

A Wireless Power Interface for Rechargeable Battery Operated Neural Recording Implants  

E-print Network

A Wireless Power Interface for Rechargeable Battery Operated Neural Recording Implants Pengfei Li describes an integrated analog front-end for wireless powering and recharging of miniature Li-ion bat is accomplished using Schottky barrier contact diodes with lower forward voltage drop for improved efficiency

Slatton, Clint

397

Electrode materials for lithium rechargeable batteries: Synthesis, spectroscopic studies and electrochemical performance  

Microsoft Academic Search

The lithium rechargeable battery is the newest member of the rechargeable battery family and is best known for its high energy density, long battery life, low self-discharge rate and light weight. This battery may become one of the most important energy sources in consumer market, industrial and military applications. Intercalation compounds play a critical role in determining the overall performance

Xulong Zhang

1997-01-01

398

Paleosols as deep regolith: implications for ground-water recharge across a loessial climosequence  

Microsoft Academic Search

Thick loess deposits consisting of paleosol sequences comprise the deep regolith of the Palouse region in eastern Washington and northern Idaho. Ground water is the principal water supply for the Palouse Basin, yet recharge mechanisms and rates through this regolith are poorly understood. Forecasting the sustainability of the water supply has been hampered because models that predict ground-water recharge are

A. T. O'Geen; P. A. McDaniel; J. Boll; C. K. Keller

2005-01-01

399

The Guarani Aquifer System: estimation of recharge along the Uruguay-Brazil border  

NASA Astrophysics Data System (ADS)

The cities of Rivera and Santana do Livramento are located on the outcropping area of the sandstone Guarani Aquifer on the Brazil-Uruguay border, where the aquifer is being increasingly exploited. Therefore, recharge estimates are needed to address sustainability. First, a conceptual model of the area was developed. A multilayer, heterogeneous and anisotropic groundwater-flow model was built to validate the conceptual model and to estimate recharge. A field campaign was conducted to collect water samples and monitor water levels used for model calibration. Field data revealed that there exists vertical gradients between confining basalts and underlying sandstones, suggesting basalts could indirectly recharge sandstone in fractured areas. Simulated downward flow between them was a small amount within the global water budget. Calibrated recharge rates over basalts and over outcropping sandstones were 1.3 and 8.1% of mean annual precipitation, respectively. A big portion of sandstone recharge would be drained by streams. The application of a water balance yielded a recharge of 8.5% of average annual precipitation. The numerical model and the water balance yielded similar recharge values consistent with determinations from previous authors in the area and other regions of the aquifer, providing an upper bound for recharge in this transboundary aquifer.

Gómez, Andrea A.; Rodríguez, Leticia B.; Vives, Luis S.

2010-11-01

400

Modeling of Groundwater Artificial Recharge by Reactivating an Old Stream Bed  

Microsoft Academic Search

This paper refers to the development and verification of a groundwater artificial recharge model in Xanthi plain, Thrace, Greece. The relative geological and hydrogeological research of the study area is described, as well as the artificial recharge application by reactivating an old stream bed of Kosynthos River, since 1994. The simulation of the aquifer system of the study area was

F. Pliakas; C. Petalas; I. Diamantis; A. Kallioras

2005-01-01

401

DISTRIBUTION OF AREAL RECHARGE TO A DISCRETE FRACTURE NETWORK (FRACNET) MODEL USING THE ANALYTIC ELEMENT METHOD  

EPA Science Inventory

Rain water filtering down through the soil will provide recharge of the saturated fractured rock aquifer. he computer model FRACNET has been designed to distribute areal recharge into linear fracture zones in order to complete the regional water balance. n this presentation, a te...

402

Recharge characteristics of a phreatic aquifer as determined by storage accumulation  

NASA Astrophysics Data System (ADS)

The cumulative storage accumulation curve (CSAC) is a tool for saturated-volume fluctuation (SVF) analysis of transient recharge to shallow phreatic aquifers discharging only to springs. The method assumes that little underflow or phreatic evapotranspiration occurs. The CSAC is a modified water-table hydrograph that distinguishes storage increase caused by recharge from loss due to springflow-induced recession. Required for the analysis are water-table fluctuations at a single representative location within the catchment of a single spring and either direct measurements or robust interpolations of springflows at different aquifer stages. The method employs empirical manipulation of head observations, varying spring catchment area to minimize CSAC water-level changes in late portions of long recessions. Results include volumetric estimates of recharge integrated over individual events and instantaneous rates of recharge to the water table, at the temporal resolution of the water-level sampling interval. The analysis may also yield physically realistic information on spring catchment and recharge focusing. In a test case in West Virginia, USA, recharge estimates by this technique were consistent with integrated springflow time series but greater than estimates based on potential evapotranspiration. Results give insight into dynamic recharge behavior over time as well as an indication of recharge catchment size.

