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Sample records for aluminium electrolytic capacitors

  1. Reliability determination of aluminium electrolytic capacitors by the mean of various methods application to the protection system of the LHC

    CERN Document Server

    Perisse, F; Rojat, G

    2004-01-01

    The lifetime of power electronic components is often calculated from reliability reports, but this method can be discussed. We compare in this article the results of various reliability reports to an accelerated ageing test of component and introduced the load-strength concept. Large aluminium electrolytic capacitors are taken here in example in the context of the protection system of LHC (Large Hadron Collider) in CERN where the level of reliability is essential. We notice important differences of MTBF (Mean Time Between Failure) according to the reliability report used. Accelerating ageing tests carried out prove that a Weibull law is more adapted to determinate failure rates of components. The load-strength concept associated with accelerated ageing tests can be a solution to determine the lifetime of power electronic components.

  2. Towards Prognostics of Electrolytic Capacitors

    Data.gov (United States)

    National Aeronautics and Space Administration — A remaining useful life prediction algorithm and degradation model for electrolytic capacitors is presented. Electrolytic capacitors are used in several applications...

  3. Hydrogel membrane electrolyte for electrochemical capacitors

    Indian Academy of Sciences (India)

    S Sampath; N A Choudhury; A K Shukla

    2009-09-01

    Polymer electrolytes are known to possess excellent physicochemical properties that are very useful for electrochemical energy systems. The mobility in polymer electrolytes is understood to be mainly due to the segmental motion of polymer chains and the ion transport is generally restricted to the amorphous phase of the polymer. Gel polymer electrolytes (GPE) that are formed using plastizicers and polymers along with ionic salts are known to exhibit liquid-like ionic conductivity while maintaining the dimensional stability of a solid matrix. In the present study, the preparation and characterization of poly(vinyl alcohol)-based hydrogel membranes (PHMEs) as electrolytes for electrochemical capacitors have been reported. Varying HClO4 dopant concentration leads to different characteristics of the capacitors. The EC comprising PHME doped with 2 M HClO4 and black pearl carbon (BPC) electrodes has been found to exhibit a maximum specific capacitance value of 97 F g-1, a phase angle value of 78°, and a maximum charge-discharge coulombic efficiency of 88%.

  4. Aging Methodologies and Prognostic Health Management for Electrolytic Capacitors

    Data.gov (United States)

    National Aeronautics and Space Administration — Understanding the ageing mechanisms of electronic components critical avionics systems such as the GPS and INAV are of critical importance. Electrolytic capacitors...

  5. Physics based Degradation Modeling and Prognostics of Electrolytic Capacitors under Electrical Overstress Conditions

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes a physics based degradation modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors are critical components in...

  6. Prognostics Health Management and Physics based failure Models for Electrolytic Capacitors

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes first principles based modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors and MOSFETs are the two major...

  7. Flake tantalum powder for manufacturing electrolytic capacitors

    Institute of Scientific and Technical Information of China (English)

    HE Jilin; YANG Guoqi; PAN Luntao; LIU Hongdong; BAO Xifang

    2008-01-01

    The FTP200 flake tantalum powder was introduced.The microstructures of the powder with leaf-like primary particles having an average flakiness of 2 to 20 and porous agglomerated particles were observed.The chemical composition,physical properties,and electrical properties of the FTP200 powder were compared with those of the FTW300 nodular powder.The FTP200 powder is more sinter-resistant,and the surface area of the flake tantalum powder under sintering at high temperature has less loss than that of the nodular tantalum powder.The specific capacitance of the flake tantalum powder is higher than that of the nodular tantalum powder with the same surface area when anodized at high voltage,Thus,the flake tantalum powder is suitable for manufacturing tantalum solid electrolytic capacitors in the range of median and high (20-63 V) voltages.

  8. Candidate organic electrolytes for electric double-layer capacitor application

    Institute of Scientific and Technical Information of China (English)

    B.Fang; Y.Wei; K.Suzuki; M.Kumagai

    2004-01-01

    Electrolytic conductivity,viscosity and electrochemical behavior were investigated for organic electrolytes based on PC(Propylene carbonate),MAN(Methoxy acetonitrile) and GBL(γ-Butyrolactone) solvents.It was found that 1 mol/L Et4NBF4-MAN had the highest conductivity,lowest viscosity and acceptable potential window.The specific capacitance and energy density obtained from the capacitor using 1 mol/L Et4NBF4-MAN as electrolyte were the highest among all the tested electrolytes.1 mol/L Et4NBF4-GBL also seemed promising to be used in electric double-layer capacitor (EDLCs).

  9. Autogenous electrolyte, non-pyrolytically produced solid capacitor structure

    Science.gov (United States)

    Sharp, D.J.; Armstrong, P.S.; Panitz, J.K.G.

    1998-03-17

    A solid electrolytic capacitor is described having a solid electrolyte comprising manganese dioxide dispersed in an aromatic polyamide capable of further cure to form polyimide linkages, the solid electrolyte being disposed between a first electrode made of valve metal covered by an anodic oxide film and a second electrode opposite the first electrode. The electrolyte autogenously produces water, oxygen, and hydroxyl groups which act as healing substances and is not itself produced pyrolytically. Reduction of the manganese dioxide and the water molecules released by formation of imide linkages result in substantially improved self-healing of anodic dielectric layer defects. 2 figs.

  10. Physics Based Modeling and Prognostics of Electrolytic Capacitors

    Science.gov (United States)

    Kulkarni, Chetan; Ceyla, Jose R.; Biswas, Gautam; Goebel, Kai

    2012-01-01

    This paper proposes first principles based modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors have become critical components in electronics systems in aeronautics and other domains. Degradations and faults in DC-DC converter unit propagates to the GPS and navigation subsystems and affects the overall solution. Capacitors and MOSFETs are the two major components, which cause degradations and failures in DC-DC converters. This type of capacitors are known for its low reliability and frequent breakdown on critical systems like power supplies of avionics equipment and electrical drivers of electromechanical actuators of control surfaces. Some of the more prevalent fault effects, such as a ripple voltage surge at the power supply output can cause glitches in the GPS position and velocity output, and this, in turn, if not corrected will propagate and distort the navigation solution. In this work, we study the effects of accelerated aging due to thermal stress on different sets of capacitors under different conditions. Our focus is on deriving first principles degradation models for thermal stress conditions. Data collected from simultaneous experiments are used to validate the desired models. Our overall goal is to derive accurate models of capacitor degradation, and use them to predict performance changes in DC-DC converters.

  11. PEO nanocomposite polymer electrolyte for solid state symmetric capacitors

    Indian Academy of Sciences (India)

    Nirbhay K Singh; Mohan L Verma; Manickam Minakshi

    2015-10-01

    Physical and electrochemical properties of polyethylene oxide (PEO)-based nanocomposite solid polymer electrolytes (NPEs) were investigated for symmetric capacitor applications. Nanosize fillers, i.e., Al2O3 and SiO2 incorporated polymer electrolyte exhibited higher ionic conductivity than those with filler-free composites. The composites have been synthesized by the completely dry (solution-free) hot-press method. The addition of filler in fractional amount to the solid polymer matrix at room temperature further enhances the ionic conductivity. Nature of the NPEs were studied using X-ray diffraction and energy-dispersive spectra analyses. Thermal stability of the resulting electrolyte was analysed by thermogravimetric analysis and differential scanning calorimetric studies. Morphology changes occurred during the addition of fillers was evidenced by scanning electronic microscope images. Solid polymer electrolytes exhibiting these parameters was found to be suitable for solid state capacitors. The results obtained from the electrolytes with an optimum compositions (PEO70AgI30)93 (Al2O3)7 and (PEO70AgI30)95 (SiO2)5 used in the (PEO70AgI30)70 (AC)30 electrodes for symmetric capacitor applications and their performances were analysed by impedance spectroscopic, Bode plot, cyclic voltammetry, discharge characteristics and leakage current profile.

  12. Chemical stability of γ-butyrolactone-based electrolytes for aluminum electrolytic capacitors

    Science.gov (United States)

    Ue, Makoto; Takeda, Masayuki; Suzuki, Yoko; Mori, Shoichiro

    γ-Butyrolactone-based electrolytes have been used as the operating electrolytes for aluminum electrolytic capacitors. The chemical stability of these electrolytes at elevated temperatures has been examined by monitoring the decrease in their electrolytic conductivities. The deteriorated electrolytes were analyzed by gas and liquid chromatography and the conductivity decrease was directly correlated with the loss of acid components. In quaternary ammonium hydrogen maleate/γ-butyrolactone electrolytes, the maleate anion decomposed by decarboxylation resulting in a complex polymer containing polyester and polyacrylate structures. Quaternary ammonium benzoate/γ-butyrolactoneelectrolytes decomposed by SN2 reactions giving alkyi benzoates and trialkylamines. The deterioration of the carboxylate salt/γ-butyrolactone electrolytes was accelerated by electrolysis.

  13. Electrolytic deposition of aluminium-magnesium-alloys from electrolytes containing organo-aluminium complexes; Elektrolytische Abscheidung von Aluminium-Magnesium-Legierungen aus aluminiumorganischen Komplexelektrolyten

    Energy Technology Data Exchange (ETDEWEB)

    Lehmkuhl, H.; Mehler, K.; Bongard, H.; Tesche, B. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Reinhold, B. [Audi AG, Ingolstadt (Germany). Technische Entwicklung

    2000-10-01

    The galvanic deposition of pure aluminium from fluoride-containing electrolytes has been developed further and for the first time aluminium and magnesium have been deposited from a toluene-solution of a halide-free organo-aluminium complex electrolyte. The rate of incorporation of magnesium can be controlled over a wide range by either adjusting the composition of the aluminium-magnesium anode or by using separate aluminium or magnesium anodic circuits. The current efficiency for both anode and cathode approaches 100%. The resulting coating is optically attractive and, depending upon the magnesium-content or the cathodic current density, can be formed as a dull or polished surface. Investigations using an electron microscope show that the surface, in contrast to that of pure aluminium, consists of spherical particles. The aluminium-magnesium coating provides excellent protection against the corrosion of magnesium components. Electrochemical investigations using, for example 25% by weight magnesium incorporation, indicate a pronounced passivity interval compared to the alloy AZ91hp. In contrast to galvanic zinc-plated and silicate-sealed examples, cyclic corrosion tests on screws simulating 10 years of exposure, show no corrosion. (orig.)

  14. Accelerated Aging in Electrolytic Capacitors for Prognostics

    Science.gov (United States)

    Celaya, Jose R.; Kulkarni, Chetan; Saha, Sankalita; Biswas, Gautam; Goebel, Kai Frank

    2012-01-01

    The focus of this work is the analysis of different degradation phenomena based on thermal overstress and electrical overstress accelerated aging systems and the use of accelerated aging techniques for prognostics algorithm development. Results on thermal overstress and electrical overstress experiments are presented. In addition, preliminary results toward the development of physics-based degradation models are presented focusing on the electrolyte evaporation failure mechanism. An empirical degradation model based on percentage capacitance loss under electrical overstress is presented and used in: (i) a Bayesian-based implementation of model-based prognostics using a discrete Kalman filter for health state estimation, and (ii) a dynamic system representation of the degradation model for forecasting and remaining useful life (RUL) estimation. A leave-one-out validation methodology is used to assess the validity of the methodology under the small sample size constrain. The results observed on the RUL estimation are consistent through the validation tests comparing relative accuracy and prediction error. It has been observed that the inaccuracy of the model to represent the change in degradation behavior observed at the end of the test data is consistent throughout the validation tests, indicating the need of a more detailed degradation model or the use of an algorithm that could estimate model parameters on-line. Based on the observed degradation process under different stress intensity with rest periods, the need for more sophisticated degradation models is further supported. The current degradation model does not represent the capacitance recovery over rest periods following an accelerated aging stress period.

  15. Influence of Electrolyte on ESR of Medium Voltage Wet Tantalum Capacitors

    Institute of Scientific and Technical Information of China (English)

    刘仲娥; 宋金荣; 陈晓静; 李忆莲; 桂娟

    2004-01-01

    In this paper, the influence of working electrolyte on high-frequency electrical performance of wet tantalum capacitors is studied. Emphasis is especially put on the study of the contribution of depolariser in reducing Equivalent Series Resistance(ESR). According to the theory of depolarization in electrochemistry and the theory of cathode capacitance of electrolytic capacitor, different kinds of depolarisers are added separately into the foregone electrolyte. Then capacitors are assembled with tantalum cores dipped with the compounded electrolytes. The best depolariser and its concentration in the whole electrolyte could be selected according to the test results of the capacitance and ESR of the capacitors. The results of our experiment show that depolariser Fe2(SO4)3 used in working electrolyte of 100 V/100 μF wet tantalum capacitors can help to obtain lower ESR and higher capacitance at frequency from 0.1 kHz to 100 kHz.

  16. New design of electric double layer capacitors with aqueous LiOH electrolyte as alternative to capacitor with KOH solution

    Science.gov (United States)

    Stepniak, Izabela; Ciszewski, Aleksander

    Activated carbon (AC) fiber cloths and a hydrophobic microporous polypropylene (PP) membrane, both modified with lithiated acetone oligomers, were used as electrodes and a separator in electric double layer capacitors (EDLCs) with aqueous lithium hydroxide (LiOH) as the electrolyte. Electrochemical characteristics of EDLCs were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge cycle tests and impedance spectroscopy (EIS), compared with a case of the capacitor with aqueous potassium hydroxide (KOH) as an electrolyte. As a result, the capacitor with LiOH aqueous solution and a modified separator and electrodes was found to exhibit higher specific capacitance, maximum energy stored and maximum power than that with KOH aqueous solution.

  17. Invalidation manner and mechanism of new type NbO electrolytic capacitor anode

    Institute of Scientific and Technical Information of China (English)

    LI Jian; YI Dan-qing; WEN Jun-jie; LIU Hui-qun; ZHONG Hui

    2005-01-01

    Niobium suboxide powder was pressed and sintered in vacuum into NbO electrolytic capacitor sintered anode..High voltage and constant current formation experiment was performed on NbO electrolytic capacitor anode,during which electrolyte was 0.01 % Ha PO4 solution, temperature was 90 C and current was 50 mA per gram sample. Through the relationship between anode voltage and time and scanning electron microscopy(SEM) images of invalidated anode and normal forming anode, invalidation manner and mechanism of NbO electrolytic capacitor anode were discussed. The results show that, the main invalidation manner of NbO electrolytic capacitor anode is not short circuit but open circuit, which is different to that of traditional Ta electrolytic capacitor anode. The reason of invalidation is that anode oxide film whose thickness increases gradually penetrates the "connection neck" among anode powder particles, which leads to the open circuit invalidation of anode. Compared with Ta electrolytic capacitor,NbO electrolytic capacitor has better security.

  18. Guidelines for the selection and application of tantalum electrolytic capacitors in highly reliable equipment

    Science.gov (United States)

    Holladay, A. M.

    1978-01-01

    Guidelines are given for the selection and application of three types of tantalum electrolytic capacitors in current use in the design of electrical and electronic circuits for space flight missions. In addition, the guidelines supplement requirements of existing military specifications used in the procurement of capacitors. A need exists for these guidelines to assist designers in preventing some of the recurring, serious problems experienced with tantalum electrolytic capacitors in the recent past. The three types of capacitors covered by these guidelines are; solid, wet foil, and tantalum cased wet slug.

  19. Thermal instability of electrolytic capacitor bank used for gas puff valve

    Science.gov (United States)

    Bellan, P. M.

    2002-08-01

    It is shown that self-heating of electrolytic capacitors causes the output current of a capacitor bank to increase with successive shots even though the charge voltage is held constant. Self heating of only 10 °C can cause a near tripling in the gas output of the gas puffing valves commonly used in spheromak research. By using metallized polypropylene film capacitors instead of electrolytic capacitors the reproducibility is substantially improved (the shot-to-shot variation in gas output is reduced to be <0.5%).

  20. Thermal instability of electrolytic capacitor bank used for gas puff valve

    OpenAIRE

    Bellan, P. M.

    2002-01-01

    It is shown that self-heating of electrolytic capacitors causes the output current of a capacitor bank to increase with successive shots even though the charge voltage is held constant. Self heating of only 10 °C can cause a near tripling in the gas output of the gas puffing valves commonly used in spheromak research. By using metallized polypropylene film capacitors instead of electrolytic capacitors the reproducibility is substantially improved (the shot-to-shot variation in gas output is r...

  1. Study and analysis of failure modes of the electrolytic capacitors and thyristors, applied to the protection system of the LHC (Large Hadron Collider); Etude et analyse des modes de defaillances des condensateurs electrolytiques a l'aluminium et des thyristors: appliquees au systeme de protection du LHC (Large Hadron Collider)

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, F

    2003-07-15

    The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity of the models is obtained. The study of the thyristors has shown that these components have little drift of parameters in static ageing, on the other hand of many failures by short-circuit were observed. These failures always have a local origin, and are due to defects of the components. The breakdown voltage strongly depends on the quality of the thyristor as well as the technology employed. (author)

  2. Physics Based Electrolytic Capacitor Degradation Models for Prognostic Studies under Thermal Overstress

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrolytic capacitors are used in several applications rang- ing from power supplies on safety critical avionics equipment to power drivers for electro-mechanical...

  3. A Model-Based Prognostics Methodology For Electrolytic Capacitors Based On Electrical Overstress Accelerated Aging

    Data.gov (United States)

    National Aeronautics and Space Administration — A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical...

  4. Bayesian Framework Approach for Prognostic Studies in Electrolytic Capacitor under Thermal Overstress Conditions

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrolytic capacitors are used in several applications rang- ing from power supplies for safety critical avionics equipment to power drivers for electro-mechanical...

  5. Effect of cerium addition on microstructure and texture of aluminum foil for electrolytic capacitors

    Institute of Scientific and Technical Information of China (English)

    王海燕; 李文学; 任慧平; 黄丽颖; 王向阳

    2010-01-01

    Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after ann...

  6. Carbon treated commercial aluminium alloys as anodes for aluminium-air batteries in sodium chloride electrolyte

    Science.gov (United States)

    Pino, M.; Herranz, D.; Chacón, J.; Fatás, E.; Ocón, P.

    2016-09-01

    An easy treatment based in carbon layer deposition into aluminium alloys is presented to enhance the performance of Al-air primary batteries with neutral pH electrolyte. The jellification of aluminate in the anode surface is described and avoided by the carbon covering. Treated commercial Al alloys namely Al1085 and Al7475 are tested as anodes achieving specific capacities above 1.2 Ah g-1vs 0.5 Ah g-1 without carbon covering. The influence of the binder proportion in the treatment as well as different carbonaceous materials, Carbon Black, Graphene and Pyrolytic Graphite are evaluated as candidates for the covering. Current densities of 1-10 mA cm-2 are measured and the influence of the alloy explored. A final battery design of 4 cells in series is presented for discharges with a voltage plateau of 2 V and 1 Wh g-1 energy density.

  7. Preparation and Application of Nano-composite Poly(vinyl alcohol) Gel Electrolyte in Electrochemical Capacitor

    Institute of Scientific and Technical Information of China (English)

    陈赟; 谭强强; 徐宇兴

    2012-01-01

    A nano-composite polymer gel electrolyte was prepared using titanium oxide nanowire,poly(vinyl alcohol) (PVA),lithium salt and organic solvent N-methyl-2-pyrrolidone (NMP).The obtained electrolyte has the potential for application in electrochemical capacitor,the PVA in it is in an amorphous state.The ionic conductivities of electrolytes increased after addition of the nanowire,and the electrolyte with 3%(ω) of nanowire exhibited the highest ionic conductivity of 3.2 mS/cm at 20 ℃,as measured by electrochemical impedance spectroscopy.The temperature dependence of the conductivity was found to be in agreement with the Arrhenius equation.Functioning as separator and electrolyte,this nano-composite PVA gel electrolyte was used to assemble the electrochemical capacitor with active carbon film as electrodes.The compositing of nanowire may extend the life of electrochemical capacitors as they keep more than 90% of their capacitance after 5 000 cycles of charging and discharging.

  8. Physics Based Electrolytic Capacitor Degradation Models for Prognostic Studies under Thermal Overstress

    Science.gov (United States)

    Kulkarni, Chetan S.; Celaya, Jose R.; Goebel, Kai; Biswas, Gautam

    2012-01-01

    Electrolytic capacitors are used in several applications ranging from power supplies on safety critical avionics equipment to power drivers for electro-mechanical actuators. This makes them good candidates for prognostics and health management research. Prognostics provides a way to assess remaining useful life of components or systems based on their current state of health and their anticipated future use and operational conditions. Past experiences show that capacitors tend to degrade and fail faster under high electrical and thermal stress conditions that they are often subjected to during operations. In this work, we study the effects of accelerated aging due to thermal stress on different sets of capacitors under different conditions. Our focus is on deriving first principles degradation models for thermal stress conditions. Data collected from simultaneous experiments are used to validate the desired models. Our overall goal is to derive accurate models of capacitor degradation, and use them to predict performance changes in DC-DC converters.

  9. Research Regarding Aluminium Eloxation from Phosphoric Acid Electrolyte

    Directory of Open Access Journals (Sweden)

    Cretu Carmen Monica

    2014-06-01

    Full Text Available The study presents the influence of production parameters on the aluminium eloxation from H3PO4 solution. The thickness and aspect of the deposited Al2O3 were determined. The electrodeposition experiments was to determine the optimum conditions for the producing of bright, continuous, adherent and compact Al2O3 layers.

  10. Towards A Model-Based Prognostics Methodology For Electrolytic Capacitors: A Case Study Based On Electrical Overstress Accelerated Aging

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a model-driven methodology for predict- ing the remaining useful life of electrolytic capacitors. This methodology adopts a Kalman filter...

  11. Bayesian Framework Approach for Prognostic Studies in Electrolytic Capacitor under Thermal Overstress Conditions

    Science.gov (United States)

    Kulkarni, Chetan S.; Celaya, Jose R.; Goebel, Kai; Biswas, Gautam

    2012-01-01

    Electrolytic capacitors are used in several applications ranging from power supplies for safety critical avionics equipment to power drivers for electro-mechanical actuator. Past experiences show that capacitors tend to degrade and fail faster when subjected to high electrical or thermal stress conditions during operations. This makes them good candidates for prognostics and health management. Model-based prognostics captures system knowledge in the form of physics-based models of components in order to obtain accurate predictions of end of life based on their current state of heal th and their anticipated future use and operational conditions. The focus of this paper is on deriving first principles degradation models for thermal stress conditions and implementing Bayesian framework for making remaining useful life predictions. Data collected from simultaneous experiments are used to validate the models. Our overall goal is to derive accurate models of capacitor degradation, and use them to remaining useful life in DC-DC converters.

  12. Electrolytes for high voltage electrochemical double layer capacitors: A perspective article

    Science.gov (United States)

    Balducci, A.

    2016-09-01

    The development of innovative electrolyte components is nowadays considered one of the most important aspects for the realization of high energy electrochemical double capacitors (EDLCs). Consequently, in the last years many investigations have been dedicated towards new solvents, new salts and ionic liquids able to replace the current electrolytes. This perspective article aims to supply a critical analysis about the results obtained so far on the development of new electrolytes for high energy EDLCs and to outline the advantages as well as the limits related to the use of these innovative components. Furthermore, this article aims to give indications about the strategies could be used in the future for a further development of advanced electrolytes.

  13. Performance of flexible capacitors based on polypyrrole/carbon fiber electrochemically prepared from various phosphate electrolytes

    Science.gov (United States)

    Yuan, Wei; Han, Gaoyi; Chang, Yunzhen; Li, Miaoyu; Xiao, Yaoming; Zhou, Haihan; Zhang, Ying; Li, Yanping

    2016-11-01

    In order to investigate the influence of electrolytes in electro-deposition solution on the capacitive properties of polypyrrole (PPy), we have chosen phosphoric acid, phosphate, hydrogen phosphate and dihydrogen phosphate as electrolyte in deposition solution respectively and electrochemically deposited PPy on carbon fibers (CFs) via galvanostatic method. The morphologies of the PPy/CFs samples have been characterized by scanning electron microscope. The specific capacitance of PPy/CFs samples has been evaluated in different electrolytes through three-electrode test system. The assembled flexible capacitors by using PPy/CFs as electrodes and H3PO4/polyvinyl alcohol as gel electrolyte have been systematically measured by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show that the electrochemical capacitors based on PPy/CFs prepared from deposition solution containing NaH2PO4·2H2O electrolyte exhibit higher specific capacitance, flexibility and excellent stability (retaining 96.8% of initial capacitance after 13,000 cycles), and that three cells connected in series can power a light-emitting diode.

  14. The Performance of 600F Power Super Capacitor Using Carbon Nanotubes Electrodes and Nonaqueous Electrolyte

    Institute of Scientific and Technical Information of China (English)

    WANGXiaofeng

    2005-01-01

    Many applications for supercapacitors have been proposed in recent years. The popularity of these devices is derived from their high energy density compared with conventional capacitors and their long cycle life and high power density relative to batteries. Supercapacitors based on charge storage at the interface between a high surface area carbon nanotubes electrode and LiClO4/PC electrolyte is assembled in this paper. The carbon nanotubes prepared catalytically exhibited double layer capacitance of 12F.g-1 in LiClO4/PC electrolyte. The performance of the capacitor depends not only on the materials used in the cells but also on the construction of the cells. Evaluation of capacitor performance by different techniques is also discussed. The performance of carbon nanotubes based capacitors for high power sources used in electronic equipment or hybrid vehicle application are described. From a constant charge-discharge test, the capacitance of 600 F and impedance of 2.5mΩ are obtained for this device. Values for the specific energy and specific power of 0.SWh-kg-1 and lkW-kg-1, respectively, are demonstrated for a cell with 2.5V maximum operating voltage.

  15. Evaluation of DC-link decoupling using electrolytic or polypropylene film capacitors in three-phase grid-connected photovoltaic inverters

    OpenAIRE

    Karanayil, Baburaj; Agelidis, Vassilios; Pou Félix, Josep

    2013-01-01

    The life expectancy and long term reliability of grid-connected three-phase photovoltaic (PV) inverters can be increased by replacing the conventional electrolytic film capacitors by metallized polypropylene film capacitors. This paper presents a detailed evaluation of a three-phase grid-connected PV inverter performance when replacing the electrolytic capacitor with a minimum value of metallized polypropylene film capacitor-one. The minimum dc bus capacitance leads to larger voltage ripples....

  16. KPF{sub 6} dissolved in propylene carbonate as an electrolyte for activated carbon/graphite capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyu [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China); Yoshio, Masaki [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2010-02-15

    KPF{sub 6} dissolved in propylene carbonate (PC) has been proposed as an electrolyte for activated carbon (AC)/graphite capacitors. The electrochemical performance of AC/graphite capacitor has been tested in XPF{sub 6}-PC or XBF{sub 4}-PC electrolytes (X stands for alkali or quaternary alkyl ammonium cations). The AC/graphite capacitor using KPF{sub 6}-PC electrolyte shows an excellent cycle-ability compared with other electrolytes containing alkali ions. The big decomposition of the PC solvent at the AC negative electrode is considerably suppressed in the case of KPF{sub 6}-PC, which fact has been correlated with the mild solvation of K{sup +} by PC solvent. The relationship between the ionic radius of cation and the corresponding specific capacitance of AC negative electrode also proves that PC-solvated K{sup +} ions are adsorbed on AC electrode instead of naked K{sup +} ions. (author)

  17. An all-solid-state electrochemical double-layer capacitor based on a plastic crystal electrolyte

    Directory of Open Access Journals (Sweden)

    Ali eaabouimrane

    2015-08-01

    Full Text Available A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C4H94NPF6, (10 molar % with succinonitrile, SCN, (N C−CH2−CH2−C N, [SCN-10%TBA-PF6]. The resultant waxy material shows a plastic crystalline phase that extend from -36 °C up to its melting at 23 °C. It shows a high ionic conductivity reaching 4 × 10−5 S/cm in the plastic crystal phase (15 °C and ~ 3 × 10−3 S/cm in the molten state (25 °C. These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC. The EDLC was assembled and its performance was tested by cyclic voltammetry, AC impedance spectroscopy and galvanostatic charge-discharge methods. Specific capacitance values in the range of 4-7 F/g. (of electrode active material were obtained in the plastic crystal phase at 15 °C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

  18. Rational design of new electrolyte materials for electrochemical double layer capacitors

    Science.gov (United States)

    Schütter, Christoph; Husch, Tamara; Viswanathan, Venkatasubramanian; Passerini, Stefano; Balducci, Andrea; Korth, Martin

    2016-09-01

    The development of new electrolytes is a centerpiece of many strategies to improve electrochemical double layer capacitor (EDLC) devices. We present here a computational screening-based rational design approach to find new electrolyte materials. As an example application, the known chemical space of almost 70 million compounds is investigated in search of electrochemically more stable solvents. Cyano esters are identified as especially promising new compound class. Theoretical predictions are validated with subsequent experimental studies on a selected case. These studies show that based on theoretical predictions only, a previously untested, but very well performing compound class was identified. We thus find that our rational design strategy is indeed able to successfully identify completely new materials with substantially improved properties.

  19. Electrochemical cell studies based on non-aqueous magnesium electrolyte for electric double layer capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekaran, Ramasamy; Ishikawa, Masashi [Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita 564-8680 (Japan); Koh, Meiten; Yamauchi, Akiyoshi [Chemical Division, Fundamental Research Department, Daikin Industries Ltd., 1-1 Nishihitotsuya, Settsu 565-8585 (Japan)

    2010-01-15

    Performances of electric double layer capacitors (EDLCs) based on an activated carbon electrode with acetonitrile (ACN), propylene carbonate (PC), or a ternary electrolyte, i.e., PC:ethylene carbonate (EC):diethyl carbonate (DEC), at 1 mol dm{sup -3} of magnesium perchlorate [Mg(ClO{sub 4}){sub 2}] salt have been investigated. The electrochemical responses were studied by impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge experiments at 25 C in a three-electrode configuration. For a comparative evaluation, lithium perchlorate (LiClO{sub 4}) salt-based systems were also evaluated. All the observed results showed typical EDLC characteristics within the potential range between 0 and 1 V vs. an Ag/Ag{sup +} reference electrode. The Mg-based systems exhibited similar or rather better performances than the corresponding Li-based electrolytes; in particular, the rate capability of Mg-based ACN and PC electrolytes was much better than the corresponding Li-based electrolytes, indicating the high accessibility and utility of activated carbon pores by solvated Mg ions. (author)

  20. Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.

    Science.gov (United States)

    Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas

    2016-02-10

    Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3

  1. Electrochemical Properties of PANI as Single Electrode of Electrochemical Capacitors in Acid Electrolytes

    Directory of Open Access Journals (Sweden)

    Haihua Zhu

    2013-01-01

    Full Text Available The polyaniline (PANI powder with globular sponge-like morphology was prepared by chemical solution polymerization, and its morphology and chemical structure were characterized by scanning electron microscope (SEM and Fourier transform infrared spectroscopy (FTIR, respectively. The single electrode of electrochemical capacitor was made using the prepared PANI powder as active material and carbon paper as current collector. Electrochemical properties of PANI as a single electrode in 1 M HCl and 1 M H2SO4 electrolyte solution were tested by galvanostatic charge/discharge (GCD and cyclic voltammetry (CV techniques. It has been found that PANI has higher specific capacitance of 302.43 Fg−1, higher specific energy of 54.44 Wh·kg−1 at 0.5 Ag−1, and higher working potential in 1 M HCl than those in 1 M H2SO4.

  2. Investigation of Interface between Ge Electrodes and Ionic Liquid Electrolytes for Electric Double Layer Capacitors

    Science.gov (United States)

    Abeysinghe, R. M.; Oguchi, H.; Kuwano, H.

    2016-11-01

    This study discusses novel way of use of ionic liquids to develop Ge-based electrodes for electric double layer capacitors (EDLC). We found that ionic liquids change their electrochemical properties depending on the amount of the absorbed water. Wet ionic liquids work as solvents to dissolve Ge and make porous structures, whereas dry ones work as electrolytes of the EDLCs. The former property was used to increase surface area of the electrodes which is desired to increase the capacity of EDLCs. This method showed another advantage in contrast to the dry ionic liquids; wet ones could fill the complex Ge pores in parallel to porous structure formation. Finally, after porous formation, we dried the ionic liquid at 100 °C and prepared the EDLCs composed of Ge porous electrodes. Cyclic voltammetry and impedance measurements indicated that the obtained devices can work as EDLCs.

  3. Further studies of the anodic dissolution in sodium chloride electrolyte of aluminium alloys containing tin and gallium

    Science.gov (United States)

    Nestoridi, Maria; Pletcher, Derek; Wharton, Julian A.; Wood, Robert J. K.

    As part of a programme to develop a high power density, Al/air battery with a NaCl brine electrolyte, the high rate dissolution of an aluminium alloy containing tin and gallium was investigated in a small volume cell. The objective was to define the factors that limit aluminium dissolution in condition that mimic a high power density battery. In a cell with a large ratio of aluminium alloy to electrolyte, over a range of current densities the extent of dissolution was limited to ∼1000 C cm -2 of anode surface by a thick layer of loosely bound, crystalline deposit on the Al alloy anode formed by precipitation from solution. This leads to a large increase in impedance and acts as a barrier to transport of ions.

  4. Further studies of the anodic dissolution in sodium chloride electrolyte of aluminium alloys containing tin and gallium

    Energy Technology Data Exchange (ETDEWEB)

    Nestoridi, Maria; Pletcher, Derek [The School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Wharton, Julian A.; Wood, Robert J.K. [School of Engineering Sciences, The University, Southampton SO17 1BJ (United Kingdom)

    2009-09-05

    As part of a programme to develop a high power density, Al/air battery with a NaCl brine electrolyte, the high rate dissolution of an aluminium alloy containing tin and gallium was investigated in a small volume cell. The objective was to define the factors that limit aluminium dissolution in condition that mimic a high power density battery. In a cell with a large ratio of aluminium alloy to electrolyte, over a range of current densities the extent of dissolution was limited to {proportional_to}1000 C cm{sup -2} of anode surface by a thick layer of loosely bound, crystalline deposit on the Al alloy anode formed by precipitation from solution. This leads to a large increase in impedance and acts as a barrier to transport of ions. (author)

  5. Morphology, thermal, electrical and electrochemical stability of nano aluminium-oxide-filled polyvinyl alcohol composite gel electrolyte

    Indian Academy of Sciences (India)

    Navin Chand; Neelesh Rai; S L Agrawal; S K Patel

    2011-12-01

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase in the concentration of Al2O3 in composite gel electrolytes increases the amorphous characteristics of pure PVA. Bulk conductivity of composite gel electrolytes increases by an order of magnitude on addition of a nano filler. Maximum conductivity of 5.81 × 10-2 S/cm is observed for 6 wt% Al2O3-filled polymer gel composite electrolytes. Temperature dependence of electrical conductivity shows a combination of Arrhenius and Vogel–Tamman–Fulcher (VTF) nature. Maximum current stability during oxidation and reduction cycle is noticed for 6 wt% Al2O3-filled PVA composite electrolyte, viz. ±1.65 V.

  6. Cycle stability of the electrochemical capacitors patterned with vertically aligned carbon nanotubes in an LiPF6-based electrolyte

    Science.gov (United States)

    Chiou, Yi-Deng; Tsai, Dah-Shyang; Lam, Hoa Hung; Chang, Chuan-Hua; Lee, Kuei-Yi; Huang, Ying-Sheng

    2013-08-01

    The miniature ultracapacitors, with interdigitated electrodes of vertically aligned carbon nanotubes (VACNTs) and an inter-electrode gap of 20 μm, have been prepared in the LiPF6 organic electrolyte with and without PVdF-HFP gel. PVdF-HFP between two opposing electrodes enhances the device reliability, but lessens its power performance because of the extra diffusion resistance. Also noteworthy are the gel influences on the cycle stability. When the applied voltage is 2.0 or 2.5 V, both the LiPF6 and the gel capacitors exhibit excellent stability, typified by a retention ratio of >=95% after 10 000 cycles. Their coulombic efficiencies quickly rise up, and hold steady at 100%. Nonetheless, when the applied voltage is 3.5 or 4.0 V, the cycle stability deteriorates, since the negative electrode potential descends below 0.9 V (vs. Li), leading to electrolyte decomposition and SEI formation. For the LiPF6 capacitor, its retention ratio could be around 60% after 10 000 cycles and the coulombic efficiency of 100% is difficult to reach throughout its cycle life. On the other hand, the gel capacitor cycles energy with a much higher retention ratio, >80% after 10 000 cycles, and a better coulombic efficiency, even though electrolyte decomposition still occurs. We attribute the superior stability of the gel capacitor to its extra diffusion resistance which slows down the performance deterioration.

  7. Growth of L-Valinium Aluminium Chloride single crystal for OLED and super-capacitor applications

    Science.gov (United States)

    Kalaivani, D.; Vijayalakshmi, S.; Theras, J. Elberin Mary; Jayaraman, D.; Joseph, V.

    2015-12-01

    L-Valinium Aluminium Chloride (LVAC), a novel semi-organic material, was grown using slow evaporation under isothermal condition. The single crystal data reveal that the grown crystal belongs to monoclinic system. The SEM micrographs give clear picture about the surface morphology. Further, they confirm the inclusion of aluminium chloride into atomic sites of L-Valine. The compositional elements present in the crystal were identified through EDAX analysis. The mass spectral analysis was carried out to determine the molecular weight of the grown crystal. The optical transparency of the grown crystal was investigated by UV-vis-NIR spectrum. FTIR spectral study was used to identify the functional groups present in the grown material. The luminescence characteristics of grown material were analysed to confirm the effect of metal ion on the ligand. This property makes the material suitable for OLED application. The supercapacitive performance of the grown crystal was finally studied using cyclic voltammetry.

  8. Spectroscopic study of plasma during electrolytic oxidation of magnesium-aluminium alloys

    Science.gov (United States)

    Jovović, J.

    2014-12-01

    Plasma during Electrolytic Oxidation (PEO) of magnesium-aluminium alloys is studied in this work by means of Optical Emission Spectroscopy (OES). Spectral line shapes of the Hβ, Al II 704.21 nm and Mg II 448.11 nm line are analyzed to measure plasma electron number density Ne. From the Hβ line profile, two PEO processes characterized by relatively low electron number densities Ne ≈ 1015 cm-3 and Ne ≈ 2 × 1016 cm-3 were discovered while the shape and shift of Al II and Mg II lines revealed the third process characterized by large electron density Ne = (1-2) × 1017 cm-3. Low Ne processes, related with breakdown in gas bubbles and on oxide surface, are not influenced by anode material or electrolyte composition. The ejection of evaporated anode material through oxide layer is designated here as third PEO process. Using the Boltzmann plot technique, electron temperature of 4000 K and 33000 K is determined from relative intensities of Mg I and O II lines, respectively. Several difficulties in the analysis of spectral line shapes are met during this study and the ways to overcome some of the obstacles are demonstrated.

  9. Studies on electrical double layer capacitor with a low-viscosity ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate as electrolyte

    Indian Academy of Sciences (India)

    G P Pandey; S A Hashmi

    2013-08-01

    The performance of an electrical double layer capacitor (EDLC) composed of high surface area activated carbon electrodes and a new ionic liquid, 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIm]TCB, as the electrolyte has been investigated by impedance spectroscopy, cyclic voltammetry and galvanostatic charge–discharge studies. The high ionic conductivity (∼1.3 × 10-2 S cm-1 at 20 °C) and low viscosity (∼22 cP) of the ionic liquid, [EMIm]TCB, make it attractive as electrolyte for its use in EDLCs. The optimum capacitance value of 195.5 F g-1 of activated carbon has been achieved with stable cyclic performance.

  10. Performance evaluation of three-phase grid-connected photovoltaic inverters using electrolytic or polypropylene film capacitors

    OpenAIRE

    Karanayil, Baburaj; Agelidis, Vassilios; Pou Félix, Josep

    2014-01-01

    In grid-connected photovoltaic (PV) power stations, improving the life expectancy and long-term reliability of three-phase PV inverters is urgently needed to match the significantly higher lifetime of the PV modules. A key contribution toward such improvement is replacing the conventional electrolytic film capacitors by metallized polypropylene film ones. This paper presents a detailed evaluation of a conventional three-phase grid-connected PV inverter performance when replacing the electroly...

  11. Lifetime Estimation of Electrolytic Capacitors in Fuel Cell Power Converter at Various Confidence Levels

    DEFF Research Database (Denmark)

    Zhou, Dao; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    DC capacitors in power electronic converters are a major constraint on improvement of the power density and the reliability. In this paper, according to the degradation data of tested capacitors, the lifetime model of the component is analyzed at various confidence levels. Then, the mission profile...... based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in a fuel cell backup power converter operating in both standby mode and operation mode. The lifetime prediction of the capacitor banks at different confidence levels is also obtained....

  12. Lifetime Estimation of Electrolytic Capacitors in Fuel Cell Power Converter at Various Confidence Levels

    DEFF Research Database (Denmark)

    Zhou, Dao; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    DC capacitors in power electronic converters are a major constraint on improvement of the power density and the reliability. In this paper, according to the degradation data of tested capacitors, the lifetime model of the component is analyzed at various confidence levels. Then, the mission profi...... based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in a fuel cell backup power converter operating in both standby mode and operation mode. The lifetime prediction of the capacitor banks at different confidence levels is also obtained....

  13. Effect of the Electrolyte Temperature and the Current Density on a Layer Microhardness Generated by the Anodic Aluminium Oxidation

    Directory of Open Access Journals (Sweden)

    Emil Spišák

    2015-01-01

    Full Text Available The paper investigates the influence of the chemical composition and temperature of electrolyte, the oxidation time, voltage, and the current density on Vickers microhardness of aluminium oxide layers, at the same time. The layers were generated in the electrolytes with different concentrations of sulphuric and oxalic acids and surface current densities 1 A·dm−2, 3 A·dm−2, and 5 A·dm−2. The electrolyte temperature varied from −1.78°C to 45.78°C. The results have showed that while increasing the electrolyte temperature at the current density of 1 A·dm−2, the increase in the layer microhardness values is approximately by 66%. While simultaneously increasing the molar concentration of H2SO4 in the electrolyte, the growth rate of the microhardness value decreases. At the current density of 3 A·dm−2, by increasing the electrolyte temperature, a reduction in the microhardness of the generated layer occurs with the anodic oxidation time less than 25 min. The electrolyte temperature is not significant with the changing values of the layer microhardness at voltages less than 10.5 V.

  14. High energy density capacitor using coal tar pitch derived nanoporous carbon/MnO{sub 2} electrodes in aqueous electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Tomko, Timothy [Energy and Mineral Engineering, University Park, PA 16802 (United States); Rajagopalan, Ramakrishnan; Lanagan, Michael [Materials Research Institute, University Park, PA 16802 (United States); Foley, Henry C. [Department of Chemical Engineering, University Park, PA 16802 (United States)

    2011-02-15

    Asymmetric aqueous electrochemical capacitors with energy densities as high as 22 Wh kg{sup -1}, power densities of 11 kW kg{sup -1} and a cell voltage of 2 V were fabricated using cost effective, high surface carbon derived from coal tar pitch and manganese dioxide. The narrow pore size distribution of the activated carbon (mean pore size {proportional_to}0.8 nm) resulted in strong electroadsorption of protons making them suitable for use as negative electrodes. Amorphous manganese dioxide anodes were synthesized by chemical precipitation method with high specific capacitance (300 F g{sup -1}) in aqueous electrolytes containing bivalent cations. The fabricated capacitors demonstrated excellent cyclability with no signs of capacitance fading even after 1000 cycles. (author)

  15. Control Method for Achieving High Power Factor in Single-Phase to Three-Phase Converters without Electrolytic Capacitors

    Science.gov (United States)

    Yokoyama, Takahiro; Ohishi, Kiyoshi; Haga, Hitoshi; Shibata, Junji

    In this paper, we propose a method for the digital control of IPM motors in order to achieve a high power factor in single-phase to three-phase power converters without reactors or electrolytic capacitors. For achieving the unity power factor under any load condition and any speed condition, we propose a new digital control method that involves the use of a new feedback technique and a new feedforward technique on the source-current regulator side. The proposed digital control system is constructed by using DSP devices. In this paper, we also propose a new method for the compensation of one sampling delay time. The superior performance of the proposed method is demonstrated by experimental results. The experimental results were obtained using 1.5[kW] inverter system, which consists of a vector control system with a 14[μF] dc-link capacitor. The maximum power factor obtained in the experiments was 96.8[%].

  16. Synthesis and Characterization of Nanostructured Manganese Dioxide Used as Positive Electrode Material for Electrochemical Capacitor with Lithium Hydroxide Electrolyte

    Institute of Scientific and Technical Information of China (English)

    YUAN,An-Bao; ZHOU,Min; WANG,Xiu-Ling; SUN,Zi-Hong; WANG,Yu-Qin

    2008-01-01

    A nanostructured manganese dioxide electrode material was prepared using a solid-reaction route starting with MnCl2·4H2O and NH4HCO3, and its electrochemical performance as a positive electrode for MnO2/activated carbon hybrid supercapacitor with 1 mol·L-1 LiOH electrolyte was reported. The material was proved to be a mixture of nanostructured γ-MnO2 and α-MnO2 containing some bound water in the structure, which was characterized by X-ray diffraction analysis, infrared spectrum analysis, and transmission electron microscope observation. Electrochemical properties of the MnO2 electrode and the MnO2/AC capacitor were investigated by cyclic voltammetry, ac impedance and galvanostatic charge/discharge methods. Experimental results showed that the MnO2 electrode exhibited faradaic pseudocapacitance behavior and higher specific capacitance in 1 mol·L-1 LiOH electrolyte. The MnO2/AC hybrid capacitor with 1 mol·L-1 LiOH electrolyte presented excellent rate charge/discharge ability and cyclic stability.

  17. A Model-based Prognostics Methodology for Electrolytic Capacitors Based on Electrical Overstress Accelerated Aging

    Data.gov (United States)

    National Aeronautics and Space Administration — A remaining useful life prediction methodology for elec- trolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical...

  18. Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF{sub 6} electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Azam, M.A., E-mail: asyadi@utem.edu.my [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Jantan, N.H.; Dorah, N.; Seman, R.N.A.R.; Manaf, N.S.A. [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Kudin, T.I.T. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); Yahya, M.Z.A. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); National Defence University of Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia)

    2015-09-15

    Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF{sub 6} non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g{sup −1}. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g{sup −1} at a scan rate of 1 mV s{sup −1}.

  19. Solid-state electric double layer capacitors fabricated with plastic crystal based flexible gel polymer electrolytes: Effective role of electrolyte anions

    Energy Technology Data Exchange (ETDEWEB)

    Suleman, Mohd; Kumar, Yogesh; Hashmi, S.A., E-mail: sahashmi@physics.du.ac.in

    2015-08-01

    Flexible gel polymer electrolyte (GPE) thick films incorporated with solutions of lithium trifluoromethanesulfonate (Li-triflate or LiTf) and lithium bis trifluoromethane-sulfonimide (LiTFSI) in a plastic crystal succinonitrile (SN), entrapped in poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP) have been prepared and characterized. The films have been used as electrolytes in the electrical double layer capacitors (EDLCs). Coconut-shell derived activated carbon with high specific surface area (∼2100 m{sup 2} g{sup −1}) and mixed (micro- and meso-) porosity has been used as EDLC electrodes. The structural, thermal, and electrochemical characterization of the GPEs have been performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impedance measurements and cyclic voltammetry. The high ionic conductivity (∼10{sup −3} S cm{sup −1} at 25 °C), good electrochemical stability window (>4.0 V) and flexible nature of the free-standing films of GPEs show their competence in the fabrication of EDLCs. The EDLCs have been tested using electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge studies. The EDLCs using LiTf based electrolyte have been found to give higher values of specific capacitance, specific energy, power density (240–280 F g{sup −1}, ∼39 Wh kg{sup −1} and ∼19 kW kg{sup −1}, respectively) than the EDLC cell with LiTFSI based gel electrolyte. EDLCs have been found to show stable performance for ∼10{sup 4} charge–discharge cycles. The comparative studies indicate the effective role of electrolyte anions on the capacitive performance of the solid-state EDLCs. - Graphical abstract: Display Omitted - Highlights: • Flexible EDLCs with succinonitrile based gel electrolyte membranes are reported. • Anionic size of salts in gel electrolytes plays important role on capacitive performance. • Li-triflate incorporated gel electrolyte shows better

  20. Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?