Ketchum, Neil J.; Donovan, Joseph J.; Avery, William H.

2000-12-01

403

Portrayal of fuzzy recharge areas for water balance modelling - a case study in northern Oman  

NASA Astrophysics Data System (ADS)

The research project IWAS Oman aims at implementing integrated water resources management (IWRM) to a pilot area in Al Batinah, Oman. This requires - amongst others - a realistic assessment of groundwater recharge to the alluvial aquifer which obviously has to be based upon the extension of recharge areas. In this context, the subsequent investigation focuses on the role of vagueness as regards the portrayal of the areas that provide water for particular aquifers. For that purpose, concepts of fuzziness in spatial analysis are applied to describe possible extents of recharge areas. In general, any water assessment is based on clearly delineated boundaries. However, in many cases, aquifer recharge areas are not clearly defined due to the nature of the study area. Hence, surfaces indicating a gradual membership to the recharge area of a particular aquifer are used in this investigation. These surfaces, which are based on available qualitative information, visualise a potential range of spatial extension. With regard to water balance calculations, functional relationships in tabular form are derived as well. Based on a regionalisation approach providing spatially distributed recharge rates, the corresponding recharge volume is calculated. Hence, this methodology provides fuzzy input data for water balance calculations. Beyond the portrayal of one singular aquifer recharge area, this approach also supports the complementary consideration of adjacent areas.

Gerner, A.; Schütze, N.; Schmitz, G. H.

2012-06-01

404

Groundwater recharge modelling using the Monte Carlo technique, Manawatu region, New Zealand  

NASA Astrophysics Data System (ADS)

The study area, the Manawatu region of New Zealand, covers approximately 4200 km 2 and contains numerous aquifers in unconsolidated Quaternary sedimentary formations. Most of the 5000 bores are shallow, with over 75% being less than 50 m. Of concern, is that 20% of bores in the south tap groundwater with a nitrate-nitrogen concentration above the drinking water standard (11.3 mg/l). An effective regional vulnerability assessment was therefore developed to mitigate this problem. While four factors largely control aquifer vulnerability in the study area, this paper focuses on developing a regional rainfall recharge model. Percolating rainwater is the major transporting agent for contaminants through soil and unsaturated zone. Mean annual recharge was calculated at each rainfall station throughout the study area using the Monte Carlo technique to randomise soil moisture parameters and approximate the variability of soils. These point estimates of recharge were then modelled spatially to produce a 'recharge surface'. Good agreement between the modelled and actual groundwater levels was obtained. Likewise, the regional recharge surface is consistent with the physical processes and the expected pattern. Uncertainty of recharge estimation is expressed as the standard deviation of the mean annual recharge resulting from the Monte Carlo modelling. Estimates of both recharge and uncertainty are presented as readily assimilated colour-coded maps which can be used by resource planners and other laypersons. This methodology is considered appropriate for other non-arid areas with limited soil and groundwater data coverage.

Bekesi, G.; McConchie, J.

1999-11-01

405

Influence of model conceptualisation on one-dimensional recharge quantification: Uley South, South Australia  

NASA Astrophysics Data System (ADS)

Model conceptualisation is a key source of uncertainty in one-dimensional recharge modelling. The effects of different conceptualisations on transient recharge predictions for the semi-arid Uley South Basin, South Australia, were investigated. One-dimensional unsaturated zone modelling was used to quantify the effect of variations of (1) lithological complexity of the unsaturated zone, and (2) representation of preferential flow pathways. The simulations considered ranges of water-table depths, vegetation characteristics, and top soil thicknesses representative for the study area. Complex lithological profiles were more sensitive to the selected vegetation characteristics and water-table depth. Scenarios considering runoff infiltration into, and preferential flow through sinkholes resulted in higher and faster recharge rates. A comparison of modelled and field-based recharge estimates indicated that: (1) the model simulated plausible recharge rates, (2) only the models with preferential flow correctly reproduced the timing of recharge, and (3) preferential flow is probably redistributed in the unsaturated zone rather than passing to the water table directly. Because different but equally plausible conceptual models produce widely varying recharge rates, field-based recharge estimates are essential to constrain the modelling results.

Ordens, Carlos M.; Post, Vincent E. A.; Werner, Adrian D.; Hutson, John L.

2014-06-01

406

Rechargeable lithium batteries. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning the design, development, evaluation, and applications of rechargeable lithium batteries. Citations discuss rechargeability, electrolyte formulation, electrode materials, high power capability, thermal management, and overcharge protection. Applications in automotive vehicles, space equipment, computers, and telephones are also discussed. (Contains a minimum of 126 citations and includes a subject term index and title list.)

NONE

1995-01-01

407

Rechargeable lithium batteries. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning the design, development, evaluation, and applications of rechargeable lithium batteries. Citations discuss rechargeability, electrolyte formulation, electrode materials, high power capability, thermal management, and overcharge protection. Applications in automotive vehicles, space equipment, computers, and telephones are also discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1995-11-01

408

Rechargeable lithium batteries. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning the design, development, evaluation, and applications of rechargeable lithium batteries. Citations discuss rechargeability, electrolyte formulation, electrode materials, high power capability, thermal management, and overcharge protection. Applications in automotive vehicles, space equipment, computers, and telephones are also discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1996-12-01

409

Self-doped block copolymer electrolytes for solid-state, rechargeable lithium batteries  

E-print Network

Self-doped block copolymer electrolytes for solid-state, rechargeable lithium batteries Donald R reserved. Keywords: Block copolymer; Lithium batteries; Transference number; Single-ion conductor 1 and cathode binder thin-�lm, solid-state, rechargeable lithium batteries of the type Li/ BCE/LiMnO2 have been

Sadoway, Donald Robert

410

Rechargeable lithium batteries. (Latest citations from the INSPEC database). Published Search  

SciTech Connect

The bibliography contains citations concerning the design, development, evaluation, and applications of rechargeable lithium batteries. Citations discuss rechargeability, electrolyte formulation, electrode materials, high power capability, thermal management, and overcharge protection. Applications in automotive vehicles, space equipment, computers, and telephones are also discussed. (Contains a minimum of 99 citations and includes a subject term index and title list.)

Not Available

1994-01-01

411

Development of advanced electrode materials for use in rechargeable lithium batteries  

Microsoft Academic Search

Batteries are a necessary companion to most portable electronic devices, and the rechargeable lithium battery is the most energy dense and lightest of all the competing battery types. These features make it the most likely battery to be used in future electronic devices, which will be smaller and have increased functionality. Therefore, the performance of the rechargeable lithium battery must

Scott Andrew Needham

2007-01-01

412

Groundwater recharge simulation under the steady-state and transient climate conditions  

Microsoft Academic Search

Groundwater recharge simulation under the steady-state and transient climate conditions Diffusive groundwater recharge is a vertical water flux through the water table, i.e. through the boundary between the unsaturated and saturated zones. This flux features temporal and spatial changes due to variations in the climatic conditions, landscape the state of vegetation, and the spatial variability of vadoze zone characteristics. In

S. Pozdniakov; N. Lykhina

2010-01-01

413

Relation of pathways and transit times of recharge water to nitrate concentrations using stable isotopes  

Microsoft Academic Search

Oxygen and hydrogen stable isotope values of precipitation, irrigation water, soil water, and ground water were used with soil-moisture contents and water levels to estimate transit times and pathways of recharge water in the unsaturated zone of a sand and gravel aquifer. Nitrate-nitrogen (nitrate) concentrations in ground water were also measured to assess their relation to seasonal recharge. Stable isotope

Matthew K. Landon; Geoffrey N. Delin; Stephen C. Komor; Charles P. Regan

2000-01-01

414

Derived Operating Rules for Allocating Recharges and Withdrawals among Unconnected Aquifers  

E-print Network

either a specified target delivery rate for withdrawals or available surface water supply to recharge solutions. The results show how cost characteristics, fraction of recharged water available for withdrawal discharge; Water storage; Pumps; Optimization. Introduction Water storage for many water supply systems

Pasternack, Gregory B.