    Science.gov (United States)

    Lian, Cheng; Liu, Honglai; Henderson, Douglas; Wu, Jianzhong

    2016-10-01

    The ionophobicity effect of nanoporous electrodes on the capacitance and the energy storage capacity of nonaqueous-electrolyte supercapacitors is studied by means of the classical density functional theory (DFT). It has been hypothesized that ionophobic nanopores may create obstacles in charging, but they store energy much more efficiently than ionophilic pores. In this study, we find that, for both ionic liquids and organic electrolytes, an ionophobic pore exhibits a charging behavior different from that of an ionophilic pore, and that the capacitance-voltage curve changes from a bell shape to a two-hump camel shape when the pore ionophobicity increases. For electric-double-layer capacitors containing organic electrolytes, an increase in the ionophobicity of the nanopores leads to a higher capacity for energy storage. Without taking into account the effects of background screening, the DFT predicts that an ionophobic pore containing an ionic liquid does not enhance the supercapacitor performance within the practical voltage ranges. However, by using an effective dielectric constant to account for ion polarizability, the DFT predicts that, like an organic electrolyte, an ionophobic pore with an ionic liquid is also able to increase the energy stored when the electrode voltage is beyond a certain value. We find that the critical voltage for an enhanced capacitance in an ionic liquid is larger than that in an organic electrolyte. Our theoretical predictions provide further understanding of how chemical modification of porous electrodes affects the performance of supercapacitors. The authors are saddened by the passing of George Stell but are pleased to contribute this article in his memory. Some years ago, DH gave a talk at a Gordon Conference that contained an approximation that George had demonstrated previously to be in error in one of his publications. Rather than making this point loudly in the discussion, George politely, quietly, and privately pointed this out

  1. A Comparison of Electrolytic Capacitors and Supercapacitors for Piezo-Based Energy Harvesting

    Science.gov (United States)

    2013-07-01

    electrolytic , and (e) 201 µF fast graphene supercapacitor. ........................................................4 Figure 5. IR drop of the... graphene arrays grown on nickel current collectors, and using 25% KOH electrolyte .* The capacitances reported in table 1 are measured values and differ...Sprague Electrolytic 212 µF 0.086 Ω 6.3 kHz 2.7 s 1.38 mJ JME Graphene 201 µF 0.0092 Ω 16 kHz 0.63 s 177 µJ (peak) *Measurement artifact Charging

  2. Synergistic effects of carboxymethyl cellulose and ZnO as alkaline electrolyte additives for aluminium anodes with a view towards Al-air batteries

    Science.gov (United States)

    Liu, Jie; Wang, Dapeng; Zhang, Daquan; Gao, Lixin; Lin, Tong

    2016-12-01

    The synergistic effects of carboxymethyl cellulose (CMC) and zinc oxide (ZnO) have been investigated as alkaline electrolyte additives for the AA5052 aluminium alloy anode in aluminium-air battery by the hydrogen evolution test, the electrochemical measurements and the surface analysis method. The combination of CMC and ZnO effectively retards the self-corrosion of AA5052 alloy in 4 M NaOH solution. A complex film is formed via the interaction between CMC and Zn2+ ions on the alloy surface. The carboxyl groups adsorbed on the surface of aluminium make the protective film more stable. The cathodic reaction process is mainly suppressed significantly. AA5052 alloy electrode has a good discharge performance in the applied electrolyte containing the composite CMC/ZnO additives.

  3. The Effects of Self-Discharge on the Performance of Symmetric Electric Double-Layer Capacitors and Active Electrolyte-Enhanced Supercapacitors: Insights from Modeling and Simulation

    Science.gov (United States)

    Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

    2017-02-01

    The effects of self-discharge on the performance of symmetric electric double-layer capacitors (EDLCs) and active electrolyte-enhanced supercapacitors were examined by incorporating self-discharge into electrochemical capacitor models during charging and discharging. The sources of self-discharge in capacitors were side reactions or redox reactions and several impurities and electric double-layer (EDL) instability. The effects of self-discharge during capacitor storage was negligible since it took a fully charged capacitor a minimum of 14.0 days to be entirely discharged by self-discharge in all conditions studied, hence self-discharge in storage condition can be ignored. The first and second charge-discharge cycle energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a capacitor of electrode effective conductivity α1 = 0.05 S/cm with only EDL instability self-discharge with current density J_{{VR}} = 1.25 × 10-3 A/cm2 were 72.33% and 72.34%, respectively. Also, energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a similar capacitor with both side reactions and redox reactions and EDL instability self-discharges with current densities J_{{VR}} = 0.00125 A/cm2 and J_{{{{VR}}1}} = 0.0032 A/cm2 were 38.13% and 38.14% respectively, compared with 84.24% and 84.25% in a similar capacitor without self-discharge. A capacitor with only EDL instability self-discharge and that with both side reactions and redox reactions and EDL instability self-discharge lost 9.73 Wh and 28.38 Wh of energy, respectively, through self-discharge during charging and discharging. Hence, EDLCs charging and discharging time is significantly dependent on the self-discharge rate which are too large to be ignored.

  4. Poly(Acrylic acid–Based Hybrid Inorganic–Organic Electrolytes Membrane for Electrical Double Layer Capacitors Application

    Directory of Open Access Journals (Sweden)

    Chiam-Wen Liew

    2016-05-01

    Full Text Available Nanocomposite polymer electrolyte membranes (NCPEMs based on poly(acrylic acid(PAA and titania (TiO2 are prepared by a solution casting technique. The ionic conductivity of NCPEMs increases with the weight ratio of TiO2.The highest ionic conductivity of (8.36 ± 0.01 × 10−4 S·cm−1 is obtained with addition of 6 wt % of TiO2 at ambient temperature. The complexation between PAA, LiTFSI and TiO2 is discussed in Attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR studies. Electrical double layer capacitors (EDLCs are fabricated using the filler-free polymer electrolyte or the most conducting NCPEM and carbon-based electrodes. The electrochemical performances of fabricated EDLCs are studied through cyclic voltammetry (CV and galvanostatic charge-discharge studies. EDLC comprising NCPEM shows the specific capacitance of 28.56 F·g−1 (or equivalent to 29.54 mF·cm−2 with excellent electrochemical stability.

  5. High energy density sodium-ion capacitors through co-intercalation mechanism in diglyme-based electrolyte system

    Science.gov (United States)

    Han, Pengxian; Han, Xiaoqi; Yao, Jianhua; Zhang, Lixue; Cao, Xiaoyan; Huang, Changshui; Cui, Gunglei

    2015-11-01

    A novel sodium-ion capacitor (NIC) was assembled using graphitic mesocarbon microbead anode and activated carbon cathode in diglyme-based electrolyte. Charge/discharge tests indicate that sodium ions can reversibly co-intercalated with diglyme solvent into graphite anode and show good rate performance. The energy densities of the NICs are as high as 93.5 and 86.5 Wh kg-1 at 573 and 2832 W kg-1 (equal to 4 C and 50 C) in the voltage window at 1-4 V, respectively. By optimizing the voltage ranges, the capacity retention of the NIC at 20 C is 98.3% even after 3000 cycles. Such superior electrochemical performance should be attributed to the reversible intercalated/deintercalated reaction of sodium ions and the formation of ternary graphite intercalation compounds in diglyme-based electrolyte. The present work pioneers new realms of hybrid energy storage system with high energy density, high power density and long cycle life.

  6. An ether-functionalised cyclic sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors

    Science.gov (United States)

    Neale, Alex R.; Murphy, Sinead; Goodrich, Peter; Schütter, Christoph; Hardacre, Christopher; Passerini, Stefano; Balducci, Andrea; Jacquemin, Johan

    2016-09-01

    A novel cyclic sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

  7. Electric double-layer capacitors with tea waste derived activated carbon electrodes and plastic crystal based flexible gel polymer electrolytes

    Science.gov (United States)

    Suleman, M.; Deraman, M.; Othman, M. A. R.; Omar, R.; Hashim, M. A.; Basri, N. H.; Nor, N. S. M.; Dolah, B. N. M.; Hanappi, M. F. Y. M.; Hamdan, E.; Sazali, N. E. S.; Tajuddin, N. S. M.; Jasni, M. R. M.

    2016-08-01

    We report a novel configuration of symmetrical electric double-layer capacitors (EDLCs) comprising a plastic crystalline succinonitrile (SN) based flexible polymer gel electrolyte, incorporated with sodium trifluoromethane sulfonate (NaTf) immobilised in a host polymer poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP). The cost-effective activated carbon powder possessing a specific surface area (SSA) of ~ 1700 m2g-1 containing a large proportion of meso-porosity has been derived from tea waste to use as supercapacitor electrodes. The high ionic conductivity (~3.6×10-3 S cm-1 at room temperature) and good electrochemical stability render the gel polymer electrolyte film a suitable candidate for the fabrication of EDLCs. The performance of the EDLCs has been tested by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge-discharge studies. The performance of the EDLC cell is found to be promising in terms of high values of specific capacitance (~270 F g-1), specific energy (~ 36 Wh kg-1), and power density (~ 33 kW kg-1).

  8. Insights into the effects of solvent properties in graphene based electric double-layer capacitors with organic electrolytes

    Science.gov (United States)

    Zhang, Shuo; Bo, Zheng; Yang, Huachao; Yang, Jinyuan; Duan, Liangping; Yan, Jianhua; Cen, Kefa

    2016-12-01

    Organic electrolytes are widely used in electric double-layer capacitors (EDLCs). In this work, the microstructure of planar graphene-based EDLCs with different organic solvents are investigated with molecular dynamics simulations. Results show that an increase of solvent polarity could weaken the accumulation of counter-ions nearby the electrode surface, due to the screen of electrode charges and relatively lower ionic desolvation. It thus suggests that solvents with low polarity could be preferable to yield high EDL capacitance. Meanwhile, the significant effects of the size and structure of solvent molecules are reflected by non-electrostatic molecule-electrode interactions, further influencing the adsorption of solvent molecules on electrode surface. Compared with dimethyl carbonate, γ-butyrolactone, and propylene carbonate, acetonitrile with relatively small-size and linear structure owns weak non-electrostatic interactions, which favors the easy re-orientation of solvent molecules. Moreover, the shift of solvent orientation in surface layer, from parallel orientation to perpendicular orientation relative to the electrode surface, deciphers the solvent twin-peak behavior near negative electrode. The as-obtained insights into the roles of solvent properties on the interplays among particles and electrodes elucidate the solvent influences on the microstructure and capacitive behavior of EDLCs using organic electrolytes.

  9. Study of ageing mechanisms of organic electrolyte super-capacitors based on activated carbons; Recherche des causes du vieillissement de supercondensateurs a electrolyte organique a base de carbones actives

    Energy Technology Data Exchange (ETDEWEB)

    Azais, Ph.

    2003-11-15

    The energy which is stored in electrochemical capacitors is proportional to the square of voltage. Consequently, the most attractive super-capacitors are those which operate in organic electrolyte medium, with an electrolyte potential window which theoretically can easily reach more than 3 V. However, even using lower values of voltage, there is a remarkable fading of the electrochemical characteristics with operating time, that is mainly characterized by capacitance loss and resistance increase. On a commercial point of view, these capacitors must be improved in order to reach the expected criterion of long operating life. In the presented work, we will determine some reasons of super-capacitors ageing in organic electrolyte (1 M solution of Et{sub 4}N{sup +} BF{sub 4}{sup -} in acetonitrile) and we will propose a treatment of activated carbon which noticeably improves the performance. A prolonged charging of electrochemical capacitors at 2.5 V, so called floating, results in gases formation and to a noticeable mass uptake of the electrodes. XPS and NMR analysis performed on carefully washed electrodes demonstrated the existence of decomposition products from the electrolyte, which are trapped in the pores of the activated carbon. These products block the pores, limiting the ions access to the active surface that causes the decay of electrochemical performances. Electrolyte decomposition is especially very high when the electrodes are constituted of carbons with a rich surface functionality, i.e. surface oxygenated groups and free radicals. Therefore, activated carbons have been submitted to thermal treatment, both in nitrogen and hydrogen atmosphere, allowing the oxygenated surface functionality to be noticeably depressed. Super-capacitors built with the treated materials have been submitted to floating during more than 2000 hours. Extremely good electrochemical performance are preserved with the electrodes obtained from activated carbons treated under hydrogen

  10. The study of aluminium anodes for high power density Al/air batteries with brine electrolytes

    Science.gov (United States)

    Nestoridi, Maria; Pletcher, Derek; Wood, Robert J. K.; Wang, Shuncai; Jones, Richard L.; Stokes, Keith R.; Wilcock, Ian

    Aluminium alloys containing small additions of both tin (∼0.1 wt%) and gallium (∼0.05 wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2 A cm -2 can be obtained at potentials close to the open circuit potential, ∼-1500 mV versus SCE. The tin exists in the alloys as a second phase, typically as ∼1 μm inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated.

  11. The study of aluminium anodes for high power density Al/air batteries with brine electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Nestoridi, Maria; Pletcher, Derek [School of Chemistry, The University, Southampton SO19 1BJ (United Kingdom); Wood, Robert J.K.; Wang, Shuncai [School of Engineering Sciences, The University, Southampton SO19 1BJ (United Kingdom); Jones, Richard L.; Stokes, Keith R.; Wilcock, Ian [dstl, Physical Sciences Department, Porton Down, Salisbury, Wilts SP4 0JQ (United Kingdom)

    2008-03-15

    Aluminium alloys containing small additions of both tin ({proportional_to}0.1 wt%) and gallium ({proportional_to}0.05 wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2 A cm{sup -2} can be obtained at potentials close to the open circuit potential, {proportional_to}-1500 mV versus SCE. The tin exists in the alloys as a second phase, typically as {proportional_to}1 {mu}m inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated. (author)

  12. Surface Morphology and Microstructure of Zinc Deposit From Imidazole with Zinc Chloride Low Temperature Molten Salt Electrolyte in The Presence of Aluminium Chloride

    Directory of Open Access Journals (Sweden)

    Shanmugasigamani Srinivasan, M. Selvam

    2013-07-01

    Full Text Available Low temperature molten salts have variety of applications in organic synthesis, catalytic processing, batteries and electrode position due to their air and water stability. They have wide potential window for their applications in voltage and temperature and hence there is a possibility to deposit metals which could not be deposited from aqueous electrolytes. Our aim and scope of our research was to deposit zinc from low temperature molten salt electrolyte (LTMS containing zinc salt in the presence of aluminium chloride at different current densities and to qualify the nature of deposits. We could identify the effect of current density on the deposit at low temperature molten salt electrolyte by analysing the nature of deposits using different instrumental techniques. Compact, adherent, dense fine grained deposits of zinc with average grain size of 40-150 nm could be obtained from low temperature molten salt electrolyte. (LTMS

  13. Molecular dynamics simulation studies of ionic liquid electrolytes for electric double layer capacitors

    Science.gov (United States)

    Hu, Zongzhi

    Molecular Dynamics (MD) simulation has been performed on various Electric Double Layer Capacitors (EDLCs) systems with different Room Temperature Ionic Liquids (RTILs) as well as different structures and materials of electrodes using a computationally efficient, low cost, united atom (UA)/explicit atom (EA) force filed. MD simulation studies on two 1-butyl-3-methylimidazolium (BMIM) based RTILs, i.e., [BMIM][BF4] and [BMIM][PF6], have been conducted on both atomic flat and corrugated graphite as well as (001) and (011) gold electrode surfaces to understand the correlations between the Electric Double Layer (EDL) structure and their corresponding differential capacitance (DC). Our MD simulations have strong agreement with some experimental data. The structures of electrodes also have a strong effect on the capacitance of EDLCs. MD simulations have been conducted on RTILs of N-methyl-N- propylpyrrolidinium [pyr13] and bis(fluorosulfonyl)imide (FSI) as well as [BMIM][PF6] on both curvature electrodes (fullerenes, nanotube, nanowire) and atomic flat electrode surfaces. It turns out that the nanowire electrode systems have the largest capacitance, following by fullerene systems. Nanotube electrode systems have the smallest capacitance, but they are still larger than that of atomically flat electrode system. Also, RTILs with slightly different chemical structure such as [Cnmim], n = 2, 4, 6, and 8, FSI and bis(trifluoromethylsulfonyl)imide (TFSI), have been examined by MD simulation on both flat and nonflat graphite electrode surfaces to study the effect of cation and anion's chemical structures on EDL structure and DC. With prismatic (nonflat) graphite electrodes, a transition from a bell-shape to a camel-shape DC dependence on electrode potential was observed with increase of the cation alkyl tail length for FSI systems. In contrast, the [Cnmim][TFSI] ionic liquids generated only a camel-shape DC on the rough surface regardless of the length of alkyl tail.

  14. Effect of electrolyte temperature on the thickness of anodic aluminium oxide (AAO layer

    Directory of Open Access Journals (Sweden)

    P. Michal

    2016-07-01

    Full Text Available Effect of electrolyte temperature on the thickness of resulting oxide layer has been studied. Unlike previous published studies this article was aimed to monitor the relationship between electrolyte temperature and resulting AAO layer thickness in interaction with other input factors affecting during anodizing process under special process condition, i.e. lower concentration of sulphuric acid, oxalic acid, boric acid and sodium chloride. According to Design of Experiments (DOE 80 individual test runs of experiment were carried out. Using statistical analysis and artificial intelligence for evaluation, the computational model predicting the thickness of oxide layer in the range from 5 / μm to 15 / μm with tolerance ± 0,5 / μm was developed.

  15. Electrolytic surface hardening of steel,cast iron and aluminium-bronze

    Institute of Scientific and Technical Information of China (English)

    Suhas Keshav Paknikar

    2006-01-01

    Electrolytic hardening process was developed in USSR in the 1950s. The process was developed but was not commercially exploited. There is no evidence of work done on this process in India. The author has done this original work applied to different materials like steel,cast iron and aluminum-bronze. This paper gives details of microstructural transformations along with hardness value achieved. There is vital scope for this process to become viable for surface hardening and selective hardening of small components.

  16. Corrosion properties of plasma electrolytic oxidation coatings on an aluminium alloy – The effect of the PEO process stage

    Energy Technology Data Exchange (ETDEWEB)

    Dehnavi, Vahid, E-mail: vdehnavi@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, N6A 5B9 ON (Canada); Shoesmith, David W., E-mail: dwshoesm@uwo.ca [Surface Science Western, Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Luan, Ben Li, E-mail: Ben.Luan@nrc-cnrc.gc.ca [National Research Council Canada, 800 Collip Circle, London, N6G4X8 ON (Canada); Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Yari, Mehdi, E-mail: myari@uwo.ca [Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Liu, Xing Yang, E-mail: XingYang.Liu@nrc-cnrc.gc.ca [National Research Council Canada, 800 Collip Circle, London, N6G4X8 ON (Canada); Rohani, Sohrab, E-mail: srohani@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, N6A 5B9 ON (Canada)

    2015-07-01

    Plasma electrolytic oxidation (PEO) coatings were grown on an aluminium alloy substrate using different processing parameters which enabled samples to be coated to different stages of the PEO process. Electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques were employed to investigate the impedance properties of the resulting oxide coatings which will determine the corrosion performance of the coated alloy. Scanning electron microscopy was used to relate the morphology of the coatings with their corrosion performance. A direct relationship was found between the stage of the PEO process, which affects the microstructure of the coatings, and the corrosion performance. Coating thickness and phase composition did not have any measurable influence on coating corrosion performance. To some degree corrosion performance could be tailored by the processing parameters. - Highlights: • Corrosion performance of PEO coatings was found to be dependent on coating stage. • The PEO stage determined by the process parameters controlled coatings morphology. • Samples coated at the end of stage 3 demonstrated better corrosion properties. • Coating thickness and phase composition showed no influence on corrosion resistance.

  17. Effects of cathodic voltages on structure and wear resistance of plasma electrolytic oxidation coatings formed on aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qingbiao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Science, Lanzhou University of Technology, Lanzhou 730050 (China); Liang, Jun, E-mail: jliang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Baixing; Peng, Zhenjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Qing [School of Science, Lanzhou University of Technology, Lanzhou 730050 (China)

    2014-04-01

    Highlights: • The PEO coating growth rate increased with the cathodic voltage increasing. • Higher cathodic voltage resulted in more compact coating structure. • The compact structure led to low surface roughness and high wear resistance. - Abstract: Plasma electrolytic oxidation (PEO) coatings were prepared on aluminium alloy using pulsed bipolar power supply at constant anodic voltage and different cathodic voltages. The samples were prepared to attain the same coating thickness by adjusting the processing time. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and tribometer were employed to investigate the microstructure, element content, phase composition and wear resistance of the coatings respectively. It was found that the coating growth rate enhanced obviously and the coatings exhibited a more compact structure with thicker inner layer and lower surface roughness when the cathodic voltage increased. The coatings were mainly composed of crystalline γ-Al{sub 2}O{sub 3} and amorphous silicate oxides and their relative content changed with the cathodic voltage. The wear resistance of the coatings improved significantly with the increase of cathodic voltage.

  18. Strong Photo-Amplification Effects in Flexible Organic Capacitors with Small Molecular Solid-State Electrolyte Layers Sandwiched between Photo-Sensitive Conjugated Polymer Nanolayers

    Science.gov (United States)

    Lee, Hyena; Kim, Jungnam; Kim, Hwajeong; Kim, Youngkyoo

    2016-02-01

    We demonstrate strong photo-amplification effects in flexible organic capacitors which consist of small molecular solid-state electrolyte layers sandwiched between light-sensitive conjugated polymer nanolayers. The small molecular electrolyte layers were prepared from aqueous solutions of tris(8-hydroxyquinoline-5-sulfonic acid) aluminum (ALQSA3), while poly(3-hexylthiophene) (P3HT) was employed as the light-sensitive polymer nanolayer that is spin-coated on the indium-tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) film substrates. The resulting capacitors feature a multilayer device structure of PET/ITO/P3HT/ALQSA3/P3HT/ITO/PET, which were mechanically robust due to good adhesion between the ALQSA3 layers and the P3HT nanolayers. Results showed that the specific capacitance was increased by ca. 3-fold when a white light was illuminated to the flexible organic multilayer capacitors. In particular, the capacity of charge storage was remarkably (ca. 250-fold) enhanced by a white light illumination in the potentiostatic charge/discharge operation, and the photo-amplification functions were well maintained even after bending for 300 times at a bending angle of 180o.

  19. Electrolytic surface hardening of steel,castiron and aluminium-bronze

    Directory of Open Access Journals (Sweden)

    Suhas Keshav Paknik a r

    2006-08-01

    Full Text Available Electrolytic hardening process w as developed in USSR in the 1950s. The process w as developed but w as not com m ercially exploited. There is no evidence of w ork done on this process in India. The author has done this originalw ork applied to different m aterials like steel, castiron and alum inum -bronze.This paper gives details ofm icrostructuraltransform ations along w ith hardness value achieved. There is vitalscope for this process to becom e viable for surfacehardening and selective hardening ofsm allcom ponents.

  20. Effects of Anode Wettability and Slots on Anodic Bubble Behavior Using Transparent Aluminium Electrolytic Cells

    Science.gov (United States)

    Zhao, Zhibin; Gao, Bingliang; Feng, Yuqing; Huang, Yipeng; Wang, Zhaowen; Shi, Zhongning; Hu, Xianwei

    2017-02-01

    Transparent aluminum electrolytic cells were used to study the effects of anode wettability and slots on bubble behavior in a similar environment to that used in industrial cells. Observations were conducted using two types of transparent cells, one with side-observation and the other with a bottom-observation cell design. Anodic bubbles rising process in the side channel is strongly affected by the wettability of the anode. After rising a short distance, the bubbles detach from the anode vertical surface at good-wetting anode cases, while the bubbles still attach to the vertical surface at poor-wetting anode cases. Anode slots of width of 4 mm are able to prevent smaller bubbles from coalescing into larger bubbles and thus decrease the bubble size and gas coverage on the anode. Anode slots also make a contribution in slightly reducing bubble thickness. With the presence of slots, the bubble-induced cell voltage oscillation decreases as well.

  1. Spectroscopic study of plasma during electrolytic oxidation of magnesium- and aluminium-alloy

    Science.gov (United States)

    Jovović, J.; Stojadinović, S.; Šišović, N. M.; Konjević, N.

    2012-10-01

    We present the results of an optical emission spectroscopy study of Plasma during Electrolytic Oxidation (PEO) of magnesium- and aluminum-alloy. Plasma electron number density Ne diagnostics is performed either from the Hβ line shape or from the width or shift of non-hydrogenic ion lines of aluminum and magnesium. The line profile analysis of the Hβ suggests presence of two PEO processes characterized by relatively low electron number densities Ne≈1.2×1015 cm-3 and Ne≈2.3×1016 cm-3. Apart from these two low Ne processes, there is the third one related to the ejection of evaporated anode material through micro-discharge channels. This process is characterized by larger electron density Ne=(1.2-1.6)1017 cm-3, which is detected from the shape and shift of aluminum and magnesium singly charged ion lines. Two low Ne values detected from the Hβ and large Ne measured from the widths and shift of ion lines suggest presence of three types of discharges during PEO with aluminum- and magnesium-alloy anode. On the basis of present and earlier results one can conclude that low Ne processes do not depend upon anode material or electrolyte composition.The electron temperature of 4000 K and 33,000 K are determined from relative intensities of Mg I and O II lines, respectively. The attention is drawn to the possibility of Ne application for Te evaluation using Saha equation what is of importance for PEO metal plasma characterization. During the course of this study, difficulties in the analysis of spectral line shapes are encountered and the ways to overcome some of the obstacles are demonstrated.

  2. Boron cross-linked graphene oxide/polyvinyl alcohol nanocomposite gel electrolyte for flexible solid-state electric double layer capacitor with high performance

    KAUST Repository

    Huang, Yi-Fu

    2014-06-01

    A new family of boron cross-linked graphene oxide/polyvinyl alcohol (GO-B-PVA) nanocomposite gels is prepared by freeze-thaw/boron cross-linking method. Then the gel electrolytes saturated with KOH solution are assembled into electric double layer capacitors (EDLCs). Structure, thermal and mechanical properties of GO-B-PVA are explored. The electrochemical properties of EDLCs using GO-B-PVA/KOH are investigated, and compared with those using GO-PVA/KOH gel or KOH solution electrolyte. FTIR shows that boron cross-links are introduced into GO-PVA, while the boronic structure inserted into agglomerated GO sheets is demonstrated by DMA analysis. The synergy effect of the GO and the boron crosslinking benefits for ionic conductivity due to unblocking ion channels, and for improvement of thermal stability and mechanical properties of the electrolytes. Higher specific capacitance and better cycle stability of EDLCs are obtained by using the GO-B-PVA/KOH electrolyte, especially the one at higher GO content. The nanocomposite gel electrolytes with excellent electrochemical properties and solid-like character are candidates for the industrial application in high-performance flexible solid-state EDLCs. © 2014 Elsevier Ltd.

  3. Situation and Outlook of the High-Voltage Electrolytic Capacitor%高压电解电容器现状及展望

    Institute of Scientific and Technical Information of China (English)

    陈永真

    2012-01-01

    简要地回顾了电解电容器的发展历程,分析了各种电子照明类电力电子电路中高压电解电容器的工作状态及对电解电容器性能的要求;阐述了带有功率因数校正的电力电子电路中电解电容器的工作状态不在以滤除100Hz及其谐波分量的电流为主,而是主要滤除功率因数校正电路和逆变器所产生的交流电流分量为主;现在国产高压电解电容器仍以100Hz的参数为设计依据设计的高压电解电容器将不适应带有功率因数校正的电力电子线路。最后提出了高压电解电容器的发展趋势:高频低阻、可承受更高的纹波电流。%The development history of the high-voltage capacitor was briefly reviewed firsdy. Working condition and performance requirement of the high-voltage capacitor employed in various power electronic circuits for electrical lighting was also analyzed. The working condition of electrolytic capacitor utilized in power electronic circuit with PFC function is mainly focusing on filtering out the current of alternating component generated by PFC inverter, not the 100Hz and its harmonic component current. At present, the high-voltage electrolytic capacitor made in China is still designed and manufactured at the standard of 100Hz, which no longer fit for power electronic circuit with PFC function. Finally, the development trend of the high-voltage electrolytic capacitor was put forward with low resistance at high frequent and endurability of higher ripple current.

  4. Study on frequency characteristic of Al electrolytic capacitor%铝电解电容器频率特性研究

    Institute of Scientific and Technical Information of China (English)

    韦春才; 董海青

    2000-01-01

    This paper studied the change law of the isotonic series-wound capacitor,the isotonic series-wound resistance,impedance and the ullage tgδ of the Al electrolytic capacitor as frequencies of AC power.It was proved that there was a superior diversity on the value of above factors between practical Al electrolytic capacitor and the ideal one at different frequencies.The main factor affecting the frequency characteristic were given as the following:the coefficient of corrosion of the Al foil surfaces the figure of the hole of scorrosion,and the character of the oxide film on the surface of the anode and cathode;the fabric of the unimpregnated liner in the capacitor,as well as the resistance and steeping of the working electrolyte and the construction of the capacitor.%研究了铝电解电容器在不同频率的交流电压下工作时,其等效串联电容上述各、等效串联电阻、阻实验表明,抗和损耗tgδ值随频率的变化情况。实验证明,实际的铝电解电容器在不同工作频率下的值与理想的铝电解电容器相比有较大差异。影响频率特性的主要因素有:阴极和阳极铝箔表面腐蚀系数的大小及腐蚀坑洞的形状;阴极和阳极铝箔表面氧化膜的性质;电容器中衬垫纸的构造;工作电解液的电阻和浸渍情况以及电容器的内外结构尺寸等。

  5. High performance solid-state electric double layer capacitor from redox mediated gel polymer electrolyte and renewable tamarind fruit shell derived porous carbon.

    Science.gov (United States)

    Senthilkumar, S T; Selvan, R Kalai; Melo, J S; Sanjeeviraja, C

    2013-11-13

    The activated carbon was derived from tamarind fruit shell and utilized as electrodes in a solid state electrochemical double layer capacitor (SSEDLC). The fabricated SSEDLC with PVA (polyvinyl alcohol)/H2SO4 gel electrolyte delivered high specific capacitance and energy density of 412 F g(-1) and 9.166 W h kg(-1), respectively, at 1.56 A g(-1). Subsequently, Na2MoO4 (sodium molybdate) added PVA/H2SO4 gel electrolyte was also prepared and applied for SSEDLC, to improve the performance. Surprisingly, 57.2% of specific capacitance (648 F g(-1)) and of energy density (14.4 Wh kg(-1)) was increased while introducing Na2MoO4 as the redox mediator in PVA/H2SO4 gel electrolyte. This improved performance is owed to the redox reaction between Mo(VI)/Mo(V) and Mo(VI)/Mo(IV) redox couples in Na2MoO4/PVA/H2SO4 gel electrolyte. Similarly, the fabricated device shows the excellent capacitance retention of 93% for over 3000 cycles. The present work suggests that the Na2MoO4 added PVA/H2SO4 gel is a potential electrolyte to improve the performance instead of pristine PVA/H2SO4 gel electrolyte. Based on the overall performance, it is strongly believed that the combination of tamarind fruit shell derived activated carbon and Na2MoO4/PVA/H2SO4 gel electrolyte is more attractive in the near future for high performance SSEDLCs.

  6. Towards A Model-based Prognostics Methodology for Electrolytic Capacitors: A Case Study Based on Electrical Overstress Accelerated Aging

    Data.gov (United States)

    National Aeronautics and Space Administration — A remaining useful life prediction methodology for elec- trolytic capacitors is presented. This methodology adopts a Kalman filter approach in conjunction with an...

  7. Vanadium Oxide Electrochemical Capacitors: An Investigation into Aqueous Capacitive Degradation, Alternate Electrolyte-Solvent Systems, Whole Cell Performance and Graphene Oxide Composite Electrodes

    Science.gov (United States)

    Engstrom, Allison Michelle

    Vanadium oxide has emerged as a potential electrochemical capacitor material due to its attractive pseudocapacitive performance; however, it is known to suffer from capacitive degradation upon sustained cycling. In this work, the electrochemical cycling behavior of anodically electrodeposited vanadium oxide films with various surface treatments in aqueous solutions is investigated at different pH. Quantitative compositional analysis and morphological studies provide additional insight into the mechanism responsible for capacitive degradation. Furthermore, the capacitance and impedance behavior of vanadium oxide electrochemical capacitor electrodes is compared for both aqueous and nonaqueous electrolyte-solvent systems. Alkali metal chloride and bromide electrolytes were studied in aqueous systems, and nonaqueous systems containing alkali metal bromides were studied in polar aprotic propylene carbonate (PC) or dimethyl sulfoxide (DMSO) solvents. The preferred aqueous and nonaqueous systems identified in the half-cell studies were utilized in symmetric vanadium oxide whole-cells. An aqueous system utilizing a 3.0 M NaCl electrolyte at pH 3.0 exhibited an excellent 96% capacitance retention over 3000 cycles at 10 mV s-1. An equivalent system tested at 500 mV s-1 displayed an increase in capacitance over the first several thousands of cycles, and eventually stabilized over 50,000 cycles. Electrodes cycled in nonaqueous 1.0 M LiBr in PC exhibited mostly non-capacitive charge-storage, and electrodes cycled in LiBr-DMSO exhibited a gradual capacitive decay over 10,000 cycles at 500 mV s-1. Morphological and compositional analyses, as well as electrochemical impedance modeling, provide additional insight into the cause of the cycing behavior. Lastly, reduced graphene oxide and vanadium oxide nanowire composites have been successfully synthesized using electrophoretic deposition for electrochemical capacitor electrodes. The composite material was found to perform with a

  8. Dimensional stability and electrochemical behaviour of ZrO2 incorporated electrospun PVdF-HFP based nanocomposite polymer membrane electrolyte for Li-ion capacitors

    Science.gov (United States)

    Solarajan, Arun Kumar; Murugadoss, Vignesh; Angaiah, Subramania

    2017-01-01

    Different weight percentages of ZrO2 (0, 3, 5, 7 and 10 wt%) incorporated electrospun PVDF-HFP nanocomposite polymer membranes (esCPMs) were prepared by electrospinning technique. They were activated by soaking in 1 M LiPF6 containing 1:1 volume ratio of EC : DMC (ethylene carbonate:dimethyl carbonate) to get electrospun nanocomposite polymer membrane electrolytes (esCPMEs). The influence of ZrO2 on the physical, mechanical and electrochemical properties of esCPM was studied in detail. Finally, coin type Li-ion capacitor cell was assembled using LiCo0.2Mn1.8O4 as the cathode, Activated carbon as the anode and the esCPME containing 7 wt% of ZrO2 as the separator, which delivered a discharge capacitance of 182.5 Fg−1 at the current density of 1Ag−1 and retained 92% of its initial discharge capacitance even after 2,000 cycles. It revealed that the electrospun PVdF-HFP/ZrO2 based nanocomposite membrane electrolyte could be used as a good candidate for high performance Li-ion capacitors.

  9. An innovative concept of use of redox-active electrolyte in asymmetric capacitor based on MWCNTs/MnO2 and Fe2O3 thin films

    Science.gov (United States)

    Chodankar, Nilesh R.; Dubal, Deepak P.; Lokhande, Abhishek C.; Patil, Amar M.; Kim, Jin H.; Lokhande, Chandrakant D.

    2016-12-01

    In present investigation, we have prepared a nanocomposites of highly porous MnO2 spongy balls and multi-walled carbon nanotubes (MWCNTs) in thin film form and tested in novel redox-active electrolyte (K3[Fe(CN)6] doped aqueous Na2SO4) for supercapacitor application. Briefly, MWCNTs were deposited on stainless steel substrate by “dip and dry” method followed by electrodeposition of MnO2 spongy balls. Further, the supercapacitive properties of these hybrid thin films were evaluated in hybrid electrolyte ((K3[Fe(CN)6 doped aqueous Na2SO4). Thus, this is the first proof-of-design where redox-active electrolyte is applied to MWCNTs/MnO2 hybrid thin films. Impressively, the MWCNTs/MnO2 hybrid film showed a significant improvement in electrochemical performance with maximum specific capacitance of 1012 Fg‑1 at 2 mA cm‑2 current density in redox-active electrolyte, which is 1.5-fold higher than that of conventional electrolyte (Na2SO4). Further, asymmetric capacitor based on MWCNTs/MnO2 hybrid film as positive and Fe2O3 thin film as negative electrode was fabricated and tested in redox-active electrolytes. Strikingly, MWCNTs/MnO2//Fe2O3 asymmetric cell showed an excellent supercapacitive performance with maximum specific capacitance of 226 Fg‑1 and specific energy of 54.39 Wh kg‑1 at specific power of 667 Wkg‑1. Strikingly, actual practical demonstration shows lightning of 567 red LEDs suggesting “ready-to sell” product for industries.

  10. Electrochemical performances of electric double layer capacitor with UV-cured gel polymer electrolyte based on poly[(ethylene glycol)diacrylate]-poly(vinylidene fluoride) blend

    Energy Technology Data Exchange (ETDEWEB)

    Chunmo Yang; Joongkee Lee; Wonil Cho; Byungwon Cho [Korea Inst. of Science and Technology, Eco-Nano Research Center, Seoul (Korea); Jehbeck Ju [Hongik Univ., Dept. of Chemical Engineering, Seoul (Korea)

    2005-03-01

    Poly[(ethylene glycol)diacrylate]-poly(vinylidene fluoride), a gel polymer blend with ethylene carbonate:dimethyl carbonate:ethylmethyl carbonate (EC:DMC:EMC, 1:1:1 volume ratio) and containing 1.0 M of lithium hexafluoro phosphate (LiPF{sub 6}) as liquid components, is employed as a gel polymer electrolyte for an electric double layer capacitor (EDLC). Its electrochemical characteristics is compared with that of liquid organic electrolyte mixture of ethylene carbonate, dimethyl carbonate and ethylmethyl carbonate in a 1:1:1 volume ratio containing 1.0 M LiPF{sub 6} salt. The specific surface area of the activated carbon powder as an active material is 1908 m{sup 2}/g. Liquid poly[(ethylene glycol)diacrylate] (PEGDA) oligomer with a high retention capability of liquid electrolytes is cured by UV irradiation and poly(vinylidene fluoride)-hexafluoropropylene (PVdF-HFP) copolymer with a porous structure endows polymer matrix with high mechanical strength. The specific capacitance of EDLC using the gel polymer electrolyte (GPE-EDLC) shows 120 F/g, which is better than the liquid organic electrolyte. Good cycling efficiency is observed for a GPE-EDLC with high retention capability of liquid components. The high specific capacitance and good cycling efficiency are most likely due to the polarization resistance of EDLC with the gel polymer electrolyte, which is lower than the liquid organic electrolyte. This may result from the distinguished adhesion between the activated carbon electrode and the gel polymer electrolyte, as well as high retention capability of liquid components. Power densities of GPE-EDLC and LOE-EDLC shows 1.88 kW/kg and 1.21 kW/kg, respectively. However, the energy densities are low in both electrolytes. The GPE-EDLC exhibits rectangular cyclic voltammogram similar to an ideal EDLC within operating voltage range of 0 V-2.5 V. It should be noted that a region of electric double layer means a wide voltage and a rapid formation. Redox currents of both

  11. Electrochemical performances of electric double layer capacitor with UV-cured gel polymer electrolyte based on poly[(ethylene glycol)diacrylate]-poly(vinylidene fluoride) blend

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chun-Mo [Eco-Nano Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)]. E-mail: ycm@kist.re.kr; Ju, Jeh Beck [Department of Chemical Engineering, Hongik University, Seoul 121-791 (Korea, Republic of); Lee, Joong Kee [Eco-Nano Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Cho, Won Il [Eco-Nano Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Cho, Byung Won [Eco-Nano Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)

    2005-03-01

    Poly[(ethylene glycol)diacrylate]-poly(vinylidene fluoride), a gel polymer blend with ethylene carbonate:dimethyl carbonate:ethylmethyl carbonate (EC:DMC:EMC, 1:1:1 volume ratio) and containing 1.0 M of lithium hexafluoro phosphate (LiPF{sub 6}) as liquid components, is employed as a gel polymer electrolyte for an electric double layer capacitor (EDLC). Its electrochemical characteristics is compared with that of liquid organic electrolyte mixture of ethylene carbonate, dimethyl carbonate and ethylmethyl carbonate in a 1:1:1 volume ratio containing 1.0 M LiPF{sub 6} salt. The specific surface area of the activated carbon powder as an active material is 1908 m{sup 2}/g. Liquid poly[(ethylene glycol)diacrylate] (PEGDA) oligomer with a high retention capability of liquid electrolytes is cured by UV irradiation and poly(vinylidene fluoride)-hexafluoropropylene (PVdF-HFP) copolymer with a porous structure endows polymer matrix with high mechanical strength. The specific capacitance of EDLC using the gel polymer electrolyte (GPE-EDLC) shows 120 F/g, which is better than the liquid organic electrolyte. Good cycling efficiency is observed for a GPE-EDLC with high retention capability of liquid components. The high specific capacitance and good cycling efficiency are most likely due to the polarization resistance of EDLC with the gel polymer electrolyte, which is lower than the liquid organic electrolyte. This may result from the distinguished adhesion between the activated carbon electrode and the gel polymer electrolyte, as well as high retention capability of liquid components. Power densities of GPE-EDLC and LOE-EDLC shows 1.88 kW/kg and 1.21 kW/kg, respectively. However, the energy densities are low in both electrolytes. The GPE-EDLC exhibits rectangular cyclic voltammogram similar to an ideal EDLC within operating voltage range of 0 V-2.5 V. It should be noted that a region of electric double layer means a wide voltage and a rapid formation. Redox currents of both

  12. Performance of electrical double layer capacitors fabricated with gel polymer electrolytes containing Li{sup +} and K{sup +}-salts: A comparison

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Manoj K., E-mail: mmanoj.ssi@gmail.com; Hashmi, S. A. [Department of Physics & Astrophysics, University of Delhi, Delhi-110007 (India)

    2015-06-24

    The comparative performance of the solid-state electrical double layer capacitors (EDLCs) based on the multiwalled carbon nanotube (MWCNT) electrodes and poly (vinaylidinefluoride-co-hexafluoropropyline) (PVdF-HFP) based gel polymer electrolytes (GPEs) containing potassium and lithium salts have been studied. The room temperature ionic conductivity of the GPEs have been found to be ∼3.8×10{sup −3} and 5.9×10{sup −3} S cm{sup −1} for lithium and potassium based systems. The performance of EDLC cells studied by impedance spectroscopy, cyclic voltammetry and constant current charge-discharge techniques, indicate that the EDLC with potassium salt containing GPE shows excellent performance almost equivalent to the EDLC with Li-salt-based GPE.

  13. Factors influencing high voltage performance of coconut char derived carbon based electrical double layer capacitor made using acetonitrile and propylene carbonate based electrolytes

    Science.gov (United States)

    Hu, Changzheng; Qu, Weiguo; Rajagopalan, Ramakrishnan; Randall, Clive

    2014-12-01

    Symmetric EDLCs made using high purity carbon electrodes derived from coconut char were tested using 1 M Tetraethylammonium hexafluorophosphate dissolved in two different solvents namely acetonitrile and propylene carbonate. The cell voltage of the capacitor made using propylene carbonate can be extended to 3.5 V and it exhibited good cycling and thermal stability upto 70 °C while the voltage was limited to below 3.0 V in acetonitrile. XPS analysis of the positive and negative electrodes of EDLCs post cycling showed that the primary degradation products were related to ring opening reactions in propylene carbonate based electrolytes while water played a key role in degradation of acetonitrile based EDLCs.

  14. 电解-电化学混合电容器的制备与性能%Fabrication and Performance of Electrolytic-Electrochemical Hybrid Capacitors

    Institute of Scientific and Technical Information of China (English)

    杨斌; 吴慧; 胡颂伟; 吕惠玲; 宋晔; 朱绪飞

    2013-01-01

      为解决电化学电容器工作电压过低的问题,本文以钽电解电容器的烧结型钽块为阳极,聚苯胺(PANI)/TiO2电化学电容器复合电极为阴极,成功制备了高能量密度、高工作电压的电解-电化学混合电容器. PANI/TiO2复合电极是通过在多孔阳极氧化钛纳米管阵列中电化学聚合PANI制得.该阴极具有优良的倍率特性,当平均功率密度为0.55 mW·cm-2时,对应的比容量仍达到10.0 mF·cm-2.由于与电解电容器复合,该混合电容器的单元工作电压可高达100 V.而且电化学电容器阴极的比容量远大于阳极,故阴极所需尺寸远小于阳极,节省的空间可用于增大阳极尺寸,从而使混合电容器的比容量极大提高.所制备的混合电容器体积能量密度和质量能量密度分别是钽电解电容器的4倍和3倍.将该混合电容器在100 V下进行短路充放电实验,循环10000次后发现容量未衰减,等效串联电阻未增加,显示出极好的循环稳定性和功率特性.计算表明其最大功率密度高达847.5 W·g-1.电化学阻抗谱显示其具有优良的阻抗特性和频率特性.%To solve the issue of comparatively low operation voltage of electrochemical capacitors, a hybrid capacitor consisting of the anode electrode of tantalum electrolytic capacitor and the cathode electrode of polyaniline (PANI)/TiO2 with high energy density and high working voltage was developed. The PANI/TiO2 composite electrode for use as the capacitor cathode was prepared by in situ electrochemical polymerization of aniline in porous anodic titania nanotube arrays on titanium foil substrates. The composite electrode showed good rate capability with a specific capacitance of 10.0 mF·cm-2 and a high power density of 0.55 mW·cm-2. Using a dielectric coated anode electrode, the single-cell hybrid capacitor could withstand working voltages as high as 100 V. As the PANI/TiO2 composite cathode only requires a

  15. Usage of Neural Network to Predict Aluminium Oxide Layer Thickness

    OpenAIRE

    2015-01-01

    This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of...

  16. Fabrication of a micro-porous Ti–Zr alloy by electroless reduction with a calcium reductant for electrolytic capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Tatsuya, E-mail: kiku@eng.hokudai.ac.jp [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Yoshida, Masumi [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Taguchi, Yoshiaki [Graduate School of Chemical Science and Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Habazaki, Hiroki; Suzuki, Ryosuke O. [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2014-02-15

    Highlights: • A metallic Ti–Zr alloy was obtained by electroless reduction for capacitor applications. • The reduction mechanisms were studied by SEM, XRD, EPMA, and an oxygen analyzer. • The alloy was obtained by electroless reduction in the presence of excess calcium reductant. • A micro-porous Ti–Zr alloy was successfully obtained. • The alloy has a low oxygen content and a large surface area. -- Abstract: A metallic titanium and zirconium micro-porous alloy for electrolytic capacitor applications was produced by electroless reduction with a calcium reductant in calcium chloride molten salt at 1173 K. Mixed TiO{sub 2}–70 at%ZrO{sub 2} oxides, metallic calcium, and calcium chloride were placed in a titanium crucible and heated under argon atmosphere to reduce the oxides with the calcium reductant. A metallic Ti–Zr alloy was obtained by electroless reduction in the presence of excess calcium reductant and showed a micro-porous morphology due to the sintering of each of the reduced particles during the reduction. The residual oxygen content and surface area of the reduced Ti–Zr alloy decreased over time during the electroless reduction. The element distributions were slightly different at the positions of the alloy and were in the composition range of Ti-69.3 at% to 74.3 at%Zr. A micro-porous Ti–Zr alloy with low oxygen content (0.20 wt%) and large surface area (0.55 m{sup 2} g{sup −1}) was successfully fabricated by electroless reduction under optimal conditions. The reduction mechanisms of the mixed and pure oxides by the calcium reductant are also discussed.

  17. Improved wet-slug capacitor

    Science.gov (United States)

    Ward, C. M.

    1976-01-01

    Capacitor uses all-tantalum seals and straight, ungelled, 30-percent sulphuric acid electrolyte to reduce leakage from order of milliamperes to low-microampere region. Design offers better reliability in severe environments encountered in military and industrial electronics systems.

  18. 电解电容加速寿命试验的研究与应用探讨%Experimental Research and Application on the Accelerated Life Test of the Electrolytic Capacitors

    Institute of Scientific and Technical Information of China (English)

    黄兆军; 范凌云

    2013-01-01

    简介:本文通过试验方法来探讨电解电容在不同温度条件下其容量、漏电流、损耗角正切值等参数的变化情况,通过试验验证和对其寿命衰减曲线的研究分析,得到一种加速电解电容寿命试验的有效方法,大大缩短了电解电容寿命试验的检验周期,极大地提高了检验效率,节省了试验成本。%In the paper, the test method to explore the electrolytic capacitors in different temperature conditions under capacity, leakage current, loss tangent value changes of the pa-rameters has been verified by experiments and analysis of the decay curve of their life. An effective accelerated life test method of the electrolytic capacitors, greatly reducing the electrolytic capacitor life test inspection cycle, greatly improves test efficiency and saves the cost of the trial.

  19. An Approach to Solid-State Electrical Double Layer Capacitors Fabricated with Graphene Oxide-Doped, Ionic Liquid-Based Solid Copolymer Electrolytes

    Directory of Open Access Journals (Sweden)

    N. F. A. Fattah

    2016-06-01

    Full Text Available Solid polymer electrolyte (SPE composed of semi-crystalline poly (vinylidene fluoride-hexafluoropropylene [P(VdF-HFP] copolymer, 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulphonyl imide [EMI-BTI] and graphene oxide (GO was prepared and its performance evaluated. The effects of GO nano-filler were investigated in terms of enhancement in ionic conductivity along with the electrochemical properties of its electrical double layer capacitors (EDLC. The GO-doped SPE shows improvement in ionic conductivity compared to the P(VdF-HFP-[EMI-BTI] SPE system due to the existence of the abundant oxygen-containing functional group in GO that assists in the improvement of the ion mobility in the polymer matrix. The complexation of the materials in the SPE is confirmed in X-ray diffraction (XRD and thermogravimetric analysis (TGA studies. The electrochemical performance of EDLC fabricated with GO-doped SPE is examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance obtained is 29.6 F∙g−1, which is observed at a scan rate of 3 mV/s in 6 wt % GO-doped, SPE-based EDLC. It also has excellent cyclic retention as it is able keep the performance of the EDLC at 94% even after 3000 cycles. These results suggest GO doped SPE plays a significant role in energy storage application.