415

A time series approach to inferring groundwater recharge using the water table fluctuation method  

Microsoft Academic Search

The water table fluctuation method for determining recharge from precipitation and water table measurements was originally developed on an event basis. Here a new multievent time series approach is presented for inferring groundwater recharge from long-term water table and precipitation records. Additional new features are the incorporation of a variable specific yield based upon the soil moisture retention curve, proper

Russell S. Crosbie; Philip Binning; Jetse D. Kalma

2005-01-01

416

COMPARATIVE LIFE CYCLE ASSESSMENT OF ALCALINE CELLS AND NI-MH RECHARGEABLE BATTERIES  

E-print Network

Page 1 COMPARATIVE LIFE CYCLE ASSESSMENT OF ALCALINE CELLS AND NI-MH RECHARGEABLE BATTERIES Jean by applying the LCA methodology to evaluate the environmental footprint of alkaline cells and Ni-MH batteries phase. Besides, the emphasis on rechargeable batteries is only justified from an environmental point

Paris-Sud XI, Université de

417

Inferring time-varying recharge from inverse analysis of long-term water levels  

USGS Publications Warehouse

Water levels in aquifers typically vary in response to time-varying rates of recharge, suggesting the possibility of inferring time-varying recharge rates on the basis of long-term water level records. Presumably, in the southwestern United States (Arizona, Nevada, New Mexico, southern California, and southern Utah), rates of mountain front recharge to alluvial aquifers depend on variations in precipitation rates due to known climate cycles such as the El Nin??o-Southern Oscillation index and the Pacific Decadal Oscillation. This investigation examined the inverse application of a one-dimensional analytical model for periodic flow described by Lloyd R. Townley in 1995 to estimate periodic recharge variations on the basis of variations in long-term water level records using southwest aquifers as the case study. Time-varying water level records at various locations along the flow line were obtained by simulation of forward models of synthetic basins with applied sinusoidal recharge of either a single period or composite of multiple periods of length similar to known climate cycles. Periodic water level components, reconstructed using singular spectrum analysis (SSA), were used to calibrate the analytical model to estimate each recharge component. The results demonstrated that periodic recharge estimates were most accurate in basins with nearly uniform transmissivity and the accuracy of the recharge estimates depends on monitoring well location. A case study of the San Pedro Basin, Arizona, is presented as an example of calibrating the analytical model to real data.

Dickinson, J.E.; Hanson, R.T.; Ferre, T.P.A.; Leake, S.A.

2004-01-01

418

MODIS-aided statewide net groundwater-recharge estimation in Nebraska.  

PubMed

Monthly evapotranspiration (ET) rates (2000 to 2009) across Nebraska at about 1-km resolution were obtained by linear transformations of the MODIS (MODerate resolution Imaging Spectroradiometer) daytime surface temperature values with the help of the Priestley-Taylor equation and the complementary relationship of evaporation. For positive values of the mean annual precipitation and ET differences, the mean annual net recharge was found by an additional multiplication of the power-function-transformed groundwater vulnerability DRASTIC-code values. Statewide mean annual net recharge became about 29 mm (i.e., 5% of mean annual precipitation) with the largest recharge rates (in excess of 100 mm/year) found in the eastern Sand Hills and eastern Nebraska. Areas with the largest negative net recharge rates caused by declining groundwater levels due to large-scale irrigation are found in the south-western region of the state. Error bounds of the estimated values are within 10% to 15% of the corresponding precipitation rates and the estimated net recharge rates are sensitive to errors in the precipitation and ET values. This study largely confirms earlier base-flow analysis-based statewide groundwater recharge estimates when considerations are made for differences in the recharge definitions. The current approach not only provides better spatial resolution than available earlier studies for the region but also quantifies negative net recharge rates that become especially important in numerical modeling of shallow groundwater systems. PMID:23216050

Szilagyi, Jozsef; Jozsa, Janos

2013-01-01

419

Groundwater recharge and evapotranspiration for two natural ecosystems covered with oak and heather  

Microsoft Academic Search

The evapotranspiration and groundwater recharge from two natural areas with high (oak) and low (heath) vegetation were estimated by calibrating a semi-physical numerical soil water and heat model to fit 8 and 7 years of TDR-measurements of water content, respectively. The measurements were made between the surface and 7 m depth. For the oak stand, the estimated annual recharge for

U. L. Ladekarl; K. R. Rasmussen; S. Christensen; K. H. Jensen; B. Hansen

2005-01-01

420

Uncertainty quantification in predicting deep aquifer recharge rates, with applicability in the Power River Basin, Wyoming  

Microsoft Academic Search

This paper proposes an approach to determine the uncertainties associated with a water budget model developed to predict recharge rates to deep aquifers in the Power River Basin of northeastern Wyoming. The inputs to this model are springtime snowmelt, streambed infiltration, infrequent convective rainfall, and evapotranspiration. The dominant recharge mechanism for the deeper aquifer units is assumed to be infiltrated

F. L. Ogden; K. Puckett

2006-01-01

421

Silicon nanowires as a rechargeable template for hydride transfer in redox biocatalysis  

NASA Astrophysics Data System (ADS)

We report a new possible application of hydrogen-terminated silicon nanowires (H-SiNWs) as a rechargeable template for hydride transfer in redox biocatalysis. H-SiNWs transfer hydride efficiently to regenerate NADH by oxidizing Si-Hx bonds. The oxidized H-SiNWs were readily recharged for the continuous regeneration of NADH and enzymatic reactions.

Lee, Hwa Young; Kim, Jae Hong; Son, Eun Jin; Park, Chan Beum

2012-11-01

422

77 FR 66084 - Tenth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems-Small...  

Federal Register 2010, 2011, 2012, 2013

...RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium Size AGENCY: Federal...of RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium...

2012-11-01

423

77 FR 56253 - Ninth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems-Small...  

Federal Register 2010, 2011, 2012, 2013

...RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium Size AGENCY: Federal...of RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium...

2012-09-12

424

76 FR 70531 - Fifth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems-Small...  

Federal Register 2010, 2011, 2012, 2013

...RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium Size AGENCY: Federal...of RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium...

2011-11-14

425

ELSEVIER Journal of Hydrology180(1996)31-53 Groundwater recharge in the Victoria Nile basin of east  

E-print Network

recharge. Recharge investigations in this environment are typically inhibited by a shortage of good quality infiltration of rainfall, an assumption implicit in the soil moisture balance approach. Deforestation over

Jones, Peter JS

426

78 FR 52107 - Special Conditions: Boeing Model 777-200, -300, and -300ER Series Airplanes; Rechargeable Lithium...  

Federal Register 2010, 2011, 2012, 2013

...airworthiness standard for lead acid batteries and nickel cadmium batteries...of the nickel cadmium and lead acid rechargeable batteries. Rechargeable lithium ion...Unlike nickel cadmium and lead acid batteries, some types of lithium...

2013-08-22

427

78 FR 76731 - Special Conditions: Boeing Model 777-200, -300, and -300ER Series Airplanes; Rechargeable Lithium...  

Federal Register 2010, 2011, 2012, 2013

...airworthiness standard for lead acid batteries and nickel cadmium batteries...of the nickel cadmium and lead acid rechargeable batteries. Rechargeable lithium ion...Unlike nickel cadmium and lead acid batteries, some types of lithium...

2013-12-19

428

Coupled Model Development between Groundwater Recharge Quantity and Climate Change in Nakdong River Watershed using GIS  

NASA Astrophysics Data System (ADS)

: Global climate change is disturbing the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes. In this study, the authors selected a relevant climate change scenario, A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by periodically and embodied as geographic information system (GIS). In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model, and the physical properties of weather, temperature, and soil layers were used as main input data. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems of ground circulation system, it may be urgent to recalculate the groundwater recharge quantity and consequent change under future climate change. The space-time calculation of changes of the groundwater recharge quantity in the study area may serve as a foundation to present additional measures to improve domestic groundwater resource management. Results showed that 26.19% of total precipitation was recharged from 1971 to 2000, 27.37% will be recharged from 2001 to 2030, 27.43% will be recharged from 2031 to 2050, and 26.06% will be recharged from 2051 to 2070, 27.88% will be recharged from 2051 to 2100. The groundwater recharge rate in this research showed susceptibility to changes in precipitation. The recharge rate was relatively little affected by the changes in Curve Number (CN), but it was rapidly reduced, as it approached the impermeable layers. Accordingly, the findings herein provide a basis for establishment of national plans on water resources management, use of groundwater in local areas for the purpose of settlement, and estimation of groundwater recharge quantities in areas where the groundwater hydrology is not measured. KEY WORDS: Groundwater recharge; Climate change; Curve Number; Special Report on Emissions Scenarios; Intergovernmental Panel on Climate Change

Lee, M.; Jeongho, L.; Changsub, S.; SeongWoo, J.