  20. The effect of hydration layers on the anodic growth and on the dielectric properties of Al{sub 2}O{sub 3} for electrolytic capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Scaduto, G., E-mail: scaduto_giuseppe@libero.it [Electrochemical Material Science Laboratory, Facoltà di Ingegneria, Università di Palermo, Viale delle Scienze, Ed. 6, 90128 Palermo (Italy); Santamaria, M., E-mail: monica.santamaria@unipa.it [Electrochemical Material Science Laboratory, Facoltà di Ingegneria, Università di Palermo, Viale delle Scienze, Ed. 6, 90128 Palermo (Italy); Bocchetta, P., E-mail: patrizia.bocchetta@unisalento.it [Dipartimento di Ingegneria dell' Innovazione, Università del Salento, via Monteroni, 73100 Lecce (Italy); Di Quarto, F., E-mail: francesco.diquarto@unipa.it [Electrochemical Material Science Laboratory, Facoltà di Ingegneria, Università di Palermo, Viale delle Scienze, Ed. 6, 90128 Palermo (Italy)

    2014-01-01

    Hydrous films were grown on high purity and cubicity Al foils for electrolytic capacitors in deionized water, ethylene glycol–deionized water and glycerol–deionized water at different immersion times. According to X-ray diffraction patterns the hydration treatment allowed growing a pseudo boehmite layer on Al surface whose morphology is appreciably affected by the bath composition. Capacitance measurements and photoelectrochemical findings suggest that a more compact barrier layer forms during the immersion in alcohol containing solutions. The hydration in water allowed saving energy and preparing more blocking oxide films. The beneficial effect of hydration in hot water on the specific capacitance was evidenced only for films formed at 300 V due to the crystallization of amorphous alumina in γ′-Al{sub 2}O{sub 3}. - Highlights: • Hydrous films were grown on Al foils in hot H{sub 2}O and alcohol–H{sub 2}O mixtures. • Hydrous films' solid state properties were studied as a function of growing condition. • Hydrous films sensitively influence charge consumption during anodizing process. • Hydrous films sensitively influence dielectric properties of anodic Al{sub 2}O{sub 3}.

  1. 节能灯用铝电解电容器工作电解液配方研究%Study on the working electrolyte of aluminum electrolytic capacitors for energy saving lamp

    Institute of Scientific and Technical Information of China (English)

    胡拥军; 秦卫卫

    2011-01-01

    以十二双酸铵、对硝基苯甲酸、次亚磷酸和高分子添加剂PA四种组分为考察因素,采用单纯形法进行试验设计,研究了节能灯用铝电解电容器的工作电解液的配方.结果表明,当乙二醇质量分数(下同)为93%,癸二酸铵为4.14%,十二双酸铵为0.9%,对硝基苯甲酸为0.16%,次亚磷酸为0.2%,高分子添加剂为1.6%时,制备的铝电解电容器(400 V,φ10 mm×20 mm)综合性能最佳:电容量为2 247 μF,损耗tanδ为3.64×10-2,漏电流为6.7 μA,电解液电导率为2 224×i0-6 S/cm,闪火电压为428V.%The simplex method was adopted to study the working electrolyte for aluminum capacitor, four solutes were used as the experimental factors. The results show that when the ethylene glycol is 93%(mass fraction, same below),ammonium sebacate is 4.14%, ammonium dodecanedioate is 0.9%, nitro-benzoic acid is 0.16%, inferior phosphite is 0.2%and the polymer additive is 1.6%, the comprehensive performance of aluminum capacitor(400 V, φ10 mm×20 mm) is best, its capacitance is 2 247 μF, tanδ is 3.64× 10-2, leakage current is 6.7 μA, and the conductivity of electrolyte is 2 224× 10-6S · cm-1,the sparking voltage is 428 V.

  2. Research on Frequency and Temperature Characteristics of Chip Organic Tantalum Solid Electrolytic Capacitor%片式有机固体钽电解电容器频率及温度特性研究

    Institute of Scientific and Technical Information of China (English)

    马腾双; 陆胜; 龙道学

    2013-01-01

    Ferric p-toluenesulfonate as oxidant, using chemical oxidation method, the conductive polymer poly 3,4-vinyl dioxythiophene (PEDT) with high conductive was synthesized on the surface of the dielectric layer on the valve metal tantalum porous sintered compact. And replacing the traditional manganese dioxide with the PEDT as cathode electrolyte to make organic tantalum solid electrolytic capacitors, frequency and temperature characteristics of these organic tantalum solid electrolytic capacitors were studied. The results showed that the equivalent series resistance (ESR) value of the tantalum electrolytic capacitor with PEDT as cathode electrolyte decreased to1/3 or less of traditional inorganic solid tantalum electrolytic capacitor ESR value, and have stable frequency characteristics and temperature characteristics, meet the modern high-frequency switching power supply filter circuit specific requirements.%以对甲苯磺酸铁为氧化剂,采用化学氧化法在阀金属钽多孔体表面电介质层上合成了具有优异导电性能的导电聚合物聚3,4-乙烯基二氧噻吩(PEDT)。并以PEDT为阴极电解质取代传统的阴极电解质二氧化锰制备有机固体钽电解电容器,对有机固体钽电解电容器的频率及温度特性进行研究。结果表明,以PEDT为阴极电解质的钽电解电容器,其等效串联电阻(ESR)值降低至传统无机固体钽电解电容器ESR值的1/3以下,具有稳定的频率特性和温度特性,能够满足现代高频开关电源滤波电路的特殊要求。

  3. Redox enhanced energy storage in an aqueous high-voltage electrochemical capacitor with a potassium bromide electrolyte

    Science.gov (United States)

    Li, Qi; Haque, Mazharul; Kuzmenko, Volodymyr; Ramani, Namrata; Lundgren, Per; Smith, Anderson D.; Enoksson, Peter

    2017-04-01

    This paper reports a detailed electrochemical investigation of a symmetric carbon-carbon electrochemical device with a potassium bromide (KBr) electrolyte. Below 1.6 V, KBr gives electrochemical double layer behavior. At higher voltages the Br- /Br3- redox reaction comes into effect and enhances the energy storage. The redox-enhanced device has a high energy density, excellent stability, as well as high coulombic and energy efficiencies even at 1.9 V. More importantly, the redox contribution can be ;triggered; by pre-cycling at 1.9 V, and remains beneficial after switching to 1.6 V. The triggering operation leads to a 22% increase in stored energy with negligible sacrifice of power. The intriguing behavior is accompanied by a series of complex variations including the shifts of electrode potential limits and the shift of potential of zero voltage. The electro-oxidation of the positive electrode and kinetics of the Br- /Br3- electrode reactions are proposed to be the main causes for the triggering phenomenon. These findings provide means to improve the design and operation of devices that contain bromine, or other redox species with a comparably high electrode potential.

  4. Some preliminary evaluations of black coating on aluminium AA2219 alloy produced by plasma electrolytic oxidation (PEO) process for space applications

    Science.gov (United States)

    Shrestha, S.; Merstallinger, A.; Sickert, D.; Dunn, B. D.

    2003-09-01

    This paper describes the results of a study of a black coating produced on aluminium AA2219 alloy using a process that involves creation of a hard ceramic oxide layer on the surface of the alloy by plasma electrolytic oxidation (PEO) known as the 'KERONITE®' process. Coating microstructure has been examined and the coating characteristics such as porosity, hardness, adhesion and phase composition were measured. The thermo-optical properties such as solar absorptance 'as' and normal infrared emittance 'en-IR' of the coating were measured in the 'as-prepared' condition and after environmental exposures to humidity, thermal cycling and UV-radiation in vacuum and to thermal shock. Comparison was made with alternative coatings produced using standard black anodising processes. The study also looked at the cold welding and friction behaviours of the coated alloy in vacuum and in an ambient laboratory environment. Standard spacecraft materials tests were conducted on the coated disc against an AISI 52100 steel ball and also against a coated pin using a pin-on-disc apparatus. Parameters such as friction coefficient and wear depth were measured and the cold welding behaviours were investigated. Test results were compared with the data generated for NiCr plated and anodised coatings. Corrosion performance was assessed using a salt spray exposure test and using an accelerated electrochemical test method. In addition, the study looked at the effect of post coating sealing with a sol-gel solution.

  5. Integrated Diagnostic/Prognostic Experimental Setup for Capacitor Degradation and Health Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes the experiments and setups for studying diagnosis and prognosis of electrolytic capacitors in DC-DC power converters. Electrolytic capacitors and...

  6. Pitting Mechanism for Aluminum Electrolytic Capacitor High Voltage Foil%铝电解电容器高压电子箔点蚀机理的研究

    Institute of Scientific and Technical Information of China (English)

    王志申; 何业东; 孙志华; 刘明; 张晓云; 陆峰

    2012-01-01

    采用极化曲线和场发射扫描电镜等方法,研究了铝电解电容器高压电子箔在高温强酸性溶液中的点蚀机理.结果表明:在开路状态下铝光箔在硫酸盐酸发孔溶液中可以产生点蚀,测到自腐蚀电位就是点蚀电位;形成隧道孔后,阳极极化曲线出现点蚀电位,且点蚀过电位与隧道孔长度之间存在线性关系.根据点蚀的微电池模型及其在阳极极化下微电池的腐蚀极化图,提出产生上述现象的原因是阳极极化时带孔铝箔的表面由阴极向阳极转变,其转变的临界点即所测到的点蚀电位.%Pitting mechanism for aluminum electrolytic capacitor high voltage foil in strong acidic solution was investigated by means of polarization curve and scanning electron microscopy(SEM). The results indicate that pitting can generate on the surface of Al foil under open circuit, and its corrosion potential measured is pitting potential. Pitting potential appears on the polarization curves of Al foil with tunnel pits, and there is linear relationship between the pitting over-potential and the tunnel length. According to micro-cell model of pitting and the corrosion polarization diagrams of micro-cell, it is thought that the surface of Al foil with tunnel pits transforms from cathode to anode during anodic polarization, and the critical point of the transformation is the measured pitting potential.

  7. High Temperature Capacitor Development

    Energy Technology Data Exchange (ETDEWEB)

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  8. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions....

  9. Application study of boric acid glycerin polyester in electrolytic capacitors%硼酸丙三醇聚酯在铝电解电容器工作电解液中的应用研究

    Institute of Scientific and Technical Information of China (English)

    周攀登; 刘仁其; 龙立平

    2013-01-01

    采用正交实验法配制了一种耐高压电容器工作电解液配方,在该配方中添加自己合成的硼酸丙三醇聚酯.研究表明,随着硼酸丙三醇聚酯的添加,电解液的电导率较未加的高,而闪火电压没有明显的变化.即硼酸丙三醇聚酯能提高该工作电解液的电导率,而对闪火电压的影响较小.%Use the orthogonal experiment method to the preparation of a high voltage capacitor work electrolyte formula, Boric acid glycerin polyester have been added to this work electrolyte. The studies showed that the conductivity of the electrolyte had improved greatly, with the addition of boric acid glycerol polyester, while no significant change in the voltage of the flash fire. It means that, boric acid glycerol polyester can improve the conductivity of the electrolyte of the working, and less impact on the voltage of the flash fire.

  10. Electrically tuned super-capacitors

    CERN Document Server

    Chowdhury, Tazima S

    2015-01-01

    Fast charging and discharging of large amounts of electrical energy make super-capacitors ideal for short-term energy storage [1-5]. In its simplest form, the super-capacitor is an electrolytic capacitor made of an anode and a cathode immersed in an electrolyte. As for an ordinary capacitor, minimizing the charge separation distance and increasing the electrode area increase capacitance. In super-capacitors, charge separation is of nano-meter scale at each of the electrode interface (the Helmholtz double layer). Making the electrodes porous increases their effective surface area [6-8]. A separating layer between the anode and the cathode electrodes is used to minimize unintentional electrical discharge (Figure 1). Here we show how to increase the capacitance of super-capacitors by more than 45 percent when modifying the otherwise passive separator layer into an active diode-like structure. Active control of super-capacitors may increase their efficiency during charge and discharge cycles. Controlling ion flow...

  11. Progress in Electrolyte Materials Used in Solid Aluminium Electrolytic Capacitors Ⅱ Solid Aluminium Electrolytic Capacitors with Conducting Polymers%铝固体电解电容器电解质研究进展Ⅱ.导电聚合物型铝固体电解电容器

    Institute of Scientific and Technical Information of China (English)

    张庆武; 周啸; 姜翠玲; 于家宁

    2002-01-01

    综述了聚吡咯(PPY)、聚苯胺和聚(3,4–次乙二氧基噻吩)(PEDOT)等导电高分子材料在铝固体电解电容器中应用的最新研究情况.聚吡咯型铝固体电解电容器明显好于TCNQ复合盐型电容器.聚苯胺和聚(3,4–次乙二氧基噻吩)型铝固体电解电容器是尚在研究还未商业化的两类新品种,后一类因其高导电性、高环境稳定性,而最具发展前景.

  12. Pyrrole-Based Conductive Polymers For Capacitors

    Science.gov (United States)

    Nagasubramanian, Ganesan; Di Stefano, Salvador

    1994-01-01

    Polypyrrole films containing various dopant anions exhibit superior capacitance characteristics. Used with nonaqueous electrolytes. Candidate for use in advanced electrochemical double-layer capacitors capable of storing electrical energy at high densities. Capacitors made of these films used in automobiles and pulsed power supplies.

  13. Usage of neural network to predict aluminium oxide layer thickness.

    Science.gov (United States)

    Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

    2015-01-01

    This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A · dm(-2) and 3 A · dm(-2) for creating aluminium oxide layer.

  14. Advanced capacitors

    Science.gov (United States)

    Ennis, J. B.; Buritz, R. S.

    1984-10-01

    This report describes an experimental program to develop and test advanced dielectric materials for capacitors for airborne power systems. Five classes of capacitors were considered: high rep rate and low rep rate pulse capacitors for use in pulse-forming networks, high voltage filter capacitors, high frequency AC capacitors for series resonant inverters, and AC filter capacitors. To meet these requirements, existing dielectric materials were modified, and new materials were developed. The initial goal was to develop an improved polysulfone film with fewer imperfections that could operate at significantly higher electrical stresses. It was shown that contaminants enter the film via the resin and solvent, and that they can be partially removed. As far as developed, however, these treatments did not significantly improved the breakdown characteristics. The technique of casting films on a roughened drum was demonstrated, and found useful in preparing textured films -- the first step toward a replacement for Kraft paper. A new material, Ultem, was proposed for use in high energy density capacitors. This new polyetherimide resin has properties similar to polysulfone and polyimide, with improvement in breakdown characteristics and temperature capability. This material was selected for further study in model capacitor designs.

  15. Entropy characterisation of overstressed capacitors for lifetime prediction

    Science.gov (United States)

    Cuadras, Angel; Romero, Ramon; Ovejas, Victoria J.

    2016-12-01

    We propose a method to monitor the ageing and damage of capacitors based on their irreversible entropy generation rate. We overstressed several electrolytic capacitors in the range of 33 μF-100 μF and monitored their entropy generation rate S˙ (t). We found a strong relationship between capacitor degradation and S˙ (t). Therefore, we proposed a threshold for S˙ (t) as an indicator of capacitor time-to-failure. This magnitude is related to both capacitor parameters and to a damage indicator such as entropy. Our method goes beyond the typical statistical laws for lifetime prediction provided by manufacturers. We validated the model as a function of capacitance, geometry, and rated voltage. Moreover, we identified different failure modes, such as heating, electrolyte dry-up and gasification from the dependence of S˙ (T) with temperature, T. Our method was implemented in cheap electrolytic capacitors but can be easily applied to any type of capacitor, supercapacitor, battery, or fuel cell.

  16. 无电解电容的填谷式SEPIC-derived LED照明驱动%Electrolytic capacitor-less SEPIC-derived LED driver with valley fill cell

    Institute of Scientific and Technical Information of China (English)

    马红波; 郑聪; 余文松; 冯全源

    2012-01-01

    The typical power supply for lighting-emitting diode (LED) lighting employs an electrolytic capacitor as the storage capacitor, which increases the size of LED drivers, reduces the power density, and shortens the lifespan, thus hampering the development of the entire LED lighting system. Additionally, the conventional single-ended primary inductance converter (SEPIC) has to employ electrolytic capacitors to meet the low output ripple requirement. Therefore, a SEPIC type ac/dc topology is proposed by introducing the operation mode of special discontinuous current mode (DCM) and inserting the valley fill cell in SEPIC. Furthermore, a prototype with 50 W power level was built to verify the feasibility of the presented converter-based LED lamp driver. The experimental results show that the measured efficiency is exceeding 90% and power factor is higher than 0. 96 under the 120 V input and full load condition.%针对传统LED照明驱动中普遍采用大电容量电解电容,造成LED驱动寿命较短、体积庞大、功率密度较低的问题,在分析传统AC/DC LED驱动拓扑的基础上,通过引入电流断续模式(DCM)和插入填谷电路单元,提出一种SEPIC型AC/DC变换拓扑,解决传统SEPIC AC/DC LED照明驱动无法消除电解电容的问题.并以此电路为基础,在实验室开发一款50 W LED照明驱动样机.测试结果表明,该样机在消除电解电容的同时,实现了高功率因数和高效率.在120 V输入下,满载功率因数和效率分别大于0.96和90%.

  17. Degradation testing and failure analysis of DC film capacitors under high humidity conditions

    DEFF Research Database (Denmark)

    Wang, Huai; Nielsen, Dennis Achton; Blaabjerg, Frede

    2015-01-01

    Metallized polypropylene film capacitors are widely used for high-voltage DC-link applications in power electronic converters. They generally have better reliability performance compared to aluminum electrolytic capacitors under electro-thermal stresses within specifications. However, the degrada...

  18. Aluminium bridges, aluminium bridge decks

    NARCIS (Netherlands)

    Soetens, F.; Straalen, IJ.J. van

    2003-01-01

    Applications of aluminium have grown considerably in building and civil engineering the last decade. In building and civil engineering the increase of aluminium applications is due to various aspects like light weight, durability and maintenance, use of extrusions, and esthetics. The paper starts wi

  19. Preparation and Molten Salt as Performances of Room Electrolyte carbon Capacitor Based on Trifluoroacetamide n CarbonLiPF6 and

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    A novel room moRen salt with an eutectic temperature of about -62℃ is prepared using LiPF6 and trifluoroacetamide as precursors. And then its performance is evaluated in carbon-carbon electrochemical double layerdifferent molar ratios are characterized and then the liquid-solid phase diagram is presented. The electrochemical performance tests show that the as-prepared LiPF6/trifluoroacetamide molten salt is a promising electrolyte candidate for carboncarbon EDLCs.

  20. Rotary capacitor

    CERN Multimedia

    1971-01-01

    The rotating wheel of the rotary capacitor representing the most critical part of the new radio-frequency system of the synchro-cyclotron. The three rows of teeth on the circumference of the wheel pass between four rows of stator blades with a minimum clearance of 1 mm at a velocity of 1700 rev/min.

  1. Alkaline Capacitors Based on Nitride Nanoparticles

    Science.gov (United States)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  2. Prognostic Techniques for Capacitor Degradation and Health Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper discusses our initial efforts in constructing physics of failure models for electrolytic capacitors subjected to electrical stressors in DC-DC power...

  3. Investigation of Production Process of Polymer Solid Electrolyte Tantalum Capacitor Based on High Specific Surface Area Tantalum Powder%基于高比容钽粉的聚合物片式电容器制备工艺研究

    Institute of Scientific and Technical Information of China (English)

    闻俊峰; 蒋亚东; 杨亚杰; 徐建华

    2012-01-01

    The fabrication process of polymer solid-electrolyte tantalum capacitor employing high capacitance tantalum powder of 50000~70000μF · V/g as anode material was investigated. The optimized fabrication process for tantalum powder pellet anode and cathode film deposition process was explored, and the obtained polymer solid-electrolyte tantalum capacitor exhibited excellent electronic performance. The influence of fabrication parameter such as-pressing density, current density of Ta2O5 film formation.and stepwise-deposition process of cathode film on capacitor performance such as capacitance, equivalent series resistance(ESR), leakage current were studied in detail. Moreover, the discussion of working mechanism about polymer solid-electrolyte tantalum capacitor was included.%针对比容为50000~70000μF ·V/g的较高比容钽粉,研究了导电聚合物聚3,4-乙烯基二氧噻吩(PEDOT)作为阴极材料的有机片式固体钽电解电容器的制备工艺,通过调整阳极体制备及阴极被覆工艺等参数实现了PEDOT在高比容钽块表面的有效被覆,获得了各项性能参数良好的聚合物片式钽电解电容器.重点研究了压制密度、形成电流密度等参数及分段被膜工艺对聚合物片式固体钽电容器容量引出、等效串联电阻、漏电流等性能的影响,并讨论了相应的电容器工作机理.

  4. Synthesis, and crystal and electronic structure of sodium metal phosphate for use as a hybrid capacitor in non-aqueous electrolyte.

    Science.gov (United States)

    Sundaram, Manickam Minakshi; Watcharatharapong, Teeraphat; Chakraborty, Sudip; Ahuja, Rajeev; Duraisamy, Shanmughasundaram; Rao, Penki Tirupathi; Munichandraiah, Nookala

    2015-12-14

    Energy storage devices based on sodium have been considered as an alternative to traditional lithium based systems because of the natural abundance, cost effectiveness and low environmental impact of sodium. Their synthesis, and crystal and electronic properties have been discussed, because of the importance of electronic conductivity in supercapacitors for high rate applications. The density of states of a mixed sodium transition metal phosphate (maricite, NaMn(1/3)Co(1/3)Ni(1/3)PO4) has been determined with the ab initio generalized gradient approximation (GGA)+Hubbard term (U) method. The computed results for the mixed maricite are compared with the band gap of the parent NaFePO4 and the electrochemical experimental results are in good agreement. A mixed sodium transition metal phosphate served as an active electrode material for a hybrid supercapacitor. The hybrid device (maricite versus carbon) in a non-aqueous electrolyte shows redox peaks in the cyclic voltammograms and asymmetric profiles in the charge-discharge curves while exhibiting a specific capacitance of 40 F g(-1) and these processes are found to be quasi-reversible. After long term cycling, the device exhibits excellent capacity retention (95%) and coulombic efficiency (92%). The presence of carbon and the nanocomposite morphology, identified through X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) studies, ensures the high rate capability while offering possibilities to develop new cathode materials for sodium hybrid devices.

  5. New Investment Rush Brings up Concern for China’s Aluminium Industry

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> Although the blind construction of the electro-lytic aluminium industry has been restricted inChina this year,an investment rush in aluminaand aluminium processing has started,whichhas brought up new concern for the industry.Whether this will follow the route of the much-heated electrolytic aluminium industry remainsa question to be answered.According to someindustry analysts,under the pressure of themacro control measures of the State on theelectrolytic aluminium industry expansion,some producers of aluminium have shiftedtheir interests to the upper and lower fields soas to raise their competitiveness over the mar-

  6. Protection of MOS capacitors during anodic bonding

    Science.gov (United States)

    Schjølberg-Henriksen, K.; Plaza, J. A.; Rafí, J. M.; Esteve, J.; Campabadal, F.; Santander, J.; Jensen, G. U.; Hanneborg, A.

    2002-07-01

    We have investigated the electrical damage by anodic bonding on CMOS-quality gate oxide and methods to prevent this damage. n-type and p-type MOS capacitors were characterized by quasi-static and high-frequency CV-curves before and after anodic bonding. Capacitors that were bonded to a Pyrex wafer with 10 μm deep cavities enclosing the capacitors exhibited increased leakage current and interface trap density after bonding. Two different methods were successful in protecting the capacitors from such damage. Our first approach was to increase the cavity depth from 10 μm to 50 μm, thus reducing the electric field across the gate oxide during bonding from approximately 2 × 105 V cm-1 to 4 × 104 V cm-1. The second protection method was to coat the inside of a 10 μm deep Pyrex glass cavity with aluminium, forming a Faraday cage that removed the electric field across the cavity during anodic bonding. Both methods resulted in capacitors with decreased interface trap density and unchanged leakage current after bonding. No change in effective oxide charge or mobile ion contamination was observed on any of the capacitors in the study.

  7. Investigation of performance degradation in metallized film capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Godec, M. [Institute of Metals and Technology, Lepi Pot 11, 1000 Ljubljana (Slovenia); Mandrino, Dj., E-mail: djordje.mandrino@imt.si [Institute of Metals and Technology, Lepi Pot 11, 1000 Ljubljana (Slovenia); Gaberšček, M. [National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia)

    2013-05-15

    Zn–Al metallized film capacitors in two different production stages were investigated to explain the decrease of capacitors performance with time. Unsealed and sealed capacitors with different aluminium content in metallization layer were investigated. Scanning electron microscopy (SEM) was used to image the surface of the metallization layers, energy dispersive X-ray spectroscopy (EDS) was used to determine the chemical composition and Auger electron spectroscopy (AES) was used to determine the chemical composition of the top of the metallization layers as well as to estimate the degree of oxidation. It was found that air humidity degraded the metallization layer of unsealed capacitors, especially at lower Al contents. Sealed capacitors were exposed to high electric fields, typical for standard usage. It was found – rather unexpectedly – that the performance was decreased by increasing Al content. A crystallographic explanation was proposed.

  8. Investigation of performance degradation in metallized film capacitors

    Science.gov (United States)

    Godec, M.; Mandrino, Dj.; Gaberšček, M.

    2013-05-01

    Zn-Al metallized film capacitors in two different production stages were investigated to explain the decrease of capacitors performance with time. Unsealed and sealed capacitors with different aluminium content in metallization layer were investigated. Scanning electron microscopy (SEM) was used to image the surface of the metallization layers, energy dispersive X-ray spectroscopy (EDS) was used to determine the chemical composition and Auger electron spectroscopy (AES) was used to determine the chemical composition of the top of the metallization layers as well as to estimate the degree of oxidation. It was found that air humidity degraded the metallization layer of unsealed capacitors, especially at lower Al contents. Sealed capacitors were exposed to high electric fields, typical for standard usage. It was found - rather unexpectedly - that the performance was decreased by increasing Al content. A crystallographic explanation was proposed.

  9. Advanced Capacitor Development.

    Science.gov (United States)

    1987-01-01

    Capacitors. ... ..................... 8 Comparison of Ultem and Polysulfone Film ..... 9 III MATERIALS DEVELOPMENT. ... ....... ....... .... 13 Candidate...Continued) Section Page C LIFE TEST DATA FOR METALLIZED POLYSULFONE AND ULTEM FILM CAPACITORS AT 140 VRMS AND ELEVATED TEMPERATURES SAMPLE SIZE 10...Polysulfone and Ultem Film Capacitors at 140 Vrms 400 Hz and 125(C ..... .......... 12 3 Life Time of Metallized Polysulfone and Ultem Film Capacitors at 140

  10. Advanced Wet Tantalum Capacitors: Design, Specifications and Performance

    Science.gov (United States)

    Teverovsky, Alexander

    2017-01-01

    Insertion of new types of commercial, high volumetric efficiency wet tantalum capacitors in space systems requires reassessment of the existing quality assurance approaches that have been developed for capacitors manufactured to MIL-PRF-39006 requirements. The specifics of wet electrolytic capacitors is that leakage currents flowing through electrolyte can cause gas generation resulting in building up of internal gas pressure and rupture of the case. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. This presentation gives a review of specifics of the design, performance, and potential reliability risks associated with advanced wet tantalum capacitors. Problems related to setting adequate requirements for DPA, leakage currents, hermeticity, stability at low and high temperatures, ripple currents for parts operating in vacuum, and random vibration testing are discussed. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  11. Room-Temperature Ionic Liquids for Electrochemical Capacitors

    Science.gov (United States)

    Fireman, Heather; Yowell, Leonard; Moloney, Padraig G.; Arepalli, Sivaram; Nikolaev, P.; Huffman, C.; Ready, Jud; Higgins, C.D.; Turano, S. P.; Kohl, P.A.; Kim, K.

    2009-01-01

    A document discusses room-temperature ionic liquids (RTILs) used as electrolytes in carbon-nanotube-based, electrochemical, double-layer capacitors. Unlike the previous electrolyte (EtNB4 in acetonitrile), the RTIL used here does not produce cyanide upon thermal decomposition and does not have a moisture sensitivity.

  12. Research on Interactive Control of Electrolytic Aluminum Load and Wind Power Output

    Directory of Open Access Journals (Sweden)

    Ge Simin

    2016-01-01

    Full Text Available With the large-scale wind power generation connected to Gansu power grid, electrolytic aluminium load has reached a certain scale at the same time, the vast majority of electrolytic aluminium load directly connects to power grid using 330kV transmission line. According to the physical characteristics and historical data, the continuous adjustment characteristic of electrolytic aluminium load is analysed. Based on this characteristic, a mathematical model for the electrolytic aluminium load is established. Aiming at reducing power network loss and wind power consumption, an optimization model based on the load regulation characteristics of electrolytic aluminium is constructed, which is optimized by particle swarm optimization algorithm. Based on the case data of Gansu power grid, the optimal method based on the load regulation characteristics of electrolytic aluminium is analysed and its feasibility is verified.

  13. Aluminium in human sweat.

    Science.gov (United States)

    Minshall, Clare; Nadal, Jodie; Exley, Christopher

    2014-01-01

    It is of burgeoning importance that the human body burden of aluminium is understood and is measured. There are surprisingly few data to describe human excretion of systemic aluminium and almost no reliable data which relate to aluminium in sweat. We have measured the aluminium content of sweat in 20 healthy volunteers following mild exercise. The concentration of aluminium ranged from 329 to 5329μg/L. These data equate to a daily excretion of between 234 and 7192μg aluminium and they strongly suggest that perspiration is the major route of excretion of systemic aluminium in humans.

  14. Accelerated Aging in Electrolytic Capacitors for Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — The focus of this work is the analysis of different degradation phenomena based on thermal overstress and electrical overstress accelerated aging systems and the use...

  15. Human exposure to aluminium.

    Science.gov (United States)

    Exley, Christopher

    2013-10-01

    Human activities have circumvented the efficient geochemical cycling of aluminium within the lithosphere and therewith opened a door, which was previously only ajar, onto the biotic cycle to instigate and promote the accumulation of aluminium in biota and especially humans. Neither these relatively recent activities nor the entry of aluminium into the living cycle are showing any signs of abating and it is thus now imperative that we understand as fully as possible how humans are exposed to aluminium and the future consequences of a burgeoning exposure and body burden. The aluminium age is upon us and there is now an urgent need to understand how to live safely and effectively with aluminium.

  16. Carbons, ionic liquids and quinones for electrochemical capacitors

    Directory of Open Access Journals (Sweden)

    Raul eDiaz

    2016-04-01

    Full Text Available Carbons are the main electrode materials used in electrochemical capacitors, which are electrochemical energy storage devices with high power densities and long cycling lifetimes. However, increasing their energy density will improve their potential for commercial implementation. In this regard, the use of high surface area carbons and high voltage electrolytes are well known strategies to increase the attainable energy density, and lately ionic liquids have been explored as promising alternatives to current state of the art acetonitrile-based electrolytes. Also, in terms of safety and sustainability ionic liquids are attractive electrolyte materials for electrochemical capacitors. In addition, it has been shown that the matching of the carbon pore size with the electrolyte ion size further increases the attainable electric double layer (EDL capacitance and energy density.The use of pseudocapacitive reactions can significantly increase the attainable energy density, and quinonic-based materials offer a potentially sustainable and cost effective research avenue for both the electrode and the electrolyte. This perspective will provide an overview of the current state of the art research on electrochemical capacitors based on combinations of carbons, ionic liquids and quinonic compounds, highlighting performances and challenges and discussing possible future research avenues. In this regard, current interest is mainly focused on strategies which may ultimately lead to commercially competitive sustainable high performance electrochemical capacitors for different applications including those requiring mechanical flexibility and biocompatibility.

  17. Carbons, ionic liquids and quinones for electrochemical capacitors

    Science.gov (United States)

    Diaz, Raul; Doherty, Andrew

    2016-04-01

    Carbons are the main electrode materials used in electrochemical capacitors, which are electrochemical energy storage devices with high power densities and long cycling lifetimes. However, increasing their energy density will improve their potential for commercial implementation. In this regard, the use of high surface area carbons and high voltage electrolytes are well known strategies to increase the attainable energy density, and lately ionic liquids have been explored as promising alternatives to current state of the art acetonitrile-based electrolytes. Also, in terms of safety and sustainability ionic liquids are attractive electrolyte materials for electrochemical capacitors. In addition, it has been shown that the matching of the carbon pore size with the electrolyte ion size further increases the attainable electric double layer (EDL) capacitance and energy density. The use of pseudocapacitive reactions can significantly increase the attainable energy density, and quinonic-based materials offer a potentially sustainable and cost effective research avenue for both the electrode and the electrolyte. This perspective will provide an overview of the current state of the art research on electrochemical capacitors based on combinations of carbons, ionic liquids and quinonic compounds, highlighting performances and challenges and discussing possible future research avenues. In this regard, current interest is mainly focused on strategies which may ultimately lead to commercially competitive sustainable high performance electrochemical capacitors for different applications including those requiring mechanical flexibility and biocompatibility.

  18. Physics of Failure Models for Capacitor Degradation in DC-DC Converters

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes a combined energy-based model with an empirical physics of failure model for degradation analysis and prognosis of electrolytic capacitors in...

  19. An Adjustable-speed System With Single-phase AC Input Based on Electrolytic Capacitor-less Tapped-inductor Single-stage Boost Inverters%单相交流输入的无电解电容抽头电感单级升压逆变器在交流调速系统中的应用

    Institute of Scientific and Technical Information of China (English)

    周玉斐; 黄文新; 赵健伍

    2014-01-01

    研究将无电解电容的单级升压逆变技术应用于变频调速系统。采用的抽头电感单级升压逆变器(tapped- inductor single-stage boost inverter,TISSBI)包含由1个抽头电感和2个二极管构成的无源网络,通过调节直通占空比和电感抽头的位置,能够实现单级升降压功能。将无电解电容的TISSBI应用于单相输入的变频调速系统,实现抗电网电压跌落、母线脉动抑制和提高输入功率因数的功能。用实验验证了理论分析方法的可行性。%This paper presented an adjustable-speed system with single-phase AC input based on the electrolytic capacitor-less single-stage boost inverter with tapped-inductor. The tapped-inductor single-stage boost inverter (TISSBI) includes an impedance network with one tapped inductor and two diodes, and it can realize buck or boost performance. In order to resist the grid voltage sags, output low frequency ripple decreasing, and input power factor improvement, this paper applied the electrolytic capacitor-less TISSBI to adjustable-speed system with single-phase AC input. Experimental results were carried out to verify the theoretical analysis.

  20. Anti corrosion layer for stainless steel in molten carbonate fuel cell - comprises phase vapour deposition of titanium nitride, aluminium nitride or chromium nitride layer then oxidising layer in molten carbonate electrolyte

    DEFF Research Database (Denmark)

    2000-01-01

    Forming an anticorrosion protective layer on a stainless steel surface used in a molten carbonate fuel cell (MCFC) - comprises the phase vapour deposition (PVD) of a layer comprising at least one of titanium nitride, aluminium nitride or chromium nitride and then forming a protective layer in situ...

  1. Single Capacitor Paradox

    CERN Document Server

    Pankovic, Vladan

    2009-01-01

    In this work single capacitor paradox (a variation of the remarkable two capacitor paradox) is considered. Simply speaking in an ideal (without any electrical resistance and inductivity) electrical circuit with single charged capacitor and switch, by transition from initial, open state (switch in OFF position) in the final, closed state (switch in ON position), there is a total loss of the initial energy of the electrical field in condenser. Given energy loss can be simply explained without any dissipative effects (Joule heating or electromagnetic waves emission) by work of the electrical field by movement of the charge from one in the other plate of the capacitor. (Two capacitors paradox can be, obviously, explained in the analogous way.)

  2. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  3. Sustainable Aluminium Systems

    Directory of Open Access Journals (Sweden)

    Sergio R. Ermolli

    2010-09-01

    Full Text Available In the present paper, an analytical presentation of some popular aluminium systems that contribute to sustainability of structures is presented. Special emphasis has been given to the properties of aluminium, while the influence of these systems in the overall performance of the structure regarding environment and economy is described. In particular, characteristics of aluminium elements such as high reflectivity and recyclability and their role in life cycle analysis (LCA are analyzed. The connections between energy efficiency and conservation of buildings and aluminium application are also discussed. Building applications such as curtain walls, window frames and facade sheets are presented and thoroughly investigated, considering their environmental and economic aspects. Furthermore, many innovative techniques that use aluminium elements in collaboration with other systems in order to produce renewable energy, such as solar panels and photovoltaics, are introduced. Finally, environmental innovations such as optimized ventilation mechanisms and light and shade management systems based on aluminium members are presented.

  4. Electric Double-layer Capacitor Based on Activated Carbon Material

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this study electric double-layer capacitors (EDLCs) based on activated carbon material and organic electrolyte (tetraethyl ammonium tetrafluoroborate) were explored. The fabrication method for EDLC is presented and the performance of EDLC was examined by using the cyclic voltammetry, constant-current charging and discharging technique, electrochemical impedance spectroscopy measurements. Influence of various components and design parameters on the performance of the capacitors were preliminarily investigated. Up to now, EDLC based on carbon materials can deliver 20.7 W/kg at the discharge rate ofI=0.3 mA, together with the energy density of 8.5 Wh/kg. Equivalent series resistance (ESR) is 0.716 Ω.cm2. The specific power of the capacitor is low and further attempts to raise the power capability of the capacitors are necessary. Some considerations are put forward to further improve the performance of EDLC.

  5. Nanocurrent oscillator indefinitely powered by a capacitor battery

    CERN Document Server

    Ragni, Luigi

    2012-01-01

    Some electrolytic capacitors show dielectric behaviour that can not be entirely explained by the well known long lasting relaxation. Extra charges able to generate a useful conduction current can be detected for an indefinite time. A squarewave oscillator based on MOSFET CMOS technology and requiring less than 2 nW was powered for 80 days at 25 {\\deg}C by a 58.2 mF capacitor battery, without voltage decrease during the last 53 days of observation. The battery consisted of three series of 16 parallel, 15 years aged, capacitors with DC capacitance of 10.9 mF. Capacitors so old, stored without voltage application, were affected by degradation and thinning of the alumina layer that could promote tunnelling of the charge. The main purpose of the present study is to stimulate further investigations aimed at confirming or disputing the observed phenomenon and, if necessary, at shedding light on its physical mechanisms.

  6. Capacitor discharge engineering

    CERN Document Server

    Früngel, Frank B A

    1976-01-01

    High Speed Pulse Technology, Volume III: Capacitor Discharge Engineering covers the production and practical application of capacitor dischargers for the generation and utilization of high speed pulsed of energy in different forms. This nine-chapter volume discusses the principles of electric current, voltage, X-rays, gamma rays, heat, beams of electrons, neutrons and ions, magnetic fields, sound, and shock waves in gases and liquids. Considerable chapters consider the applications of capacitor discharges, such as impulse hardening of steel, ultrapulse welding of precision parts, X-ray flash t

  7. Rows of Dislocation Loops in Aluminium Irradiated by Aluminium Ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1967-01-01

    Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along <110 > directions. ©1967 The American Institute of Physics......Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along directions. ©1967 The American Institute of Physics...

  8. Soft capacitor fibers for electronic textiles

    Science.gov (United States)

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-09-01

    A highly flexible, conductive polymer-based fiber with high electric capacitance is reported. The fiber is fabricated using fiber drawing method, where a multimaterial macroscopic preform is drawn into a submillimeter capacitor microstructured fiber. A typical measured capacitance per unit length of our fibers is 60-100 nF/m which is about 3 orders magnitude higher than that of a coaxial cable of a comparable diameter. The fiber has a transverse resistivity of 5 kΩ m. Softness, lightweight, absence of liquid electrolyte, and ease of scalability to large production volumes make the fibers interesting for various smart textile applications.

  9. A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

    DEFF Research Database (Denmark)

    Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

    2015-01-01

    Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...... accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different...

  10. Preparation and Performances of Room Molten Salt as Electrolyte in Carbon-carbon Capacitor Based on LiPFe and Trifluoroacetamide%LiPF6/三氟乙酰胺室温熔盐的制备及在碳-碳电容器中的性能

    Institute of Scientific and Technical Information of China (English)

    左晓希; 李奇; 刘建生; 肖信; 范成杰; 南俊民

    2012-01-01

    利用LiPF6和三氟乙酰胺为前驱物,制备了低共熔温度约为-62℃的室温熔盐,并测试了该熔盐作为碳-碳电化学电容器(EDLCs)电解液时的性能。其中,使用差示扫描量热法(DSC)和红外光谱法(FTIR)分析了不同LiPF6和三氟乙酰胺配比熔盐的热稳定性,拟制了该二元组分的共熔相图,认为LiPF6和三氟乙酰胺极性基团间的氢键作用促成了室温熔盐的形成。循环伏安(CV)、交流阻抗(EIS)和电导等测定结果表明,所制备的LiPF6/三氟乙酰胺电解液的室温电导率为1.30mS/cm,电化学窗口大于5.6V,大于60℃的使用温度,作为电解液可满足碳-碳EDLCs的使用要求。%A novel room molten salt with an eutectic temperature of about -62℃ is prepared using LiPF6 and trifluoroacetamide as precursors. And then its performances are evaluated in carbon-carbon electrochemical double layer capacitor (EDLC) as electrolyte. The thermal properties of the complex electrolyte with different molar ratios are characterized and then the liquid-solid phase diagram is presented by using differential scanning calorimeter (DSC) and Fourier transform infrared spectroscopy (FTIR). The hydrogen bonding interaction between LiPF6 and trifluoroacetamide molecules is attributed to the formation of the as-prepared molten salt. In addition, the results of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and conductance tests show that the as-prepared LiPF6/trifluoroacetamide electrolyte has a maximum conductance at room temperature, i.e. 1.30 mS/cm, a stable electrochemical window of ca. 5.6 V, an applicable temperature of more than 60℃, suggesting it is a promising electrolyte candidate for carbon-carbon EDLCs.

  11. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

    Science.gov (United States)

    Kulkarni, Chetan S.; Celaya, Jose Ramon; Biswas, Gautam; Goebel, Kai

    2012-01-01

    This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions. Electrolytic capacitors have higher failure rates than other components in electronic systems like power drives, power converters etc. Our current work focuses on developing first-principles-based degradation models for electrolytic capacitors under varying electrical and thermal stress conditions. Prognostics and health management for electronic systems aims to predict the onset of faults, study causes for system degradation, and accurately compute remaining useful life. Accelerated life test methods are often used in prognostics research as a way to model multiple causes and assess the effects of the degradation process through time. It also allows for the identification and study of different failure mechanisms and their relationships under different operating conditions. Experiments are designed for aging of the capacitors such that the degradation pattern induced by the aging can be monitored and analyzed. Experimental setups and data collection methods are presented to demonstrate this approach.

  12. Charge fluctuations in nano-scale capacitors

    CERN Document Server

    Limmer, David T; Salanne, Mathieu; Chandler, David; Madden, Paul A; van Roij, René; Rotenberg, Benjamin

    2013-01-01

    The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with histogram reweighting techniques. This approach offers an efficient and accurate route to the differential capacitance and is broadly applicable. We demonstrate these methods with three different capacitors: pure water between platinum electrodes, and a pure as well as a solvent-based organic electrolyte each between graphite electrodes. The total charge distributions with the pure solvent and solvent-based electrolytes are remarkably Gaussian, while in the pure ionic liquid the total charge distribution displays distinct non-Gaussian features, suggesting significant potential-driven changes in the organization of the interfacial fluid.

  13. The comparison of possibilities at using of different electrolytes in the process of anodizing aluminum

    Directory of Open Access Journals (Sweden)

    M. Gombar

    2014-01-01

    Full Text Available The contribution researches and solves the suitability of utilize of electrolyte, consisting of the oxalic acid, boric acid, sodium chloride and aluminium cations in the process of anodizing aluminium in operating conditions of electrolyte T = 22 °C, t = time of oxidation and the size of at least 210 an applied voltage U = 12 V. The appropriate use of the electrolyte is judged by the thickness of the anodic aluminium oxide layer (AAO formed on the basis of the monitoring and the resulting quality of the sample surface.

  14. Breakdown voltage of discrete capacitors under single-pulse conditions

    Science.gov (United States)

    Domingos, H.; Scaturro, J.; Hayes, L.

    1981-01-01

    For electrostatic capacitors the breakdown voltage is inherently related to the properties of the dielectric, with the important parameters being the dielectric field strength which is related to the dielectric constant and the dielectric thickness. These are not necessarily related to the capacitance value and the rated voltage, but generally the larger values of capacitance have lower breakdown voltages. Foil and wet slug electrolytics can withstand conduction currents pulses without apparent damage (in either direction for foil types). For solid tantalums, damage occurs whenever the capacitor charges to the forming voltage.

  15. Recovery in aluminium

    DEFF Research Database (Denmark)

    Gundlach, Carsten

    2006-01-01

    In the present thesis the development of a unique experimental method for volume characterisation of individual embedded crystallites down to a radius of 150 nm is presented. This method is applied to in-situ studies of recovery in aluminium. The method is an extension of 3DXRD microscopy, an X...... are represented as strings. To identify the strings a combination of a 5D connected component type algorithm and multi-peak fitting was found to be superior. The first use of the method was a study of recovery of a deformed aluminium alloy (AA1050). The aluminium alloy was deformed by cold rolling to a thickness...

  16. Capacitor discharge pulse analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  17. Engineering electrochemical capacitor applications

    Science.gov (United States)

    Miller, John R.

    2016-09-01

    Electrochemical capacitor (EC) applications have broadened tremendously since EC energy storage devices were introduced in 1978. Then typical applications operated below 10 V at power levels below 1 W. Today many EC applications operate at voltages approaching 1000 V at power levels above 100 kW. This paper briefly reviews EC energy storage technology, shows representative applications using EC storage, and describes engineering approaches to design EC storage systems. Comparisons are made among storage systems designed to meet the same application power requirement but using different commercial electrochemical capacitor products.

  18. Promethium-147 capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Kavetskiy, A.; Yakubova, G.; Lin, Q.; Chan, D.; Yousaf, S.M. [TRACE Photonics Inc., 1680 West Polk Avenue, Charleston, Illinois 61920 (United States); Bower, K. [TRACE Photonics Inc., 1680 West Polk Avenue, Charleston, Illinois 61920 (United States)], E-mail: kbower@tracephotonics.com; Robertson, J.D.; Garnov, A.; Meier, D. [Department of Chemistry and University of Missouri Research Reactor, 1513 Reactor Park Drive, Columbia, Missouri 65211 (United States)

    2009-06-15

    Beta particle surface fluxes for tritium, Ni-63, Pm-147, and Sr-90 sources were calculated in this work. High current density was experimentally achieved from Pm-147 oxide in silica-titana glass. A 96 GBq (2.6 Ci) Pm-147 4{pi}-source with flux efficiency greater than 50% was used for constructing a direct charge capacitor with a polyimide coated collector and vacuum as electrical insulation. The capacitor connected to high resistance (T{omega}) loads produced up to 35 kV. Overall conversion efficiency was over 10% (on optimal load)

  19. A Magnesium-Activated Carbon Hybrid Capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, HD; Shterenberg, I; Gofer, Y; Doe, RE; Fischer, CC; Ceder, G; Aurbach, D

    2013-12-11

    Prototype cells of hybrid capacitor were developed, comprising activated carbon (AC) cloth and magnesium (Mg) foil as the positive and negative electrodes, respectively. The electrolyte solution included ether solvent (TBF) and a magnesium organo-halo-aluminate complex 0.25 M Mg2Cl3+-Ph2AlCl2-. In this solution Mg can be deposited/dissolved reversibly for thousands of cycles with high reversibility (100% cycling efficiency). The main barrier for integrating porous AC electrodes with this electrolyte solution was the saturation of the pores with the large ions in the AC prior to reaching the potential limit. This is due to the existence of bulky Mg and Al based ionic complexes consisting Cl, alkyl or aryl (R), and THF ligands. This problem was resolved by adding 0.5 M of lithium chloride (LiCl), thus introducing smaller ionic species to the solution. This Mg hybrid capacitor system demonstrated a stable cycle performance for many thousands of cycles with a specific capacitance of 90 Fg(-1) for the AC positive electrodes along a potential range of 2.4 V. (C) 2014 The Electrochemical Society. All rights reserved.

  20. Carbon-Nanotube-Based Electrochemical Double-Layer Capacitor Technologies for Spaceflight Applications

    Science.gov (United States)

    Arepalli, S.; Fireman, H.; Huffman, C.; Maloney, P.; Nikolaev, P.; Yowell, L.; Kim, K.; Kohl, P. A.; Higgins, C. D.; Turano, S. P.

    2005-01-01

    Electrochemical double-layer capacitors, or supercapacitors, have tremendous potential as high-power energy sources for use in low-weight hybrid systems for space exploration. Electrodes based on single-wall carbon nanotubes (SWCNTs) offer exceptional power and energy performance due to the high surface area, high conductivity, and the ability to functionalize the SWCNTs to optimize capacitor properties. This paper will report on the preparation of electrochemical capacitors incorporating SWCNT electrodes and their performance compared with existing commercial technology. Preliminary results indicate that substantial increases in power and energy density are possible. The effects of nanotube growth and processing methods on electrochemical capacitor performance is also presented. The compatibility of different SWCNTs and electrolytes was studied by varying the type of electrolyte ions that accumulate on the high-surface-area electrodes.

  1. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    OpenAIRE

    Cassayre, Laurent; Soucek, Pavel; Mendes, Eric; Malmbeck, Rikard; Nourry, Christophe; Eloirdi, Rachel; Glatz, Jean-Paul

    2011-01-01

    Pyrochemical processes in molten LiCl–KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide–aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorina...

  2. Low-temperature Electrodeposition of Aluminium from Lewis Acidic 1-Allyl-3-methylimidazolium Chloroaluminate Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    郑勇; 张锁江; 吕兴梅; 王倩; 左勇; 刘恋

    2012-01-01

    Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium. Systematic studies on deposition process have been performed by cYClic voltammetry and chronoamperometry. The surface morphology and X-ray diffraction (XRD) patterns of deposits prepared at different experimental conditions were also investigated. It was shown that the nucleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited. The crys- tallographic orientation of deposits was mainly influenced by temperature and current density. Smooth, dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA.cm^-2 and 313.2-353.2 K. More- over, the current efficiency of deposition and purity of aluminium have been significantly improved, demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.

  3. Development of electrostatic supercapacitors by atomic layer deposition on nanoporous anodic aluminium oxides for energy harvesting applications

    Directory of Open Access Journals (Sweden)

    Lucia eIglesias

    2015-03-01

    Full Text Available Nanomaterials can provide innovative solutions for solving the usual energy harvesting and storage drawbacks that take place in conventional energy storage devices based on batteries or electrolytic capacitors, because they are not fully capable for attending the fast energy demands and high power densities required in many of present applications. Here, we report on the development and characterization of novel electrostatic supercapacitors made by conformal Atomic Layer Deposition on the high open surface of nanoporous anodic alumina membranes employed as templates. The structure of the designed electrostatic supercapacitor prototype consists of successive layers of Aluminium doped Zinc Oxide, as the bottom and top electrodes, together Al2O3 as the intermediate dielectric layer. The conformality of the deposited conductive and dielectric layers, together with their composition and crystalline structure have been checked by XRD and electron microscopy techniques. Impedance measurements performed for the optimized electrostatic supercapacitor device give a high capacitance value of 200 µF/cm2 at the frequency of 40 Hz, which confirms the theoretical estimations for such kind of prototypes, and the leakage current reaches values around of 1.8 mA/cm2 at 1 V. The high capacitance value achieved by the supercapacitor prototype together its small size turns these devices in outstanding candidates for using in energy harvesting and storage applications.

  4. The cellular toxicity of aluminium.

    Science.gov (United States)

    Exley, C; Birchall, J D

    1992-11-07

    Aluminium is a serious environmental toxicant and is inimical to biota. Omnipresent, it is linked with a number of disorders in man including Alzheimer's disease, Parkinson's dementia and osteomalacia. Evidence supporting aluminium as an aetiological agent in such disorders is not conclusive and suffers principally from a lack of consensus with respect to aluminium's toxic mode of action. Obligatory to the elucidation of toxic mechanisms is an understanding of the biological availability of aluminium. This describes the fate of and response to aluminium in any biological system and is thus an important influence of the toxicity of aluminium. A general theme in much aluminium toxicity is an accelerated cell death. Herein mechanisms are described to account for cell death from both acute and chronic aluminium challenges. Aluminium associations with both extracellular surfaces and intracellular ligands are implicated. The cellular response to aluminium is found to be biphasic having both stimulatory and inhibitory components. In either case the disruption of second messenger systems is observed and GTPase cycles are potential target sites. Specific ligands for aluminium at these sites are unknown though are likely to be proteins upon which oxygen-based functional groups are orientated to give exceptionally strong binding with the free aluminium ion.

  5. Fatal aluminium phosphide poisoning

    Directory of Open Access Journals (Sweden)

    Meena Mahesh Chand

    2015-06-01

    Full Text Available Aluminium phosphide (AlP is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. AlP has currently aroused interest with a rising number of cases in the past four decades due to increased use for agricultural and non-agricultural purposes. Its easy availability in the markets has increased also its misuse for committing suicide. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. Poisoning with AlP has often occurred in attempts to commit suicide, and that more often in adults than in teenagers. This is a case of suicidal consumption of aluminium phosphide by a 32-year-old young medical anesthetist. Toxicological analyses detected aluminium phosphide. We believe that free access of celphos tablets in grain markets should be prohibited by law.

  6. Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

    OpenAIRE

    Wang, Di-Yan; Wei, Chuan-yu; Lin, Meng-Chang; Pan, Chun-Jern; Chou, Hung-Lung; Chen, Hsin-An; Gong, Ming; Wu, Yingpeng; Yuan, Chunze; Angell, Michael; Hsieh, Yu-Ju; Chen, Yu-Hsun; Wen, Cheng-Yen; Chen, Chun-Wei; Hwang, Bing-Joe

    2017-01-01

    Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g−1 with Coulombic efficiency ∼98%, at a current density of 99 mA g−1 (0.9 C) with clear discharge voltag...

  7. Proton Conducting Polymer Electrolytes and Its Applications

    Institute of Scientific and Technical Information of China (English)

    S. Selvasekarapandian; G. Hirankumar; R. Baskaran; M.S. Bhuvaneswari

    2005-01-01

    @@ 1Introduction Proton conducting solid polymer electrolytes have been extensively studied due to their potential applications in electrochemical devices such as batteries, super capacitors, electrochromic windows, sensors etc[1,2]Many researchers have studied the behaviour of inorganic based polymer electrolytes as proton conductors and their applications in solid state devices at room temperature[3]. But, inorganic acid doped electrolytes have some serious disadvantages like corrosion towards the electrode and hazardous. Hence, there is need for searching new electrolyte which is stable towards the electrode. It has been reported that the ammonium salts which behaves like alkali metal salt are good dopant to the polymer matrix[4, 5] for the development of proton conducting polymer electrolyte. The proton conductors based on poly (ethylene oxide)[6], poly (ethylene succinate)[7], poly (ethylene glycol)[8], as host matrix doped with ammonium salt have already been reported.

  8. Suspended graphene variable capacitor

    Science.gov (United States)

    AbdelGhany, M.; Mahvash, F.; Mukhopadhyay, M.; Favron, A.; Martel, R.; Siaj, M.; Szkopek, T.

    2016-12-01

    Electromechanical variable capacitors, or varactors, find a wide range of applications including sensing applications and the tuning of electrical circuit resonance. We demonstrate a nano-electromechanical graphene varactor, a variable capacitor wherein the capacitance is tuned by voltage controlled deflection of a dense array of suspended graphene membranes. The low flexural rigidity of graphene monolayers is exploited to achieve low actuation voltage and high tunable capacitance density in an ultra-thin structure. Large arrays comprising thousands of suspensions were fabricated to give a tunable capacitance of over 10 pF mm-2. This capacitance density suggests that graphene offers a potential solution to the challenge of reducing the size of micro-electromechanical systems (MEMS). A capacitance tuning of 55% was achieved with a 10 V actuating voltage, exceeding the 50% tuning limit of Hookean parallel plate pull-in without the use of complex mechanical schemes that occupy substrate area. Capacitor behavior was investigated experimentally, and described by a simple theoretical model. Mechanical properties of the graphene membranes were measured independently using atomic force microscopy. We present a comparison of state-of-the-art MEMS and graphene varactors. The quality factor of graphene varactors is limited by graphene sheet resistance, pull-in voltage can be improved with more aggressive scaling, while the power handling and cycling stability of graphene varactors remains unknown.

  9. Substituted Quaternary Ammonium Salts Improve Low-Temperature Performance of Double-Layer Capacitors

    Science.gov (United States)

    Brandon, Erik J.; Smart, Marshall C.; West, William C.

    2011-01-01

    Double-layer capacitors are unique energy storage devices, capable of supporting large current pulses as well as a very high number of charging and discharging cycles. The performance of doublelayer capacitors is highly dependent on the nature of the electrolyte system used. Many applications, including for electric and fuel cell vehicles, back-up diesel generators, wind generator pitch control back-up power systems, environmental and structural distributed sensors, and spacecraft avionics, can potentially benefit from the use of double-layer capacitors with lower equivalent series resistances (ESRs) over wider temperature limits. Higher ESRs result in decreased power output, which is a particular problem at lower temperatures. Commercially available cells are typically rated for operation down to only 40 C. Previous briefs [for example, Low Temperature Supercapacitors (NPO-44386), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), p. 32, and Supercapacitor Electrolyte Solvents With Liquid Range Below 80 C (NPO-44855), NASA Tech Briefs, Vol. 34, No. 1 (January 2010), p. 44] discussed the use of electrolytes that employed low-melting-point co-solvents to depress the freezing point of traditional acetonitrile-based electrolytes. Using these modified electrolyte formulations can extend the low-temperature operational limit of double-layer capacitors beyond that of commercially available cells. This previous work has shown that although the measured capacitance is relatively insensitive to temperature, the ESR can rise rapidly at low temperatures, due to decreased electrolyte conductance within the pores of the high surface- area carbon electrodes. Most of these advanced electrolyte systems featured tetraethylammonium tetrafluoroborate (TEATFB) as the salt. More recent work at JPL indicates the use of the asymmetric quaternary ammonium salt triethylmethylammonium tetrafluoroborate (TEMATFB) or spiro-(l,l')-bipyrrolidium tetrafluoroborate (SBPBF4) in a 1:1 by volume solvent

  10. The moving plate capacitor paradox

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2000-03-01

    For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  11. Aluminium in human breast tissue.

    Science.gov (United States)

    Exley, Christopher; Charles, Lisa M; Barr, Lester; Martin, Claire; Polwart, Anthony; Darbre, Philippa D

    2007-09-01

    Aluminium is omnipresent in everyday life and increased exposure is resulting in a burgeoning body burden of this non-essential metal. Personal care products are potential contributors to the body burden of aluminium and recent evidence has linked breast cancer with aluminium-based antiperspirants. We have used graphite furnace atomic absorption spectrometry (GFAAS) to measure the aluminium content in breast biopsies obtained following mastectomies. The aluminium content of breast tissue and breast tissue fat were in the range 4-437 nmol/g dry wt. and 3-192 nmol/g oil, respectively. The aluminium content of breast tissue in the outer regions (axilla and lateral) was significantly higher (P=0.033) than the inner regions (middle and medial) of the breast. Whether differences in the regional distribution of aluminium in the breast are related to the known higher incidence of tumours in the outer upper quadrant of the breast remains to be ascertained.

  12. Bioaccumulation of Aluminium in Hydromacrophytes in Polish Coastal Lakes

    Directory of Open Access Journals (Sweden)

    Senze Magdalena

    2015-03-01

    Full Text Available The research on aluminium content was conducted in water and on aquatic flora of Polish lakes in the central part of the coast. The study included the lakes Sarbsko, Choczewskie, Bia.e, K.odno, D.brze and Salino investigated in the summer of 2013. The examined lakes belong mainly to the direct basin of the Baltic Sea. Samples of aquatic plants and lake waters were collected. In the water samples pH and electrolytic conductivity were measured. The aluminium content was determined both in water and aquatic plants. Submerged hydromacrophyte studies included Myriophyllum alterniflorum L., Potamogeton perfoliatus L. and Ceratophyllum demersum L. Emergent hydromacrophyte studies included Phragmites australis (Cav. Trin. ex Steud., Juncus bulbosus L., Iris pseudacorus L., Eleocharis palustris (L. Roem. % Schult., Phalaris arundinacea L., Carex riparia Curt., Mentha aquatic L., Stratiotes aloides L., Alisma plantago-aquatica L., Glyceria maxima (Hartman Holmb., Sagittaria sagittifolia L., Scirpus lacustris L. and Typha angustifolia L. The purpose of this investigation was the determination of the aluminium content in submerged and emergent hydromacrophytes and also the definition of their bioaccumulative abilities. The average concentration of aluminium in water was 2.68 fęg Al dm.3. The average content of aluminium in plants was 2.8015 mg Al kg.1. The bioaccumulation factor ranged from BCF=19.74 to BCF=16619. On the basis of the analysis of the aluminium content in water and aquatic plants results show that both water and plants were characterized by a moderate level of aluminium. The recorded concentrations indicate a mid-range value and are much lower than those which are quoted for a variety of surface waters in various parts of the world.

  13. Fire exposed aluminium structures

    NARCIS (Netherlands)

    Maljaars, J.; Fellinger, J.H.H.; Soetens, F.

    2006-01-01

    Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical pr

  14. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1999-04-27

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  15. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  16. Synthesis of MgO templated mesoporous carbons and its use for capacitor electrode

    Directory of Open Access Journals (Sweden)

    Yasushi Soneda

    2013-01-01

    Full Text Available Mesoporous carbons (MPCs with large specificsurface area are synthesized by the heat-treatmentand subsequent acid treatment of magnesium citrate.The MPCs obtained are examined as electrodematerials for electric double layer capacitor and showthe huge gravimetric capacitance with superior rateperformance in sulphuric acid electrolyte. The MPCsalso realize the larger capacitance than conventionalactivated carbon in organic electrolyte andextraordinary high retention of capacitance at verylow temperature, such as 80% of room temperaturevalue at -60 °C.

  17. Surface morphology, composition and thermal behavior of tungsten-containing anodic spark coatings on aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lukiyanchuk, I.V.; Rudnev, V.S.; Kuryavyi, V.G.; Boguta, D.L.; Bulanova, S.B.; Gordienko, P.S

    2004-01-01

    Anodic spark coatings on aluminium alloy were prepared in aqueous electrolytes with sodium tungstate. The influence of boric acid addition in the electrolyte on the surface morphology, elemental and phase composition of the coatings was investigated. In both cases the coatings contained O, Al and W. The coatings obtained in electrolyte with boric acid and sodium tungstate contain also B at approximately 1 at.%. Scanning electron microscopy indicated that the coatings had three layers: the grey underlayer of anodic alumina, the second black layer of crystalline or amorphous aluminium tungstate agglomerated into fibers and the outer green layer of WO{sub 3}. It was proposed that isopoly- and heteropolyanions in the electrolyte used take part in the coating growth.

  18. A Simple, Successful Capacitor Lab

    Science.gov (United States)

    Ennis, William

    2011-01-01

    Capacitors are a fundamental component of modern electronics. They appear in myriad devices and in an enormous range of sizes. Although our students are taught the function and analysis of capacitors, few have the opportunity to use them in our labs.

  19. Aluminium and human breast diseases.

    Science.gov (United States)

    Darbre, P D; Pugazhendhi, D; Mannello, F

    2011-11-01

    The human breast is exposed to aluminium from many sources including diet and personal care products, but dermal application of aluminium-based antiperspirant salts provides a local long-term source of exposure. Recent measurements have shown that aluminium is present in both tissue and fat of the human breast but at levels which vary both between breasts and between tissue samples from the same breast. We have recently found increased levels of aluminium in noninvasively collected nipple aspirate fluids taken from breast cancer patients (mean 268 ± 28 μg/l) compared with control healthy subjects (mean 131 ± 10 μg/l) providing evidence of raised aluminium levels in the breast microenvironment when cancer is present. The measurement of higher levels of aluminium in type I human breast cyst fluids (median 150 μg/l) compared with human serum (median 6 μg/l) or human milk (median 25 μg/l) warrants further investigation into any possible role of aluminium in development of this benign breast disease. Emerging evidence for aluminium in several breast structures now requires biomarkers of aluminium action in order to ascertain whether the presence of aluminium has any biological impact. To this end, we report raised levels of proteins that modulate iron homeostasis (ferritin, transferrin) in parallel with raised aluminium in nipple aspirate fluids in vivo, and we report overexpression of mRNA for several S100 calcium binding proteins following long-term exposure of MCF-7 human breast cancer cells in vitro to aluminium chlorhydrate.

  20. Debye length dependence of the anomalous dynamics of ionic double layers in a parallel plate capacitor

    NARCIS (Netherlands)

    Kortschot, R. J.; Philipse, A. P.; Erné, B. H.

    2014-01-01

    The electrical impedance spectrum of simple ionic solutions is measured in a parallel plate capacitor at small applied ac voltage. The influence of the ionic strength is investigated using several electrolytes at different concentrations in solvents of different dielectric constants. The electric do

  1. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  2. Moisture in multilayer ceramic capacitors

    Science.gov (United States)

    Donahoe, Daniel Noel

    When both precious metal electrode and base metal electrode (BME) capacitors were subjected to autoclave (120°C/100% RH) testing, it was found that the precious metal capacitors aged according to a well known aging mechanism (less than 3% from their starting values), but the BME capacitors degraded to below the -30% criterion at 500 hours of exposure. The reasons for this new failure mechanism are complex, and there were two theories that were hypothesized. The first was that there could be oxidation or corrosion of the nickel plates. The other hypothesis was that the loss of capacitance was due to molecular changes in the barium titanate. This thesis presents the evaluation of these hypotheses and the physics of the degradation mechanism. It is concluded by proof by elimination that there are molecular changes in the barium titanate. Furthermore, the continuous reduction in capacitor size makes the newer base metal electrode capacitors more vulnerable to moisture degradation than the older generation precious metal capacitors. In addition, standard humidity life testing, such as JESD-22 THB and HAST, will likely not uncover this problem. Therefore, poor reliability due to degradation of base metal electrode multilayer ceramic capacitors may catch manufacturers and consumers by surprise.

  3. Telangiectasia in aluminium workers: a follow up.

    Science.gov (United States)

    Thériault, G; Gingras, S; Provencher, S

    1984-08-01

    A five step investigation was carried out to gain a better understanding of the morbidity that accompanied the development of telangiectasia on aluminium workers and to find its cause. Fifty workers with multiple telangiectasia when matched with normal controls showed the same amount of illness except that evidence of ischaemia on the ECG was found in nine cases and one control. The cases did not show an excess of abnormal biochemical tests. The basic histopathological lesion affected the surrounding tissue rather than the vessels themselves. Working in the current environment and wearing masks seems to protect young workers from developing the lesions. The Soderberg and not the prebake process was associated with the lesions; the causative agent is probably a gas that contains both hydrocarbons and fluoride components emitted from the electrolytic reactors.

  4. Split-phase motor running as capacitor starts motor and as capacitor run motor

    Directory of Open Access Journals (Sweden)

    Yahaya Asizehi ENESI

    2016-07-01

    Full Text Available In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The magnitude of capacitor that will develop maximum torque in capacitor start motor and capacitor run motor are investigated and determined by simulation. Each of these capacitors is connected to the auxiliary winding of split-phase motor thereby transforming it into capacitor start or capacitor run motor. The starting current and starting torque of the split-phase motor (SPM, capacitor run motor (CRM and capacitor star motor (CSM are compared for their suitability in their operational performance and applications.

  5. Anti-perovskite solid electrolyte compositions

    Science.gov (United States)

    Zhao, Yusheng; Daemen, Luc Louis

    2015-12-26

    Solid electrolyte antiperovskite compositions for batteries, capacitors, and other electrochemical devices have chemical formula Li.sub.3OA, Li.sub.(3-x)M.sub.x/2OA, Li.sub.(3-x)N.sub.x/3OA, or LiCOX.sub.zY.sub.(1-z), wherein M and N are divalent and trivalent metals respectively and wherein A is a halide or mixture of halides, and X and Y are halides.

  6. Fractal Structures For Mems Variable Capacitors

    KAUST Repository

    Elshurafa, Amro M.

    2014-08-28

    In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape separated by a vertical distance from a lower first metal plate with a complementary fractal shape; and a substrate above which the capacitor body is suspended.

  7. First Principles Study of Aluminium Vacancy in Wurtzite Aluminium Nitride

    Institute of Scientific and Technical Information of China (English)

    GAO Ting-Ge; YI Jue-Min; ZHOU Zi-Yao; HU Xiao-Dong

    2008-01-01

    @@ We report that the aluminium vacancy in wurtzite AIN brings about two impurity levels e and a2 in the band gap, not just one single t2 level The aluminium vacancy carries a magnetic moment of 1 μB in the ground state. The molecule orbit of the aluminium vacancy becomes e↑↑ a2↑ rather than e↑↑ a2↑. The calculation is carried out by using the CASTEP code. The intrinsic symmetry of wurtzite A1N is the driving force for this spin splitting. Finally the symmetry of wurtzite AlN results in an anti-ferromagnetic coupling between the aluminium vacancies, as is predicted. Our findings are helpful to gain a more through understanding of the structural and spin property of aluminium vacancy in wurtzite AIN.

  8. Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

    Directory of Open Access Journals (Sweden)

    C. Lekakou

    2011-01-01

    Full Text Available This paper investigates electrochemical double-layer capacitors (EDLCs including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF and a multiwall carbon nanotube (CNT electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance tests. The best separator was a glass fibre-fine pore filter. The carbon woven fabric electrode and the corresponding supercapacitor exhibited superior performance per unit area, whereas the multiwall carbon nanotube electrode and corresponding supercapacitor demonstrated excellent specific properties. The hybrid CWF-CNT electrodes did not show a combined improved performance due to the lack of carbon nanotube penetration into the carbon fibre fabric.

  9. Deformation of Cases in High Capacitance Value Wet Tantalum Capacitors under Environmental Stresses

    Science.gov (United States)

    Teverovsky, Alexander

    2016-01-01

    Internal gas pressure in hermetic wet tantalum capacitors is created by air, electrolyte vapor, and gas generated by electrochemical reactions at the electrodes. This pressure increases substantially with temperature and time of operation due to excessive leakage currents. Deformation of the case occurs when the internal pressure exceeds pressure of the environments and can raise significantly when a part operates in space. Contrary to the cylinder case wet tantalum capacitors that have external sealing by welding and internal sealing provided by the Teflon bushing and crimping of the case, no reliable internal sealing exists in the button case capacitors. Single seal design capacitors are used for high capacitance value wet tantalum capacitors manufactured per DLA L&M drawings #04003, 04005, and 10011, and require additional analysis to assure their reliable application in space systems. In this work, leakage currents and case deformation of button case capacitors were measured during different environmental test conditions. Recommendations for derating, screening and qualification testing are given. This work is a continuation of a series of NEPP reports related to quality and reliability of wet tantalum capacitors.

  10. Electrochemical characterization of MnO2 as the cathode material for a high voltage hybrid capacitor

    Institute of Scientific and Technical Information of China (English)

    Jian-ling Li; Fei Gao; Yan Jing; Rui-ying Miao; Ke-zhong Wu; Xin-dong Wang

    2009-01-01

    Manganese dioxide (MnO_2) was prepared using the ultrasonic method. Its electrochemical performance was evaluated as the cathode material for a high voltage hybrid capacitor. And the specific capacitance of the MnO_2 electrode reached 240 F-g-1. The new hybrid capacitor was constructed, combining Al/Al_2O_3 as the anode and MnO_2 as the cathode with electrolyte for the aluminum electrolytic capacitor to solve the problem of low working voltage of a supercapacitor unit. The results showed that the hybrid ca-pacitor had a high energy density and the ability of quick charging and discharging according to the electrochemical performance test. The capacitance was 84.4 μF, and the volume and mass energy densities were greatly improved compared to those of the traditional aluminum electrolytic capacitor of 47 μF. The analysis of electrochemical impedance spectroscopy (EIS) showed that the hybrid ca-pacitor had good impedance characteristics.

  11. Fractal Structures For Fixed Mems Capacitors

    KAUST Repository

    Elshurafa, Amro M.

    2014-08-28

    An embodiment of a fractal fixed capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure. The capacitor body has a first plate with a fractal shape separated by a horizontal distance from a second plate with a fractal shape. The first plate and the second plate are within the same plane. Such a fractal fixed capacitor further comprises a substrate above which the capacitor body is positioned.

  12. Treatment of dairy effluents by electrocoagulation using aluminium electrodes.

    Science.gov (United States)

    Tchamango, Serge; Nanseu-Njiki, Charles P; Ngameni, Emmanuel; Hadjiev, Dimiter; Darchen, André

    2010-01-15

    This work sets out to examine the efficiency of an electrolytic treatment: electrocoagulation, applied to dairy effluents. The experiments were carried out using a soluble aluminium anode on artificial wastewater derived from solutions of milk powder. The flocks generated during this treatment were separated by filtration. The analysis of the filtrates showed that the chemical oxygen demand (COD) was reduced by up to 61% while the removal of phosphorus, nitrogen contents, and turbidity were 89, 81 and 100%, respectively. An analogous treatment applied to phosphate and lactose solutions revealed that lactose was not eliminated, a fact that could account for the rather poor lowering of the COD. Compared to the chemical coagulation treatment with aluminium sulphate, the efficiency of the electrocoagulation technique was almost identical. However the wastewaters treated by electrocoagulation differed by the fact that they exhibited a lower conductivity and a neutral pH value (by contrast to the acid nature of the solution treated by the chemical coagulation). This result (low conductivity, neutral pH) tends to show that it may be possible to recycle the treated water for some industrial uses. Moreover, the electrocoagulation process uses fewer reagents: the mass of the aluminium anode dissolved during the treatment is lower compared to the quantity of the aluminium salt used in chemical coagulation. These two observations clearly show that the electrocoagulation technique is more performing.

  13. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  14. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2005-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  15. Asymmetric Electrochemical Capacitors - Stretching the Limits of Aqueous Electrolytes

    Science.gov (United States)

    2011-07-01

    including templated mesoporous carbon, 51 nanotubes, 52 – 55 nanofoams, 56 and graphene 57 have been used as base struc- tures for MnOx-modifi ed...surface and recombine with OH – as the electrode is discharged, although typically with considerable hysteresis between the charge and discharge

  16. High Energy Density Capacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Capacitor size and reliability are often limiting factors in pulse power, high speed switching, and power management and distribution (PMAD) systems. T/J...

  17. Technology of Pulse Power Capacitors

    Science.gov (United States)

    Qin, Shanshan

    Polymer film of pulse discharge capacitors operated at high repetition rate dissipates substantial power. The thermal conductivity of biaxially oriented polypropylene (BOPP) is measured as a function of metallization resistivity. The thermal conductivity in the plane of the film is about twice that of bulk polypropylene. Thermal design is optimized based on the measurement for large capacitors with multiple windings in a container. High discharge speed results in high current density at the wire arc sprayed end connections which tend to deteriorate gradually, resulting in capacitor failure during operation. To assure the end connection quality before assembly, a test procedure and apparatus for end connection integrity was developed based on monitoring the partial discharge pattern from end connection during discharge. The mechanism of clearing is analyzed which shows arc extinguishes due to the increased arc length and reduced energy so that capacitor can function normally after breakdown. In the case of a clearing discharge, the power dissipation appears to increase with time, although this is not a feature of previous models. Submicrosecond discharge requires minimizing inductance which can be achieved by optimizing the winding structure so that submicrosecond discharge becomes practical. An analysis of the inductance of multisection, very high voltage capacitors is carried out, which identifies low inductance structures for this type of capacitor.

  18. Aluminium in Drinkwater: voorkomen, herkomst en gezondheidsaspecten

    NARCIS (Netherlands)

    Versteegh JFM; de Boer JLM; van den Velde-Koerts T

    1992-01-01

    Aluminium can occur in drinking water because of the application of aluminium salts as a coagulant in the treatment of drinking water. In the Netherlands mostly iron salts are used instead of aluminium. Besides this aluminium can be present in the source for drinking water. In shallow groundwater

  19. Physics Based Degradation Models for Capacitor Prognostics under Thermal Overstress Conditions

    Directory of Open Access Journals (Sweden)

    Kai Goebel

    2013-01-01

    Full Text Available Electronics subsystems for monitoring, control, and enhanced functionality play an increasingly important role in safety critical systems. Electrolytic capacitors are an important component in several key subsystems that range from power supplies on safety critical avionics equipment to power drivers for electro-mechanical actuators. These capacitors are known to have comparatively low reliability, and given their criticality in electronics subsystems they are a good candidate for component level monitoring and prognostics. Prognostics provides a way to assess remaining useful life of components and systems based on their current state of health and their anticipated future use and operating conditions. Past experiences have shown that capacitor degradation and failures are quite prevalent under high electrical and thermal stress conditions that they are often subjected to during operations. Our focus in this work is on deriving a physics-based degradation model for electrolytic capacitors under thermal stress conditions. As part of our methodology, we study the effects of accelerated aging due to thermal stress on a batch of identically manufactured capacitors operating at different temperatures. This provides a framework for supplementing theoretical modeling with data collected from simultaneous experiments, which is then used to validate the derived models.

  20. Aluminium, antiperspirants and breast cancer.

    Science.gov (United States)

    Darbre, P D

    2005-09-01

    Aluminium salts are used as the active antiperspirant agent in underarm cosmetics, but the effects of widespread, long term and increasing use remain unknown, especially in relation to the breast, which is a local area of application. Clinical studies showing a disproportionately high incidence of breast cancer in the upper outer quadrant of the breast together with reports of genomic instability in outer quadrants of the breast provide supporting evidence for a role for locally applied cosmetic chemicals in the development of breast cancer. Aluminium is known to have a genotoxic profile, capable of causing both DNA alterations and epigenetic effects, and this would be consistent with a potential role in breast cancer if such effects occurred in breast cells. Oestrogen is a well established influence in breast cancer and its action, dependent on intracellular receptors which function as ligand-activated zinc finger transcription factors, suggests one possible point of interference from aluminium. Results reported here demonstrate that aluminium in the form of aluminium chloride or aluminium chlorhydrate can interfere with the function of oestrogen receptors of MCF7 human breast cancer cells both in terms of ligand binding and in terms of oestrogen-regulated reporter gene expression. This adds aluminium to the increasing list of metals capable of interfering with oestrogen action and termed metalloestrogens. Further studies are now needed to identify the molecular basis of this action, the longer term effects of aluminium exposure and whether aluminium can cause aberrations to other signalling pathways in breast cells. Given the wide exposure of the human population to antiperspirants, it will be important to establish dermal absorption in the local area of the breast and whether long term low level absorption could play a role in the increasing incidence of breast cancer.

  1. Electrolytes Test

    Science.gov (United States)

    ... mean? High or low electrolyte levels can be caused by several conditions and diseases. Generally, they are affected by how much is consumed in the diet and absorbed by the body, the amount of water in a person's body, and the amount eliminated ...

  2. The toxicity of aluminium in humans.

    Science.gov (United States)

    Exley, C

    2016-06-01

    We are living in the 'aluminium age'. Human exposure to aluminium is inevitable and, perhaps, inestimable. Aluminium's free metal cation, Alaq(3+), is highly biologically reactive and biologically available aluminium is non-essential and essentially toxic. Biologically reactive aluminium is present throughout the human body and while, rarely, it can be acutely toxic, much less is understood about chronic aluminium intoxication. Herein the question is asked as to how to diagnose aluminium toxicity in an individual. While there are as yet, no unequivocal answers to this problem, there are procedures to follow to ascertain the nature of human exposure to aluminium. It is also important to recognise critical factors in exposure regimes and specifically that not all forms of aluminium are toxicologically equivalent and not all routes of exposure are equivalent in their delivery of aluminium to target sites. To ascertain if Alzheimer's disease is a symptom of chronic aluminium intoxication over decades or breast cancer is aggravated by the topical application of an aluminium salt or if autism could result from an immune cascade initiated by an aluminium adjuvant requires that each of these is considered independently and in the light of the most up to date scientific evidence. The aluminium age has taught us that there are no inevitabilities where chronic aluminium toxicity is concerned though there are clear possibilities and these require proving or discounting but not simply ignored.

  3. Force on an Asymmetric Capacitor

    CERN Document Server

    Bahder, T B; Bahder, Thomas B.; Fazi, Chris

    2002-01-01

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of patents by Thomas Townsend Brown. At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes: ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least three orders of magnitude too small to explain the magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, however, it is difficult to see how ionic dr...

  4. Development and experimental study of oil-free capacitor module for plasma focus device

    Science.gov (United States)

    Sharma, Ravindra Kumar; Sharma, Archana

    2017-03-01

    This development is concerned with the compact capacitor module for a plasma focus device. Oil-free, non-standard geometry capacitors are designed and developed for high current delivery in sub-microseconds time. Metalized dielectric film based pulse capacitor becomes progressively less viable at currents above 10 kA. It is due to reliability and energy scaling difficulties, based on effects such as vaporization, high resistivity, and end connection. Bipolar electrolytic capacitors are also not preferred due to their limited life and comparatively low peak current delivery. Bi-axially oriented polypropylene (BOPP) film with extended aluminum foil is a combination to deliver moderately high power. But, electrically weak points, relative permittivity, and the edge gap margins have made its adoption difficult. A concept has been developed in lab for implementing the above combination in a less complex and costly manner. This paper concerns the development and testing process techniques for quite different hollow cylindrical, oil-free capacitors (4 μ F , 10 kV, 20 nH). Shot life of 1000 has been experimentally performed on the test bed at its rated energy density level. The technological methods and engineering techniques are now available and utilized for manufacturing and testing of BOPP film based oil-free capacitors.

  5. The production of niobium powder and electric properties of niobium capacitors

    Science.gov (United States)

    Yoon, Jae Sik; Cho, Sung Wook; Kim, Yang Soo; Kim, Byung Il

    2009-06-01

    In order to evaluate the electrical and frequency properties of niobium powder manufactured by the metallothermic reduction method for use as a capacitor, the present study measured capacitor performance evaluation factors such as leakage current, permittivity loss (tanδ) and capacitance, etc. The niobium powder used in this experiment was processed using the external continuous supply method and had large coarse globular particles of 0.5 μm to 1.0 μm, but the granularity distribution was very irregular. Capacitance decreased significantly from 150 μF in electrolyte (wet cap) to 130 μF after carbon (C)/silver (Ag) solution coating, and to around 115 μF after aging, falling within the capacity tolerance of tantalum capacitors. Converted to CV/g, capacitance was around 81,000 CV/g. Permittivity loss (tanδ) decreased significantly from 13.0 % after C/Ag coating to 7.5 % after aging, satisfying the general standard level of 10 % or less. Leakage current was 2.5 μA after C/Ag coating and 3.0 μA after aging, both less than the standard level of 6.3 μA. On the whole, the niobium capacitor showed somewhat more unstable characteristics than commercial tantalum capacitors but is nonetheless considered applicable as a future substitute for tantalum capacitors.

  6. Architecture Analysis of High Performance Capacitors (POSTPRINT)

    Science.gov (United States)

    2009-07-01

    includes the measurement of heat dissipated from a recently developed fluorenyl polyester (FPE) capacitor under an AC excitation. II. Capacitor ...AFRL-RZ-WP-TP-2010-2100 ARCHITECTURE ANALYSIS OF HIGH PERFORMANCE CAPACITORS (POSTPRINT) Hiroyuki Kosai and Tyler Bixel UES, Inc...2009 4. TITLE AND SUBTITLE ARCHITECTURE ANALYSIS OF HIGH PERFORMANCE CAPACITORS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c

  7. Materials Science Constraints on the Development of Aluminium Reduction Cells

    Science.gov (United States)

    Metson, James; McIntosh, Grant; Etzion, Ronny

    The Hall-Heroult process for the production of Aluminium metal is some 125 years old. The process is energy constrained by the need to shed around half of the (electrical) energy supplied to the cell as waste heat. The molten cryolite electrolyte is sufficiently aggressive that the only reliable method of protecting the side wall of the cell is to maintain a frozen layer of electrolyte at the hot face of the sidewall. Thus the lack of a cryolite resistant sidewall is but one of several materials science constraints which still limit the energy efficiency of the process. An inert anode and non-consumable cathode are also significant challenges which limit cell life and energy efficiency. Thus there are major challenges in both materials development and new conceptual cell designs to improve the efficiency of this process.

  8. Microstructure and Properties of Composite Coatings Obtained on Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Bara M.

    2016-09-01

    Full Text Available This paper presents methods of modifying the anode surface layers of Al2O3 by introducing carbon to their microstructure. Composite coatings were prepared using two different methods. In the first, coatings were formed by means of oxidation under constant current conditions. Anodic oxidation of aluminium was conducted in a multicomponent electrolyte with the addition of organic acids and graphite. The second method was based on the formation of oxide coatings in an electrolyte without the addition of graphite or heat treatment of the layers of succinic acid. The obtained coatings were tested using SEM, TEM, and GDOES (glow discharge optical emission spectrometry and their tribological and stereometric properties were measured. The study demonstrated the beneficial effects of the methods when used to improve the tribological properties of sliding couples.

  9. Split-phase motor running as capacitor starts motor and as capacitor run motor

    OpenAIRE

    2016-01-01

    In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The ma...

  10. Optimization of Design Parameters and Operating Conditions of Electrochemical Capacitors for High Energy and Power Performance

    Science.gov (United States)

    Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

    2017-03-01

    Theoretical expressions for performance parameters of different electrochemical capacitors (ECs) have been optimized by solving them using MATLAB scripts as well as via the MATLAB R2014a optimization toolbox. The performance of the different kinds of ECs under given conditions was compared using theoretical equations and simulations of various models based on the conditions of device components, using optimal values for the coefficient associated with the battery-kind material ( K BMopt) and the constant associated with the electrolyte material ( K Eopt), as well as our symmetric electric double-layer capacitor (EDLC) experimental data. Estimation of performance parameters was possible based on values for the mass ratio of electrodes, operating potential range ratio, and specific capacitance of electrolyte. The performance of asymmetric ECs with suitable electrode mass and operating potential range ratios using aqueous or organic electrolyte at appropriate operating potential range and specific capacitance was 2.2 and 5.56 times greater, respectively, than for the symmetric EDLC and asymmetric EC using the same aqueous electrolyte, respectively. This enhancement was accompanied by reduced cell mass and volume. Also, the storable and deliverable energies of the asymmetric EC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 12.9 times greater than those of the symmetric EDLC using aqueous electrolyte, again with reduced cell mass and volume. The storable energy, energy density, and power density of the asymmetric EDLC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 5.56 times higher than for a similar symmetric EDLC using aqueous electrolyte, with cell mass and volume reduced by a factor of 1.77. Also, the asymmetric EDLC with the same type of electrode and suitable electrode mass ratio, working potential range ratio, and proper organic electrolyte

  11. Dispersion strengthening of aluminium-aluminium-oxide products

    DEFF Research Database (Denmark)

    Hansen, Niels

    1970-01-01

    The true stress-true strain curves at room temperature and at 400°C were determined for various types of aluminium-aluminium-oxide products containing from 0.2 to 4.7 weight per cent of aluminium oxide. The effect of particles on the initial flow stress and the flow stress for 0.2% offset at room...... temperature and at 400°C is in agreement with Orowan's theory. The increase in flow stress at room temperature for strain values below 3 per cent was related to the plastic strain by the equation σ-σoy=k1ε 1/2, where σoy is the initial flow stress and where k1 increases for increasing volume fraction...... and decreasing particle size of the dispersed particles. A general expression for k1 was derived for the relationship between the dislocation density and the strain in dispersion-strengthened products...

  12. Preparation of aluminium lakes by electrocoagulation

    OpenAIRE

    Prapai Pradabkham

    2008-01-01

    Aluminium lakes have been prepared by electrocoagulation employing aluminium as electrodes. The electrocoagulation is conducted in an aqueous alcoholic solution and is completed within one hour. The dye content in the lake ranges approximately between 4-32%.

  13. Development and fabrication of a 1.5 F - 5 V solid state super capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Staiti, P.; Lufrano, F. [CNR-ITAE, Istituto di Tecnologie Avanzate Per l' Energia Inicola Giordanoi, Messina (Italy)

    2004-07-01

    A five cells super-capacitor prototype with special electrolyte is designed and fabricated at the Institute CNR-ITAE of Messina. It has a nominal capacitance of 1.5 F and a maximum voltage of 5 V. The electrodes of prototype are formed of high surface area carbon material and Nafion ionomer. Nafion is used as an electrolyte membrane separator between the electrodes of each single cell and as a binder/ion conductor in the electrodes. The fabricated prototype achieves specific capacitance of 114 F/g (referred to the weight of active carbon materials for single electrode), that is comparable to the specific capacitance previously obtained from a smaller scale single cell of same type of super-capacitor. A power density of 1.4 kW/l and a RC-time constant of 0.3 s have been calculated for the device. (authors)

  14. Electrolytic fixer.

    Science.gov (United States)

    Stevens

    1982-12-01

    Interest in the recovery of silver from radiographic film generates a need to understand the operating procedures of recovery units utilizing the electrolytic fixer principle. Tailing or terminal units and recirculation units using electrolysis are evaluated. Difficulties encountered in the number of Coulombs applied to a specific amount of fixer are discussed. Reduction of sulfiding as a result of electrolysis and variations in film volumes are noted. The quantity and quality of silver collected can be improved by being aware of alterations in chemical activity used in a silver recovery program.

  15. Alloys of uranium and aluminium with low aluminium content; Alliages uranium-aluminium a faible teneur en aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Cabane, G.; Englander, M.; Lehmann, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Uranium, as obtained after spinning in phase {gamma}, presents an heterogeneous structure with large size grains. The anisotropic structure of the metal leads to an important buckling and surface distortion of the fuel slug which is incompatible with its tubular cladding for nuclear fuel uses. Different treatments have been made to obtain an isotropic structure presenting high thermal stability (laminating, hammering and spinning in phase {alpha}) without success. Alloys of uranium and aluminium with low aluminium content present important advantage in respect of non allied uranium. The introduction of aluminium in the form of intermetallic compound (UAl{sub 2}) gives a better resistance to thermal fatigue. Alloys obtained from raw casting present an improved buckling and surface distortion in respect of pure uranium. This improvement is obtained with uranium containing between 0,15 and 0,5 % of aluminium. An even more improvement in thermal stability is obtained by thermal treatments of these alloys. These new characteristics are explained by the fine dispersion of the UAl{sub 2} particles in uranium. The results after treatments obtained from an alloy slug containing 0,4 % of aluminium show no buckling or surface distortion and no elongation. (M.P.)

  16. Energy conversion from aluminium and phosphate rich solution via ZnO activation of aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, Gymama, E-mail: gslaught@umbc.edu; Sunday, Joshua; Stevens, Brian

    2015-08-01

    Electrochemical power sources have motivated intense research efforts in the development of alternative ‘green’ power sources for ultra-low powered bioelectronic devices. Biofuel cells employ immobilized enzymes to convert the available chemical energy of organic fuels directly into electricity. However, biofuel cells are limited by short lifetime due to enzyme inactivation and frequent need to incorporate mediators to shuttle electrons to the final electron acceptor. In this context, other electrochemical power sources are necessary in energy conversion and storage device applications. Here we report on the fabrication and characterization of a membrane-free aluminium/phosphate cell based on the activation of aluminium (Al) using ZnO nanocrystal in an Al/phosphate cell as a ‘green’ alternative to the traditional enzymatic biofuel cells. The hybrid cell operates in neutral phosphate buffer solution and physiological saline buffer. The ZnO modifier in the phosphate rich electrolyte activated the pitting of Al resulting in the production of hydrogen, as the reducing agent for the reduction of H{sub 2}PO{sub 4}{sup −} ions to HPO{sub 3}{sup 2−} ions at a formal potential of −0.250 V vs. Ag/AgCl. Specifically, the fabricated cell operating in phosphate buffer and physiological saline buffer exhibit an open-circuit voltage of 0.810 V and 0.751 V and delivered a maximum power density of 0.225 mW cm{sup −2} and 1.77 mW cm{sup −2}, respectively. Our results demonstrate the feasibility of generating electricity by activating Al as anodic material in a hybrid cell supplied with phosphate rich electrolyte. Our approach simplifies the construction and operation of the electrochemical power source as a novel “green” alternative to the current anodic substrates used in enzymatic biofuel cells for low power bioelectronics applications. - Graphical abstract: Display Omitted - Highlights: • ZnO activation of metallic Al for generating electricity for

  17. Anodisation of Aluminium Alloys by Micro-Capillary Technique as a Tool for Reliable, Cost-Efficient, and Quick Process Parameter Determination

    Directory of Open Access Journals (Sweden)

    Daniela Nickel

    2016-01-01

    Full Text Available Anodisation is essential for improving surface properties of aluminium alloys and composites regarding wear and corrosion behaviour. Optimisation of the anodising process depends on microstructural constituents contained in aluminium alloys and represents a key task, consisting of the control of process parameters and electrolyte formulation. We applied the micro-capillary technique known from corrosion studies and modified it to form anodic aluminium oxide films on high-strength aluminium alloys in comparison to pure aluminium in sulphuric acid. A glass capillary with an opening of 800 μm in diameter was utilized. Corresponding electrochemical measurements during potentiodynamic and potentiostatic anodisation revealed anodic current responses similar to conventional anodisation. The measurement of film thickness was adapted to the thin anodised spots using ellipsometry and energy dispersive X-ray analysis. Cross sections prepared by focused ion beam milling confirm the thickness results and show the behaviour of intermetallic phases depending on the anodising potential. Consequently, micro-capillary anodising proved to be an effective tool for developing appropriate anodisation conditions for aluminium alloys and composites because it allows quick variation of electrolyte composition by applying low electrolyte volumes and rapid film formation due to short process durations at small areas and more flexible variation of process parameters due to the used set-up.

  18. Design and analysis of aluminium brdiges

    NARCIS (Netherlands)

    Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Applications of aluminium have grown considerably in building and civil engineering the last decade, which is due to various aspects: light weight, durability and maintenance, use of extrusions. The paper starts with a short history of aluminium bridges and then focuses on aluminium bridges in the N

  19. Buckwheat stomatal traits under aluminium toxicity

    Directory of Open Access Journals (Sweden)

    Oleksandr E. Smirnov

    2014-04-01

    Full Text Available Aluminium influence on some stomatal parameters of common buckwheat (Fagopyrum esculentum Moench. was studied. Significant changes in stomatal density, stomatal index and stomatal shape coefficient under aluminium treatment were revealed. Stomatal closure and no difference in total stomatal potential conductance index of treatment plants were suggested as aluminium resistance characteristics.

  20. Electrically Variable or Programmable Nonvolatile Capacitors

    Science.gov (United States)

    Shangqing, Liu; NaiJuan, Wu; Ignatieu, Alex; Jianren, Li

    2009-01-01

    Electrically variable or programmable capacitors based on the unique properties of thin perovskite films are undergoing development. These capacitors show promise of overcoming two important deficiencies of prior electrically programmable capacitors: Unlike in the case of varactors, it is not necessary to supply power continuously to make these capacitors retain their capacitance values. Hence, these capacitors may prove useful as components of nonvolatile analog and digital electronic memories. Unlike in the case of ferroelectric capacitors, it is possible to measure the capacitance values of these capacitors without changing the values. In other words, whereas readout of ferroelectric capacitors is destructive, readout of these capacitors can be nondestructive. A capacitor of this type is a simple two terminal device. It includes a thin film of a suitable perovskite as the dielectric layer, sandwiched between two metal or metal oxide electrodes (for example, see Figure 1). The utility of this device as a variable capacitor is based on a phenomenon, known as electrical-pulse-induced capacitance (EPIC), that is observed in thin perovskite films and especially in those thin perovskite films that exhibit the colossal magnetoresistive (CMR) effect. In EPIC, the application of one or more electrical pulses that exceed a threshold magnitude (typically somewhat less than 1 V) gives rise to a nonvolatile change in capacitance. The change in capacitance depends on the magnitude duration, polarity, and number of pulses. It is not necessary to apply a magnetic field or to cool the device below (or heat it above) room temperature to obtain EPIC. Examples of suitable CMR perovskites include Pr(1-x)Ca(x)MnO3, La(1-x)S-r(x)MnO3,and Nb(1-x)Ca(x)MnO3. Figure 2 is a block diagram showing an EPIC capacitor connected to a circuit that can vary the capacitance, measure the capacitance, and/or measure the resistance of the capacitor.

  1. YANG-MILLS FIELD CAPACITOR

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2015-10-01

    Full Text Available The article presents a project of the capacitor in the Yang-Mills theory. Model capacitor represents the equipotential surfaces separated by a space. To describe the mechanism of condensation chromodynamics field used numerical models developed based on an average of the Yang-Mills theory. In the present study, we used eight-scalar component model that in the linear case is divided into two groups containing three or five fields respectively. In contrast to classical electrodynamics, a static model of the Yang-Mills is not divided into independent equations because of the nonlinearity of the model itself. However, in the case of a linear theory separation is possible. It is shown that in this particular case, the Yang-Mills theory is reduced to Poisson theory, which describes the electrostatic and magnetostatic phenomena. In the present work it is shown that in a certain region of the parameters of the capacitor of the Yang-Mills theory on the functional properties of the charge accumulation and retention of the field is similar to the capacitor of the electrostatic field or a magnet in magnetostatics. This means that in nature there are two types of charges, which are sources of macroscopic Yang-Mills field, which are similar to the properties of electric and magnetic charges in the Poisson theory. It is shown that in Yang-Mills only one type of charge may be associated with the distribution density of the substance, while another type of charge depends on the charge distribution of the first type. This allows us to provide an explanation for the lack of symmetry between electric and magnetic charges

  2. Development of solar selective absorber layers on aluminium. Final report; Entwicklung solarselektiver Absorberschichten auf Aluminium fuer Solarkollektoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hoenicke, D.; Moeller, T.; Schwarz, T.

    1998-01-31

    A new electrolytic process was developed to form solar selective layers on aluminium. In the developed process, both the formation of the alumina layer and the deposition of metals into the layer takes place in only one treatment step using a single electrolysis bath. The main step of the so called ISOC-method (impulse structured oxide ceramic) is the anodic oxidation of aluminium which was carried out by using a pulse technique at different voltages. During the anodic polarisation a thin alumina ceramic layer was formed, while the cathodic led to the metal deposition as copper and nickel. The conditions of the electrolysis were varied in order to estimate optimal parameters achieving solar selective layers with high selectivity. Furthermore, a scale-up of the lab scale apparatus to a mini plant was carried out. Finally, the corrosion resistance of the absorber layers was improved by the formation of a thin hydrophobic overlayer using a sol-gel treatment. (orig.) [Deutsch] Ein neuartiges Behandlungsverfahren zur Erzeugung von solarselektiven Absorberschichten auf Aluminium wurde entwickelt. Bei dieser elektrochemischen Behandlung wird in einem Einstufenprozess mit einem Elektrolyten durch eine Kombination von anodischer Oxidation und bipolarer Pulsbehandlung auf der Oberflaeche des Aluminiums eine impulsstrukturierte Oxidkeramik (ISOK) erzeugt. Dabei entsteht durch eine anodische Oxidation eine strukturierte Aluminiumoxidschicht. Bei der bipolaren Pulsbehandlung erfolgt dann eine Abscheidung der im ISOK-Elektrolyten befindlichen Metalle Cu und Ni auf oder in die Aluminiumoxidoberflaeche. Die ISOK-Behandlung wurde vom Labormassstab zu einem ISOK-Verfahren im Miniplant-Massstab entwickelt. Der Einfluss der elektrischen Parameter und der chemischen Zusammensetzung der ISOK-Elektrolyte wurde untersucht. Durch eine auf das ISOK-Verfahren abgestimmte Nachbehandlung, ein Tauchverfahren in einer Sol-Gel-Loesung, entsteht ein Schichtsystem mit hoher Solarselektivitaet

  3. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    in aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...