2011-12-01

429

Climate Impact on Groundwater Recharge in Southeastern Louisiana and Southwestern Mississippi  

NASA Astrophysics Data System (ADS)

Increases of concentrations of CO2 and other greenhouse gases have a significant effect on global climate, precipitation and hydrology, which in turn influences recharge to aquifers. Groundwater recharge study is imperative to the sole source aquifer, for example the Southern Hills aquifer system in southeastern Louisiana and southwestern Mississippi, which provides more than 50 percent of the drinking water consumed in the area overlying the aquifer and has no substitute drinking water source(s). To trace the climate impact and its consequent groundwater availability, this study developed a GIS-based integrated framework to connect climate models to a high-resolution hydrologic model to quantify long-term groundwater recharge. We employed the Hydrologic Evaluation of Landfill Performance (HELP3) model as our hydrologic model to estimate spatial-temporal distribution of potential recharge for a regional scale. HELP3 model was especially suitable for our recharge study due to Louisiana humid climate and the use of a regional-scale water budget approach. Detailed surficial soil property and land cover were obtained from the NRCS and the USGS to derive maps of curve number for the HELP3 model. Wireline well logs and drillers logs were analyzed to determine stratigraphic lithology and the first major sand encountered beneath the soil layer. For a regional scale, we used global circulation model (GCM) downscaled daily precipitation and temperature obtained from USGS CASCaDE Project Climate Data as the forcing input to the HELP3 model. The emission scenarios considered in this study were A2, B1 and A1FI from Parallel Climate Model 1 (PCM) and from the NOAA Geophysical Fluid Dynamics Lab's GFDL CM2.1 model. We used the computed runoff from USGS WaterWatch along with the HELP3 model to calculate the recharge index (RI) and delineate the recharge index map for individual hydrologic units in terms of Hydrologic Unit Codes (HUCs). The recharge index was defined as the percentage of precipitation that recharges aquifers. High-resolution recharge index maps were obtained to quantify the spatial impact of climate change on long-term groundwater availability. The framework was applied to the recharge study on the Southern Hills aquifer system overlain by twenty HUCs. The RI map for the Southern Hill aquifer system was obtained based on the computed runoff data from 1951 to 2000 in WaterWatch. Then the HELP3 model was applied to recharge estimation from 2000 to 2050. The results showed the differences in recharge estimation given different climate scenarios. Moreover, the results showed spatial-temporal variation of recharge in the aquifer system due to variations in land use, soil characteristics and predicted meteorological variables.

Beigi, E.; Tsai, F. T.

2012-12-01

430

3/5/2014 Micro-Windmill Technology: Future Uses Include Recharging Your Smartphone | Philippine Latest News http://philsense.com/2014/01/11/micro-windmill-technology-future-uses-include-recharging-your-smartphone/ 1/6  

E-print Network

3/5/2014 Micro-Windmill Technology: Future Uses Include Recharging Your Smartphone | Philippine Latest News http://philsense.com/2014/01/11/micro-windmill-technology-future-uses-include-recharging-your-smartphone Micro-Windmill Technology: Future Uses Include Recharging Your Smartphone Your ads w ill be inserted

Chiao, Jung-Chih

431

4/2/2014 Micro windmills maysoon recharge your mobile phone -Yahoo News Philippines https://ph.news.yahoo.com/micro-windmills-may-soon-recharge-mobile-phone-091158453.html 1/1  

E-print Network

4/2/2014 Micro windmills maysoon recharge your mobile phone - Yahoo News Philippines https://ph.news.yahoo.com/micro-windmills-may-soon-recharge-mobile-phone-091158453.html 1/1 Micro windmills may soon recharge your mobile phone GMA News Online ­ Mon, Jan 13, 2014 Taking a cue from the Dutch

Chiao, Jung-Chih

432

1/12/14 Researchers Develop Micro-Windmills to Recharge Cell Phones www.sciencespacerobots.com/researchers-develop-micro-windmills-to-recharge-cell-phones-11020142 1/2  

E-print Network

1/12/14 Researchers Develop Micro-Windmills to Recharge Cell Phones www.sciencespacerobots.com/researchers-develop-micro-windmills-to-recharge-cell-phones-Windmills to Recharge Cell Phones A University of Texas at Arlington research associate and electrical engineering be used to charge cell phone batteries by embedding hundreds of them in a cell phone sleeve

Chiao, Jung-Chih

433

2/17/2014 TechnologyUses Micro-Windmills to Recharge Cell Phones http://powerelectronics.com/print/blog/technology-uses-micro-windmills-recharge-cell-phones?group_id=17022 1/2  

E-print Network

2/17/2014 TechnologyUses Micro-Windmills to Recharge Cell Phones http://powerelectronics.com/print/blog/technology-uses-micro-windmills-recharge-cell-phones?group_id=17022 1/2 print | close Technology Uses Micro-Windmills to Recharge Cell Phones Fri, 2014-01-24 14:30 A UT Arlington (Texas) research