  4. Performance of a combined capacitor based on ultrafine nickel oxide/carbon nanotubes composite electrodes

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng Wang; Yanqiu Cao; Yiqiang Lu; Qiqian Sha; Ji Liang

    2004-01-01

    A new sol-gel process for the preparation of ultrafine nickel hydroxide electrode materials was developed. The composite electrodes consisting of carbon nanotubes and Ni(OH)2 were developed by mixing the hydroxide and carbon nanotubes together in different mass ratios. In order to enhance energy density, a combined type pseudocapacitor/electric double layer capacitor was considered and its electrochemical properties were characterized by cyclic voltammetry and dc charge/discharge test. The combined capacitor shows excellent capacitor behavior with an operating voltage up to 1.6 V in KOH aqueous electrolyte. Stable charge/discharge behaviors were observed with much higher specific capacitance values of 24 F/g compared with that of EDLC (12F/g) by introducing 60% Ni(OH)2 in the anode material. By using the modified anode of a Ni(OH)2/carbon nanotubes composite electrode, the specific capacitance of the cell was less sensitive to discharge current density compared with that of the capacitor employing pure nickel hydroxide as anode. The combined capacitor in this study exhibits high energy density and stable power characteristics.

  5. Mechanism of Nickel-Aluminium Alloy Electroplating

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The effect of operating conditions on the aluminium content of Ni-Al alloy deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results indicate that the plated aluminuim content will be increased with the rise of current density in a given range.When the current density is 2.5A/dm2,nickle-aluminium alloy containing 13.1 wt% aluminium will be deposited.The plated aluminium content will be increased by 2wt% as 0.1mol/L NaF is added to the bath.

  6. Charging/Safety-Interlock Connection For Capacitor Bank

    Science.gov (United States)

    Rippel, Wally E.

    1990-01-01

    Electrically controlled mechanical interlock apparatus prevents connection of bank of capacitors to battery or other dc power supply until capacitors precharged to nearly full supply voltage. Precharge eliminates excessive inrush current, which damages capacitors, wires, or connectors. Circuit in apparatus also discharges capacitors after power turned off or capacitors disconnected from power supply.

  7. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Pei Hsuan Doris Lu

    2015-01-01

    Full Text Available This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodising in electrolytes containing the extrinsic impurities in ionic form. The ions become trapped in the formed anodic oxide during anodisation, therefore enabling the impurity to be introduced into the silicon, with aluminium, during laser-doping. This codoping process can be used to create very heavily doped surface layers which can reduce contact resistance on metallisation, whilst the deeper doping achieved by the intrinsic aluminium may act to shield the surface from minority carriers. laser-doping through AAO layers can be performed without introducing any voids in the silicon or fumes which may be harmful to human health.

  8. Quantum, Photo-Electric Single Capacitor Paradox

    CERN Document Server

    Kapor, Darko

    2009-01-01

    In this work single capacitor paradox (a variation of the remarkable two capacitor paradox) is considered in a new, quantum discrete form. Simply speaking we consider well-known usual, photoelectric effect experimental device, i.e. photo electric cell, where cathode and anode are equivalently charged but non-connected. It, obviously, represents a capacitor that initially, i.e. before action of the photons with individual energy equivalent to work function, holds corresponding energy of the electrical fields between cathode and anode. Further, we direct quantum discretely photons, one by one, toward cathode where according to photo-electrical effect electrons discretely, one by one, will be emitted and directed toward anode. It causes discrete discharge of the cell, i.e. capacitor and discrete decrease of the electrical field. Finally, total discharge of the cell, i.e. capacitor, and total disappearance of the electrical field and its energy will occur. Given, seemingly paradoxical, capacitor total energy loss...

  9. High frequency model of stacked film capacitors

    Science.gov (United States)

    Talbert, T.; Joubert, C.; Daude, N.; Glaize, C.

    2001-11-01

    Polypropylene metallized capacitors are of general use in power electronics because of their reliability, their self-healing capabilities, and their low price. Though the behavior of metallized coiled capacitors has been discussed, no work has been carried out on stacked and flattened metallized capacitors. The purpose of this article is to suggest an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors. We first solve the equation of propagation of the magnetic potential vector (A) in the dielectric of an homogeneous material. Then, we suggest an original method of resolution, like the one used for resonant cavities, in order to present an analytical solution of the problem. Finally, we give some experimental results proving that the physical knowledge of the parameters of the capacitor (dimension of the component, and material constants), enables us to calculate an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors.

  10. Microchemistry in aluminium sheet production

    NARCIS (Netherlands)

    Lok, Z.J.

    2005-01-01

    The production of aluminium sheet alloys from as-cast ingots is a complex process, involving several rolling operations in combination with various thermal heat treatments. Through their influence on the alloy microchemistry and microstructure, these thermomechanical treatments are all aimed at cont

  11. Low-Inductance Capacitor For Low Temperatures

    Science.gov (United States)

    Rhodes, David B.; Jones, Stephen B.; Franke, John M.

    1989-01-01

    Planar capacitor made on epoxy/fiberglass printed-circuit board. Planar design and flat copper plates ensure low inductance and low series resistance. Planar construction minimized effects of thermal contraction, and epoxy/fiberglass substrate ensured high breakdown voltage. Design is simple, and this type of capacitor easy for any printed-circuit-board facility to fabricate. Design suitable for any small-capacitance, high-voltage capacitor, whether operating at low or high temperature.

  12. The tantalum-cased tantalum capacitor

    Science.gov (United States)

    Moynihan, J. D.

    1977-01-01

    Tantalum-cased tantalum capacitors were tested with regard to temperature stability, capacitance ratio, surge current capabilities, shock, vibration, and thermal shock. They were found to be superior to the conventional wet slug tantalum capacitor cased in silver, since they are more resistant to sulfuric acid. The tantalum-cased tantalum capacitors are widely accepted for use in critical electronic equipment because of their excellent performance and reliability.

  13. Capacitor discharges, magnetohydrodynamics, X-rays, ultrasonics

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology, Volume 1: Capacitor Discharges - Magnetohydrodynamics - X-Rays - Ultrasonics deals with the theoretical and engineering problems that arise in the capacitor discharge technique.This book discusses the characteristics of dielectric material, symmetrical switch tubes with mercury filling, and compensation conductor forms. The transformed discharge for highest current peaks, ignition transformer for internal combustion engines, and X-ray irradiation of subjects in mechanical motion are also elaborated. This text likewise covers the transformed capacitor discharge in w

  14. Capacitors with low equivalent series resistance

    Science.gov (United States)

    Fleig, Patrick Franz (Inventor); Lakeman, Charles D. E. (Inventor); Fuge, Mark (Inventor)

    2011-01-01

    An electric double layer capacitor (EDLC) in a coin or button cell configuration having low equivalent series resistance (ESR). The capacitor comprises mesh or other porous metal that is attached via conducting adhesive to one or both the current collectors. The mesh is embedded into the surface of the adjacent electrode, thereby reducing the interfacial resistance between the electrode and the current collector, thus reducing the ESR of the capacitor.

  15. A Two-terminal Active Capacitor

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai

    2017-01-01

    This letter proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. It is application independent and can be specified by rated...... voltage, ripple current, equivalent series resistance, and operational frequency range. The concept, control method, self-power scheme, and impedance characteristics of the active capacitor are presented. A case study of the proposed active capacitor for a capacitive DC-link application is discussed...

  16. Evaluation of Polymer Hermetically Sealed Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander A.

    2014-01-01

    Polymer cathode tantalum capacitors have lower ESR (equivalent series resistance) compared to other types of tantalum capacitors and for this reason have gained popularity in the electronics design community. Their use allows improved performance of power supply systems along with substantial reduction of size and weight of the components used. However, these parts have poor thermal stability and can degrade in humid environments. Polymer hermetically sealed (PHS) capacitors avoid problems related to environmental degradation of molded case parts and can potentially replace current wet and solid hermetically sealed capacitors. In this work, PHS capacitors manufactured per DLA LAM DWG#13030 are evaluated for space applications. Several lots of capacitors manufactured over period from 2010 to 2014 were tested for the consistency of performance, electrical and thermal characteristics, highly accelerated life testing, and robustness under reverse bias and random vibration conditions. Special attention was given to analysis of leakage currents and the effect of long-term high temperature storage on capacitors in as is condition and after hermeticity loss. The results show that PHS capacitors might be especially effective for low-temperature applications or for system requiring a cold start-up. Additional screening and qualification testing have been recommended to assure the necessary quality of capacitors for space projects.

  17. Fluoro-Compounds in Electrolytes for Energy Storage Devices

    Institute of Scientific and Technical Information of China (English)

    Makoto; Ue

    2007-01-01

    1 Results Electrochemical energy storage devices such as lithium-ion batteries[1-2] and double-layer capacitors[3-4] have attracted a great deal of attention because of their potential application to electric hybrid vehicles. They utilize nonaqueous electrolyte solutions comprising from organic solvents and lithium or quaternary ammonium salts with fluorine-containing anions. This is because the relatively large anions with electron-withdrawing atoms enable ionic dissociation in dipolar aprotic solvents...

  18. The Capacitive Behaviors of Manganese Dioxide Thin-Film Electrochemical Capacitor Prototypes

    Directory of Open Access Journals (Sweden)

    Suh Cem Pang

    2011-01-01

    Full Text Available We have documented the fabrication of manganese dioxide (MnO2 thin-film electrochemical capacitor (EC prototypes with dual-planar electrode configuration. These EC prototypes exhibited good capacitive behaviors in mild Na2SO4 aqueous electrolyte. Enhanced capacitive behaviors of EC prototypes were observed upon prolonged voltammetric cycling which could be associated with microstructural transformation of MnO2 thin-film electrodes from densely packed plate-like to irregular petal-like surface morphology. Effects of voltammetric scan rates, prolonged voltammetric cycling, electrolyte composition, and electrolyte concentration on the surface morphology of MnO2 thin-film electrodes, and associated capacitive behaviors of MnO2 thin-film EC prototypes were investigated by cyclic voltammetry (CV, electrochemical impedance spectroscopy (EIS, and galvanostatic charge/discharge (GCD techniques. Results of both CV and EIS indicated that thin-film MnO2 EC prototypes exhibited the highest specific capacitance of 327 F/g in 0.2 M Na2SO4 aqueous electrolyte. Being environmentally benign and cheap, MnO2 thin-film electrochemical capacitors have high potential utility as pulsed power sources, as well as load-leveling functions in various consumer electronic devices.

  19. Reliability-Oriented Design and Analysis of Input Capacitors in Single-Phase Transformer-less Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    While 99% efficiency has been reported, the target of 20 years of service time imposes new challenge to cost-effective solutions for grid-connected photovoltaic (PV) inverters. Aluminum electrolytic capacitors are the weak-link in terms of reliability and lifetime in single-phase PV systems....... A reliability-oriented design guideline is proposed in this paper for the input capacitors in single-phase transformer-less PV inverters. The guideline ensures that the service time requirement is to be accomplished under different power levels and ambient temperature profiles. The theoretical analysis has been...

  20. Bumblebee pupae contain high levels of aluminium.

    Directory of Open Access Journals (Sweden)

    Christopher Exley

    Full Text Available The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD value of 51.0 (33.0 μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer's disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline.

  1. Bumblebee pupae contain high levels of aluminium.

    Science.gov (United States)

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer's disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline.

  2. Hybrid carbon nanostructure assemblage for high performance pseudo-capacitors

    Directory of Open Access Journals (Sweden)

    A. K. Mishra

    2012-06-01

    Full Text Available Investigation of novel nanocomposites for pseudo-capacitors with high capacitance and energy density is the spotlight of current energy research. In the present work, hybrid carbon nanostructure assemblage of graphene and multiwalled carbon nanotubes has been used as carbon support to nanostructured RuO2 and polyaniline for high energy supercapacitors. Maximum specific capacitances of 110, 235 and 440 F g−1 at the voltage sweep rate of 10 mV s−1 and maximum energy densities of 7, 12.5 and 20.5 Wh kg−1 were observed for carbon assemblage and its RuO2 and polyanilne decorated nanocomposites, respectively, with 1M H2SO4 as electrolyte.

  3. Capacitor film surface assessment studies

    Science.gov (United States)

    Galperin, I.; White, W.

    1985-02-01

    In the present investigation of the optical surface of the three widely used, biaxially oriented capacitor films, polypropylene, polyvinylidene fluoride, and polyester, with attention to film surface defects and thickness variation, the defects and their rate of occurrence proved traceable in terms of polymer structure, chemical grouping, and fabrication processing. Film thickness variation was small, yet differed for each film type. Film breakdown voltages have been determined, and alternative causes for the voltage values obtained are proposed. A reciprocal relation is noted between the film breakdown voltage and the dielectric constant.

  4. Friction Welding of Aluminium and Aluminium Alloys with Steel

    Directory of Open Access Journals (Sweden)

    Andrzej Ambroziak

    2014-01-01

    Full Text Available The paper presents our actual knowledge and experience in joining dissimilar materials with the use of friction welding method. The joints of aluminium and aluminium alloys with the different types of steel were studied. The structural effects occurring during the welding process were described. The mechanical properties using, for example, (i microhardness measurements, (ii tensile tests, (iii bending tests, and (iv shearing tests were determined. In order to obtain high-quality joints the influence of different configurations of the process such as (i changing the geometry of bonding surface, (ii using the interlayer, or (iii heat treatment was analyzed. Finally, the issues related to the selection of optimal parameters of friction welding process were also investigated.

  5. Rep-rated long-life capacitor development

    Science.gov (United States)

    Galperin, I.

    1983-03-01

    The characterization of polypropylene and polyolefin resins for capacitor film usage was studied. One polypropylene resin was selected for capacitor POP film fabrication. A polyolefin resin was upgraded for POP film fabrication. Two new capacitor films were developed - a post orientation processed, two layer, polypropylene film and a polyolefin resin film. New criteria for judging film quality are developed and instituted. A capacitor film test plan has been formulated. Test capacitor designs and a capacitor test plan have been devised.

  6. Soft capacitor fibers using conductive polymers for electronic textiles

    Science.gov (United States)

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-11-01

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its cross section the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using the fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometers of fibers can be obtained from a single preform with fiber diameters ranging between 500 and 1000 µm. A typical measured capacitance of our fibers is 60-100 nF m-1 and it is independent of the fiber diameter. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kΩ m L-1, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, the absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage.

  7. Cryogenic Capacitors for Low-Temperature Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop low-temperature multilayer ceramic capacitors (MLCCs) capable of operating at cyrogenic temperatures (<77K). These capacitors...

  8. Aluminium in Allergies and Allergen immunotherapy.

    Science.gov (United States)

    Jensen-Jarolim, Erika

    2015-01-01

    Aluminium is a hot topic in the current debate. Exposure occurs due to environmental, dietary and intentional exposure to aluminium, such as in vaccines where it was introduced in 1926. In spite of the fact that it is a typical Th2 adjuvant, aluminium redirects the immune response in systemic allergen immunotherapy (SIT) upon prolonged immunization. SIT in the US, and SLIT in general, are at present non-adjuvanted therapies, but in Europe aluminium is used as adjuvant in most SIT preparations. It enhances the safety of SIT by local deposition of the allergen. Undesired properties of aluminium adjuvants comprise acute and chronic inflammation at the injection site, its Th2 immune stimulatory capacity, its accumulation besides biodistribution in the body. The adjuvant and safety profile of aluminium adjuvants in allergy vaccines are discussed, as well as the need for putting modern delivery systems and adjuvants on the fast track.

  9. Aluminium and nickel in human albumin solutions

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Sandberg, E

    1989-01-01

    Five different brands of commercially available human albumin solutions for infusion were analysed for their aluminium and nickel contents by atomic absorption spectrometry. The aluminium concentrations ranged from 12 micrograms/l to 1109 micrograms/l and the nickel concentrations ranged from 17...... micrograms/l to 77 micrograms/l. Examination of the aluminium and nickel contents of the constituents for the production of one brand showed too low levels to explain the final contamination of the product. By following the aluminium and nickel concentrations of the same brand during the production...... of a batch of albumin solution, filtration was shown to contribute to contamination, although the largest increase in aluminium as well as nickel concentrations appeared during the bulk concentrating process. To avoid health risks to certain patients, regulations should be established requiring aluminium...

  10. Dietary aluminium Intake Level for Rent Animals in a Primary and Secondary Aluminium Industry Surrounding Area

    OpenAIRE

    2010-01-01

    The study was carried out in an aluminium industry surrounding area on purpose to evaluate dietary aluminium intake level for rent animals originated from fodder and water consumed by them. There were taken feed and water samples in different periods and from increasing distances from industrial platform, determined the aluminium level by atomic spectroscopy and calculated the rations for cattle and poultry. Conclusions: aluminium dietary intake level by ration depends by forage period for st...

  11. Ultra-thin multilayer capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy Jerome; Monson, Todd C.

    2009-06-01

    The fabrication of ultra-thin lanthanum-doped lead zirconium titanate (PLZT) multilayer ceramic capacitors (MLCCs) using a high-power pulsed ion beam was studied. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The goal of this work was to increase the energy density of ceramic capacitors through the formation of a multilayer device with excellent materials properties, dielectric constant, and standoff voltage. For successful device construction, there are a number of challenging requirements including achieving correct stoichiometric and crystallographic composition of the deposited PLZT, as well as the creation of a defect free homogenous film. This report details some success in satisfying these requirements, although 900 C temperatures were necessary for PLZT perovskite phase formation. These temperatures were applied to a previously deposited multi-layer film which was then post-annealed to this temperature. The film exhibited mechanical distress attributable to differences in the coefficient of thermal expansion (CTE) of the various layers. This caused significant defects in the deposited films that led to shorts across devices. A follow-on single layer deposition without post-anneal produced smooth layers with good interface behavior, but without the perovskite phase formation. These issues will need to be addressed in order for ion beam deposited MLCCs to become a viable technology. It is possible that future in-situ heating during deposition may address both the CTE issue, and result in lowered processing temperatures, which in turn could raise the probability of successful MLCC formation.

  12. Switched-capacitor isolated LED driver

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Seth R.; Kline, Mitchell

    2016-03-22

    A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

  13. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    Directory of Open Access Journals (Sweden)

    Hojin Choi

    2015-06-01

    Full Text Available The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013. Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  14. Toxicity of aluminium on five aquatic invertebrates; Aluminiums toksisitet paa 5 akvatiske invertebrater

    Energy Technology Data Exchange (ETDEWEB)

    Moe, J. [Oslo Univ. (Norway)

    1996-01-01

    The conference paper deals with the experiments done by investigating the effects from the toxicity of aluminium on aquatic invertebrates. The aim of the experiments was to compare the toxicity of unstable aluminium compounds with stable forms of aluminium. 8 refs., 2 figs., 2 tabs.

  15. A biogeochemical cycle for aluminium?

    Science.gov (United States)

    Exley, Christopher

    2003-09-15

    The elaboration of biogeochemical cycles for elements which are known to be essential for life has enabled a broad appreciation of the homeostatic mechanisms which underlie element essentiality. In particular they can be used effectively to identify any part played by human activities in element cycling and to predict how such activities might impact upon the lithospheric and biospheric availability of an element in the future. The same criteria were the driving force behind the construction of a biogeochemical cycle for aluminium, a non-essential element which is a known ecotoxicant and a suspected health risk in humans. The purpose of this exercise was to examine the concept of a biogeochemical cycle for aluminium and not to review the biogeochemistry of this element. The cycle as presented is rudimentary and qualitative though, even in this nascent form, it is informative and predictive and, for these reasons alone, it is deserving of future quantification. A fully fledged biogeochemical cycle for aluminium should explain the biospheric abundance of this element and whether we should expect its (continued) active involvement in biochemical evolution.

  16. Mechanical and frictional behaviour of nano-porous anodised aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Tsyntsaru, N., E-mail: tintaru@phys.asm.md [Institute of Applied Physics of ASM, 5 Academy str., Chisinau, MD 2028 (Moldova, Republic of); Kavas, B., E-mail: bkavas@ford.com.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Ford Otomotiv San A.S., Istanbul (Turkey); Sort, J., E-mail: jordi.sort@uab.cat [Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Spain); Urgen, M., E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Celis, J.-P., E-mail: jean-pierre.celis@mtm.kuleuven.be [KU Leuven, Dept. MTM, Kasteelpark Arenberg 44, B-3001 (Belgium)

    2014-12-15

    The porous structure of anodic aluminium oxide (AAO) can be used in versatile applications such as a lubricant reservoir in self-lubricating systems. Such systems are subjected to biaxial loading, which can induce crack formation and propagation, ultimately leading to catastrophic mechanical failure. In this study, the mechanical and tribological behaviour of AAO, prepared from two different types of electrolytes (sulphuric and oxalic acids), are studied in detail. The electrolytic conditions are adjusted to render highly tuneable average pore diameters (between 16 and 75 nm), with porosity levels ranging from 9% to 65%. Well-ordered porous AAO are produced by two-step anodization at rather low temperatures. Mechanical properties, mainly hardness and Young's modulus, are investigated using nanoindentation. Both the porosity degree and the composition of the electrolytic baths used to prepare the AAO have an influence on the mechanical properties. Ball-on-flat configuration was used to estimate the tribological behaviour under dry conditions. No major cracks were observed by scanning electron microscopy, neither after indentation or fretting tests. In the running-in period of tribology experiments the pores were filled with debris. This was followed by the formation of a highly adherent tribolayer – a third body consisting of fine worn particles originated from both the sample and the counterbody. Pore diameter and porosity percentage are found to strongly affect hardness and Young's modulus, but they do not have a major effect on the frictional behaviour. - Highlights: • Well-ordered porous AAO with pore diameters between 16 and 75 nm were produced. • Porosity and composition of electrolytic baths influence the mechanical properties. • Ball-on-flat configuration was used in tribological testing under dry conditions. • Adherent tribolayer consisting of fine worn particles prevents AAO from cracking. • Testing parameters are moreover essential

  17. Polyvinyl alcohol-polystyrene sulphonic acid blend electrolyte for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Selva Kumar, M. [Department of Chemistry, National Institute of Technology Karnataka Surathkal, Srinivasnagar 575025 (India); Bhat, D. Krishna, E-mail: denthaje@gmail.co [Department of Chemistry, National Institute of Technology Karnataka Surathkal, Srinivasnagar 575025 (India)

    2009-05-01

    A new polymer blend electrolyte based on poly vinyl alcohol and poly styrene sulphonic acid has been studied as an electrolyte for supercapcitors. A carbon-carbon supercapacitor has been fabricated using this electrolyte and its electrochemical characteristics and performance have been studied. The conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. The real and imaginary parts of the electrical modulus of samples show a long tail feature, which can be attributed to high capacitance of the material. The super capacitor showed a fairly good specific capacitance of 40Fg{sup -1} and a time constant of 5 s.

  18. Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate in water-rich binary aqueous mixtures of tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    R. C. Thakur

    2014-12-01

    Full Text Available Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate have been determined in water rich binary aqueous mixtures of tetrahydrofuran (5, 10, 15, 20% by weight of tetrahydrofuran with the help of density measurements. The density measurements were made by using Ward and Millero method and results have been analysed by Masson’s equation and interpreted in terms of ion-ion or ion –solvent interactions. The partial molar volumes vary with temperature as a power series of temperature. Structure making or breaking capacities of aluminium salts have been inferred from the sign à2/ Φvo p i.e second derivative of partial molar volume with respect to temperature at constant pressure. The aluminium salts have been found as structure breakers in binary aqueous mixture of tetrahydrofuran.

  19. Effect of the layer of anodized 7075-T6 aluminium corrosion properties

    Science.gov (United States)

    Montoya Z, R. D.; L, E. Vera; Pineda T, Y.; Cedeño, M. L.

    2017-01-01

    Aluminium alloys are widely used in various sectors of industry. The 7075-T6 alloy corresponding to an Al-Zn T6, is mostly used as structural component in the aviation industry, due to the good relationship between weight and mechanical properties. However, the negative point of this alloys is the resistance to corrosion, which is why they need to be coated with an anodic film. Different surface treatments, such as anodizing, are used to improve corrosion resistance. Anodizing is an electrolytic process by which a protective layer on aluminium known as “alumina” is formed, this is formed by the passage of an electric current in an acidic electrolyte. This investigation presents a study of the effect of the thickness of layers of alumina deposited by anodized method, in the corrosion resistance of 7075-T6 aluminium. This study was performed by using in a solution of tartaric acid - sulfuric acid and an inorganic salt. To evaluate the influence alumina layer thickness on the corrosion properties some tests were carried out by using the electrochemical spectroscopy impedances (EIS) technique and Tafel polarization curves. It was found that the grown of the thickness of film favourably influences in the corrosion resistance.

  20. Impact resistant electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Veith, Gabriel M.; Armstrong, Beth L.; Tenhaeff, Wyatt E.; Dudney, Nancy J.

    2017-03-07

    A passively impact resistant composite electrolyte composition includes an electrolyte solvent, up to 2M of an electrolyte salt, and shear thickening ceramic particles having a polydispersity index of no greater than 0.1, an average particle size of in a range of 50 nm to 1 .mu.m, and an absolute zeta potential of greater than .+-.40 mV.

  1. 2014 NEPP Tasks Update for Ceramic and Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander A.

    2014-01-01

    Presentation describes recent development in research on MnO2, wet, and polymer tantalum capacitors. Low-voltage failures in multilayer ceramic capacitors and techniques to reveal precious metal electrode (PME) and base metal electrode (BME) capacitors with cracks are discussed. A voltage breakdown technique is suggested to select high quality low-voltage BME ceramic capacitors.

  2. Novel Synthesis of Aluminium Oxide Nanofibers

    Science.gov (United States)

    2001-11-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012177 TITLE: Novel Synthesis of Aluminium Oxide Nanofibers DISTRIBUTION...ADP012174 thru ADP012259 UNCLASSIFIED Mat. Res. Soc. Symp. Proc. Vol. 703 © 2002 Materials Research Society V1.8 Novel Synthesis of Aluminium Oxide Nanofibers

  3. Preparation of aluminium lakes by electrocoagulation

    Directory of Open Access Journals (Sweden)

    Prapai Pradabkham

    2008-07-01

    Full Text Available Aluminium lakes have been prepared by electrocoagulation employing aluminium as electrodes. The electrocoagulation is conducted in an aqueous alcoholic solution and is completed within one hour. The dye content in the lake ranges approximately between 4-32%.

  4. Lactobacillus plantarum CCFM639 alleviates aluminium toxicity.

    Science.gov (United States)

    Yu, Leilei; Zhai, Qixiao; Liu, Xiaoming; Wang, Gang; Zhang, Qiuxiang; Zhao, Jianxin; Narbad, Arjan; Zhang, Hao; Tian, Fengwei; Chen, Wei

    2016-02-01

    Aluminium (Al) is the most abundant metal in the earth's crust. Al exposure can cause a variety of adverse physiological effects in humans and animals. Our aim was to demonstrate that specific probiotic bacteria can play a special physiologically functional role in protection against Al toxicity in mice. Thirty strains of lactic acid bacteria (LAB) were tested for their aluminium-binding ability, aluminium tolerance, their antioxidative capacity, and their ability to survive the exposure to artificial gastrointestinal (GI) juices. Lactobacillus plantarum CCFM639 was selected for animal experiments because of its excellent performance in vitro. Forty mice were divided into four groups: control, Al only, Al plus CCFM639, and Al plus deferiprone (DFP). CCFM639 was administered at 10(9) CFU once daily for 10 days, followed by a single oral dose of aluminium chloride hexahydrate at 5.14 mg aluminium (LD50) for each mouse. The results showed that CCFM639 treatment led to a significant reduction in the mortality rates with corresponding decrease in intestinal aluminium absorption and in accumulation of aluminium in the tissues and amelioration of hepatic histopathological damage. This probiotic treatment also resulted in alleviation of hepatic, renal, and cerebral oxidative stress. The treatment of L. plantarum CCFM639 has potential as a therapeutic dietary strategy against acute aluminium toxicity.

  5. Locale instabiliteit van aluminium constructiedelen bij brand

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.

    2006-01-01

    Dragende constructiedelen van aluminium legeringen, zoals toegepast in bouwconstructies maar ook in schepen en offshore platforms, moeten zodanig ontworpen worden dat mensen veilig kunnen vluchten als er brand uitbreekt. Door de lage smelttemperatuur van aluminium vraagt brand de nodige aandacht in

  6. Rapidly solidified aluminium for optical applications

    NARCIS (Netherlands)

    Gubbels, G.P.H.; Venrooy, B.W.H. van; Bosch, A.J.; Senden, R.

    2008-01-01

    This paper present the results of a diamond turning study of a rapidly solidified aluminium 6061 alloy grade, known as RSA6061. It is shown that this small grain material can be diamond turned to smaller roughness values than standard AA6061 aluminium grades. Also, the results are nearly as good as

  7. Asymmetric Supercapacitors with Dominant Pseudocapacitance in Neutral Aqueous Electrolyte

    Science.gov (United States)

    Mao, Yuanbing; Li, Qiang

    2015-03-01

    Electrochemical capacitors (ECs) are promising power sources for portable electronics and hybrid electric vehicles. To solve the poor ionic conductivity, intrinsic inflammability and toxicity issues of current ECs incorporating organic electrolytes, aqueous electrolyte-based asymmetric supercapacitors (ASCs) have been attracting intensive attention recently. In this presentation, prototype MnO2-NFs//KCl//CNTs supercapacitor cells in neutral aqueous electrolyte allow rapid charge/discharge kinetics, fast ionic response, and evident pseudocapacitive dominance due to the unique MnO2-NF architecture and novel ASC design. For the first time, the respective contributions of the pseudocapacitance and EDL capacitance to the overall electrochemical performance of ASCs were differentiated with a proof of pseudocapacitive dominance (qpseudo/qdl = 2.5). To sum, this study provides a brilliant proof-of-concept design of novel supercapacitors with pseudocapacitive dominance to achieve ultimate energy storage applications with both high energy and power density.

  8. Acoustic properties of aluminium foams

    Directory of Open Access Journals (Sweden)

    García, L. E.

    2008-09-01

    Full Text Available The article discusses normal incidence sound absorption by aluminium foam manufactured with powder metallurgy technology. Aluminium foams with different surface morphologies were obtained by varying the type of precursor and adding filler materials during the foaming process. The sound absorption coefficients found for these aluminium foams were compared to the coefficient for commercial foams marketed under the name ALPORAS. The effect of foam thickness on the absorption coefficient was studied for each sample prepared. The combination of good acoustic and mechanical properties makes aluminium foams particularly attractive products. The study included an analysis of the effect of 2-, 5- and 10-cm air gaps on the sound absorption coefficient. The results showed that such gaps, which are routinely used in construction to reduce the reverberation period in indoor premises, raised the low frequency absorption coefficient significantly. This increase was found to depend on aluminium foam density and thickness and the depth of the air gap. In this same line, we have investigated the absorption coefficient of the aluminium foams combined with a mineral fiber panel.Se presenta un estudio del coeficiente de absorción acústica a incidencia normal de espumas de aluminio fabricadas mediante la técnica pulvimetalúrgica. Se fabricaron espumas de aluminio de distinta morfología superficial variando el tipo de precursor y usando materiales de relleno durante el proceso de espumación. Se muestra un estudio comparativo del coeficiente de absorción acústica de las espumas de aluminio fabricadas y las espumas comerciales conocidas como ALPORAS. Para cada muestra fabricada se estudió la influencia del espesor sobre el valor del coeficiente de absorción.El atractivo de las espumas de aluminio radica en que en ellas se combinan interesantes propiedades acústicas y mecánicas. Se analizó el efecto de una cámara de aire de 2, 5 y 10 cm de anchura sobre el

  9. Galvanostatic electrodeposition of aluminium nano-rods for Li-ion three-dimensional micro-battery current collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oltean, Gabriel, E-mail: gabriel.oltean@mkem.uu.s [Department of Materials Chemistry, Angstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden); Nyholm, Leif; Edstroem, Kristina [Department of Materials Chemistry, Angstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden)

    2011-03-30

    Research highlights: {yields} Galvanostatic electrodeposition of aluminium nano-rods. {yields} Electrodeposition in ionic liquid electrolyte. {yields} Commercial alumina membrane used as template. {yields} Current pulses allow better diffusion into the pores of the membrane. {yields} Short nucleation potential pulses result in improved homogeneity of the deposit. - Abstract: Constant current and pulsed current electrodeposition of aluminium nano-rods, for use as three-dimensional (3D) Li-ion micro-battery current collectors, have been studied using an ionic liquid electrolyte (1-ethyl-3-methylimidazolium chloride/aluminium chloride) and a template consisting of a commercial alumina membrane. It is shown that the homogeneity of the height of the rods can be improved significantly by inclusion of a short (i.e. 50 ms) potential pulse prior to the controlled current deposition step. The latter potential step increased the number of aluminium nuclei on the aluminium substrate and the best results were obtained for a potential of -0.9 V vs. Al/Al{sup 3+}. The obtained nanostructured surfaces, which were characterized using electron microscopy and X-ray diffraction, consisted of parallel aligned aluminium nano-rods homogeneously distributed over the entire surface of the substrate. A narrower height distribution for the rods was obtained using a pulsed galvanostatic approach then when using a constant current, most likely due to the less favourable diffusion conditions in the latter case. The results also indicate that depletion and iR drop effects within the nano-pores result in a more homogeneous height distribution. It is concluded that the height distribution of the nano-rods is controlled by a combination of the nucleation probability in each pore at the start of the experiment, and the homogeneity of the diameters of the pores within the commercial alumina membranes employed as the electrodeposition template.

  10. Analytical study, by modelling methods, of the alkali and alkaline earth cations influence on the stability and the reactivity of aluminium (III) oxides or halides complexes; Etude analytique, par des techniques de modelisation, de l`influence de cations alcalins ou alcalino-terreux sur la stabilite et la reactivite de complexes de l`aluminium(III) avec des ions halogenures ou oxydes

    Energy Technology Data Exchange (ETDEWEB)

    Bouyer, F.

    1995-10-05

    The electric power consumption in aluminium production and electrorefining processes is high. A study of the electrochemical processes can be very useful for a better understanding of phenomena in electrolytic baths and then for reducing the production costs. A structural and vibrational analysis of species which exist in ionic solutions has been carried out with software based on the functional density theory. Concerning the electrolyte used for the aluminium refining, the anions study has shown that the aluminium chloro-fluoride complexes are preferentially tetrahedral. Moreover, the aluminium oxyfluoride complexes structures (which come from the alumina dissolution in cryolitic media) have been analyzed in the same way and the preferential coordination numbers for aluminium and oxygen have been shown clearly. The anionic model (which is limited to the nearest aluminium neighbours) does not allow to account for the thermodynamics of the cryolitic media. A more elaborated model has then been found to obtain the cryolite structure. The reactions enthalpies have been estimated and have lead to the calculus of species concentration gradients in liquid phase. The counterions effects as for instance sodium and calcium have been investigated. A model for the gaseous phase allowing to know the preferential species has been given. At last, a statistic thermochemistry program has been conceived and developed. It gives the thermodynamical functions at all temperature for the different complexes and allows to reckon the reactions coefficients in gaseous phase as well as the partial pressures profiles with those of calcium and sodium fluorides. (O.M.) 204 refs.

  11. Aluminium Diphosphamethanides: Hidden Frustrated Lewis Pairs.

    Science.gov (United States)

    Styra, Steffen; Radius, Michael; Moos, Eric; Bihlmeier, Angela; Breher, Frank

    2016-07-04

    The synthesis and characterisation of two aluminium diphosphamethanide complexes, [Al(tBu)2 {κ(2) P,P'-Mes*PCHPMes*}] (3) and [Al(C6 F5 )2 {κ(2) P,P'-Mes*PCHPMes*}] (4), and the silylated analogue, Mes*PCHP(SiMe3 )Mes* (5), are reported. The aluminium complexes feature four-membered PCPAl core structures consisting of diphosphaallyl ligands. The silylated phosphine 5 was found to be a valuable precursor for the synthesis of 4 as it cleanly reacts with the diaryl aluminium chloride [(C6 F5 )2 AlCl]2 . The aluminium complex 3 reacts with molecular dihydrogen at room temperature under formation of the acyclic σ(2) λ(3) ,σ(3) λ(3) -diphosphine Mes*PCHP(H)Mes* and the corresponding dialkyl aluminium hydride [tBu2 AlH]3 . Thus, 3 belongs to the family of so-called hidden frustrated Lewis pairs.

  12. Hydroxyaluminosilicates and acute aluminium toxicity in fish

    Science.gov (United States)

    Exley; Pinnegar; Taylor

    1997-11-21

    The essentiality of silicon in biology might be explained in the terms of its chemistry with aluminium. In a previous study we demonstrated the elimination of acute aluminium toxicity in fish by silicon. We suggested that the reaction of silicic acid with aluminium to form hydroxyaluminosilicates reduced the biological availability, and hence toxicity, of aluminium. Though assumed in a burgeoning number of studies and contended in others this detoxification mechanism has remained unproven. Herein we have tested the toxicity of hydroxyaluminosilicates in fish and in doing so we have provided evidence which strongly supports a role for hydroxyaluminiosilicates in the elimination of acute aluminium toxicity in fish by silicon.Copyright 1997 Academic Press Limited Copyright 1997 Academic Press Limited

  13. Study on the treatment of photovoltaic wastewater using electrocoagulation: fluoride removal with aluminium electrodes--characteristics of products.

    Science.gov (United States)

    Drouiche, N; Aoudj, S; Hecini, M; Ghaffour, N; Lounici, H; Mameri, N

    2009-09-30

    In this work, treatment of synthetic fluoride-containing solutions by electrocoagulation method using aluminium electrodes has been studied. Electrocoagulation was investigated for applied potential (10-30 V), electrolysis time and supporting electrolyte (NaCl) concentration (0-100mg/L). The results showed that with increasing applied potential and electrolysis time, the Al(3+) dosage increases, and thereby favouring the fluoride ions removal. It was also observed that defluoridation is dependant on the concentration of supporting electrolyte. Finally, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy of X-rays and Fourier transform infrared spectroscopy were used to characterize the solid products formed by aluminium electrodes during the EC process.

  14. Study on the treatment of photovoltaic wastewater using electrocoagulation: Fluoride removal with aluminium electrodes-Characteristics of products

    Energy Technology Data Exchange (ETDEWEB)

    Drouiche, N., E-mail: nadjibdrouiche@yahoo.fr [Silicon Technology Development Unit (UDTS), 2, Bd Frantz Fanon BP140, Alger-7-merveilles, 16200 (Algeria); Laboratory of Environmental Biotechnologies, Ecole Polytechnique d' Alger - 10, Avenue Pasteur El-Harrach (Algeria); Aoudj, S.; Hecini, M. [Silicon Technology Development Unit (UDTS), 2, Bd Frantz Fanon BP140, Alger-7-merveilles, 16200 (Algeria); Ghaffour, N. [Middle East Desalination Research Center, P.O. Box 21, P.C.133, Muscat (Oman); Lounici, H.; Mameri, N. [Laboratory of Environmental Biotechnologies, Ecole Polytechnique d' Alger - 10, Avenue Pasteur El-Harrach (Algeria)

    2009-09-30

    In this work, treatment of synthetic fluoride-containing solutions by electrocoagulation method using aluminium electrodes has been studied. Electrocoagulation was investigated for applied potential (10-30 V), electrolysis time and supporting electrolyte (NaCl) concentration (0-100 mg/L). The results showed that with increasing applied potential and electrolysis time, the Al{sup 3+} dosage increases, and thereby favouring the fluoride ions removal. It was also observed that defluoridation is dependant on the concentration of supporting electrolyte. Finally, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy of X-rays and Fourier transform infrared spectroscopy were used to characterize the solid products formed by aluminium electrodes during the EC process.

  15. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  16. Physical and Electrical Characterization of Polymer Aluminum Capacitors

    Science.gov (United States)

    Liu, David; Sampson, Michael J.

    2010-01-01

    Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

  17. Physical and Electrical Characterization of Aluminum Polymer Capacitors

    Science.gov (United States)

    Liu, David; Sampson, Michael J.

    2010-01-01

    Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

  18. Thermal simulation for geometric optimization of metallized polypropylene film capacitors

    OpenAIRE

    El-Husseini, M.,; Venet, Pascal; Rojat, Gérard; Joubert, Charles

    2002-01-01

    In this paper, we use an analytic model to calculate the losses in the metallized polypropylene film capacitors. The model is validated experimentally for capacitors having the same capacitance but different geometry. For each group of capacitors a temperature distribution in the roll is assumed with the aim of optimizing its thermal performance. It appears that the heating of a long capacitor is higher than that of an equivalent flat capacitor subjected to the same electric stresses.

  19. Automated Test Stand for HEV Capacitor Testing

    Energy Technology Data Exchange (ETDEWEB)

    Seiber, Larry Eugene [ORNL; Armstrong, Gary [Maverick Systems

    2007-01-01

    As capacitor manufacturers race to meet the needs of the hybrid-electric vehicle (HEV) of the future, many trade-offs at the system level as well as the component level must be considered. Even though the ultra-capacitor has the spot light for recent research and development (R&D) for HEVs, the electrostatic capacitor is also the subject of R&D (for HEVs as well as wireless communications). The Department of Energy has funded the Oak Ridge National Laboratory's Power Electronic and Electric Machinery Research Center to develop an automated test to aid in the independent testing of prototype electrostatic capacitors. This paper describes the design and development of such a stand.

  20. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.

  1. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    Nebera; A.; Markusbkin; Yu.; Azarov; V.; Ermolaev; N.

    2005-01-01

    Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.……

  2. Electric field mapping inside metallized film capacitors

    DEFF Research Database (Denmark)

    Nielsen, Dennis Achton; Popok, Vladimir; Pedersen, Kjeld

    2015-01-01

    and durability and serves as verification that failure- and degradation mechanisms remain the same at different stress levels during accelerated testing. In this work we have used Kelvin probe force microscopy (KPFM) to analyze metallized film capacitors with the purpose of determining the degradation mechanism......(s) they suffered from accelerated testing. We have prepared film capacitors for analysis by micro-sectioning and verified the quality of the preparation procedure using optical and atomic force microscopy. The potential distribution in the layer structure (alternating 7 µm thick dielectric and 50-100 nm thick...... of the metallization stripes had lost contact to the end-spray. Thus, it is shown that the surface electric potential distributions on micro-sectioned film capacitors can be obtained through KPFM analysis. We have, from KPFM measurements, shown that the degraded capacitors under investigation had suffered from...

  3. Definite Solution of the Two Capacitors Paradox

    CERN Document Server

    Pankovic, Vladan

    2009-01-01

    In this work we suggest very simple solution of the two capacitors paradox in the completely ideal (without any electrical resistance or inductivity) electrical circuit. Namely, it is shown that electrical field energy loss corresponds to works done by electrical fields of both capacitors by movement of the electrical charge. It is all and nothing more (some dissipative processes, e.g. Joule heating and electromagnetic wave emission effects) is necessary.

  4. Transmission Line Resonator Segmented with Series Capacitors

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Boer, Vincent; Petersen, Esben Thade

    2016-01-01

    Transmission line resonators are often used as coils in high field MRI. Due to distributed nature of such resonators, coils based on them produce inhomogeneous field. This work investigates application of series capacitors to improve field homogeneity along the resonator. The equations for optimal...... values of evenly distributed capacitors are presented. The performances of the segmented resonator and a regular transmission line resonator are compared....

  5. Anisotropic magnetocapacitance in ferromagnetic-plate capacitors

    Science.gov (United States)

    Haigh, J. A.; Ciccarelli, C.; Betz, A. C.; Irvine, A.; Novák, V.; Jungwirth, T.; Wunderlich, J.

    2015-04-01

    The capacitance of a parallel-plate capacitor can depend on the applied magnetic field. Previous studies have identified capacitance changes induced via classical Lorentz force or spin-dependent Zeeman effects. Here we measure a magnetization direction-dependent capacitance in parallel-plate capacitors where one plate is a ferromagnetic semiconductor, gallium manganese arsenide. This anisotropic magnetocapacitance is due to the anisotropy in the density of states dependent on the magnetization through the strong spin-orbit interaction.

  6. Integrated capacitors for conductive lithographic film circuits

    OpenAIRE

    Harrey, PM; Evans, PSA; Harrison, DJ

    2001-01-01

    This paper reports on fabrication of low-value embedded capacitors in conductive lithographic film (CLF) circuit boards. The CLF process is a low-cost and high speed manufacturing technique for flexible circuits and systems. We report on the construction and electrical characteristics of CLF capacitor structures printed onto flexible substrates. These components comprise a single polyester dielectric layer, which separates the printed electrode films. Multilayer circuit boards with printed co...

  7. A Reaction Coating on Aluminium Alloys by Laser Processing

    NARCIS (Netherlands)

    Zhou, X.B.; Hosson, J.Th.M. De

    1993-01-01

    An aluminium oxide layer of 100 µm in thickness has been successfully coated on aluminium alloy 6061 and pure aluminium using a powder mixture of silicon oxide and aluminium by laser processing. A strong Al/Al2O3 interface was formed. The exothermic chemical reaction between SiO2 and Al may promote

  8. Studies on Recast-layer in EDM using Aluminium Powder Mixed Distilled Water Dielectric Fluid

    Directory of Open Access Journals (Sweden)

    Khalid Hussain Syed

    2013-04-01

    Full Text Available In this paper, an attempt has been made to study the effect of aluminium powder when mixed in the distilled water dielectric fluid. The work and tool electrode materials used are W300 diesteel and electrolytic copper respectively. Pulse peak current, pulse on-time and concentration of aluminium powder are taken as the process parameters. The output response considered is white layer thickness (WLT. The experiments are planned using face centered central composite design procedure. Empirical model is developed for WLT using response surface methodology (RSM to study the effect ofprocess parameters. Optical microscopy results show that low thickness of white-layer 17.14 μm is obtained at high concentration of powder of 4 g/l and low peak current of 6 A.

  9. Determining water content in activated carbon for double-layer capacitor electrodes

    Science.gov (United States)

    Egashira, Minato; Izumi, Takuma; Yoshimoto, Nobuko; Morita, Masayuki

    2016-09-01

    Karl-Fisher titration is used to estimate water contents in activated carbon and the distribution of impurity-level water in an activated carbon-solvent system. Normalization of the water content of activated carbon is attempted using vacuum drying after immersion in water was controlled. Although vacuum drying at 473 K and 24 h can remove large amounts of water, a substantial amount of water remains in the activated carbon. The water release to propylene carbonate is less than that to acetonitrile. The degradation of capacitor cell capacitance for activated carbon with some amount of water differs according to the electrolyte solvent type: acetonitrile promotes greater degradation than propylene carbonate does.

  10. Effect of acid oxidization of carbon nanotube electrode on the capacitances of double layer capacitors

    Institute of Scientific and Technical Information of China (English)

    LI; Chensha; WANG; Dazhi; LIANG; Tongxiang; WANG; Xiaofen

    2004-01-01

    Polarizable electrode of electric double layer capacitor was made from carbon nanotubes. The effect of acid oxidation of electrode on the specific capacitance was studied. Oxidation removed the redundant carbon, expanded the pore size and introduced some kinds of functional groups on the surface of CNTs. The specific capacit ance of the electrodes with organic electrolyte was increased from 21.4 to 49.6 F/gafter being oxidized at a volume ratio of H2SO4 to HNO3 of 3:1.

  11. Investigation of the charging characteristics of micrometer sized droplets based on parallel plate capacitor model.

    Science.gov (United States)

    Zhang, Yanzhen; Liu, Yonghong; Wang, Xiaolong; Shen, Yang; Ji, Renjie; Cai, Baoping

    2013-02-01

    The charging characteristics of micrometer sized aqueous droplets have attracted more and more attentions due to the development of the microfluidics technology since the electrophoretic motion of a charged droplet can be used as the droplet actuation method. This work proposed a novel method of investigating the charging characteristics of micrometer sized aqueous droplets based on parallel plate capacitor model. With this method, the effects of the electric field strength, electrolyte concentration, and ion species on the charging characteristics of the aqueous droplets was investigated. Experimental results showed that the charging characteristics of micrometer sized droplets can be investigated by this method.