Chiao, Jung-Chih

434

4/2/2014 Micro-windmills can recharge cell phones -PC Advisor http://www.pcadvisor.co.uk/news/digital-home/3497368/micro-windmills-can-recharge-cell-phones/ 1/12  

E-print Network

4/2/2014 Micro-windmills can recharge cell phones - PC Advisor http://www.pcadvisor.co.uk/news/digital-home/3497368/micro-windmills-can-recharge-cell-phones/ 1/12 Sign In Sign in with your email address Sign up;4/2/2014 Micro-windmills can recharge cell phones - PC Advisor http

Chiao, Jung-Chih

435

2/1/2014 New Micro-Windmill TechnologyTo Recharge Cell Phone Batteries http://www.technocrazed.com/new-micro-windmill-technology-to-recharge-cell-phone-batteries 1/4  

E-print Network

2/1/2014 New Micro-Windmill TechnologyTo Recharge Cell Phone Batteries http://www.technocrazed.com/new-micro-windmill-technology-to-recharge-cell-phone-batteries manual winding or new batteries. It is the researchers' dream to recharge the cell phone batteries automatically. So that these batteries provide the unlimited autonomy to the users. Luckily, an electrical

Chiao, Jung-Chih

436

Dissolved Organic Carbon Influences Microbial Community Composition and Diversity in Managed Aquifer Recharge Systems  

PubMed Central

This study explores microbial community structure in managed aquifer recharge (MAR) systems across both laboratory and field scales. Two field sites, the Taif River (Taif, Saudi Arabia) and South Platte River (Colorado), were selected as geographically distinct MAR systems. Samples derived from unsaturated riverbed, saturated-shallow-infiltration (depth, 1 to 2 cm), and intermediate-infiltration (depth, 10 to 50 cm) zones were collected. Complementary laboratory-scale sediment columns representing low (0.6 mg/liter) and moderate (5 mg/liter) dissolved organic carbon (DOC) concentrations were used to further query the influence of DOC and depth on microbial assemblages. Microbial density was positively correlated with the DOC concentration, while diversity was negatively correlated at both the laboratory and field scales. Microbial communities derived from analogous sampling zones in each river were not phylogenetically significantly different on phylum, class, genus, and species levels, as determined by 16S rRNA gene pyrosequencing, suggesting that geography and season exerted less sway than aqueous geochemical properties. When field-scale communities derived from the Taif and South Platte River sediments were grouped together, principal coordinate analysis revealed distinct clusters with regard to the three sample zones (unsaturated, shallow, and intermediate saturated) and, further, with respect to DOC concentration. An analogous trend as a function of depth and corresponding DOC loss was observed in column studies. Canonical correspondence analysis suggests that microbial classes Betaproteobacteria and Gammaproteobacteria are positively correlated with DOC concentration. Our combined analyses at both the laboratory and field scales suggest that DOC may exert a strong influence on microbial community composition and diversity in MAR saturated zones. PMID:22798375

Li, Dong; Sharp, Jonathan O.; Saikaly, Pascal E.; Ali, Shahjahan; Alidina, Mazahirali; Alarawi, Mohammed S.; Keller, Stephanie; Hoppe-Jones, Christiane

2012-01-01

437

Comparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA  

USGS Publications Warehouse

Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1 to about 1000 m2. A fourth method (RORA, a basin-scale analysis of streamflow records using a recession-curve-displacement technique) yielded recharge estimates at a scale of 10-1000s of km2. The RORA basin-scale recharge estimates were regionalized to estimate recharge for the entire State of Minnesota on the basis of a regional regression recharge (RRR) model that also incorporated soil and climate data. Recharge rates estimated by the RRR model compared favorably to the local and basin-scale recharge estimates. RRR estimates at study locations were about 41% less on average than the unsaturated-zone water-balance estimates, ranged from 44% greater to 12% less than estimates that were based on the three WTF approaches, were about 4% less than the age dating of ground-water estimates, and were about 5% greater than the RORA estimates. Of the methods used in this study, the WTF method is the simplest and easiest to apply. Recharge estimates made on the basis of the UZWB method were inconsistent with the results from the other methods. Recharge estimates using the RRR model could be a good source of input for regional ground-water flow models; RRR model results currently are being applied for this purpose in USGS studies elsewhere. ?? 2006 Elsevier B.V. All rights reserved.

Delin, G. N.; Healy, R. W.; Lorenz, D. L.; Nimmo, J. R.

2007-01-01

438

Data-Conditioned Distributions of Groundwater Recharge Under Climate Change Scenarios  

NASA Astrophysics Data System (ADS)

Groundwater recharge is likely to be impacted by climate change, with changes in precipitation amounts altering moisture availability and changes in temperature affecting evaporative demand. This could have major implications for sustainable aquifer pumping rates and contaminant transport into groundwater reservoirs in the future, thus making predictions of recharge under climate change very important. Unfortunately, in dry environments where groundwater resources are often most critical, low recharge rates are difficult to resolve due to high sensitivity to modeling and input errors. Some recent studies on climate change and groundwater have considered recharge using a suite of general circulation model (GCM) weather predictions, an obvious and key source of uncertainty. This work extends beyond those efforts by also accounting for uncertainty in other land-surface model inputs in a probabilistic manner. Recharge predictions are made using a range of GCM projections for a rain-fed cotton site in the semi-arid Southern High Plains region of Texas. Results showed that model simulations using a range of unconstrained literature-based parameter values produce highly uncertain and often misleading recharge rates. Thus, distributional recharge predictions are found using soil and vegetation parameters conditioned on current unsaturated zone soil moisture and chloride concentration observations; assimilation of observations is carried out with an ensemble importance sampling method. Our findings show that the predicted distribution shapes can differ for the various GCM conditions considered, underscoring the importance of probabilistic analysis over deterministic simulations. The recharge predictions indicate that the temporal distribution (over seasons and rain events) of climate change will be particularly critical for groundwater impacts. Overall, changes in recharge amounts and intensity were often more pronounced than changes in annual precipitation and temperature, thus suggesting high susceptibility of groundwater systems to future climate change. Our approach provides a probabilistic sensitivity analysis of recharge under potential climate changes, which will be critical for future management of water resources.

McLaughlin, D.; Ng, G. C.; Entekhabi, D.; Scanlon, B.

2008-12-01

439

Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte  

NASA Astrophysics Data System (ADS)

Aqueous lithium-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. But all reported aqueous lithium-ion battery systems have shown poor stability: the capacity retention is typically less than 50% after 100 cycles. Here, the stability of electrode materials in an aqueous electrolyte was extensively analysed. The negative electrodes of aqueous lithium-ion batteries in a discharged state can react with water and oxygen, resulting in capacity fading upon cycling. By eliminating oxygen, adjusting the pH values of the electrolyte and using carbon-coated electrode materials, LiTi2(PO4)3/Li2SO4/LiFePO4 aqueous lithium-ion batteries exhibited excellent stability with capacity retention over 90% after 1,000 cycles when being fully charged/discharged in 10 minutes and 85% after 50 cycles even at a very low current rate of 8 hours for a full charge/discharge offering an energy storage system with high safety, low cost, long cycling life and appropriate energy density.

Luo, Jia-Yan; Cui, Wang-Jun; He, Ping; Xia, Yong-Yao

2010-09-01

440

Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte.  

PubMed

Aqueous lithium-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. But all reported aqueous lithium-ion battery systems have shown poor stability: the capacity retention is typically less than 50% after 100 cycles. Here, the stability of electrode materials in an aqueous electrolyte was extensively analysed. The negative electrodes of aqueous lithium-ion batteries in a discharged state can react with water and oxygen, resulting in capacity fading upon cycling. By eliminating oxygen, adjusting the pH values of the electrolyte and using carbon-coated electrode materials, LiTi(2)(PO(4))(3)/Li(2)SO(4)/LiFePO(4) aqueous lithium-ion batteries exhibited excellent stability with capacity retention over 90% after 1,000 cycles when being fully charged/discharged in 10 minutes and 85% after 50 cycles even at a very low current rate of 8 hours for a full charge/discharge offering an energy storage system with high safety, low cost, long cycling life and appropriate energy density. PMID:20729897

Luo, Jia-Yan; Cui, Wang-Jun; He, Ping; Xia, Yong-Yao

2010-09-01

441

Temporal and spatial scaling of hydraulic response to recharge in fractured aquifers: Insights from a frequency domain analysis  

E-print Network

Temporal and spatial scaling of hydraulic response to recharge in fractured aquifers: Insights from investigate the hydraulic response to recharge of a fractured aquifer, using a frequency domain approach scaling of hydraulic response to recharge in fractured aquifers: Insights from a frequency domain analysis

Paris-Sud XI, Université de

442

Continuous aqueous tritium monitor  

DOEpatents

An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture and selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration.

McManus, Gary J. (Idaho Falls, ID); Weesner, Forrest J. (Idaho Falls, ID)

1989-05-30