  12. Superconcentrated electrolytes for a high-voltage lithium-ion battery

    Science.gov (United States)

    Wang, Jianhui; Yamada, Yuki; Sodeyama, Keitaro; Chiang, Ching Hua; Tateyama, Yoshitaka; Yamada, Atsuo

    2016-06-01

    Finding a viable electrolyte for next-generation 5 V-class lithium-ion batteries is of primary importance. A long-standing obstacle has been metal-ion dissolution at high voltages. The LiPF6 salt in conventional electrolytes is chemically unstable, which accelerates transition metal dissolution of the electrode material, yet beneficially suppresses oxidative dissolution of the aluminium current collector; replacing LiPF6 with more stable lithium salts may diminish transition metal dissolution but unfortunately encounters severe aluminium oxidation. Here we report an electrolyte design that can solve this dilemma. By mixing a stable lithium salt LiN(SO2F)2 with dimethyl carbonate solvent at extremely high concentrations, we obtain an unusual liquid showing a three-dimensional network of anions and solvent molecules that coordinate strongly to Li+ ions. This simple formulation of superconcentrated LiN(SO2F)2/dimethyl carbonate electrolyte inhibits the dissolution of both aluminium and transition metal at around 5 V, and realizes a high-voltage LiNi0.5Mn1.5O4/graphite battery that exhibits excellent cycling durability, high rate capability and enhanced safety.

  13. Investigation of the aluminium-aluminium oxide reversible transformation as observed by hot stage electron microscopy.

    Science.gov (United States)

    Grove, C. A.; Judd, G.; Ansell, G. S.

    1972-01-01

    Thin foils of high purity aluminium and an Al-Al2O3 SAP type of alloy were oxidised in a specially designed hot stage specimen chamber in an electron microscope. Below 450 C, amorphous aluminium oxide formed on the foil surface and was first detectable at foil edges, holes, and pits. Islands of aluminium then nucleated in this amorphous oxide. The aluminium islands displayed either a lateral growth with eventual coalescence with other islands, or a reoxidation process which caused the islands to disappear. The aluminium island formation was determined to be related to the presence of the electron beam. A mechanism based upon electron charging due to the electron beam was proposed to explain the nucleation, growth, coalescence, disappearance, and geometry of the aluminium islands.

  14. Characteristics of cast and welded aluminium nodes

    Energy Technology Data Exchange (ETDEWEB)

    Oedegaard, J.; Polanco, M.; Syvertsen, F.; Sund, H. [SINTEF, Trondheim (Norway). Materials Technology

    2000-07-01

    It has been demonstrated that sand cast aluminium nodes can be produced with properties that gives competitive energy absorption capacity compared with welded aluminium nodes. Sand cast nodes could be mass-produced to a low cost and with properties that should be competitive to the properties of fusion welded nodes. This may open for simpler and more cost-effective joint alternatives when production of aluminium space-frames and subassemblies are in focus. Cast nodes joined to extruded members by adhesive bonding could be one example. (orig.)

  15. Thermal transformations of aluminium-aluminium oxide systems in nanosize layers

    OpenAIRE

    2007-01-01

    Aluminium film of more than 2 nm thick indicates, but less than 2 nm do not indicate characteristic absorption and reflection bands for aluminium in range ?=190...1100 nm. By spectrophotometric, gravimetric and microscopic methods it is stated that thickness, mass and absorption, reflection spectrum of aluminium films (d=2...200 nm) undergo considerable transformations as a result of heat treatment in an interval of temperatures 373...600 K during 1...140 min in atmospheric conditions. Kineti...

  16. Elevated brain aluminium and early onset Alzheimer’s disease in an individual occupationally exposed to aluminium: a case report

    OpenAIRE

    2014-01-01

    Introduction Aluminium is a known neurotoxin and occupational exposure to aluminium has been implicated in neurological disease including Alzheimer’s disease. Here we present the first comprehensive and unequivocal data demonstrating significantly elevated brain aluminium content in an individual occupationally exposed to aluminium. Case presentation A 66-year-old Caucasian man who died with Alzheimer’s disease showed significantly elevated brain aluminium content, 2.98 (2.73) μg/g dry weight...

  17. Dietary aluminium Intake Level for Rent Animals in a Primary and Secondary Aluminium Industry Surrounding Area

    Directory of Open Access Journals (Sweden)

    Mărioara Drugă

    2010-05-01

    Full Text Available The study was carried out in an aluminium industry surrounding area on purpose to evaluate dietary aluminium intake level for rent animals originated from fodder and water consumed by them. There were taken feed and water samples in different periods and from increasing distances from industrial platform, determined the aluminium level by atomic spectroscopy and calculated the rations for cattle and poultry. Conclusions: aluminium dietary intake level by ration depends by forage period for studied species, rations structure and distance from industrial platform and didn’t reach toxic level in any case.

  18. The meaning of aluminium exposure on human health and aluminium-related diseases.

    Science.gov (United States)

    Crisponi, Guido; Fanni, Daniela; Gerosa, Clara; Nemolato, Sonia; Nurchi, Valeria M; Crespo-Alonso, Miriam; Lachowicz, Joanna I; Faa, Gavino

    2013-02-01

    The aim of this review is to attempt to answer extremely important questions related to aluminium-related diseases. Starting from an overview on the main sources of aluminium exposure in everyday life, the principal aspects of aluminium metabolism in humans have been taken into consideration in an attempt to enlighten the main metabolic pathways utilised by trivalent metal ions in different organs. The second part of this review is focused on the available evidence concerning the pathogenetic consequences of aluminium overload in human health, with particular attention to its putative role in bone and neurodegenerative human diseases.

  19. Molecular Simulations of Graphene-Based Electric Double-Layer Capacitors

    Science.gov (United States)

    Kalluri, Raja K.; Konatham, Deepthi; Striolo, Alberto

    2011-03-01

    Towards deploying renewable energy sources it is crucial to develop efficient and cost-effective technologies to store electricity. Traditional batteries are plagued by a number of practical problems that at present limit their widespread applicability. One possible solution is represented by electric double-layer capacitors (EDLCs). To deploy EDLCs at the large scale it is necessary to better understand how electrolytes pack and diffuse within narrow charged pores. We present here simulation results for the concentrated aqueous solutions of NaCl, CsCl, and NaI confined within charged graphene-based porous materials. We discuss how the structure of confined water, the salt concentration, the ions size, and the surface charge density determine the accumulation of electrolytes within the porous network. Our results, compared to data available for bulk systems, are critical for relating macroscopic observations to molecular-level properties of the confined working fluids. Research supported by the Department of Energy.

  20. Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

    KAUST Repository

    Lu, Yingying

    2014-08-10

    Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost-effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

  1. Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

    Science.gov (United States)

    Lu, Yingying; Tu, Zhengyuan; Archer, Lynden A.

    2014-10-01

    Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost-effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

  2. High-Temperature Capacitor Polymer Films

    Science.gov (United States)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  3. Shear Viscosity of Aluminium under Shock Compression

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-Sheng; YANG Mei-Xia; LIU Qi-Wen; CHEN Jun-Xiang; JING Fu-Qian

    2005-01-01

    @@ Based on the Newtonian viscous fluid model and the analytic perturbation theory of Miller and Ahrens for the oscillatory damping of a sinusoidal shock front, a flyer-impact technique is developed to investigate the effecti veviscosity of shocked aluminium.

  4. 电解铝阳极保温覆盖料震荡输送撒布机的电机控制系统研究%Research on the Motor Control System of Vibration Conveying Spreader Covered with Insulation Material of Electrolytic Aluminium Anode

    Institute of Scientific and Technical Information of China (English)

    郭天圣; 姜惠敏; 柴兆森

    2015-01-01

    This paper shows the fuzzy control algorithm for motor control system of electrolytic aluminum anode insu⁃lation material covered vibration conveying spreader,and introduces the the design idea, structure and realization of the algorithm. The results show that the system can solve the problem in the process of the electrolytic aluminum an⁃ode heat insulation material covering well, improve the working efficiency, and improve the working environment.%本文说明了电解铝阳极保温覆盖料震荡输送撒布机的电机控制系统模糊控制算法,介绍了算法的设计思想、结构以及实现。实践结果表明,该系统能较好地解决人工进行电解铝阳极保温覆盖料过程的问题,提高了工作效率,改善了工作环境。

  5. Electrical Conductivity of Aluminium Alloy Foams

    Institute of Scientific and Technical Information of China (English)

    凤仪; 郑海务; 朱震刚; 祖方遒

    2002-01-01

    Closed-cell aluminium alloy foams were produced using the powder metallurgical technique. The effect of porosityand cell diameter on the electrical conductivity of foams was investigated and the results were compared with anumber of models. It was found that the percolation theory can be successfully applied to describe the dependenceof the electrical conductivity of aluminium alloy foams on the relative density. The cell diameter has a negligibleeffect on the electrical conductivity of foams.

  6. DETERMINATION OF IMPURITY ELEMENTS IN ALUMINIUM

    Institute of Scientific and Technical Information of China (English)

    侯小琳; 张永保

    1994-01-01

    Twenty five impurity elements in aluminium applied as reactor material are determined.Titanium and nickel are determined with epithermal neutron activation analysis(NAA),magnesium and silicon by inductance coupling plasma emission spectra(ICP),other elements by thermal NAA.The fission coefficient of uranium is given by an experiment,the interferences of uranium to Ce,Nd,Mo,Zr,La,Sm are subtracted.The detection limits of these methods to all of impurity elements in aluminium are calculated.

  7. Bumblebee Pupae Contain High Levels of Aluminium

    OpenAIRE

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a mic...

  8. Bumblebee pupae contain high levels of aluminium

    OpenAIRE

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a mic...

  9. A universal model for nanoporous carbon supercapacitors applicable to diverse pore regimes, carbon materials, and electrolytes.

    Science.gov (United States)

    Huang, Jingsong; Sumpter, Bobby G; Meunier, Vincent

    2008-01-01

    Supercapacitors, commonly called electric double-layer capacitors (EDLCs), are emerging as a novel type of energy-storage device with the potential to substitute batteries in applications that require high power densities. In response to the latest experimental breakthrough in nanoporous carbon supercapacitors, we propose a heuristic theoretical model that takes pore curvature into account as a replacement for the EDLC model, which is based on a traditional parallel-plate capacitor. When the pore size is in the mesopore regime (2-50 nm), counterions enter mesoporous carbon materials and approach the pore wall to form an electric double-cylinder capacitor (EDCC); in the micropore regime (50 nm) at which pores are large enough so that pore curvature is no longer significant, the EDCC model can be reduced naturally to the EDLC model. We present density functional theory calculations and detailed analyses of available experimental data in various pore regimes, which show the significant effects of pore curvature on the supercapacitor properties of nanoporous carbon materials. It is shown that the EDCC/EWCC model is universal for carbon supercapacitors with diverse carbon materials, including activated carbon materials, template carbon materials, and novel carbide-derived carbon materials, and with diverse electrolytes, including organic electrolytes, such as tetraethylammonium tetrafluoroborate (TEABF(4)) and tetraethylammonium methylsulfonate (TEAMS) in acetonitrile, aqueous H(2)SO(4) and KOH electrolytes, and even an ionic liquid electrolyte, such as 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI-TFSI). The EDCC/EWCC model allows the supercapacitor properties to be correlated with pore size, specific surface area, Debye length, electrolyte concentration and dielectric constant, and solute ion size It may lend support for the systematic optimization of the properties of carbon supercapacitors through experiments. On the basis of the insight

  10. Development of high energy density electrical double layer capacitors

    Science.gov (United States)

    Devarajan, Thamarai selvi

    Electrochemical Double Layer capacitors (EDLCs) have shown themselves as a viable energy storage alternative. EDLCs have high power density, faster charge/discharge, wide operating temperature and long cycle life compared to batteries since it stores charge by physical separation. Despites all their advantages, their low energy density stand as a bottleneck for capacitors. This research aims to increase the energy density of EDLC without compromising the power density. Energy is proportional to the square of cell voltage. Cell voltage is mainly dependent on electrolyte breakdown. Electrolytes also provide ions for charge separation and conduction. Therefore various electrolytes (Solutes and Solvents) which can give high concentration, solubility and decomposition potential were characterized in the first part of the research. In that study, a novel ionic liquid OPBF4 had higher capacitance and comparable voltage window compared to commercial TEABF4 in Acetonitrile. However, the increased polarity of the fixed ring O-atom and the ion-ion interaction in OPBF4 was responsible for lowering its conductivity. Oxygenated ionic compounds with alkyl groups had lower stability due to beta elimination between two electron withdrawing atoms. Volume based thermodynamics and quantum chemical calculations were used to calculate ion size, HOMO/LUMO energies, and free energy changes and establish relationship with capacitance, redox potential and melting points respectively. In addition free energy of fusion was used to predict the melting point. Ion size had correlation with capacitance due to compact double layer formation. Free energy changes did not explain the differences in melting point and predicted dielectric constant was inconsistent with the polarity. This is presumably due to using Van der Waals volume instead of crystal structure volume and insufficient incorporation of polarization term. The HOMO/LUMO energies gave direct relation between oxidation and reduction

  11. High-current, high-frequency capacitors

    Science.gov (United States)

    Renz, D. D.

    1983-06-01

    The NASA Lewis high-current, high-frequency capacitor development program was conducted under a contract with Maxwell Laboratories, Inc., San Diego, California. The program was started to develop power components for space power systems. One of the components lacking was a high-power, high-frequency capacitor. Some of the technology developed in this program may be directly usable in an all-electric airplane. The materials used in the capacitor included the following: the film is polypropylene, the impregnant is monoisopropyl biphenyl, the conductive epoxy is Emerson and Cuming Stycast 2850 KT, the foil is aluminum, the case is stainless steel (304), and the electrode is a modified copper-ceramic.

  12. Wide Temperature DC Link Capacitors for Aerospace Power Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop advanced DC link capacitors using flexible ultrathin glass dielectric materials. The glass capacitor will be able to be operated in a broad...

  13. Tracer studies of anodic films formed on aluminium in malonic and oxalic acids

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Vergara, S.J. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: s.garcia-vergara@manchester.ac.uk; Skeldon, P.; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Habakaki, H. [Graduate School of Engineering, Hokkaido University, N13-W8, Sapporo 060-8628 (Japan)

    2007-12-30

    Using a tungsten-containing layer, incorporated into sputtering-deposited aluminium, as a tracer, the growth of porous anodic films in malonic and oxalic acid electrolytes has been investigated using transmission electron microscopy, Rutherford backscattering spectroscopy and nuclear reaction analysis. Comparisons were also made with films formed in phosphoric acid electrolyte, which have been studied previously. The findings reveal a distortion of the tracer layer within the barrier region of the porous films, evident as a lagging of the tracer beneath the pores relative to that in the adjacent cell wall region. Further, the films are significantly thicker than the layer of metal consumed during anodizing and display smooth-sided pores. The anodizing behaviours are consistent with a major role for field-assisted flow of film material within the barrier layer in the development of the pores.

  14. Printed Barium Strontium Titanate capacitors on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Sette, Daniele [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg); Kovacova, Veronika [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Defay, Emmanuel, E-mail: emmanuel.defay@list.lu [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg)

    2015-08-31

    In this paper, we show that Barium Strontium Titanate (BST) films can be prepared by inkjet printing of sol–gel precursors on platinized silicon substrate. Moreover, a functional variable capacitor working in the GHz range has been made without any lithography or etching steps. Finally, this technology requires 40 times less precursors than the standard sol–gel spin-coating technique. - Highlights: • Inkjet printing of Barium Strontium Titanate films • Deposition on silicon substrate • Inkjet printed silver top electrode • First ever BST films thinner than 1 μm RF functional variable capacitor that has required no lithography.

  15. The Paradox of Two Charged Capacitors

    CERN Document Server

    Singal, Ashok K

    2013-01-01

    It is shown that the famous paradox of two charged capacitors is successfully resolved if one properly considers all the energy changes in the system when some of the charges are transferred from one capacitor to the other. It happens so even when the connecting wire has an identically zero resistance, giving rise to no Ohmic losses in the wire. It is shown that in such a case the "missing energy" goes into the kinetic energy of conducting charges. It is shown that radiation plays no significant role in resolving the paradox. The problem can also be formulated and successfully resolved in an alternate form, without involving connecting wires in a circuit.

  16. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.;

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  17. Electrodynamic thermal breakdown of a capacitor insulator

    Science.gov (United States)

    Emel'Yanov, O. A.

    2011-11-01

    A mechanism of the electrical breakdown is proposed for modern metal-field capacitors with the well-known property of self-healing of the breakdown strength. Upon an increase in the working voltage, the self-healing time increases to tens of microseconds, and the heating of adjacent insulator layers becomes significant. The propagating thermally activated conduction wave facilitates the enhancement of the electric field up to breakdown values. Analysis of the dynamics of electric field increase is carried out for capacitors based on polyethylene terephthalate (PET) dielectric.

  18. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  19. Synthesis of boron/nitrogen substituted carbons for aqueous asymmetric capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Tomko, Timothy [Energy and Mineral Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Rajagopalan, Ramakrishnan, E-mail: rur12@psu.edu [Materials Research Institute, Pennsylvania State University, 270 MRL Bldg., University Park, PA 16802 (United States); Aksoy, Parvana [Energy Institute, Pennsylvania State University, University Park, PA 16802 (United States); Foley, Henry C. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2011-06-01

    Highlights: > Synthesis of highly substituted boron and nitrogen containing carbons (BCN) for ultracapacitor applications. > Evidence for strong electroadsorption of protons on BCN. > Increased specific capacitance per unit area and improved cell voltage in aqueous asymmetric capacitors. - Abstract: Boron/nitrogen substituted carbons were synthesized by co-pyrolysis of polyborazylene/coal tar pitch blends to yield a carbon with a boron and nitrogen content of 14 at% and 10 at%, respectively. The presence of heteroatoms in these carbons shifted the hydrogen evolution overpotential to -1.4 V vs Ag/AgCl in aqueous electrolytes, providing a large electrochemical potential window ({approx}2.4 V) as well as a specific capacitance of 0.6 F/m{sup 2}. An asymmetric capacitor was fabricated using the as-prepared low surface area carbon as the negative electrode along with a redox active manganese dioxide as the positive electrode. The energy density of the capacitor exceeded 10 Wh/kg at a power density of 1 kW/kg and had a cycle life greater than 1000 cycles.

  20. An Aqueous Metal-ion Capacitor with Oxidised Carbon Nanotubes and Metallic Zinc Electrodes

    Directory of Open Access Journals (Sweden)

    Yuheng Tian

    2016-10-01

    Full Text Available An aqueous metal ion capacitor comprising of a zinc anode, an oxidized carbon nanotubes (oCNTs cathode and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn2+, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC. The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm-2 (corresponding to 53 F g-1 in the range of 0-1.8 V at 10 mV s-1 and a stable cycling performance up to 5000 cycles.

  1. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae [Chungbuk National Univ., Chungju (Korea, Republic of)

    2013-06-15

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m{sup 2}/g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn{sub 2}O{sub 4}, LiCoO{sub 2} as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF{sub 6}, TEABF{sub 4}) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn{sub 2}O{sub 4}/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

  2. Synthesis of Cerium Dioxide High-k Thin Films as a Gate Dielectric in MOS Capacitor

    Directory of Open Access Journals (Sweden)

    Anil G. Khairnar

    2013-07-01

    Full Text Available In the present study, the Al/CeO2 / p-Si MOS capacitor was fabricated by depositing the Aluminium (Al metal layer by thermal evaporation technique on sol-gel derived CeO2 high-k thin films on p-Si substrate. The deposited CeO2 films were characterized by Ellipsometer to study the refractive index that is determined to be 3.62. The FTIR analysis was carried out to obtain chemical bonding characteristics. Capacitance-voltage measurements of Al/CeO2 /p-Si MOS capacitor were carried out to determine the dielectric constant, equivalent oxide thickness (EOT and flat band shift (VFB for the deposited CeO2 film of 16.22, 1.62 nm and 0.7 V respectively. The conductance voltage curve was used to determine the interface trap density (Dit at the CeO2 / p-Si interface that is calculated to be 1.29 × 1013 cm – 2 eV – 1 for measurement frequency of 500 kHz.

  3. A preliminary study of the dermal absorption of aluminium from antiperspirants using aluminium-26.

    Science.gov (United States)

    Flarend, R; Bin, T; Elmore, D; Hem, S L

    2001-02-01

    Aluminium chlorohydrate (ACH), the active ingredient in many antiperspirants, was labeled with the radioisotope 26Al. The labeled ACH was then fractionated into about 100 samples using gel filtration chromatography. Each fraction was analyzed for 26Al and total aluminium content. Aluminium-26 was only detected in the fractions that also contained aluminium, which verified that the ACH was uniformly labeled. 84 mg of the labeled ACH was then applied to a single underarm of two adult subjects with blood and urine samples being collected over 7 weeks. Tape-stripping and mild washings of the skin were also collected for the first 6 days. Results indicate that only 0.012% of the applied aluminium was absorbed through the skin. At this rate, about 4 microg of aluminium is absorbed from a single use of ACH on both underarms. This is about 2.5% of the aluminium typically absorbed by the gut from food over the same time period. Therefore, a one-time use of ACH applied to the skin is not a significant contribution to the body burden of aluminium.

  4. Determination of Aluminium Content in Aluminium Hydroxide Formulation by FT-NIR Transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Søndergaard, Ib;

    2007-01-01

    A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis...

  5. Comparative study of formation and corrosion performance of porous alumina and ceramic nanorods formed in different electrolytes by anodization

    Energy Technology Data Exchange (ETDEWEB)

    Raj, V., E-mail: alaguraj2@rediffmail.com; Mumjitha, M., E-mail: mumjitha@gmail.com

    2014-01-15

    Highlights: • Alumina–titania coatings were fabricated by anodization in a single step. • The universal and cheap sulphuric acid was used as the reference electrolyte. • The minimum concentration of PTO is used to achieve ceramic nanorods. • Dense ceramic coatings were achieved at low current density and room temperature. • Anodized coatings show better corrosion resistance compared to bare aluminium. -- Abstract: Fabrication of Al{sub 2}O{sub 3}–TiO{sub 2} nanoceramic coatings on aluminium was carried out in a single step using cost effective sulphuric acid electrolyte with the addition of potassium titanium oxalate (PTO) by anodization method. For comparison, the anodization was also carried out in sulphuric acid electrolyte alone. The effect of composition of the electrolyte, current density and electrolyte concentration on formation and surface characteristics of anodic alumina and ceramic coatings produced from different electrolytes have been investigated. The growth process, surface morphology, nanostructure, distribution of chemical elements, phase constitutions and corrosion resistance of the coatings formed in two different electrolytes were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Tafel polarization technique and electrochemical impedance spectroscopy (EIS). As the concentration of electrolyte and current density increased, the surface properties of the coating increased up to certain content and beyond that they decreased. Dense, uniform nanoceramic coatings with less surface defects were obtained from sulphuric acid + PTO electrolyte. The corrosion studies reveal that ceramic coating formed in sulphuric acid + PTO electrolyte offers better corrosion resistance compared to the alumina coating formed in sulphuric acid electrolyte.

  6. High Energy Density Capacitors for Pulsed Power Applications

    Science.gov (United States)

    2009-07-01

    high energy density energy storage capacitors. High efficency capacitors are available with energy densities as high as 3 J/cc for 1000 shots or...GENERAL ATOMICS ENERGY PRODUCTS Engineering Bulletin HIGH ENERGY DENSITY CAPACITORS FOR PULSED POWER APPLICATIONS Fred MacDougall, Joel...00-2009 4. TITLE AND SUBTITLE High Energy Density Capacitors for Pulsed Power Applications 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  7. Design and Characterization of Vertical Mesh Capacitors in Standard CMOS

    DEFF Research Database (Denmark)

    Christensen, Kåre Tais

    2001-01-01

    This paper shows how good RF capacitors can be made in a standard digital CMOS process. The capacitors which are also well suited for binary weighted switched capacitor banks show very good RF performance: Q-values of 57 at 4.0 GHz, a density of 0.27 fF/μ2, 2.2 μm wide shielded unit capacitors, 6...

  8. Aluminium exclusion and aluminium tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    Ivano eBrunner

    2013-06-01

    Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

  9. Application of Proton Conduction Boehmite Electrolyte to Single Chamber Fuel Cell

    Science.gov (United States)

    Kimura, Takeshi; Nagata, Akiyoshi

    The power generation characteristic at room temperature of a single chamber fuel cell using a novel hydrated aluminium oxide, pseudoboehmite (pb) proton conductor as the electrolyte was studied based on dependence on the crystal structure and treatment temperature of pb electrolytes generated by the hot water treatment of Al and Al2O3 films evaporated on the glass substrate. A single fuel cell using the pb electrolyte could be fabricated in various gas mixtures of hydrogen and oxygen at room temperature. Maximum open circuit voltage was obtained at a fuel cell using pb electrolytes generated by the soak treatment of Al and Al2O3 films during 4 hours in the hot water of 90°C.

  10. Dendritic Ni(Cu)-polypyrrole hybrid films for a pseudo-capacitor

    Science.gov (United States)

    Choi, Bit Na; Chun, Woo Won; Qian, Aniu; Lee, So Jeong; Chung, Chan-Hwa

    2015-11-01

    Dendritic Ni(Cu)-polypyrrole hybrid films are fabricated for a pseudo-capacitor in a unique morphology using two simple methods: electro-deposition and electrochemical de-alloying. Three-dimensional structures of porous dendrites are prepared by electro-deposition within the hydrogen evolution reaction (HER) at a high cathodic potential; the high-surface-area structure provides sufficient redox reactions between the electrodes and the electrolyte. The dependence of the active-layer thickness on the super-capacitor performance is also investigated, and the 60 μm-thick Ni(Cu)PPy hybrid electrode presents the highest performance of 659.52 F g-1 at the scan rate of 5 mV s-1. In the thicker layers, the specific capacitance became smaller due to the diffusion limitation of the ions in an electrolyte. The polypyrrole-hybridization on the porous dendritic Ni(Cu) electrode provides superior specific capacitance and excellent cycling stability due to the improvement in electric conductivity by the addition of conducting polypyrrole in the matrices of the dendritic nano-porous Ni(Cu) layer and the synergistic effect of composite materials.

  11. Relation between the ion size and pore size for an electric double-layer capacitor.

    Science.gov (United States)

    Largeot, Celine; Portet, Cristelle; Chmiola, John; Taberna, Pierre-Louis; Gogotsi, Yury; Simon, Patrice

    2008-03-05

    The research on electrochemical double layer capacitors (EDLC), also known as supercapacitors or ultracapacitors, is quickly expanding because their power delivery performance fills the gap between dielectric capacitors and traditional batteries. However, many fundamental questions, such as the relations between the pore size of carbon electrodes, ion size of the electrolyte, and the capacitance have not yet been fully answered. We show that the pore size leading to the maximum double-layer capacitance of a TiC-derived carbon electrode in a solvent-free ethyl-methylimmidazolium-bis(trifluoro-methane-sulfonyl)imide (EMI-TFSI) ionic liquid is roughly equal to the ion size (approximately 0.7 nm). The capacitance values of TiC-CDC produced at 500 degrees C are more than 160 F/g and 85 F/cm(3) at 60 degrees C, while standard activated carbons with larger pores and a broader pore size distribution present capacitance values lower than 100 F/g and 50 F/cm(3) in ionic liquids. A significant drop in capacitance has been observed in pores that were larger or smaller than the ion size by just an angstrom, suggesting that the pore size must be tuned with sub-angstrom accuracy when selecting a carbon/ion couple. This work suggests a general approach to EDLC design leading to the maximum energy density, which has been now proved for both solvated organic salts and solvent-free liquid electrolytes.

  12. Iodine encapsulation in CNTs and its application for electrochemical capacitor

    Science.gov (United States)

    Taniguchi, Y.; Ishii, Y.; Rashid, M.; Syakirin, A.; Al-zubaidi, A.; Kawasaki, S.

    2016-07-01

    We report the experimental results for new type electrochemical capacitor using iodine redox reaction in single-walled carbon nanotubes (SWCNTs). It was found that the energy density of the present redox capacitor using SWCNTs is almost three times larger than that of the normal electric double layer capacitor.

  13. Design of activated carbon/activated carbon asymmetric capacitors

    Directory of Open Access Journals (Sweden)

    Isabel ePiñeiro-Prado

    2016-03-01

    Full Text Available Supercapacitors are energy storage devices that offer a high power density and a low energy density in comparison with batteries. Their limited energy density can be overcome by using asymmetric configuration in mass electrodes, where each electrode works within their maximum available potential window, rendering the maximum voltage output of the system. Such asymmetric capacitors must be optimized through careful electrochemical characterization of the electrodes for accurate determination of the capacitance and the potential stability limits. The results of the characterization are then used for optimizing mass ratio of the electrodes from the balance of stored charge. The reliability of the design largely depends on the approach taken for the electrochemical characterization. Therefore, the performance could be lower than expected and even the system could break down, if a well thought out procedure is not followed.In this work, a procedure for the development of asymmetric supercapacitors based on activated carbons is detailed. Three activated carbon materials with different textural properties and surface chemistry have been systematically characterized in neutral aqueous electrolyte. The asymmetric configuration of the masses of both electrodes in the supercapacitor has allowed to cover a higher potential window, resulting in an increase of the energy density of the three devices studied when compared with the symmetric systems, and an improved cycle life.

  14. Elaboration of a microstructured inkjet-printed carbon electrochemical capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Pech, David; Brunet, Magali; Fabre, Norbert; Mesnilgrente, Fabien; Conedera, Veronique; Durou, Hugo [LAAS-CNRS, Universite de Toulouse, 7 av. du Colonel Roche, F-31077 Toulouse (France); Taberna, Pierre-Louis; Simon, Patrice [CIRIMAT-CNRS, Universite de Toulouse, 118 route de Narbonne, F-31062 Toulouse (France)

    2010-02-15

    Carbon-based micro-supercapacitors dedicated to energy storage in self-powered modules were fabricated with inkjet printing technology on silicon substrate. An ink was first prepared by mixing an activated carbon powder with a PTFE polymer binder in ethylene glycol stabilized with a surfactant then deposited by inkjet on patterned gold current collectors with the substrate heated at 140 C in order to assure a good homogeneity. Electrochemical micro-capacitors with electrodes in an interdigital configuration were fabricated, and characterized using electrochemical techniques in 1 M Et{sub 4}NBF{sub 4} propylene carbonate electrolyte. These micro-devices show an excellent capacitive behavior over a wide potential range of 2.5 V for a cell capacitance of 2.1 mF cm{sup -2}. The newly developed technology will allow the integration of the storage device as close as possible to the MEMS-based energy harvesting device, minimizing power losses through connections. (author)

  15. Toxicity of dissolved and precipitated aluminium to marine diatoms.

    Science.gov (United States)

    Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

    2016-05-01

    Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as aluminium exposure varied between diatom species. C. closterium was the most sensitive species (10% inhibition of growth rate (72-h IC10) of 80 (55-100)μg Al/L (95% confidence limits)) while M. polymorphus (540 (460-600)μg Al/L) and P. tricornutum (2100 (2000-2200)μg Al/L) were less sensitive (based on measured total aluminium). Dissolved aluminium was the primary contributor to toxicity in C. closterium, while a combination of dissolved and precipitated aluminium forms contributed to toxicity in M. polymorphus. In contrast, aluminium toxicity to the most tolerant diatom P. tricornutum was due predominantly to precipitated aluminium. Preliminary investigations revealed the sensitivity of C. closterium and M. polymorphus to aluminium was influenced by initial cell density with aluminium toxicity significantly (paluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated aluminium.

  16. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Science.gov (United States)

    Cassayre, L.; Souček, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P.

    2011-07-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl 3. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl 3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl 2/UAl 3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl 5 and UCl 6. The results showed high efficient chlorination at a temperature of 150 °C.

  17. Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

    Science.gov (United States)

    Wang, Di-Yan; Wei, Chuan-Yu; Lin, Meng-Chang; Pan, Chun-Jern; Chou, Hung-Lung; Chen, Hsin-An; Gong, Ming; Wu, Yingpeng; Yuan, Chunze; Angell, Michael; Hsieh, Yu-Ju; Chen, Yu-Hsun; Wen, Cheng-Yen; Chen, Chun-Wei; Hwang, Bing-Joe; Chen, Chia-Chun; Dai, Hongjie

    2017-02-01

    Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion-graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ~110 mAh g-1 with Coulombic efficiency ~98%, at a current density of 99 mA g-1 (0.9 C) with clear discharge voltage plateaus (2.25-2.0 V and 1.9-1.5 V). The cell has a capacity of 60 mAh g-1 at 6 C, over 6,000 cycles with Coulombic efficiency ~ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C-Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.

  18. Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

    Science.gov (United States)

    Wang, Di-Yan; Wei, Chuan-Yu; Lin, Meng-Chang; Pan, Chun-Jern; Chou, Hung-Lung; Chen, Hsin-An; Gong, Ming; Wu, Yingpeng; Yuan, Chunze; Angell, Michael; Hsieh, Yu-Ju; Chen, Yu-Hsun; Wen, Cheng-Yen; Chen, Chun-Wei; Hwang, Bing-Joe; Chen, Chia-Chun; Dai, Hongjie

    2017-01-01

    Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g−1 with Coulombic efficiency ∼98%, at a current density of 99 mA g−1 (0.9 C) with clear discharge voltage plateaus (2.25–2.0 V and 1.9–1.5 V). The cell has a capacity of 60 mAh g−1 at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C–Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode. PMID:28194027

  19. Single Switched Capacitor Battery Balancing System Enhancements

    Directory of Open Access Journals (Sweden)

    Joeri van Mierlo

    2013-04-01

    Full Text Available Battery management systems (BMS are a key element in electric vehicle energy storage systems. The BMS performs several functions concerning to the battery system, its key task being balancing the battery cells. Battery cell unbalancing hampers electric vehicles’ performance, with differing individual cell voltages decreasing the battery pack capacity and cell lifetime, leading to the eventual failure of the total battery system. Quite a lot of cell balancing topologies have been proposed, such as shunt resistor, shuttling capacitor, inductor/transformer based and DC energy converters. The shuttling capacitor balancing systems in particular have not been subject to much research efforts however, due to their perceived low balancing speed and high cost. This paper tries to fill this gap by briefly discussing the shuttling capacitor cell balancing topologies, focusing on the single switched capacitor (SSC cell balancing and proposing a novel procedure to improve the SSC balancing system performance. This leads to a new control strategy for the SSC system that can decrease the balancing system size, cost, balancing time and that can improve the SSC balancing system efficiency.

  20. Special Section: Electrochemical capacitors: Guest Editor's note

    Science.gov (United States)

    Balducci, Andrea

    2016-09-01

    Electrochemical capacitors (i.e., supercapacitors) are nowadays considered as one of the most important electrochemical storage devices. Thanks to their high power, extraordinary cycle life and high reliability these devices are currently used in a large number of applications, rendering them indispensible for our daily life.

  1. Circular plate capacitor with different disks

    CERN Document Server

    Paffuti, Giampiero; Di Lieto, Alberto; Maccarrone, Francesco

    2016-01-01

    In this paper we write a system of integral equations for a capacitor composed by two disks of different radii, generalizing Love's equation for equal disks. We compute the complete asymptotic form of the capacitance matrix both for large and small distances obtaining a generalization of Kirchhoff's formula for the latter case.

  2. Electrostatic spray deposition based lithium ion capacitor

    Science.gov (United States)

    Agrawal, Richa; Chen, Chunhui; Wang, Chunlei

    2016-05-01

    Conventional Electrochemical double-layer capacitors (EDLCs) are well suited as power devices that can provide large bursts of energy in short time periods. However, their relatively inferior energy densities as compared to their secondary battery counterparts limit their application in devices that require simultaneous supply of both high energy and high power. In the wake of addressing this shortcoming of EDLCs, the concept of hybridization of lithium-ion batteries (LIBs) and EDLCs has attracted significant scientific interest in recent years. Such a device, generally referred to as the "lithium-ion capacitor" typically utilizes a lithium intercalating electrode along with a fast charging capacitor electrode. Herein we have constructed a lithium hybrid electrochemical capacitor comprising a Li4Ti5O12-TiO2 (LTO-TiO2) anode and a reduced graphene oxide and carbon nanotube (rGO-CNT) composite cathode using electrostatic spray deposition (ESD). The electrodes were characterized using scanning electron microscopy and X-ray diffraction studies. Cyclic voltammetry and galvanostatic charge-discharge measurements were carried out to evaluate the electrochemical performance of the individual electrodes and the full hybrid cells.

  3. Aluminium toxicity in winter wheat

    Directory of Open Access Journals (Sweden)

    Szabó A.

    2015-01-01

    Full Text Available Aluminium is the most frequent metal of the earth crust; it occurs mainly as biologically inactive, insoluble deposit. Environmental problems, industrial contaminations and acid rains increase the soil acidity, leading to the mobilization of Al. Half of the world’s potential arable lands are acidic; therefore, Al-toxicity decreases crop productivity. Wheat is a staple food for 35% of the world population. The effects of Al-stress (0.1 mM were studied on winter wheat; seedlings were grown hydroponically, at acidic pH. After two weeks, the root weight was decreased; a significant difference was found in the P- and Ca-content. The shoot weight and element content changed slightly; Al-content in the root was one magnitude higher than in the shoot, while Al-translocation was limited. The root plasma membrane H+-ATPase has central role in the uptake processes; Al-stress increased the Mg2+-ATPase activity of the microsomal fraction.

  4. Investigation of the formability of aluminium alloys at elevated temperatures

    Science.gov (United States)

    Tisza, M.; Budai, D.; Kovács, P. Z.; Lukács, Zs

    2016-11-01

    Aluminium alloys are more and more widely applied in car body manufacturing. Increasing the formability of aluminium alloys are one of the most relevant tasks in todays’ research topics. In this paper, the focus will be on the investigation of the formability of aluminium alloys concerning those material grades that are more widely applied in the automotive industry including the 5xxx and 6xxx aluminium alloy series. Recently, besides the cold forming of aluminium sheets the forming of aluminium alloys at elevated temperatures became a hot research topic, too. In our experimental investigations, we mostly examined the EN AW 5754 and EN AW 6082 aluminium alloys at elevated temperatures. We analysed the effect of various material and process parameters (e.g. temperature, sheet thickness) on the formability of aluminium alloys with particular emphasis on the Forming Limit Diagrams at elevated temperatures in order to find the optimum forming conditions for these alloys.

  5. Structural colours and applications to anodised aluminium surfaces

    DEFF Research Database (Denmark)

    Johansen, Villads Egede

    This thesis investigates possible ways of creating aluminium with a milky white, metallic appearance for decorative purposes. Since white cannot be obtained through traditional absorption based dyeing of aluminium, optical mechanisms based on scattering by nanostructures are studied in order...

  6. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    M P S Chandrawat; R N Yadav

    2000-02-01

    The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.

  7. Rep rated long life capacitor development: Phase 1 and 2

    Science.gov (United States)

    Galperin, I.; White, W.; Haskell, K.; Ennis, J.

    1984-09-01

    Polypropylene and polyolefin resins were characterized and processed into capacitor films. New capacitor films were developed--a post oriented processed, two layer polypropylene film and upgraded polyolefin film. Criteria for judging film quality were developed. Field life data were verified with paper/polypropylene capacitors on the Maxwell rep rate facility. A11 polypropylene film capacitors were developed with lifetimes in excess of 10 to the 7th power discharges at energy densities for the finished capacitor of 18.3 J/lb and projected to more than 20 J/lb.

  8. From Science to Industry: The Sites of Aluminium in France from the Nineteenth to the Twentieth Century.

    Science.gov (United States)

    Le Roux, Muriel

    2015-05-01

    This paper explores the history of the isolation and industrial production of aluminium in France, from the work of Henri Sainte-Claire Deville in the 1850s to the latter part of the twentieth century, focusing on the relationships between academic research and industrial exploitation. In particular, it identifies a culture and organisation of research and development, "learning-by-doing," that emerged in the French aluminium industry following the establishment of the first electrolytic production facilities in the late 1880s by Paul Héroult, who, along with the American Charles Hall, patented the electrolytic method of producing the metal. This French method of R&D was a product both of a scientific culture that saw a continuity between scientific research and industrial application, and of a state policy that, unlike in Germany or the United States, was late to recognise the importance of fostering, on a large scale, the relations between academic chemistry and industry. It was only after World War II that the French state came fully to recognise the importance of underpinning industry with scientific research. And it was only from the 1960s, in the face of intensifying global competition, the risks of pollution, and the cost of energy, that the major aluminium firm Pechiney et Cie was able to replace a culture of "learning-by-doing" by one that integrated fundamental science with the production process.

  9. Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys

    OpenAIRE

    2013-01-01

    Corrosion resistance of aluminium alloys is related to the composition and morphology of the oxide film on the surface of aluminium. In this paper we investigated the use of steam on the surface modification of aluminium to produce boehmite films. The study reveals a detailed investigation of the effect of vapour pressure, structure of intermetallic particles and thickness of boehmite films on the corrosion behaviour of aluminium alloys.

  10. Humidity Testing of PME and BME Ceramic Capacitors with Cracks

    Science.gov (United States)

    Teverovsky, Alexander A.; Herzberger, Jaemi

    2014-01-01

    Cracks in ceramic capacitors are one of the major causes of failures during operation of electronic systems. Humidity testing has been successfully used for many years to verify the absence of cracks and assure quality of military grade capacitors. Traditionally, only precious metal electrode (PME) capacitors were used in high reliability applications and the existing requirements for humidity testing were developed for this type of parts. With the advance of base metal electrode (BME) capacitors, there is a need for assessment of the applicability of the existing techniques for the new technology capacitors. In this work, variety of different PME and BME capacitors with introduced cracks were tested in humid environments at different voltages and temperatures. Analysis of the test results indicates differences in the behavior and failure mechanisms for BME and PME capacitors and the need for different testing conditions.

  11. Solid electrolytic fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Masayasu; Yamauchi, Yasuhiro; Kamisaka, Mitsuo; Notomi, Kei.

    1989-04-21

    Concerning a solid electrolytic fuel cell with a gas permeable substrate pipe, a fuel electrode installed on this substrate pipe and an air electrode which is laminated on this fuel electrode with the electrolyte in between, the existing fuel cell of this kind uses crystals of CaMnO3, etc. for the material of the air electrode, but its electric resistance is big and in order to avert this, it is necessary to make the film thickness of the air electrode big. However, in such a case, the entry of the air into its inside worsens and the cell performance cannot develop satisfactorily. In view of the above, in order to obtain a high performance solid electrolytic fuel cell which can improve electric conductivity without damaging diffusion rate of the air, this invention proposes with regard to the aforementioned solid electrolytic fuel cell to install a heat resistant and conductive member inside the above air electrode. 6 figs.

  12. Polymer electrolyte reviews. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mac Callum, J.R.; Vincent, C.A.

    1987-01-01

    The development of polymer electrolytes which have potential applications in battery technology has resulted in an escalation of research into the synthesis of new macromolecular supports and the mechanisms of ionic transport within the solid matrix. Investigation of the properties of polymer electrolytes has brought together polymer chemists and electrochemists, and the understanding of the solubility and transport of electrolytes in organic polymers is now developing from this pooled experience. This book deals with experimental, theoretical and applied aspects of solid solutions of electrolytes used in coordinating polymer matrices. Attention is focused on the synthesis and properties of these new materials, the mechanisms of conduction processes and practical applications, especially with regard to battery technology.

  13. Electrolytic oxidation of anthracite

    Science.gov (United States)

    Senftle, F.E.; Patton, K.M.; Heard, I.

    1981-01-01

    An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

  14. Aluminium allergy and granulomas induced by vaccinations for children

    DEFF Research Database (Denmark)

    Andersen, Rosa Marie O; Zachariae, Claus; Johansen, Jeanne Duus

    2014-01-01

    Vaccination with aluminium-adsorbed vaccines can induce aluminium allergy with persistent itching subcutaneous nodules at the injection site - vaccination granulomas. In this article we give an overview of childhood aluminium-adsorbed vaccines available in Denmark. Through literature studies we...... examine the incidence, the symptoms and the prognosis for the vaccination granulomas and the allergy. Finally we discuss the status in Denmark....

  15. Stability of aluminium beams in case of fire

    NARCIS (Netherlands)

    Meulen, O.R. van der; Soetens, F.; Maljaars, J.

    2014-01-01

    Fire is often the dominant design criterion for aluminium structures. Present design rules for aluminium constructions in fire neglect both the decrease in susceptibility to local buckling and the effects of creep, that are intrinsic to aluminium. They may therefore either overestimate or underestim

  16. [Aluminium allergy and granulomas induced by vaccinations for children].

    Science.gov (United States)

    Andersen, Rosa Marie Ø; Zachariae, Claus; Johansen, Jeanne Duus

    2015-04-27

    Vaccination with aluminium-adsorbed vaccines can induce aluminium allergy with persistent itching subcutaneous nodules at the injection site – vaccination granulomas. In this article we give an overview of childhood aluminium-adsorbed vaccines available in Denmark. Through literature studies we examine the incidence, the symptoms and the prognosis for the vaccination granulomas and the allergy. Finally we discuss the status in Denmark.

  17. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  18. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Aluminium hydroxide-induced granulomas in pigs

    DEFF Research Database (Denmark)

    Valtulini, S; Macchi, C; Ballanti, P

    2005-01-01

    The effect of intramuscular injection of 40 mg/2 ml aluminium hydroxide in the neck of pigs was examined in a number of ways. The investigation followed repeated slaughterhouse reports, according to which 64.8% of pigs from one particular farm were found at slaughter to have one or more nodules...... in the muscles of the neck (group slaughtered). The pigs had been injected with a vaccine containing 40 mg/2 ml dose of aluminium hydroxide as adjuvant. Research consisted of two phases: first, an epidemiological study was carried out, aimed at determining the risk factors for the granulomas. The results...... and adjuvant) to pigs inoculated twice with apyrogenic bi-distilled water (group water) and to pigs inoculated once with the adjuvant and once with apyrogenic bi-distilled water (group adjuvant/water). Both studies agreed in their conclusions, which indicate that the high amount of aluminium hydroxide...

  20. High energy density capacitors using nano-structure multilayer technology

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1992-08-01

    Today, many pulse power and industrial applications are limited by capacitor performance. While incremental improvements are anticipated from existing capacitor technologies, significant advances are needed in energy density to enable these applications for both the military and for American economic competitiveness. We propose a program to research and develop a novel technology for making high voltage, high energy density capacitors. Nano-structure multilayer technologies developed at LLNL may well provide a breakthrough in capacitor performance. Our controlled sputtering techniques are capable of laying down extraordinarily smooth sub-micron layers of dielectric and conductor materials. With this technology, high voltage capacitors with an order of magnitude improvement in energy density may be achievable. Well-understood dielectrics and new materials will be investigated for use with this technology. Capacitors developed by nano-structure multilayer technology are inherently solid state, exhibiting extraordinary mechanical and thermal properties. The conceptual design of a Notepad capacitor is discussed to illustrate capacitor and capacitor bank design and performance with this technology. We propose a two phase R&D program to address DNA`s capacitor needs for electro-thermal propulsion and similar pulse power programs. Phase 1 will prove the concept and further our understanding of dielectric materials and design tradeoffs with multilayers. Nano-structure multilayer capacitors will be developed and characterized. As our materials research and modeling prove successful, technology insertion in our capacitor designs will improve the possibility for dramatic performance improvements. In Phase 2, we will make Notepad capacitors, construct a capacitor bank and demonstrate its performance in a meaningful pulse power application. We will work with industrial partners to design full scale manufacturing and move this technology to industry for volume production.

  1. The binding of phosphonic acids at aluminium oxide surfaces and correlation with passivation of aluminium flake.

    Science.gov (United States)

    Cooper, Rachel J; Camp, Philip J; Henderson, David K; Lovatt, Paul A; Nation, David A; Richards, Stuart; Tasker, Peter A

    2007-04-07

    Measurements of adsorption isotherms of a series of thirteen mono- and di-phosphonic acids have shown that these bind strongly to the surface of high surface area aluminium trihydroxide. The incorporation of such phosphonates into a suspension of aluminium flake in an aqueous medium, modelling the continuous phase of a water-based paint, greatly suppresses the evolution of hydrogen. Whilst strong binding of the phosphonate to aluminium oxides is an essential criterion for good passivation, other factors such as the hydrophobicity of the ligand are also important in suppressing hydrogen-evolution.

  2. Diamond grooving of rapidly solidified optical aluminium

    Science.gov (United States)

    Abou-El-Hossein, Khaled; Hsu, Wei-Yao; Ghobashy, Sameh; Cheng, Yuan-Chieh; Mkoko, Zwelinzima

    2015-10-01

    Traditional optical aluminium grades such as Al 6061 are intensively used for making optical components for applications ranging from mould insert fabrication to laser machine making. However, because of their irregular microstructure and relative inhomogeneity of material properties at micro scale, traditional optical aluminium may exhibit some difficulties when ultra-high precision diamond turned. Inhomogeneity and micro-variation in the material properties combined with uneven and coarse microstructure may cause unacceptable surface finish and accelerated tool wear, especially in grooving operation when the diamond tool edge is fully immersed in the material surface. Recently, new grades of optical aluminium that are featured by their ultra-fine microstructure and improved material properties have been developed to overcome the problem of high tool wear rates. The new aluminium grades have been developed using rapid solidification process which results in extremely small grain sizes combined with improved mechanical properties. The current study is concerned with investigating the performance of single-point diamond turning when grooving two grades of rapidly solidified aluminium (RSA) grades: RSA905 which is a high-alloyed aluminium grade and RSA443 which has a high silicon content. In this study, two series of experiments employed to create radial microgrooves on the two RSA grades. The surface roughness obtained on the groove surface is measured when different combinations of cutting parameters are used. Cutting speed is varied while feed rate and depth of cut were kept constant. The results show that groove surface roughness produced on RSA443 is higher than that obtained on RSA905. Also, the paper reports on the effect of cutting speed on surface roughness for each RSA grade.

  3. New aluminium alloys with high lithium content

    Energy Technology Data Exchange (ETDEWEB)

    Schemme, K.; Velten, B.

    1989-06-01

    Since the early 80's there have been made great efforts to replace the high strength aluminium alloys for the aircraft and space industry by a new generation of aluminium-lithium alloys. The attractivity of this kind of alloys could be increased by a further reduction of their density, caused by an increasing lithium content (/ge/ 5 wt.% Li). Therefore binary high-lithium containing alloys with low density are produced and metallografically investigated. A survey of their strength and wear behavior is given by using tensile tests and pin abrasing tests. (orig.).

  4. Anode characterisation and gas diffusion behaviour in aluminium smelting

    Science.gov (United States)

    Putri, Epma; Brooks, Geoffrey; Snook, Graeme; Eick, Ingo

    2017-01-01

    Over the past century, significant research on different aspects of the Hall-Héroult process has been conducted to increase energy efficiency. Bubble generation at the anode reaction and its contribution to the overall voltage drop in aluminium production holds significant potential for energy saving, yet the details of the gas transport mechanism for bubble nucleation behaviour are not completely understood. The multi-step electrochemical reaction releases predominantly CO2 gas along with CO gas, which is a reduction product formed by reaction of CO2 with the anode carbon. Complicating the reaction is the multiple paths by which the gas can diffuse (either through the porous anode or the electrolyte bath). There has been no detailed investigation of the correlation between gas diffusion as a function of anode and bath properties. In the present study, the porosity measurement techniques in the anode will be used to understand the relation of gas diffusion and anode properties. A porosimetric study was conducted for two different anode samples using mercury intrusion porosimetry (MIP) and hydrostatic method. The MIP method provides important anode properties information such as density, percent porosity, pore size distribution, permeability, and tortuosity factor which affect gas diffusion and anode performance. The Knudsen number obtained from MIP data shows both Knudsen diffusion and molecular diffusion need to be considered when predicting the effective diffusion.

  5. Anodization of Aluminium using a fast two-step process

    Indian Academy of Sciences (India)

    Murugaiya Sridar Ilango; Amruta Mutalikdesai; Sheela K Ramasesha

    2016-01-01

    Ultra-fast two-step anodization method is developed for obtaining ordered nano-pores on aluminium (Al) foil. First anodization was carried out for 10 min, followed by 3 min of second anodization at high voltage (150 V) compared to previous reports of anodization times of 12 h (40-60 V). The pore dimensions on anodized alumina are 180 nm for pore diameter and 130 nm for inter-pore distance. It was evident that by increasing the anodization voltage to 150 V, the diameter of the pores formed was above 150 nm. The electrolyte and its temperature affect the shape and size of the pore formation. At lower anodization temperature, controlled pore formation was observed. The anodized samples were characterized using the field emission scanning electron microscope (FE-SEM) to determine the pore diameter and inter-pore distance. Using UVVisible spectroscopy, the reflectance spectra of anodized samples were measured. The alumina (Al2O3) peaks were identified by x-ray diffraction (XRD) technique. The x-ray photo electron spectroscopy (XPS) analysis confirmed the Al 2p peak at 73.1 eV along with the oxygen O 1s at 530.9 eV and carbon traces C 1s at 283.6 eV.

  6. Repassivation Investigations on Aluminium: Physical Chemistry of the Passive State

    Science.gov (United States)

    Nagy, Tristan Oliver; Weimerskirch, Morris Jhängi Joseph; Pacher, Ulrich; Kautek, Wolfgang

    2016-09-01

    We show the temporal change in repassivation mechanism as a time-dependent linear combination of a high-field model of oxide growth (HFM) and the point defect model (PDM). The observed switch in transient repassivation current-decrease under potentiostatic control occurs independently of the active electrode size and effective repassivation time for all applied overpotentials. For that, in situ depassivation of plasma electrolytically oxidized (PEO) coatings on aluminium was performed with nanosecond laser pulses at 266 nm and the repassivation current transients were recorded as a function of pulse number. A mathematical model combines the well established theories of oxide-film formation and growth kinetics, giving insight in the non linear transient behaviour of micro-defect passivation. According to our findings, the repassivation process can be described as a charge consumption via two concurrent channels. While the major current-decay at the very beginning of the fast healing oxide follows a point-defect type exponential damping, the HFM mechanism supersedes gradually, the longer the repassivation evolves. Furthermore, the material seems to reminisce former laser treatments via defects built-in during depassivation, leading to a higher charge contribution of the PDM mechanism at higher pulse numbers.

  7. China’s Aluminium Consumption and the Related Policies

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>China is a major aluminium consumer country in the world. In 2005, China produced 7.81 million tons aluminium and imported 640,000 tons. Meanwhile, China also exported 1.32 million tons aluminium in 2005. China’s apparent consumption of aluminium in 2005 was about 7.1 million tons, which was 9.3 times over that in 1990. China’s aluminium consumption growth has kept at an annual average of 16.1 per cent since 1990, which makes China the

  8. China’s Production and Market of Aluminium Extruded Profiles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Chinese aluminium extrusion industry came into existence at the early 1950s with most products used in military industry and national defence.At the beginning of 1980s,the produc- tion of construction aluminium profiles started simultaneously in North and South China.In the following thirty years,the aluminium extru- sion industry entered into a quickly developing stage with a focus on construction aluminium profiles.With the blooming real estate industry, the demand for construction aluminium profiles from the domestic market has a tendency of yearly increase.From 2000,the quick devel- opments of China’s auto and railway vehicle

  9. Challenges in LCA modelling of multiple loops for aluminium cans

    DEFF Research Database (Denmark)

    Niero, Monia; Olsen, Stig Irving

    packaging scrap sources (i.e. used beverage can and mixed aluminium packaging) to understand the limiting factors for multiple loop aluminium can recycling. Secondly, we performed a comparative LCA of aluminium can production and recycling in multiple loops considering the two aluminium packaging scrap...... this information to perform an LCA of 30 recycling loops based on the actual alloy composition. From the comparative LCA the closed product loop option (i.e. using used beverage can scraps) turned out to have lower environmental impact than the open loop option (i.e. using mixed aluminium packaging scraps...

  10. Aluminium: a natural adjuvant in Leishmania transmission via sand flies?

    Science.gov (United States)

    Maingon, Rhayza; Khela, Amandeep; Sampson, Christopher; Ward, Richard; Walker, Karen; Exley, Christopher

    2008-11-01

    Genetically identical Leishmania chagasi/infantum parasites cause both atypical cutaneous leishmaniasis and visceral leishmaniasis. In this report we have tested the first part of a hypothesis that states that the form of this disease that is manifested depends upon the adjuvant-like activity of aluminium of dietary origin accumulated in the salivary gland of the sand fly vector. In sand flies fed aluminium-supplemented sucrose we have used histochemistry to qualitatively identify aluminium in their salivary glands and graphite furnace atomic absorption spectrometry to quantify the aluminium content of dissected salivary glands. Aluminium may be acting as a natural adjuvant in some forms of leishmaniasis.

  11. Matching Properties of Femtofarad and Sub-Femtofarad MOM Capacitors

    KAUST Repository

    Omran, Hesham

    2016-04-21

    Small metal-oxide-metal (MOM) capacitors are essential to energy-efficient mixed-signal integrated circuit design. However, only few reports discuss their matching properties based on large sets of measured data. In this paper, we report matching properties of femtofarad and sub-femtofarad MOM vertical-field parallel-plate capacitors and lateral-field fringing capacitors. We study the effect of both the finger-length and finger-spacing on the mismatch of lateral-field capacitors. In addition, we compare the matching properties and the area efficiency of vertical-field and lateral-field capacitors. We use direct mismatch measurement technique, and we illustrate its feasibility using experimental measurements and Monte Carlo simulations. The test-chips are fabricated in a 0.18 \\\\mutext{m} CMOS process. A large number of test structures is characterized (4800 test structures), which improves the statistical reliability of the extracted mismatch information. Despite conventional wisdom, extensive measurements show that vertical-field and lateral-field MOM capacitors have the same matching properties when the actual capacitor area is considered. Measurements show that the mismatch depends on the capacitor area but not on the spacing; thus, for a given mismatch specification, the lateral-field MOM capacitor can have arbitrarily small capacitance by increasing the spacing between the capacitor fingers, at the expense of increased chip area.

  12. Irradiation damage in aluminium single crystals produced by 50-keV aluminium and copper ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.;

    1968-01-01

    Aluminium single crystals, thin enough to be examined by electron microscopy, have been irradiated with 50-keV aluminium and copper ions. The irradiation fluxes were in the range 1011–1014 cm−2 s−1 and the doses were from 6 × 1012 to 6 × 1014 cm−2. Irradiation along either a or a direction produc...

  13. Flexural buckling of fire exposed aluminium columns

    NARCIS (Netherlands)

    Maljaars, J.; Twilt, L.; Soetens, F.

    2009-01-01

    In order to study buckling of fire exposed aluminium columns, a finite element model is developed. The results of this model are verified with experiments. Based on a parametric study with the finite element model, it is concluded that the simple calculation model for flexural buckling of fire expos

  14. Aluminium building and civil engineering structures

    NARCIS (Netherlands)

    Soetens, F.; Mennink, J.

    1999-01-01

    The design of aluminium structures in building and civil engineering applications is different from designing in traditional materials. This difference is based on the physical and mechanical properties of the material and the freedom of cross-sectional shape provided by the extrusion manufacturing

  15. Dissolved aluminium in the Southern Ocean

    NARCIS (Netherlands)

    Middag, R.; van Slooten, C.; de Baar, H. J. W.; Laan, P.

    2011-01-01

    Dissolved aluminium (Al) occurs in a wide range of concentrations in the world oceans. The concentrations of Al in the Southern Ocean are among the lowest ever observed. An all-titanium CTD sampling system makes it possible to study complete deep ocean sections of Al and other trace elements with th

  16. Aluminium overhead highway traffic sign structures

    NARCIS (Netherlands)

    Courage, W.M.G.; Soetens, F.; Noordzij, R.; Drabbels, J.

    1998-01-01

    This paper deals with the design and manufacturing of aluminium overhead sign structures. These gantries are built up by using two X-shaped column frames connected by a triangular space frame girder. Slenderness and a low solidity ratio were objectives in the architectonic design. Braces and main ch

  17. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    pressure steam produced by an autoclave at a temperature of 107 – 121 °C and pressure of 15 -17 psi for 10 minutes to produce a thin coating of aluminium oxide. The aim of this study is to understand the effect of high pressure steam with and without different chemical additives on surface morphology...

  18. Molecular breeding of cereals for aluminium resistance

    Science.gov (United States)

    Aluminium (Al3+) toxicity is the primary factor limiting crop production on acidic soils worldwide. In addition to an application of lime for soil amelioration, Al3+ resistant plant varieties have been deployed to raise productivity on such hostile soils. This has been possible due to the exploita...

  19. Indentation of aluminium foam at low velocity

    Directory of Open Access Journals (Sweden)

    Shi Xiaopeng

    2015-01-01

    Full Text Available The indentation behaviour of aluminium foams at low velocity (10 m/s ∼ 30 m/s was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ∼10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ∼10 m/s velocity may be caused by plastic wave effect.

  20. Thermodynamic energy exchange in a moving plate capacitor

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2001-09-01

    In this paper we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. The plates are attracted together, but a demon restores the plates of the capacitor to their original position when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the open question is how? This is unsolved, however we explore the concept of a moving plate capacitor by examining the case where it is still excited by thermal noise, but where the restoring force on the capacitor plates is provided by a simple spring rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  1. Method of manufacturing a shapeable short-resistant capacitor

    Science.gov (United States)

    Taylor, Ralph S.; Myers, John D.; Baney, William J.

    2013-04-02

    A method that employs a novel combination of conventional fabrication techniques provides a ceramic short-resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The method allows thinner and more flexible ceramic capacitors to be made. The method includes forming a first thin metal layer on a substrate; depositing a thin, ceramic dielectric layer over the metal layer; depositing a second thin metal layer over the dielectric layer to form a capacitor exhibiting a benign failure mode; and separating the capacitor from the substrate. The method may also include bending the resulting capacitor into a serpentine arrangement with gaps between the layers that allow venting of evaporated electrode material in the event of a benign failure.

  2. Performance of thin-film ferroelectric capacitors for EMC decoupling.

    Science.gov (United States)

    Li, Huadong; Subramanyam, Guru

    2008-12-01

    This paper studied the effects of thin-film ferroelectrics as decoupling capacitors for electromagnetic compatibility applications. The impedance and insertion loss of PZT capacitors were measured and compared with the results from commercial off-the-shelf capacitors. An equivalent circuit model was extracted from the experimental results, and a considerable series resistance was found to exist in ferroelectric capacitors. This resistance gives rise to the observed performance difference around series resonance between ferroelectric PZT capacitors and normal capacitors. Measurements on paraelectric (Ba,Sr)TiO(3)-based integrated varactors do not show this significant resistance. Some analyses were made to investigate the mechanisms, and it was found that it can be due to the hysteresis in the ferroelectric thin films.

  3. Thermodynamic energy exchange in a moving plate capacitor.

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2001-09-01

    In this paper we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. The plates are attracted together, but a demon restores the plates of the capacitor to their original position when the voltage across the capacitor is small-hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the open question is how? This is unsolved, however we explore the concept of a moving plate capacitor by examining the case where it is still excited by thermal noise, but where the restoring force on the capacitor plates is provided by a simple spring rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other. (c) 2001 American Institute of Physics.

  4. High energy density capacitor testing for the AFWL SHIVA

    Science.gov (United States)

    Smith, D. L.; Reinovsky, R. E.

    Lifetime testing and analysis of small samples of high energy density (HED) discharge capacitors at the AFWL were conducted to find a component suitable for upgrading the SHIVA capacitor bank to a 6 MJ facility. Evaluation was performed with discharge conditions of approximately 250 kA per capacitor at 60 to 70% reversal and 2 microsec quarter period. Dielectric systems including Kraft paper with caster oil impregnant and Kraft paper, polypropylene with DiOctyl Phthalate (DOP) impregnant were tested.

  5. Seebeck effect in electrolytes.

    Science.gov (United States)

    Chikina, I; Shikin, V; Varlamov, A A

    2012-07-01

    We study Seebeck effect in liquid electrolytes, starting from its simple neutral analog--thermodiffusion (so-called Ludwig-Soret or Soret effect). It is observed that when two or more subsystems of mobile particles are subjected to the temperature gradient, various types of them respond to it differently. In the case when these fractions, with different mobility parameters (Soret coefficients), are oppositely charged (a case typical for electrolytes), the nonhomogeneous internal electric field is generated. The latter field prevents these fractions from space separation and determines the intensity of the appearing Seebeck effect.

  6. Multichannel discharge between jet electrolyte cathode and jet electrolyte anode

    NARCIS (Netherlands)

    Shakirova, E. F.; Gaitsin, Al. F.; Son, E. E.

    2011-01-01

    We present the results of an experimental study of multichannel discharge between a jet electrolyte cathode and jet electrolyte anode within a wide range of parameters. We pioneer the reveal of the burning particularities and characteristics of multichannel discharge with jet electrolyte and droplet

  7. Capacitor performance limitations in high power converter applications

    DEFF Research Database (Denmark)

    El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

    2013-01-01

    High voltage low inductance capacitors are used in converters as HVDC-links, snubber circuits and sub model (MMC) capacitances. They facilitate the possibility of large peak currents under high frequent or transient voltage applications. On the other hand, using capacitors with larger equivalent...... series inductances include the risk of transient overvoltages, with a negative effect on life time and reliability of the capacitors. These allowable limits of such current and voltage peaks are decided by the ability of the converter components, including the capacitors, to withstand them over...

  8. Improved Design Techniques for Switched-Capacitor Ladder Filters.

    Science.gov (United States)

    Hsu, Teng-Hsien

    Using the new developments of MOS technology, switched-capacitor filters which consist of operational amplifiers, capacitors and switches in monolithic form, were widely investigated and put into practical forms. The switched-capacitor ladder filters have derived from doubly-terminated reactance two-ports. The main part of this dissertation is aimed at improving the efficiency and eliminating some shortcomings of the bilinear design technique. Two novel input stages which incorporate the necessary sample-and-hold function into the bilinear ladder filters are presented. The circuits are insensitive to parasitic capacitances. Some techniques to reduce the number of operational amplifier for bilinear switched-capacitor ladder filters are given. The number of top-plate parasitic-sensitive capacitors is less than in any of the existing design techniques. The clock feedthrough effects of pseudo-N-path switched-capacitor filter using lowpass filters as path filters are eliminated by the improved technique with doubling the number of operational amplifiers. Two-phase pseudo -N-path switched-capacitor filters can be obtained by tripling the number of operational amplifiers. The design technique for extending bilinear lowpass switched-capacitor ladder filters from odd orders to even orders is presented. One of the factors limiting the speed of bilinear switched-capacitor ladder filters is the delay-free loops. The techniques for breaking delay-free loops of low-order switched -capacitor filters are introduced. Digital ladder filters can be obtained through those switched-capacitor filters without delay-free loops. Numerical examples are given to compare the following digital filters: general cascade realization, wave digital filter, the digital filters derived from switched-capacitor filters - cascade and ladder. An improved high speed switched-capacitor linear interpolator, and nonlinear interpolators are described. The circuits are completely parasitic-insensitive. Two

  9. Reliability of capacitors for DC-link applications - An overview

    DEFF Research Database (Denmark)

    Wang, Huai; Blaabjerg, Frede

    2013-01-01

    DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of DC-link in power electronic converters...... from two aspects: 1) reliability-oriented DC-link design solutions; 2) conditioning monitoring of DC-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics-of-failure...

  10. Supercapacitors based on two dimensional VO2 nanosheet electrodes in organic gel electrolyte

    KAUST Repository

    Rakhi, R.B.

    2016-10-16

    VO2 is a low band-gap semiconductor with relatively high conductivity among transition metal oxides, which makes it an interesting material for supercapacitor electrode applications. The performance of VO2 as supercapacitor electrode in organic electrolytes has never been reported before. Herein, two-dimensional nanosheets of VO2 are prepared by the simultaneous solution reduction and exfoliation from bulk V2O5 powder by hydrothermal method. A specific capacitance of 405 Fg−1 is achieved for VO2 based supercapacitor in an organic electrolyte, in three electrode configuration. The symmetric capacitor based on VO2 nanosheet electrodes and the liquid organic electrolyte exhibits an energy density of 46 Wh kg−1 at a power density of 1.4 kW kg−1 at a constant current density of 1 Ag−1. Furthermore, flexible solid-state supercapacitors are fabricated using same electrode material and Alumina-silica based gel electrolyte. The solid-state device delivers a specific capacitance of 145 Fg−1 and a device capacitance of 36 Fg−1 at a discharge current density of 1 Ag−1. Series combination of three solid state capacitors is capable of lighting up a red LED for more than 1 minute.

  11. Aluminium in brain tissue in familial Alzheimer's disease.

    Science.gov (United States)

    Mirza, Ambreen; King, Andrew; Troakes, Claire; Exley, Christopher

    2017-03-01

    The genetic predispositions which describe a diagnosis of familial Alzheimer's disease can be considered as cornerstones of the amyloid cascade hypothesis. Essentially they place the expression and metabolism of the amyloid precursor protein as the main tenet of disease aetiology. However, we do not know the cause of Alzheimer's disease and environmental factors may yet be shown to contribute towards its onset and progression. One such environmental factor is human exposure to aluminium and aluminium has been shown to be present in brain tissue in sporadic Alzheimer's disease. We have made the first ever measurements of aluminium in brain tissue from 12 donors diagnosed with familial Alzheimer's disease. The concentrations of aluminium were extremely high, for example, there were values in excess of 10μg/g tissue dry wt. in 5 of the 12 individuals. Overall, the concentrations were higher than all previous measurements of brain aluminium except cases of known aluminium-induced encephalopathy. We have supported our quantitative analyses using a novel method of aluminium-selective fluorescence microscopy to visualise aluminium in all lobes of every brain investigated. The unique quantitative data and the stunning images of aluminium in familial Alzheimer's disease brain tissue raise the spectre of aluminium's role in this devastating disease.

  12. Microemulsion extraction separation and determination of aluminium species by spectrofluorimetry.

    Science.gov (United States)

    Lu, Jusheng; Tian, Jiuying; Guo, Na; Wang, Yan; Pan, Yichun

    2011-01-30

    A simple and sensitive microemulsion extraction separation method was developed for the speciation of aluminium in tea samples by spectrofluorimetry. With 8-hydroxyquinoline (8-HQ) as the chelating agent and Triton X-100 Winsor II microemulsion as the extractant, separation of aluminium species in different pH solutions was achieved by microemulsion extraction. The formation of microemulsion, the conditions of extraction and determination of aluminium species were studied. The results showed that, the contents of aluminium species in tea leaves and infusions samples, such as total aluminium, total soluble aluminium, total granular aluminium, inorganic aluminium except Al-F, and (Al-F+Al-org), were obtained successfully under the optimal conditions. The limit of detection was 0.23 μg L(-1) in pH 9.5 solution, and 0.59 μg L(-1) in pH 6.0 solution respectively; the precision (RSD) for 11 replicate measurements of 10 μg L(-1) aluminium was 2.1% in pH 9.5 solution, and 2.8% in pH 6.0 solution respectively; the recoveries for the spiked samples were 96.8-103.5%. The proposed method is simple and efficient, which has been applied to the speciation of aluminium in tea samples with satisfactory results.

  13. Foaming-electrolyte fuel cell

    Science.gov (United States)

    Nanis, L.; Saunders, A. P.

    1970-01-01

    Foam structure feeds fuel gas solution into electrolyte. Fuel gas reacts at static, three-phase interface between fuel gas, electrolyte, and electrode material. The foam forms an electrical contact between main body of electrolyte and the electrode, and aids in removal of by-products of the chemical reaction.

  14. Secondary Activation of Commercial Activated Carbon and its Application in Electric Double Layer Capacitor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The cheap commercial activated carbon (AC) was improved through the secondary activation under steam in the presence of FeCl2 catalyst in the temperature range of 800-950℃ and its application in electric double layer capacitors (EDLCs) with organic electrolyte was studied. The re-activation of AC results in the increases in both specific capacitance and high rate capability of EDLCs. For AC treated under optimized conditions, its discharge specific capacitance increases up to 55.65 F/g, an increase of about 33% as compared to the original AC, and the high rate capability was increased significantly. The good performances of EDLC with improved AC were correlated to the increasing mesoporous ratio.

  15. Characterization of Microporous Activated Carbon Electrodes for Electric Double-layer Capacitors

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-han; LIU Ling; SONG Huai-he

    2004-01-01

    Activated carbons (ACs) with a wide range of surface areas were made from petroleum coke by means of KOH activation. The electrochemical characterization was carried out for several activated carbons used as polariz able electrodes of electric double-layer capacitors (EDLCs) in an aqueous electrolytic solution. The porous structures and electrochemical double-layer capacitance of the activated carbons were investigated by virtue of nitrogen gas adsorption and constant current cycling(CCC) methods. The relationship among the surface area, pore volume of the activated carbons and specific double-layer capacitance was discussed. It was found that the specific capacitance of ACs increased linearly with the increase of surface area. The presence of mesopores in the activated carbons with very high surface area(>2000 m2/g) was not very effective for them to be used as EDLCs. The influence of chemical characteristics of the activated carbons on the double layer formation could be considered to be negligible.

  16. A micro-structured Si-based electrodes for high capacity electrical double layer capacitors

    Science.gov (United States)

    Krikscikas, Valdas; Oguchi, Hiroyuki; Yanazawa, Hiroshi; Hara, Motoaki; Kuwano, Hiroki

    2014-11-01

    We challenged to make basis for Si electrodes of electric double layer capacitors (EDLC) used as a power source of micro-sensor nodes. Mcroelectromechanical systems (MEMS) processes were successfully introduced to fabricate micro-structured Si-based electrodes to obtain high surface area which leads to high capacity of EDLCs. Study of fundamental properties revealed that the microstructured electrodes benefit from good wettability to electrolytes, but suffer from electric resistance. We found that this problem can be solved by metal-coating of the electrode surface. Finally we build an EDLC consisting of Au-coated micro-structured Si electrodes. This EDLC showed capacity of 14.3 mF/cm2, which is about 530 times larger than that of an EDLC consisting of flat Au electrodes.

  17. Interactions of alkali metals and electrolyte with cathode carbons

    Energy Technology Data Exchange (ETDEWEB)

    Naas, Tyke

    1997-12-31

    The Hall-Heroult process for electrolytic reduction of alumina has been the only commercial process for production of primary aluminium. The process runs at high temperature and it is important to minimize the energy consumption. To save energy it is desirable to reduce the operating temperature. This can be achieved by adding suitable additives such as LiF or KF to the cryolitic electrolyte. This may conflict with the objective of extending the lifetime of the cathode linings of the cell as much as possible. The thesis investigates this possibility and the nature of the interactions involved. It supports the hypothesis that LiF-additions to the Hall-Heroult cell electrolyte is beneficial to the carbon cathode performance because the diminished sodium activity reduces the sodium induced stresses during the initial period of electrolysis. The use of KF as an additive is more dangerous, but the results indicate that additions up to 5% KF may be tolerated in acidic melts with semigraphitic or graphitic cathodes with little risk of cathode problems. 153 refs., 94 figs., 30 tabs.

  18. Important parameters affecting the cell voltage of aqueous electrical double-layer capacitors

    Science.gov (United States)

    Wu, Tzu-Ho; Hsu, Chun-Tsung; Hu, Chi-Chang; Hardwick, Laurence J.

    2013-11-01

    This study discusses and demonstrates how the open-circuit potential and charges stored in the working potential window on positive and negative electrodes affect the cell voltage of carbon-based electrical double-layer capacitors (EDLCs) in aqueous electrolytes. An EDLC consisting of two activated carbon electrodes is employed as the model system for identifying these key parameters although the potential window of water decomposition can be simply determined by voltammetric methods. First, the capacitive performances of an EDLC with the same charge on positive and negative electrodes are evaluated by cyclic voltammetric, charge-discharge, electrochemical impedance spectroscopic (EIS) analyses, and inductance-capacitance-resistance meter (LCR meter). The principles for obtaining the highest acceptable cell voltage of such symmetric ECs with excellent reversibility and capacitor-like behaviour are proposed. Aqueous charge-balanced EDLCs can be operated as high as 2.0 V with high energy efficiency (about 90%) and only 4% capacitance loss after the 600-cycle stability checking. The necessity of charge balance (but not capacitance balance) for positive and negative electrodes is substantiated from the lower acceptable cell voltage of charge-unbalanced EDLCs.

  19. Feet sunk in molten aluminium: The burn and its prevention.

    Science.gov (United States)

    Alonso-Peña, David; Arnáiz-García, María Elena; Valero-Gasalla, Javier Luis; Arnáiz-García, Ana María; Campillo-Campaña, Ramón; Alonso-Peña, Javier; González-Santos, Jose María; Fernández-Díaz, Alaska Leonor; Arnáiz, Javier

    2015-08-01

    Nowadays, despite improvements in safety rules and inspections in the metal industry, foundry workers are not free from burn accidents. Injuries caused by molten metals include burns secondary to molten iron, aluminium, zinc, copper, brass, bronze, manganese, lead and steel. Molten aluminium is one of the most common causative agents of burns (60%); however, only a few publications exist concerning injuries from molten aluminium. The main mechanisms of lesion from molten aluminium include direct contact of the molten metal with the skin or through safety apparel, or when the metal splash burns through the pants and rolls downward along the leg. Herein, we report three cases of deep dermal burns after 'soaking' the foot in liquid aluminium and its evolutive features. This paper aims to show our experience in the management of burns due to molten aluminium. We describe the current management principles and the key features of injury prevention.

  20. What is the risk of aluminium as a neurotoxin?

    Science.gov (United States)

    Exley, Christopher

    2014-06-01

    Aluminium is neurotoxic. Its free ion, Al(3+) (aq), is highly biologically reactive and uniquely equipped to do damage to essential cellular (neuronal) biochemistry. This unequivocal fact must be the starting point in examining the risk posed by aluminium as a neurotoxin in humans. Aluminium is present in the human brain and it accumulates with age. The most recent research demonstrates that a significant proportion of individuals older than 70 years of age have a potentially pathological accumulation of aluminium somewhere in their brain. What are the symptoms of chronic aluminium intoxication in humans? What if neurodegenerative diseases such as Alzheimer's disease are the manifestation of the risk of aluminium as a neurotoxin? How might such an (outrageous) hypothesis be tested?

  1. Photoluminescence from Nd Doped Anodic Aluminium Oxide

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhang-Kai; PENG Xiao-Niu; SU Xiong-Rui; HAO Zhong-Hua

    2009-01-01

    We prepare Nd doped anodic aluminium oxide (Nd:AAO) template by using Nd doped aluminium foils through two-step anodization processes. Photoluminescence (PL) from the Nd:AAO template with the annealing temper-ature higher than 400℃ is observed, and the PL intensity enhanced with the increasing annealing temperature is found. We investigate the crystallization of Nd:AAO template and the excitation wavelength dependence of PL intensity, showing that the PL results from the Nd doped in the template. The approach presented may probably facilitate the fabricating of AAO with good light-emitting property, which can be used in fabrication of multifunctional nanosized films and may find applications in photonic devices.

  2. Nanoporous Aluminium Oxide Membranes as Cell Interfaces

    Directory of Open Access Journals (Sweden)

    Dorothea Brüggemann

    2013-01-01

    Full Text Available Nanoporous anodic aluminium oxide (AAO has become increasingly important in biomedical applications over the past years due to its biocompatibility, increased surface area, and the possibility to tailor this nanomaterial with a wide range of surface modifications. AAO nanopores are formed in an inexpensive anodisation process of pure aluminium, which results in the self-assembly of highly ordered, vertical nanochannels with well-controllable pore diameters, depths, and interpore distances. Because of these outstanding properties AAO nanopores have become excellent candidates as nanostructured substrates for cell-interface studies. In this comprehensive review previous surveys on cell adhesion and proliferation on different AAO nanopore geometries and surface modifications are highlighted and summarised tabularly. Future applications of nanoporous alumina membranes in biotechnology and medicine are also outlined, for instance, the use of nanoporous AAO as implant modifications, coculture substrates, or immunoisolation devices.

  3. The Friction of Saline Ice on Aluminium

    Directory of Open Access Journals (Sweden)

    Christopher Wallen-Russell

    2016-01-01

    Full Text Available The friction of ice on other materials controls loading on offshore structures and vessels in the Arctic. However, ice friction is complicated, because ice in nature exists near to its melting point. Frictional heating can cause local softening and perhaps melting and lubrication, thus affecting the friction and creating a feedback loop. Ice friction is therefore likely to depend on sliding speed and sliding history, as well as bulk temperature. The roughness of the sliding materials may also affect the friction. Here we present results of a series of laboratory experiments, sliding saline ice on aluminium, and controlling for roughness and temperature. We find that the friction of saline ice on aluminium μice-al=0.1 typically, but that this value varies with sliding conditions. We propose physical models which explain the variations in sliding friction.

  4. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  5. Multiply-negatively charged aluminium clusters and fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Noelle

    2008-07-15

    Multiply negatively charged aluminium clusters and fullerenes were generated in a Penning trap using the 'electron-bath' technique. Aluminium monoanions were generated using a laser vaporisation source. After this, two-, three- and four-times negatively charged aluminium clusters were generated for the first time. This research marks the first observation of tetra-anionic metal clusters in the gas phase. Additionally, doubly-negatively charged fullerenes were generated. The smallest fullerene dianion observed contained 70 atoms. (orig.)

  6. Improvement of photodynamic activity of aluminium sulphophthalocyanine due to biotinylation

    Science.gov (United States)

    Meerovich, Irina G.; Jerdeva, Victoria V.; Derkacheva, Valentina M.; Meerovich, Gennadii A.; Lukyanets, Eugeny A.; Kogan, Eugenia A.; Savitsky, Alexander P.

    2003-09-01

    The photodynamic activity of dibiotinylated aluminium sulphophthalocyanine in vitro and in vivo were studied. It was obtained that in vitro dibiotinylated aluminium sulphophthalocyanine provides the effective damage of small cell lung carcinoma OAT-75. In vivo dibiotinylated aluminium sulphophthalocyanine causes destruction of tumor (Erlich carcinoma), results in total necrosis of tumor tissue and expresses vascular damage (trombosis and destruction of vascular walls) even in concentration 0.25 mg/kg of a body weight.

  7. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  8. Un-optimistic Prospects for the Westward Movement of Aluminium

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>The westward movement of aluminium is essential for the industrial development.Up till now,the northwestern area has planned to construct more than 40 aluminium projects with a total production capacity of over 20 million tons.The future rate of progress of newly constructed projects are directly related to the supplies of the aluminium market,having critical guiding meaning for the trends of

  9. Wearing tests on aluminium coated with diamond by triboadhesion

    Institute of Scientific and Technical Information of China (English)

    J.M.RodríguezLelis; B.D.Angulo; J.O.Colín; J.PorcayoCalderón

    2001-01-01

    In this work the results obtained from subjecting aluminium coated with diamond by tri-boadhesion to a wearing process with a plane rider. Here it is shown the ratio of the normal toshearing forces, called friction factor, as an indication of the resistance of the surface. It was foundthat the film of the aluminium coated with diamond resisted three times compared with the oxida-tion film of commercial aluminium, which for the purpose of this work was considered withoutcoating.

  10. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    N Vidhya Sagar; K S Anand; A C Mithun; K Srinivasan

    2006-12-01

    Friction factor has been determined for CP aluminium and aluminium–zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits sticking whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier than that of CP aluminium at 773 K. As zinc content increases up to 10 wt% the friction factor decreases up to 0.02.

  11. Telangiectasia in aluminium workers: a follow up.

    OpenAIRE

    Thériault, G.; Gingras, S.; Provencher, S

    1984-01-01

    A five step investigation was carried out to gain a better understanding of the morbidity that accompanied the development of telangiectasia on aluminium workers and to find its cause. Fifty workers with multiple telangiectasia when matched with normal controls showed the same amount of illness except that evidence of ischaemia on the ECG was found in nine cases and one control. The cases did not show an excess of abnormal biochemical tests. The basic histopathological lesion affected the sur...

  12. Welding distortion of aluminium structural members

    Energy Technology Data Exchange (ETDEWEB)

    Goglio, L. [Politecnico di Torino (Italy). Dept. of Mech.; Gugliotta, A. [Politecnico di Torino (Italy). Dept. of Mech.; Pasquino, D. [Politecnico di Torino (Italy). Dept. of Mech.

    1996-12-31

    The paper deals with the angular distortion induced in aluminium tubular beams during welding to prepare T junctions. The research, based on experimental measurements, makes use of statistical methods to identify the parameters (beam section, weld length, welding direction, etc.) that influence the angular change. The results are discussed also considering a model known from the literature. It is found that the distortion is generally low and can be minimized by a proper welding process. (orig.)

  13. China will Reduce Aluminium Export in 2005

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>Starting from January 1, 2005, China eliminated the 8 per cent export tax rebate for aluminium, and further more, the exporters will have to pay 5 per cent export tax. This is beyond the expectations of the producers, for most of them thought only the 8 per cent export tax rebate would be eliminated and it was still too early to add the export tax.

  14. Low Voltage Electrolytic Capacitor Pulse Forming Inductive Network for Electric Weapons

    Science.gov (United States)

    2006-06-01

    reliable high- current, high-energy pulses of many megawatts. Pulsed alternators potentially have the same maintenance issues as other motor...high-energy pulses of many megawatts. Pulsed alternators potentially have the same maintenance issues as other motor-generator sets, so a solid...on an all-electric ship, those challenges are being met. The naval railgun, the army railgun, coilguns , and other electric weapon systems such as

  15. Bayesian Framework Approach for Prognostic Studies in Electrolytic Capacitor under Thermal Overstress Conditions

    Science.gov (United States)

    2012-09-01

    supplies are widely used in DC-DC converters because of their high efficiency and compact size. Buck - boost DC-DC converter steps voltage levels up/down...remaining useful life in DC-DC converters . 1. INTRODUCTION Avionics systems play a critical role in many aspects of air- craft flight control. As the system...efficiency of the DC- DC converters in a significant manner and also impose a risk on instantiating cascading failures on other connected subsys- tems

  16. Semi-conducting carbon nanotube as variable capacitor

    Science.gov (United States)

    Ozmaian, M.; Naghdabadi, R.

    2013-12-01

    This paper proposes a novel, one-part, variable capacitor, using semi-conducting carbon nanotube (CNT). This variable capacitor works based on the change in the electronic structure of CNTs under applied voltage and deformations. Positive and negative charges are stored at both ends of a non-zero band gap nanotube which works as metallic electrodes in parallel plate capacitors. Also the neutral strip in the middle acts as the dielectric part of a conventional capacitor under the influence of an external electric field. Mechanical strains on carbon nanotube change its band gap energy and thus the length of neutral strip and charged regions. The lengths of these parts are primarily dependent on the nanotube chirality, deformation mode and applied voltage. This way, different parts of a conventional cantilever, parallel plate or bridge capacitor are reduced to a one part semi-conducting CNT capacitor. Analytical calculations based on classical electrostatics and density of states (DOS) relations are employed to investigate the effect of CNTs geometry, applied voltage and deformations on capacitive features. The proposed CNT-variable-capacitor can be useful for nano-electromechanical systems (NEMS), including displacement measurement sensors and tunable capacitor in integrated circuits.

  17. Trench capacitor and method for producing the same

    NARCIS (Netherlands)

    Liu, J.; Roest, A.L.; Roozeboom, F.; Shabro, V.

    2013-01-01

    A method of fabricating a trench capacitor, and a trench capacitor fabricated thereby, are disclosed. The method involves the use of a vacuum impregnation process for a sol-gel film, to facilitate effective deposition of high-permittivity materials within a trench in a semiconductor substrate, to pr

  18. A Switched Capacitor Harmonic Compensation Part for Switching Supplies

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    A new approach based on switched capacitor network to harmonic compensation for switching supplies is presented in the paper,The basic principle is discussed.SPICE simulation is applied to analyze the behaviour of the switched capacitor harmonic compensation part.

  19. Direct Mismatch Characterization of femto-Farad Capacitors

    KAUST Repository

    Omran, Hesham

    2015-08-17

    Reducing the capacitance of programmable capacitor arrays, commonly used in analog integrated circuits, is necessary for low-energy applications. However, limited mismatch data is available for small capacitors. We report mismatch measurement for a 2fF poly-insulator-poly (PIP) capacitor, which is the smallest reported PIP capacitor to the best of the authors’ knowledge. Instead of using complicated custom onchip circuitry, direct mismatch measurement is demonstrated and verified using Monte Carlo Simulations and experimental measurements. Capacitive test structures composed of 9 bit programmable capacitor arrays (PCAs) are implemented in a low-cost 0:35m CMOS process. Measured data is compared to mismatch of large PIP capacitors, theoretical models, and recently published data. Measurement results indicate an estimated average relative standard deviation of 0.43% for the 2fF unit capacitor, which is better than the reported mismatch of metal-oxide-metal (MOM) fringing capacitors implemented in an advanced 32nm CMOS process.

  20. Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis

    CERN Document Server

    Gallay, R

    2015-01-01

    One of the main concerns for power electronic engineers regarding capacitors is to predict their remaining lifetime in order to anticipate costly failures or system unavailability. This may be achieved using a Weibull statistical law combined with acceleration factors for the temperature, the voltage, and the humidity. This paper discusses the different capacitor failure modes and their effects and consequences.

  1. Charging damage in floating metal-insulator-metal capacitors

    NARCIS (Netherlands)

    Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

    2002-01-01

    In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMC) is reported. The damage is caused by the build up of a voltage potential difference between the two plates of the capacitor. A simple logarithmic relation is discovered between the damage by this voltage potentia

  2. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  3. Advanced Polymer Electrolytes for High-energy-density Power Sources

    Institute of Scientific and Technical Information of China (English)

    D. Golodnitsky; E. Livshits; R. Kovarsky; E. Peled

    2005-01-01

    @@ 1Introduction The preparation of highly controlled thin films of lithium ion conducting organic materials is becoming a challenging but rewarding goal in view of obtaining high-performance technological devices like solid-state polymer batteries and capacitors. The classical polymer electrolyte consists of organic macromolecules (usually polyether polymer) that are doped with inorganic (typically lithium) salts. Poly(ethylene oxide) (PEO) is the most commonly employed polymer in PEs because of the peculiar array in the (-CH2-CH2-O-)n chain providing the ability to solvate low-lattice-energy lithium salts. For three decades the major research attention was focused on amorphous polymer electrolytes in the belief that ionic conductivity occurs in a manner somewhat analogous to gas diffusion through polymer membranes. Segmental motion of the polymer chains continuously creates free volume, into which the ions migrate, and this process allows ions to progress across the electrolyte. Such a view was established by a number of experiments, and denied the possibility of ionic conductivity in crystalline polymer phases. This concept has been recently overturned by our group, demonstrating that conductivity comes about as a result of permanent conducting pathways for the movement of ions.

  4. Effect of activated carbon and electrolyte on properties of supercapacitor

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Effect of activated carbon and electrolyte on electrochemical properties of organic supercapacitor was investigated. The results show that specific surface area and mesoporosity of activated carbon influence specific capacitance. If specific surface area is larger and mesoporosity is higher, the specific capacitance will become bigger. Specific surface area influences resistance of carbon electrode and consequently influences power property and pore size distribution. If specific surface area is smaller and mesoporosity is higher, the power property will become better. Ash influences leakage current and electrochemical cycling stability. If ash content is lower, the performance will become better. The properties of supercapacitor highly depend on the electrolyte. The compatibility of electrolyte and activated carbon is a determining factor of supercapacitor's working voltage. LiPF6/(EC+EMC+DMC) is inappropriate for double layer capacitor. MeEt3NPF4/PC has higher specific capacitance than EtnNPFn/PC because methyl's electronegativity value is lower than ethyl and MeEt3N+ has more positive charges and stronger polarizability than Et4N+ when an ethyl is substituted by methyl.

  5. Al current collector surface treatment and carbon nano tubes influences on Carbon / Carbon super-capacitors performances

    Energy Technology Data Exchange (ETDEWEB)

    Portet, C.; Taberna, P.L.; Simon, P. [Universite Paul Sabatier, CIRIMAT-LCMIE, 31 - Toulouse (France)

    2004-07-01

    Performances of 4 cm{sup 2} carbon/carbon super-capacitors cells using Al current collectors foils in organic electrolyte are presented; the improvement of electrode material has been investigated. In a first part, a surface treatment of the Al current collector is proposed in order to improve contact surface between the current collector and the active material leading to an internal resistance decrease. The process consists in an etching of the Al foil and is followed by a carbonaceous sol-gel deposit. Galvano-static cycling and Electrochemical Impedance Spectroscopy measurements of super-capacitors all assembled with treated Al foil were tested over 10,000 cycles: an ESR of 0.5 {omega} cm{sup 2} and a capacitance of 95 F g{sup -1} of activated carbon are obtained and performances remain stable during cycling. The second part is devoted to the study of Carbon Nano Tubes (CNTs) adding into the active material on the performances of super-capacitors. A content of 15% of CNTs appears to be the best composition; the ESR is 0.4 {omega} cm{sup 2} (20% lowered as compared to a cell using activated carbon based electrode) and the capacitance remain high 93 F g{sup -1} of carbonaceous active material. (authors)

  6. Thermal formation of corundum from aluminium hydroxides prepared from various aluminium salts

    Indian Academy of Sciences (India)

    J Temuujin; Ts JADAMBAA; K J D Mackenzie; P Angerer; F Porte; F Riley

    2000-08-01

    Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form -Al2O3 at ∼ 400°C but the formation of -Al2O3 at 1200°C occurs more readily in the material derived from the sulfate. This contains a higher concentration of anionic impurities related to differences in the solubility of the original aluminium salts. The sulfate is retained in the gel to higher temperatures at which its eventual decomposition may lead to the formation of a reactive pore structure which facilitates the nucleation of -Al2O3.

  7. Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium.

    Science.gov (United States)

    Lee, Woo; Schwirn, Kathrin; Steinhart, Martin; Pippel, Eckhard; Scholz, Roland; Gösele, Ulrich

    2008-04-01

    Nanoporous anodic aluminium oxide has traditionally been made in one of two ways: mild anodization or hard anodization. The first method produces self-ordered pore structures, but it is slow and only works for a narrow range of processing conditions; the second method, which is widely used in the aluminium industry, is faster, but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the mild and hard anodization processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic aluminium oxide films while maintaining high throughput. We use pulse anodization to delaminate a single as-prepared anodic film into a stack of well-defined nanoporous alumina membrane sheets, and also to fabricate novel three-dimensional nanostructures.

  8. Synthesis of aluminium nanoparticles by arc evaporation of an aluminium cathode surface

    Indian Academy of Sciences (India)

    M Gazanfari; M Karimzadeh; S Ghorbani; M R Sadeghi; G Azizi; H Karimi; N Fattahi; Z Karimzadeh

    2014-06-01

    Aluminium nanoparticles (Al Nps) are synthesized using arc discharge method by applying direct current between aluminium electrodes in liquid environment without any use of vacuum equipment, heat exchangers, high temperatures furnaces and inert gases. After synthesis of Al Nps, in situ coating process on the nanoparticles was performed immediately. The effects of media on the yield and morphology of aluminium nanoparticles were investigated. Analysis result of the samples indicated that particle size was less than 30 nm, when 120 A/cm2 arc current was used. In addition, coating agent can affect arc velocity, arc stability, morphology and composition of the nanoparticles. Resultant nanoparticles were identified using X-ray powder diffraction (XRD), also their surface morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and finally the accuracy of coating was assessed with infrared (IR) spectroscopy.

  9. Friction stir welding (FSW of aluminium foam sandwich panels

    Directory of Open Access Journals (Sweden)

    M. Bušić

    2016-07-01

    Full Text Available The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and flexural strength for three-point bending test have been determined for samples taken from the welded joints. Results have confirmed anticipated effects of independent variables.

  10. A Reaction Coating on Aluminium Alloys by Laser Processing

    OpenAIRE

    1993-01-01

    An aluminium oxide layer of 100 µm in thickness has been successfully coated on aluminium alloy 6061 and pure aluminium using a powder mixture of silicon oxide and aluminium by laser processing. A strong Al/Al2O3 interface was formed. The exothermic chemical reaction between SiO2 and Al may promote the metal/oxide wetting and the formation of Al2O3 layer. This new approach of ceramic coating on metals using a chemical reaction of other ceramics with metals may be applied to other systems.

  11. Techniques for Reduction of the Parasitic Inductance of Decoupling Capacitors

    Science.gov (United States)

    Bernal, J.; Freire, M. J.

    2016-05-01

    The ability for providing effective decoupling of decoupling capacitors is mainly limited by its parasitic inductance. In this work we propose some new techniques for placing surface mount decoupling capacitors on a printed circuit board that make use of mutual inductance effects between currents on adjacent capacitors to provide significant reduction of the impedance seen at high frequencies at the input of the set of decoupling capacitors. This allows to keep the impedance of the power distribution network below the target impedance with a reduced number of decoupling capacitors, thus reducing cost and, more importantly in aerospace applications, saving space on the board. This technique does not require complex previous calculations or experimental adjustments to be implemented and consequently it has no negative impact in the time of design of practical circuits.

  12. Nanoporous hybrid electrolytes

    KAUST Repository

    Schaefer, Jennifer L.

    2011-01-01

    Oligomer-suspended SiO2-polyethylene glycol nanoparticles are studied as porous media electrolytes. At SiO2 volume fractions, , bracketing a critical value y ≈ 0.29, the suspensions jam and their mechanical modulus increase by more than seven orders. For >y, the mean pore diameter is close to the anion size, yet the ionic conductivity remains surprisingly high and can be understood, at all , using a simple effective medium model proposed by Maxwell. SiO 2-polyethylene glycol hybrid electrolytes are also reported to manifest attractive electrochemical stability windows (0.3-6.3 V) and to reach a steady-state interfacial impedance when in contact with metallic lithium. © 2010 The Royal Society of Chemistry.

  13. Electrolytes for advanced batteries

    Energy Technology Data Exchange (ETDEWEB)

    Blomgren, G.E. [Energizer, Westlake, OH (United States)

    1999-09-01

    The choices of the components of the electrolyte phase for advanced batteries (lithium and lithium ion batteries) are very sensitive to the electrodes which are used. There are also a number of other requirements for the electrolyte phase, which depend on the cell design and the materials chosen for the battery. The difficulty of choice is compounded when the cell is a rechargeable one. This paper looks at each of these requirements and the degree to which they are met for lithium and lithium ion batteries. The discussion is broken into sections on anode or negative electrode stability requirements, cathode or positive electrode stability requirements, conductivity needs, viscosity and wetting requirements. The effects of these properties and interactions on the performance of batteries are also discussed. (orig.)

  14. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  15. Electrolyte Concentrates Treat Dehydration

    Science.gov (United States)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  16. Ionogel Electrolytes through Sol-Gel Processing

    Science.gov (United States)

    Horowitz, Ariel I.

    Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica

  17. Anodic oxides on InAlP formed in sodium tungstate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Suleiman, A. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: p.skeldon@manchester.ac.uk; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Echeverria, F. [Corrosion and Protection Group, University of Antioquia, Medellin (Colombia); Graham, M.J.; Sproule, G.I.; Moisa, S.; Quance, T. [Institute for Microstructural Sciences, National Research Council of Canada, Montreal Road, Ottawa K1A 0R6 (Canada); Habazaki, H. [Graduate Engineering School, Hokkaido University, N13 W8, Kita-ku, Sapporo 060-8628 (Japan)

    2010-02-15

    Amorphous anodic oxide films on InAlP have been grown at high efficiency in sodium tungstate electrolyte. The films are shown to comprise an outer layer containing indium species, an intermediate layer containing indium and aluminium species and an inner layer containing indium, aluminium and phosphorus species{sub .} The layering correlates with the influence on cation migration rates of the energies of In{sup 3+}-O, Al{sup 3+}-O and P{sup 5+}-O bonds, which increase in this order. The film surface becomes increasingly rough with increase of the anodizing voltage as pores develop in the film, which appear to be associated with generation of oxygen gas.

  18. Plasma Electrolytic Oxidation (PEO) Coatings on an A356 Alloy for Improved Corrosion and Wear Resistance

    Science.gov (United States)

    Peng, Zhijing

    Plasma electrolytic oxidizing (PEO) is an advanced technique that has been used to deposit thick and hard ceramic coatings on aluminium (Al) alloys. This work was however to use the PEO process to produce thin ceramic oxide coatings on an A356 Al alloy for improving corrosion and wear resistance of the alloy. Effects of current density and treatment time on surface morphologies and thickness of the PEO coatings were investigated. The improvement of galvanic corrosion properties of the coated A356 alloy vs. steel and carbon fibre were evaluated in E85 fuel or NaCl environments. Tribological properties of the coatings were studied with comparison to the uncoated A356 substrate and other commercially-used engine bore materials. The research results indicated that the PEO coatings could have excellent tribological and corrosion properties for aluminium engine applications.

  19. Mechanical and Abrasive Wear Properties of Anodic Oxide Layers Formed on Aluminium

    Institute of Scientific and Technical Information of China (English)

    W.Bensalah; K.Elleuch; M.Feki; M.Wery; H.F.Ayedi

    2009-01-01

    Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The Vickers microhardness, D (HV0.2). and the abrasion weight loss, Wa (mg) were measured. Influence of oxalic acid concentration (Cox), bath temperature (T) and anodic current density (J) on D and Wa has been examined, and the sulphuric acid concentration (Caul) was maintained at 160 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), optical microscopy and glow-discharge optical emission spectroscopy (GDOES). It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

  20. Formation and Characterization of Ceramic Nanocomposite Crystalline Coatings on Aluminium by Anodization

    Institute of Scientific and Technical Information of China (English)

    M.Mubarak Ali; V.Raj

    2013-01-01

    Ceramic nanocomposite coatings have been synthesized on aluminium by using lithium sulphate electrolyte with zirconium silicate additive by anodization.The effects of current density (CD) on microhardness,structure,composition and surface topography of the oxide layer formed at various CDs (0.1-0.25 A/cm2) have been studied.Crystalline coatings formed at 0.25 A/cm2 have been (width 95 nm) observed with a relatively uniform distribution confirmed by scanning electron microscopy.Additionally,the average microhardness value of ceramic nanocomposite coatings fabricated from lithium sulphate-zirconium silicate bath is approximately 8.5 times higher than that of the as-received aluminium.The surface statistics of the coatings is discussed in detail to explain the roughness and related parameters for better understanding.These observations demonstrate the importance of surface statistics in controlling the morphology of the coatings and its properties.From the X-ray diffraction investigations,it can be concluded that the formed nanocomposite coatings are crystalline in nature and that the crystallinity of the coatings decreases with increasing applied current density.

  1. A new synthesis process for aluminium nitride. Nouveau procede de synthese du nitrure d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Haussonne, J.M. (CNET, Centre Lannion B, 22 (France)); Lostec, J. (CNET, Centre Lannion B, 22 (France)); Bertot, J.P. (CNET, Centre Lannion B, 22 (France)); Lostec, L. (CNET, Centre Lannion B, 22 (France)); Sadou, S. (CNET, Centre Lannion B, 22 (France))

    1993-04-01

    Thermodynamic considerations show that, even at room temperature, pure aluminium can react with nitrogen to form the aluminium nitride AlN. However, pure aluminium does not exist: it is always surrounded by an alumina shell that protects the metal from further reactions. Furthermore, in the hypothesis where one has been able to make aluminium react with nitrogen, an aluminium nitride shell will protect as well the metal core from further oxidation. Prompted by the Lanxide process allowing to form Al/Al[sub 2]O[sub 3] composites, we have mixed aluminium powders with lithium salts, and easily synthesized pure aluminium nitride by heating the mixed powders in nitrigen at temperatures ranging from 800 to 1200 C. Starting from aluminium powders with a specific area ranging from 0.3 to 4 m[sup 2]/g, we have been able to produce aluminium nitride with specific are ranging from 1 to 20 m[sup 2]/g. Mixed with Y[sub 2]O[sub 3]-CaO and sintered at 1720 C in N[sub 2], we obtained AlN ceramics owning 92% density and 160 W/m.K thermal conductivity. (orig.).

  2. Electrolyte materials - Issues and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Balbuena, Perla B. [Department of Chemical Engineering, and Department of Materials Science and Engineering, Texas A and M University, College Station, Texas, 77843 (United States)

    2014-06-16

    Electrolytes are vital components of an electrochemical energy storage device. They are usually composed of a solvent or mixture of solvents and a salt or a mixture of salts which provide the appropriate environment for ionic conduction. One of the main issues associated with the selection of a proper electrolyte is that its electronic properties have to be such that allow a wide electrochemical window - defined as the voltage range in which the electrolyte is not oxidized or reduced - suitable to the battery operating voltage. In addition, electrolytes must have high ionic conductivity and negligible electronic conductivity, be chemically stable with respect to the other battery components, have low flammability, and low cost. Weak stability of the electrolyte against oxidation or reduction leads to the formation of a solid-electrolyte interphase (SEI) layer at the surface of the cathode and anode respectively. Depending on the materials of the electrolyte and those of the electrode, the SEI layer may be composed by combinations of organic and inorganic species, and it may exert a passivating role. In this paper we discuss the current status of knowledge about electrolyte materials, including non-aqueous liquids, ionic liquids, solid ceramic and polymer electrolytes. We also review the basic knowledge about the SEI layer formation, and challenges for a rational design of stable electrolytes.

  3. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Hasvold, Oe.; Johansen, K.H.; Mollestad, O.; Forseth, S.; Stoerkersen, N. [Forsvarets Forskningsinstitutt, Kjeller (Norway)

    1999-07-01

    In 1993, the Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on a UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m. (orig.)

  4. There is (still too much aluminium in infant formulas

    Directory of Open Access Journals (Sweden)

    Burrell Shelle-Ann M

    2010-08-01

    Full Text Available Abstract Background Infant formulas are sophisticated milk-based feeds for infants which are used as a substitute for breast milk. Historically they are known to be contaminated by aluminium and in the past this has raised health concerns for exposed infants. We have measured the aluminium content of a number of widely used infant formulas to determine if their contamination by aluminium and consequent issues of child health persists. Methods Samples of ready-made milks and powders used to make milks were prepared by microwave digestion of acid/peroxide mixtures and their aluminium content determined by THGA. Results The concentration of aluminium in ready-made milks varied from ca 176 to 700 μg/L. The latter concentration was for a milk for preterm infants. The aluminium content of powders used to make milks varied from ca 2.4 to 4.3 μg/g. The latter content was for a soya-based formula and equated to a ready-to-drink milk concentration of 629 μg/L. Using the manufacturer's own guidelines of formula consumption the average daily ingestion of aluminium from infant formulas for a child of 6 months varied from ca 200 to 600 μg of aluminium. Generally ingestion was higher from powdered as compared to ready-made formulas. Conclusions The aluminium content of a range of well known brands of infant formulas remains high and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies. Recent research demonstrating the vulnerability of infants to early exposure to aluminium serves to highlight an urgent need to reduce the aluminium content of infant formulas to as low a level as is practically possible.

  5. Speciation analysis of aluminium and aluminium fluoride complexes by HPIC-UVVIS.

    Science.gov (United States)

    Frankowski, Marcin; Zioła-Frankowska, Anetta

    2010-10-15

    The study presents a new analytical method for speciation analysis in fractionation of aluminium fluoride complexes and free Al(3+) in soil samples. Aluminium speciation was studied in model solutions and soil extract samples by means of high performance ion chromatography (HPIC) with UV-VIS detection using post-column reaction with tiron for the separation and detection of aluminium fluoride complex and Al(3+) forms during one analysis. The paper presents particular stages of the chromatographic process optimization involving selecting the appropriate eluent strength, type of elution or concentration and quantity of derivatization reagent. HPIC was performed on a bifunctional analytical column Dionex IonPac CS5A. The use of gradient elution and the eluents A: 1M NH(4)Cl and B: water acidified to pH of eluent phase, enabled full separation of fluoride aluminium forms as AlF(2)(+), AlF(3)(0), AlF(4)(-) (first signal), AlF(2+) (second signal) and form Al(3+) in a single analytical procedure. The proposed new method HPIC-UVVIS was applied successfully in the quantitative and qualitative analysis of soil samples.

  6. Aluminium and iron air pollution near an iron casting and aluminium foundry in Turin district (Italy).

    Science.gov (United States)

    Polizzi, Salvatore; Ferrara, Mauro; Bugiani, Massimiliano; Barbero, Domenico; Baccolo, Tiziana

    2007-09-01

    This work reports the results of an environmental survey carried out in an industrial area in the Province of Turin: its main aim is to assess the levels of iron and aluminium in the outside air during the period from July to September to assess the influence of industrial activity (a cast-iron and aluminium foundry) which is interrupted during the month of August, on the level of metals present in the air. Conducting the analysis during this period of time made it possible to avoid the confounding effect of pollution due to domestic central heating. The measurements were taken from nine areas at different distances from the foundry in the area and according to the direction of the prevailing winds, as deduced from the historical data. The results of this survey show a statistically significant difference in iron and aluminium levels in the outside air in the geographic areas between the two main periods examined: during August (no foundry activity) v/s July-September (foundry activity). The values recorded are: Aluminium 0.4+/-0.45 microg/m(3) v/s 1.12+/-1.29 microg/m(3) (pIron 0.95+/-0.56 microg/m(3) v/s 1.6+/-1.0 microg/m(3) (piron tended to be higher in the areas farther away from the foundry site in the areas located along the path of the prevailing winds.

  7. Chemical sensitivity of Mo gate Mos capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, R.M.; Aragon, R. [Laboratorio de Peliculas delgadas, Facultad de Ingenieria, Paseo Colon 850, 1063, Buenos Aires (Argentina)

    2006-07-01

    Mo gate Mos capacitors exhibit a negative shift of their C-V characteristic by up to 240 mV, at 125 C, in response to 1000 ppm hydrogen, in controlled nitrogen atmospheres. The experimental methods for obtaining capacitance and conductance, as a function of polarisation voltage, as well as the relevant equivalent circuits are reviewed. The single-state interface state density, at the semiconductor-dielectric interface, decreases from 2.66 x 10{sup 11} cm{sup -2} e-v{sup -1}, in pure nitrogen, to 2.5 x 10{sup 11} cm{sup -2} e-v{sup -1} in 1000 ppm hydrogen in nitrogen mixtures, at this temperature. (Author)

  8. Tailored Aluminium based Coatings for Optical Appearance and Corrosion Resistance

    DEFF Research Database (Denmark)

    Aggerbeck, Martin

    of these applications, but the use of recycled aluminium compromises this due to the presence of increased levels of impurity and alloying elements. Knowledge on how different alloying elements affect the optical appearance might therefore increase the applicability of recycled aluminium. It was investigated how...

  9. Enhanced corrosion protection by microstructural control of aluminium brazing sheet

    NARCIS (Netherlands)

    Norouzi Afshar, F.

    2013-01-01

    Aluminium brazing sheet is a sandwich material made out of two aluminium alloys (AA4xxx/AA3xxx) and is widely used in automotive heat exchangers. One of the main performance criteria for heat exchanger units is the lifetime of the product. The lifetime of the heat exchanger units is determined by th

  10. CAD implementation of design rules for aluminium extrusion dies

    NARCIS (Netherlands)

    Ouwerkerk, van Gijs

    2009-01-01

    Aluminium extrusion is an industrial forming process that is used to produce long profiles of a constant cross-section. This cross-section is shaped by the opening in a steel tool known as the die. The understanding of the mechanics of the aluminium extrusion process is still limited. The flow of al

  11. New Policies to Control the Aluminium Industry Expansion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>Information from China Nonferrous Metals Industry Association (CNIA) shows that new government policies on China’s aluminium industry will be released soon in order to control the rapid expansion of the aluminium industry which consumes large amount of power resources. Based on the new policies, investors of

  12. Aluminium salt slag characterization and utilization--a review.

    Science.gov (United States)

    Tsakiridis, P E

    2012-05-30

    Aluminium salt slag (also known as aluminium salt cake), which is produced by the secondary aluminium industry, is formed during aluminium scrap/dross melting and contains 15-30% aluminium oxide, 30-55% sodium chloride, 15-30% potassium chloride, 5-7% metallic aluminium and impurities (carbides, nitrides, sulphides and phosphides). Depending on the raw mix the amount of salt slag produced per tonne of secondary aluminium ranges from 200 to 500 kg. As salt slag has been classified as toxic and hazardous waste, it should be managed in compliance with the current legislation. Its landfill disposal is forbidden in most of the European countries and it should be recycled and processed in a proper way by taking the environmental impact into consideration. This paper presents a review of the aluminium salt slag chemical and mineralogical characteristics, as well as various processes for metal recovery, recycling of sodium and potassium chlorides content back to the smelting process and preparation of value added products from the final non metallic residue.

  13. Aluminium removal from water after defluoridation with the electrocoagulation process.

    Science.gov (United States)

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  14. Chalco Calls for End of More Control Measures on Aluminium

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> To control the investment rush in electrolyticaluminium in recent years and ensure thehealthy development of China’s aluminium in-dustry, the State Council recently released aseries of adjustment policies and control meas-ures,which effectively prevented theinvestment rush and limited the aluminium out-put growth.

  15. Combined Corrosion and Wear of Aluminium Alloy 7075-T6

    NARCIS (Netherlands)

    Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

    2016-01-01

    The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

  16. Development of High Temperature Capacitor Technology and Manufacturing Capability

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-05-15

    The goal of the Development of High Temperature Capacitor Technology and Manufacturing Capability program was to mature a production-ready supply chain for reliable 250°C FPE (fluorinated polyester) film capacitors by 2011. These high-temperature film capacitors enable both the down hole drilling and aerospace industries by enabling a variety of benefits including: - Deeper oil exploration in higher temperature and pressure environments - Enabling power electronic and control equipment to operate in higher temperature environments - Enabling reduced cooling requirements of electronics - Increasing reliability and life of capacitors operating below rated temperature - Enabling capacitors to handle higher electrical losses without overheating. The key challenges to bringing the FPE film capacitors to market have been manufacturing challenges including: - FPE Film is difficult to handle and wind, resulting in poor yields - Voltage breakdown strength decreases when the film is wound into capacitors (~70% decrease) - Encapsulation technologies must be improved to enable higher perature operation - Manufacturing and test cycle time is very long As a direct result of this program most of the manufacturing challenges have been met. The FPE film production metalization and winding yield has increased to over 82% from 70%, and the voltage breakdown strength of the wound capacitors has increased 270% to 189 V/μm. The high temperature packaging concepts are showing significant progress including promising results for lead attachments and hermetic packages at 200°C and non-hermetic packages at 250°C. Manufacturing and test cycle time will decrease as the market for FPE capacitors develops.

  17. Electrochemical double-layer capacitors based on functionalized graphene

    Science.gov (United States)

    Pope, Michael Allan

    Graphene is a promising electrode material for electrochemical double-layer capacitors (EDLCs) used for energy storage due to its high electrical conductivity and theoretical specific surface area. However, the intrinsic capacitance of graphene is known to be low and governed by the electronic side of the interface. Furthermore, graphene tends to aggregate and stack together when processed into thick electrode films. This significantly lowers the ion-accessible specific surface area (SSA). Maximizing both the SSA and the intrinsic capacitance are the main problems addressed in this thesis in an effort to improve the specific capacitance and energy density of EDLCs. In contrast to pristine graphene, functionalized graphene produced by the thermal exfoliation of graphite oxide contains residual functional groups and lattice defects. To study how these properties affect the double-layer capacitance, a model electrode system capable of measuring the intrinsic electrochemical properties of functionalized graphene was developed. To prevent artifacts and uncertainties related to measurements on porous electrodes, the functionalized graphene sheets (FGSs) were assembled as densely tiled monolayers using a Langmuir-Blodgett technique. In this way, charging can be studied in a well-defined 2D geometry. The possibility of measuring and isolating the intrinsic electrochemical properties of FGS monolayers was first demonstrated by comparing capacitance and redox probe measurements carried out on coatings deposited on passivated gold and single crystal graphite substrates. This monolayer system was then used to follow the double-layer capacitance of the FGS/electrolyte interface as the structure and chemistry of graphene was varied by thermal treatments ranging from 300 °C to 2100 °C. Elemental analysis and Raman spectroscopy were used to determine the resulting chemical and structural transformation upon heat treatment. It was demonstrated that intrinsically defective

  18. Advancing Polymer-Supported Ionogel Electrolytes Formed via Radical Polymerization

    Science.gov (United States)

    Visentin, Adam F.

    Applications ranging from consumer electronics to the electric grid have placed demands on current energy storage technologies. There is a drive for devices that store more energy for rapid consumption in the case of electric cars and the power grid, and safer, versatile design options for consumer electronics. Electrochemical double-layer capacitors (EDLCs) are an option that has garnered attention as a means to address these varied energy storage demands. EDLCs utilize charge separation in electrolytes to store energy. This energy storage mechanism allows for greater power density (W kg -1) than batteries and higher energy density (Wh kg-1) than conventional capacitors - along with a robust lifetime in the range of thousands to millions of charge-discharge cycles. Safety and working voltage windows of EDLCs currently on the market are limited by the organic solvents utilized in the electrolyte. A potential solution lies in the replacement of the organic solvents with ionic liquids, or room-temperature molten salts. Ionic liquids possess many superior properties in comparison to conventional solvents: wide electrochemical window, low volatility, nonflammability, and favorable ionic conductivity. It has been an endeavor of this work to exploit these advantages while altering the liquid form factor into a gel. An ionic liquid/solid support scaffold composite electrolyte, or ionogel, adds additional benefits: flexible device design, lower encapsulation weight, and elimination of electrolyte leakage. This work has focused on investigations of a UV-polymerizable monomer, poly(ethylene glycol) diacrylate, as a precursor for forming ionogels in situ. The trade-off between gaining mechanical stability at the cost of ionic conductivity has been investigated for numerous ionogel systems. While gaining a greater understanding of the interactions between the gel scaffold and ionic liquid, an ionogel with the highest known ionic conductivity to date (13.1 mS cm-1) was

  19. Investigation of Tantalum Wet Slug Capacitor Failures in the Apollo Telescope Mount Charger Battery Regulator Modules

    Science.gov (United States)

    Williams, J. F.; Wiedeman, D. H.

    1973-01-01

    This investigation describes the capacitor failures and to identify the cause of the failure mechanism. Early failures were thought to have happened because of age and/or abuse since the failed capacitors were dated 1967. It is shown that all 1967 capacitors were replaced with 1972 capacitors.

  20. Capacitive Energy Storage from - 50o to 100o Using an Ionic Liquid Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Rongying [Universite Paul Sabatier, Toulouse Cedex, France.; Taberna, Pierre-Louis [Universite Paul Sabatier, Toulouse Cedex, France.; Santini, Sebastien [SOLVIONIC Company, Toulouse, France; Presser, Volker [ORNL; Perez, Carlos R. [Drexel University; Malbosc, Francois [SOLVIONIC Company, Toulouse, France; Rupesinghe, Nalin L. [AIXTRON, Cambridge, UK; Teo, Kenneth B. K. [AIXTRON, Cambridge, UK; Gogotsi, Yury G. [Drexel University; Simon, Patrice [Universite Paul Sabatier, Toulouse Cedex, France.

    2011-01-01

    Relying on redox reactions, most batteries are limited in their ability to operate at very low or very high temperatures. While performance of electrochemical capacitors is less dependent on the temperature, present-day devices still cannot cover the entire range needed for automotive and electronics applications under a variety of environmental conditions. We show that the right combination of the exohedral nanostructured carbon (nanotubes and onions) electrode and a eutectic mixture of ionic liquids can dramatically extend the temperature range of electrical energy storage, thus defying the conventional wisdom that ionic liquids can only be used as electrolytes above room temperature. We demonstrate electrical double layer capacitors able to operate from 50 to 100 C over a wide voltage window (up to 3.7 V) and at very high charge/discharge rates of up to 20 V/s.

  1. Stabilization of FGD gypsum for its disposal in landfills using amorphous aluminium oxide as a fluoride retention additive.

    Science.gov (United States)

    Alvarez-Ayuso, E; Querol, X

    2007-09-01

    The applicability of amorphous aluminium oxide as a fluoride retention additive to flue gas desulphurisation (FGD) gypsum was studied as a way of stabilizing this by-product for its disposal in landfills. Using a batch method the sorption behaviour of amorphous aluminium oxide was evaluated at the pH (about 6.5) and background electrolyte conditions (high chloride and sulphate concentrations) found in FGD gypsum leachates. It was found that fluoride sorption on amorphous aluminium oxide was a very fast process with equilibrium attained within the first half an hour of interaction. The sorption process was well described by the Langmuir model, offering a maximum fluoride sorption capacity of 61.7 mg g(-1). Fluoride sorption was unaffected by chloride co-existing ions, while slightly decreased (about 20%) by competing sulphate ions. The use of amorphous aluminium oxide in the stabilization of FGD gypsum proved to greatly decreased its fluoride leachable content (in the range 5-75% for amorphous aluminium oxide doses of 0.1-2%, as determined by the European standard EN 12457-4 [EN-12457-4 Characterization of waste-leaching-compliance test for leaching of granular waste materials and sludges-Part 4: one stage batch test at a liquid to solid ratio of 10 l/kg for materials with particle size below 10mm (without or with size reduction)]), assuring the characterization of this by-product as a waste acceptable at landfills of non-hazardous wastes according to the Council Decision 2003/33/EC [Council Decision 2003/33/EC of 19 December 2002. Establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC] on landfill of wastes. Furthermore, as derived from column leaching studies, the proposed stabilization system proved to be highly effective in simulated conditions of disposal, displaying a fluoride leaching reduction value about 81% for an amorphous aluminium oxide added amount of 2%.

  2. Durability of Lacquered Aluminium Profile Considering Tropical Weather Conditions

    Directory of Open Access Journals (Sweden)

    Rigoberto Marrero Águila

    2013-11-01

    Full Text Available Searching for solutions against the degradation of materials by corrosion effect, is a common practice to use alloys such as aluminium instead of steel due to the advantages obtained. The lacquered aluminium profiles can substitute other materials like wood, in the carpentry production, becoming an economic saving. There is an increasingly use of aluminium replacing other traditional materials in the constructions in process, but its quality has been reduced in a considerable amount of installations. In this research, aluminium profiles from five different sources were submitted to a trial in natural exposition conditions at the Tropical weather condition Testing Lab, in order to evaluate their behaviour and establish, for the first time in our country, standing rules for lacquered aluminium profiles to be strictly fulfilled by manufacturers and importers. The results will allow modifying thickness standards of this type of coating, to guaranty its durability and to eliminate the failures provoked by our high severe weather conditions.

  3. Experimental investigations on mechanical behavior of aluminium metal matrix composites

    Science.gov (United States)

    Rajesh, A. M.; Kaleemulla, Mohammed

    2016-09-01

    Today we are widely using aluminium based metal matrix composite for structural, aerospace, marine and automobile applications for its light weight, high strength and low production cost. The purpose of designing metal matrix composite is to add the desirable attributes of metals and ceramics to the base metal. In this study we developed aluminium metal matrix hybrid composite by reinforced Aluminium7075 alloy with silicon carbide (SiC) and aluminium oxide (alumina) by method of stir casting. This technique is less expensive and very effective. The Hardness test and Wear test were performed on the specimens which are prepared by stir casting techniques. The result reveals that the addition of silicon carbide and alumina particles in aluminium matrix improves the mechanical properties.

  4. Aluminium/iron reinforced polyfurfuryl alcohol resin as advanced biocomposites

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    2016-07-01

    Full Text Available Aluminium and iron are widely used in construction sectors for the preparation of advanced composites with epoxy resins as matrices. In recent times, there are several reports on the polymerization of polyfufuryl alcohol (PFA a thermoset bioresins from furfuryl alcohol (FA. FA is obtained from waste of sugarcane bagasse. In this work, first the possibility of curing PFA from FA in the presence of aluminium or iron has been explored. Absorbance results from colorimeter/spectrophotometerindicated that the curing of FA to PFA in presence of aluminium started easily while in presence of iron the curing of FA to PFA could not start. Based on the above results, aluminium wire reinforced composites were successfully prepared with three different weight fractions (0.13, 0.09 and 0.07 of aluminium wire. The mechanical properties of these composites were determined theoretically and reported.

  5. Floating body cell a novel capacitor-less DRAM cell

    CERN Document Server

    Ohsawa, Takashi

    2011-01-01

    DRAM together with NAND Flash is driving semiconductor technologies with wide spectrum of usage ranging from PC, mobile phone and digital home appliances to solid-state disk (SSD). However, the DRAM cell which consists of a data storage capacitor (1C) and a switching transistor (1T) is facing serious difficulty in shrinking the size of the capacitor whose capacitance needs to be kept almost constant (20~30fF) throughout generations. The availability of a new DRAM cell which does not rely on an explicit capacitor for storing its data is more than ever awaited for further increasing the bit dens

  6. Solid state electrolyte systems

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, L.R.; Armstrong, B.L.; Armstrong, T.R. [Pacific Northwest Lab., Richland, WA (United States)] [and others

    1997-12-01

    Lanthanum gallates are a new family of solid electrolytes that exhibit high ionic conductivity and are stable to high temperatures. Compositions have been developed that are as much as a factor of two more conductive than yttria-stabilized zirconia at a given temperature, through partial replacement of lanthanum by calcium, strontium, and/or barium and through partial replacement of gallium by magnesium. Oxide powders were prepared using combustion synthesis techniques developed in this laboratory; these were sintered to >95% of theoretical density and consisted of a single crystalline phase. Electrical conductivities, electron and ion transference numbers, thermal expansion, and phase behavior were evaluated as a function of temperature and oxygen partial pressure. A key advantage of the use of lanthanum gallate electrolytes in solid oxide fuel cells is that the temperature of operation may be lowered to perhaps 800 C, yet provide approximately the same power density as zirconia-based cells operating at 1000 C. Ceramic electrolytes that conduct both oxygen ions and electrons are potentially useful to passively separate pure oxygen from an air source at low cost. In such materials, an oxygen ion flux in one direction is charge-compensated by an opposing electron flux. The authors have examined a wide range of mixed ion and electron conducting perovskite ceramics in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, where M = Sr, Ca, and Ba, and N = Pr, Mn, Ni, Cu, Ti, and Al, as well as mixed conducting brownmillerite ceramics, and have characterized oxygen permeation behavior, defect chemistry, structural and phase stability, and performance as cathodes.

  7. Corrosion behaviour of ion implanted aluminium alloy in 0.1 M NaCl electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Chu, J.W.; Evans, P.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Aluminum and its alloys are widely used in industry because of their light weight, high strength and good corrosion resistance which is due to the formation of a protective oxide layer. However, under saline conditions such as those encountered in marine environments, this group of metals are vulnerable to localised degradation in the form of pitting corrosion. This type of corrosion involves the adsorption of an anion, such as chlorine, at the oxide solution interface. Ion implantation of metal ions has been shown to improve the corrosion resistance of a variety of materials. This effect occurs : when the implanted species reduces anion adsorption thereby decreasing the corrosion rate. In this paper we report on the pitting behavior of Ti implanted 2011 Al alloy in dilute sodium chloride solution. The Ti implanted surfaces exhibited an increased pitting potential and a reduced oxygen uptake. 5 refs., 3 figs.

  8. Forming of aluminium alloy friction stir welds

    Science.gov (United States)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  9. Friction stir welding of single crystal aluminium

    DEFF Research Database (Denmark)

    Fonda, Richard Warren; Wert, John A.; Reynolds, A.P.

    2007-01-01

    Friction stir welds were prepared in different orientations in an aluminium single crystal. The welds were quenched to preserve the microstructure surrounding the tool and then electron backscattered diffraction was used to reveal the generation of grain boundaries and the evolution...... of crystallographic texture around the tool in each weld. The extent of both dynamic recrystallisation and conventional recrystallisation varied considerably as a function of weld orientation. As the base plate begins to interact with the deformation field surrounding the tool, regions of the single crystal rotate...

  10. CERN: very large magnet with aluminium winding

    Energy Technology Data Exchange (ETDEWEB)

    Wittgenstein, F.A.

    1984-10-25

    The construction of an octagonal solenoid from trapezoidal plates of Al, 6m long and 6cm thick, assembled by electron beam welding, for installation in a laboratory 50m underground is described. The objective is to create a field of 0.5T in a volume of 1000m/sup 3/ for the L3 particle detector of the LEP accelerator project. Principal dimensions and weights of the structure are given and its three stages of implementation are described, with reference to the contributions from the Swiss aluminium industry.

  11. Volatilisation and oxidation of aluminium scraps fed into incineration furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Biganzoli, Laura, E-mail: laura.biganzoli@mail.polimi.it [Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy); Gorla, Leopoldo; Nessi, Simone; Grosso, Mario [Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Aluminium packaging partitioning in MSW incineration residues is evaluated. Black-Right-Pointing-Pointer The amount of aluminium packaging recoverable from the bottom ashes is evaluated. Black-Right-Pointing-Pointer Aluminium packaging oxidation rate in the residues of MSW incineration is evaluated. Black-Right-Pointing-Pointer 80% of aluminium cans, 51% of trays and 27% of foils can be recovered from bottom ashes. - Abstract: Ferrous and non-ferrous metal scraps are increasingly recovered from municipal solid waste incineration bottom ash and used in the production of secondary steel and aluminium. However, during the incineration process, metal scraps contained in the waste undergo volatilisation and oxidation processes, which determine a loss of their recoverable mass. The present paper evaluates the behaviour of different types of aluminium packaging materials in a full-scale waste to energy plant during standard operation. Their partitioning and oxidation level in the residues of the incineration process are evaluated, together with the amount of potentially recoverable aluminium. About 80% of post-consumer cans, 51% of trays and 27% of foils can be recovered through an advanced treatment of bottom ash combined with a melting process in the saline furnace for the production of secondary aluminium. The residual amount of aluminium concentrates in the fly ash or in the fine fraction of the bottom ash and its recovery is virtually impossible using the current eddy current separation technology. The average oxidation levels of the aluminium in the residues of the incineration process is equal to 9.2% for cans, 17.4% for trays and 58.8% for foils. The differences between the tested packaging materials are related to their thickness, mechanical strength and to the alloy.

  12. Thermally responsive polymer electrolytes for inherently safe electrochemical energy storage

    Science.gov (United States)

    Kelly, Jesse C.

    Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in electrochemical energy storage devices, while preserving the performance, lifetimes, and versatility that large-format systems require. Initial work focused on the development of a model system that demonstrated the concept of RPEs in an electrochemical device. Aqueous electrolyte solutions of polymers exhibiting properties that change in response to temperature were developed for applications in EDLCs and supercapacitors. These "smart materials" provide a means to control electrochemical systems where polymer phase separation at high temperatures affects electrolyte properties and inhibits device performance. Aqueous RPEs were synthesized using N-isopropylacrylamide, which governs the thermal properties, and fractions of acrylic acid or vinyl sulfonic acids, which provide ions to the solution. The molecular properties of these aqueous RPEs, specifically the ionic composition, were shown to influence the temperature-dependent electrolyte properties and the extent to which these electrolytes control the energy storage characteristics of a supercapacitor device. Materials with high ionic content provided the highest room temperature conductivity and electrochemical activity; however, RPEs with low ionic content provided the highest "on

  13. Electrolytic Plasma Processing for Sequential Cleaning and Coating Deposition for Cadmium Plating Replacement

    Science.gov (United States)

    2008-08-01

    Al(OH)3 precipitation pH≈5 to 8. Bulk pH of 0.1M aluminium sulphate solution is about 3.5, and it is further reduced due to collateral hydrogen...a surface. For cleaning, the electrolyte can be a simple sodium bicarbonate solution (typically 10%) or ammonium chloride. As measured by SEM and...reduction of the metallic ions. Sodium sulphate and Al powder was added in the bath for one experiment and produced a more uniform coating. The intention

  14. A Power-Efficient Wireless Capacitor Charging System Through an Inductive Link

    OpenAIRE

    Lee, Hyung-Min; Ghovanloo, Maysam

    2013-01-01

    A power-efficient wireless capacitor charging system for inductively powered applications has been presented. A bank of capacitors can be directly charged from an ac source by generating a current through a series charge injection capacitor and a capacitor charger circuit. The fixed charging current reduces energy loss in switches, while maximizing the charging efficiency. An adaptive capacitor tuner compensates for the resonant capacitance variations during charging to keep the amplitude of ...

  15. Electrochemical Capacitor Development for Pulsed Power Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this NASA Phase II SBIR Project, we will continue the development of graphitic nanosheets (GNS) for electrochemical capacitor (EC) electrode materials. In the...

  16. Compact 20-kiloampere pulse-forming-network capacitor bank

    Science.gov (United States)

    Posta, S. J.; Michels, C. J.

    1973-01-01

    Bank uses commercially available high-energy-density capacitors for energy storage and silicon-controlled rectifiers for switching. Low voltage design employing solid-state switching is utilized in lieu of conventional gas discharge switching.

  17. Fringe Capacitance of a Parallel-Plate Capacitor.

    Science.gov (United States)

    Hale, D. P.

    1978-01-01

    Describes an experiment designed to measure the forces between charged parallel plates, and determines the relationship among the effective electrode area, the measured capacitance values, and the electrode spacing of a parallel plate capacitor. (GA)

  18. Generalised Impedance Converters with only Transconductance Elements and Grounded Capacitors

    Directory of Open Access Journals (Sweden)

    Iqbal A. Khan

    2002-01-01

    capacitors in the realisation of continuous time filters lend to electronic tunability and compatibility to integration in contemporary IC technologies. The generalised impedance converters are also verified using PSPICE-based simulation.

  19. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    Science.gov (United States)

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  20. A Composite Capacitor/Inductor Assembly for Resonant Circuits

    Science.gov (United States)

    Hull, J. P.; Scholfield, D. W.

    2001-06-01

    Resonant structures are of interest due to their ability to produce oscillatory voltages in circuits. Past resonant structures have typically been designed using a lumped element capacitor for energy storage and a separate inductor. A composite capacitor/inductor assembly has been developed which merges the capacitance utilized for energy storage into the inductor, creating a consolidated electrical component. Composite capacitor/inductor assemblies are of interest due to the ability of these devices to produce resonant responses with one half the number of parts required by more traditional resonant structures. This composite capacitor/inductor could be utilized in applications of frequency band suppression or frequency band pass for frequencies in excess of 100 MHz, or where a resonant circuit is required to reside in an area of minimum space - such as a printed circuit board or an integrated circuit. The device and the mathematical treatment to predict the device's performance are described.

  1. Calorimetric measurement and modelling of the equivalent series of capacitors

    Science.gov (United States)

    Seguin, B.; Gosse, J. P.; Ferrieux, J. P.

    1999-12-01

    The equivalent series resistance of polypropylene capacitors has been determined under rated voltage, in the range 1 kHz 1 MHz, between 220 K and 370 K by a calorimetric technique. The original feature of this determination of capacitor losses lies in the use of the isothermal calorimetry and in the measurement of an electrical power and not of a temperature increase. The frequency dependence of the equivalent series resistance, at various temperatures, enables to separate the losses in the conducting material from those in the dielectric and to get their respective variations as a function of frequency and temperature. These variations of the equivalent series resistance with frequency at a given temperature have been reproduced by using an equivalent circuit composed of resistors, inductors and capacitors. This model has been verified for non-sinusoidal waveforms such as those met with in a filtering circuit and is used to evaluate by simulation the losses of the capacitor.

  2. Aluminium matrix composites: Challenges and opportunities

    Indian Academy of Sciences (India)

    M K Surappa

    2003-02-01

    Aluminium matrix composites (AMCs) refer to the class of light weight high performance aluminium centric material systems. The reinforcement in AMCs could be in the form of continuous/discontinuous fibres, whisker or particulates, in volume fractions ranging from a few percent to 70%. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently several grades of AMCs are manufactured by different routes. Three decades of intensive research have provided a wealth of new scientific knowledge on the intrinsic and extrinsic effects of ceramic reinforcement vis-a-vis physical, mechanical, thermo-mechanical and tribological properties of AMCs. In the last few years, AMCs have been utilised in high-tech structural and functional applications including aerospace, defence, automotive, and thermal management areas, as well as in sports and recreation. It is interesting to note that research on particle-reinforced cast AMCs took root in India during the 70’s, attained industrial maturity in the developed world and is currently in the process of joining the mainstream of materials. This paper presents an overview of AMC material systems on aspects relating to processing, microstructure, properties and applications.

  3. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  4. Electrochemical Cells with Intermediate Capacitor Elements

    CERN Document Server

    Grebel, Haim

    2015-01-01

    Our goal is to electronically regulate electrochemical cells. For this, we introduced a third element, called the gate, which was placed between the cathode and the anode electrodes of the cell. Voltage applied to this element controlled the local potential of the electrolyte, thus impacting the flow of ions within the cell. The flow of ions was monitored by the electronic current in the external cell's circuit. We provide simulations and experimental data as proof to the validity of this concept. This is but the first step towards a demonstration of a two-dimensional, bi-carrier ion transistors.

  5. Development of a recycling process for tantalum from capacitor scraps

    Science.gov (United States)

    Mineta, Kunio; Okabe, Toru H.

    2005-02-01

    A process based on oxidation treatment at elevated temperature, followed by mechanical separation and chemical treatment, was investigated to develop an effective process for recycling tantalum from capacitor scraps. By this process, tantalum oxide powder, free of SiO2 or other impurities, was recovered from capacitor scrap. Tantalum powder with 99 mass% purity was recovered by magnesiothermic reduction of the obtained tantalum oxide powder.

  6. Solid State Capacitor Discharge Pulsed Power Supply Design for Railguns

    Science.gov (United States)

    2007-03-01

    CAPACITOR DISCHARGE PULSED POWER SUPPLY DESIGN FOR RAILGUNS by Jesse H. Black March 2007 Thesis Advisor: Alexander L. Julian Co-Advisor...switched power supply capable of providing 50 kJ from a high voltage capacitor to a railgun . The efficiency with which energy is transferred from a...also produce a smaller electromagnetic pulse. Voltage limitations on the thyristors require two in series acting as a single switch. Railgun

  7. Study of ac electrical properties of aluminium-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Elimat, Z M [Applied Science Department, Ajloun University College, Al-Balqa Applied University, Amman (Jordan); Zihlif, A M [Physics Department, University of Jordan, Amman (Jordan); Ragosta, G [Institute of Chemistry and Polymer Technology (ICTP), CNR-Possouli, Napoli (Italy)], E-mail: adzh@ju.edu.jo

    2008-08-21

    Ac electrical properties of aluminium flakes-epoxy composites were studied as a function of the composition, frequency and temperature. The dielectric constant increased smoothly with an increase in the concentration of aluminium. An increase in the dielectric constant was observed with the temperature as well as with a decrease in the frequency. The observed increase in the values of the dielectric constant with the aluminium concentration was attributed to interfacial polarization. It was found that ac electrical conductivity increases with increasing content of aluminium, temperature and frequency. The observed enhancement in ac conductivity is attributed to the increase in the number of conduction paths created by the aluminium flake contacts in the composite to give a higher electrical conductivity. Also, the activation energy of aluminium flakes-epoxy composites was determined, as well as the values of the dielectric constant. Compared with various theoretical models, Bruggman's formula gives a better fit. The universal power-law model of ac conductivity is observed in epoxy-aluminium composites. The calculated power exponent (about unity) is physically acceptable within this applied model.

  8. Does allergen-specific immunotherapy induce contact allergy to aluminium?

    Science.gov (United States)

    Netterlid, Eva; Hindsén, Monica; Siemund, Ingrid; Björk, Jonas; Werner, Sonja; Jacobsson, Helene; Güner, Nuray; Bruze, Magnus

    2013-01-01

    Persistent, itching nodules have been reported to appear at the injection site after allergen-specific immuno-therapy with aluminium-precipitated antigen extract, occasionally in conjunction with contact allergy to aluminium. This study aimed to quantify the development of contact allergy to aluminium during allergen-specific immunotherapy. A randomized, controlled, single-blind multicentre study of children and adults entering allergen-specific immunotherapy was performed using questionnaires and patch-testing. A total of 205 individuals completed the study. In the 3 study groups all subjects tested negative to aluminium before allergen-specific immunotherapy and 4 tested positive after therapy. In the control group 4 participants tested positive to aluminium. Six out of 8 who tested positive also had atopic dermatitis. Positive test results were found in 5/78 children and 3/127 adults. Allergen-specific immunotherapy was not shown to be a risk factor for contact allergy to aluminium. Among those who did develop aluminium allergy, children and those with atopic dermatitis were more highly represented.

  9. Using a Fixed and Switched-Capacitor Bank to Investigate Harmonic Resonance and Capacitor Bank Switching in a Distribution Network

    Directory of Open Access Journals (Sweden)

    J.C. Attachie

    2014-03-01

    Full Text Available Harmonic resonance often manifests as high harmonic voltages in a power system. This produces losses and affects other consumers in the grid negatively. Capacitance switching applications also involve not only interrupting capacitive currents, but also the energizing of capacitor banks, cables and overhead lines. The applications of capacitors are extensively used in power systems for voltage support and power factor correction. However, the main concern arising from the use of capacitors is the possibility of system resonance. This study investigates the frequent capacitor bank tripping and damages in one of the distribution substations of the Electricity Company of Ghana (ECG. The study was conducted using the Electromagnetic Transient Program (EMTP software for the simulation. The results showed that, the failures were related to harmonic resonance. Selected series connected inductors were recommended to shift the resonant frequencies of the network below characteristics harmonic frequencies.

  10. A Hydrogen-Evolving Hybrid-Electrolyte Battery with Electrochemical/Photoelectrochemical Charging from Water Oxidation.

    Science.gov (United States)

    Jin, Zhaoyu; Li, Panpan; Xiao, Dan

    2017-02-08

    Decoupled hydrogen and oxygen production were successfully embedded into an aqueous dual-electrolyte (acid-base) battery for simultaneous energy storage and conversion. A three-electrode configuration was adopted, involving an electrocatalytic hydrogen-evolving electrode as cathode, an alkaline battery-type or capacitor-type anode as shuttle, and a charging-assisting electrode for electro-/photoelectrochemically catalyzing water oxidation. The conceptual battery not only synergistically outputs electricity and chemical fuels with tremendous specific energy and power densities, but also supports various approaches to be charged by pure or solar-assisted electricity.

  11. Installation of capacitors in plants which have synchronous machines; Instalacao de capacitores em plantas que possuem maquinas sincronas

    Energy Technology Data Exchange (ETDEWEB)

    Gennari, Jorge L.; Vasconcellos, Alexandre S. de [Figener Engenheiros Associados (Brazil)

    1996-07-01

    Generators and synchronous motors may supply the necessary power factor correction, which tends to turn unnecessary the installation of capacitors. However, it is necessary to calculate how much more the company will pay in electric power bill when the stop of such machinery be necessary, either in a programed or emergency situation. Therefore, the decision of installing capacitors depends on this calculation. This work shows some criteria and results of a study case. 3 figs., 6 tabs.

  12. Optimal design of capacitor-driven coilgun

    Science.gov (United States)

    Kim, Seog-Whan; Jung, Hyun-Kyo; Hahn, Song-Yop

    1994-03-01

    This paper presents an analysis and optimal design of a capacitor-driven inductive coilgun. An equivalent circuit is used for a launch simulation of the coilgun. The circuit equations are solved together with the equation of motion of the projectile by using the Runge-Kutta method. The numerical results are compared with the experimental values to verify the usefulness of the developed simulation program. It is shown that the numerical and the experimental results are in a good agreement. In the design of the system the optimization is achieved by employing the genetic algorithm. The resultant specifications of the coilgun optimally designed by the proposed algorithm are tested by experiment. Finally the obtained results are compared with those designed by approximate equations and by linear search methods as well. It is found that the proposed algorithm gives a better result in the energy efficiency of the system, namely it enables one to obtain a higher muzzle velocity of the projectile with the same amount of energy.

  13. Carbide Derived Carbon Super Capacitor Application

    Science.gov (United States)

    Appelgate, James; Bauer, Dave; Quirin, James; Lofland, S. E.; Hettinger, J. D.; Heon, M.; Gogotsi, Y.

    2010-02-01

    Supercapacitors can be applied into many different fields from nano-robots to high density energy storage. Growing TiC films from a know recipe and removing the transition metal element, Titanium, by chlorination leaves a carbon film that can then be applied as an electrode in a super capacitor. The problem is when the Titanium is removed from the film the stress induced by this process causes the films to fracture into isolated islands. The islands allow electrons to travel across them every easily, but there is no transfer of electrons from island to island. We present results of an investigation of a technique control the location of the fractures and use them to our benefit. Ideally, we want to create them to fracture in parallel lines. To force these fractures into straight lines we will purchase substrates with thermal SiO2 created on the surface of Si. Using an etching process we will removed a channel of SiO2 the same as the thickness of the TiC film we plan on growing. These channels will allow the fractures to form in a correlated way creating a straight line. )

  14. Thickness Evaluation of Aluminium Plate Using Pulsed Eddy Current Technique

    Science.gov (United States)

    Singh, Gurpartap; Bapat, Harsh Madhukar; Singh, Bhanu Pratap; Bandyopadhyay, Manojit; Puri, Rakesh Kumar; Badodkar, Deepak Narayanrao

    2013-10-01

    This paper describes a pulsed eddy current (PEC) based non-destructive testing system used for detection of thickness variation in aluminium plate. A giant magneto-resistive sensor has been used instead of pick up coil for detecting resultant magnetic field. The PEC response signals obtained from 1 to 5 mm thickness change in aluminium plate were investigated. Two time domain features, namely peak value and time to peak, of PEC response were used for extracting information about thickness variation in aluminium plate. The variation of peak value and time to peak with thickness was compared. A program was developed to display the thickness variation of the tested sample.

  15. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  16. Effects of aluminium surface morphology and chemical modification on wettability

    DEFF Research Database (Denmark)

    Rahimi, Maral; Fojan, Peter; Gurevich, Leonid;

    2014-01-01

    Aluminium alloys are some of the predominant metals in industrial applications such as production of heat exchangers, heat pumps. They have high heat conductivity coupled with a low specific weight. In cold working conditions, there is a risk of frost formation on the surface of aluminium...... in the presence of water vapour, which can lead to the deterioration of equipment performance. This work addresses the methods of surface modification of aluminium and their effect of the underlying surface morphology and wettability, which are the important parameters for frost formation. Three groups of real...

  17. Cold forming of aluminium - State of the art

    DEFF Research Database (Denmark)

    Bay, Niels

    1997-01-01

    to that of unalloyed steel. After description of the different types of alloys and their individual properties and applications, the special requirements for tool design by cold forging in aluminium is discussed. Finally, a large number of industrial examples on cold forged aluminium components are presented. (C) 1997......The ongoing development of cold forging technology has been manifested lately by the increasing application of components in cold forged aluminium alloys. Applying precipitation hardening alloys components with great strength/weight ratio can be produced with a strength comparable...

  18. Study of fatigue behaviour of 7475 aluminium alloy

    Indian Academy of Sciences (India)

    B B Verma; J D Atkinson; M Kumar

    2001-04-01

    Fatigue properties of a thermomechanically treated 7475 aluminium alloy have been studied in the present investigation. The alloy exhibited superior fatigue life compared to conventional structural aluminium alloys and comparable stage II crack growth rate. It was also noticed that the fatigue crack initiated from a surface grain and the crack extension was dominated by ductile striations. Analysis also revealed that this alloy possessed fracture toughness and tensile properties superior to that noticed with other structural aluminium alloys. Therefore the use of this alloy can safely reduce the overall weight of the aircraft.

  19. Optimization of Magnesium Metal into Commercially Pure Aluminium

    Directory of Open Access Journals (Sweden)

    Vandana J Rao

    2014-02-01

    Full Text Available The present investigation, involve development of Al-Mg systems by addition of magnesium into commercially pure aluminium. The amounts of magnesium added into commercially pure aluminium are of 1 and 2 wt%. The recoveries of magnesium are around 85-90%.Remaining Mg react with oxygen and float on the liquid aluminium. Presence of magnesium creates two phenomena. One is solid solution hardening and other is intermetallics formation. Both the phenomena checked by microstructural changes and by measuring the electrical conductivity values. By increasing the Mg, content mechanical properties (hardness and tensile strength increases and electrical conductivity decreases.

  20. Effect of pressurized steam on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Ambat, Rajan

    2012-01-01

    Purpose - The purpose of this paper is to understand the effect of pressurized steam on surface changes, structures of intermetallic particles and corrosion behavior of AA1050 aluminium. Design/methodology/approach - Industrially pure aluminium (AA1050, 99.5 per cent) surfaces were exposed...... reactivities was observed due to the formation of the compact oxide layer. Originality/value - This paper reveals a detailed investigation of how pressurized steam can affect the corrosion behaviour of AA1050 aluminium and the structure of Fe-containing intermetallic particles....