Abstract: An apparatus and a method for producing, capturing and storing hydrogen in a hydrogen absorption rod. The hydrogen absorption rod comprises a zeolite core material surrounding a conductive rod, wherein the zeolite core material is suitable for releasing captured hydrogen to a hydrogen fuel cell. More specifically, the apparatus and method utilize solar-generated electric current to separate hydrogen from water, whereupon the released hydrogen is captured in the hydrogen absorption rod. The hydrogen absorption rod is configured to allow for ease and safety of transportation, storage, and use of hydrogen gas in hydrogen fuel cells.

Abstract: One embodiment of the present invention is a hydrogen generator that includes: (a) an anode material; (b) a cathode material; and (c) an electrolyte; wherein the electrolyte comprises a metal hydride, at least one stabilizing agent, and a solvent; and wherein hydrogen gas is generated whenever the anode material and the cathode material are electrically connected.

Abstract: Methods and systems for generating sulfuric acid (102) are disclosed. In some embodiments, the method includes combusting a sulfur-containing material (114) with a gas including oxygen (116) to produce a first stream of sulfur dioxide (118), mixing water with the first stream of sulfur dioxide to produce a mixed stream, using an energy, electrolytically converting (108) the mixed stream of sulfur dioxide and water into sulfuric acid (102) and hydrogen (122), generating a source of energy (126) from the hydrogen, and providing the source of energy as at least a portion of the energy for electrolytically converting the first stream of sulfur dioxide and water into sulfuric acid and hydrogen. In some embodiments, the system includes a first chamber for combusting a sulfur-containing material to produce a first stream of sulfur dioxide, an electrolytic cell (108) for converting the first stream into sulfuric acid and hydrogen, and a fuel cell (112) for generating an energy source from the hydrogen.

Abstract: The invention relates to a method of making a nanotubular titania substrate having a titanium dioxide surface comprised of a plurality of vertically oriented titanium dioxide nanotubes containing oxygen vacancies, including the steps of anodizing a titanium metal substrate in an acidified fluoride electrolyte and annealing the titanium oxide surface in a non-oxidating atmosphere. The invention further relates to a nanotubular titania substrate having an annealed titanium dioxide surface comprised of self-ordered titanium dioxide nanotubes containing oxygen vacancies. The invention further relates to a photo-electrolysis method for generating H2 wherein the photo-anode is a nanotubular titania substrate of the invention. The invention also relates to an electrochemical method of synthesizing CdZn/CdZnTe nanowires, wherein a nanoporous TiO2 template was used in combination with non-aqueous electrolyte.

Abstract: An electro-galvanic hydrogen generator system that has two or more anode materials; a cathode material; and an electrolyte. The electrolyte comprises a metal hydride, at least one stabilizing agent, and a solvent. Hydrogen gas is generated whenever an anode material and the cathode material are electrically connected, and the different anode materials can be used separately or in combination to control the quantity and rate of hydrogen generation. An insulating shield may be used to catch reaction debris from the anodes. A removable inert layer may cover the electrodes. The use of cell pressure may regulate the rate of hydrogen generation. The hydrogen generator may have a separate catalyst chamber, and the hydrogen generator may also function as a battery.

Abstract: Fluid treatment apparatus having an alloy disk assembly comprised of a plurality of disks, each prepared from the metal elements copper, zinc, nickel, silver, and tin, which individually exhibit great propensity for reducing scale formation in flow conduits; particularly when combined together to form the fluid treatment alloy disk assembly of this disclosure. The disk assembly is housed within a suitable enclosure having passageways arranged to effect countercurrent flow through a series of apertured disks. The close proximity of the counterflowing streams within the alloy disk assembly provide unexpected advances in the art of fluid treatment.

Abstract: To maximize and maintain the antioxidant or pro-oxidant state for foods, beverages, personal care products, cosmetics, nutritional supplements, reagents, analytical standards, medical device formulations, pharmaceutical preparations or drags, the present invention discloses methods and devices to control redox equilibrium of such preparations throughout the processing steps and storage prior to, or at, the time of administration or use. The preparations (solid or liquid form) can then be stored in a redox-controlled container, package or applicator as described in the specification. Foods, beverages, personal care products, cosmetics, nutritional supplements, reagents, analytical standards, medical device formulations, pharmaceutical preparations and drugs stored in reactive oxidation states can be activated and stabilized by electrical voltages applied with a small battery and electrodes designed into the applicator, container or package.

Abstract: An apparatus for creating hydrogen from the disassociation of water using sunlight (photoelectrolysis) is provided. The system utilizes an aqueous fluid filled container which functions both to hold the water to be disassociated and as a light collecting lens. A photovoltaic module is positioned at a point to most efficiently accept the refracted light from the fluid filled container. A pair of electrodes which are coupled to the photovoltaic module are disposed within the fluid and configured to split the water into hydrogen and oxygen.

Abstract: The fast and convenient usage of clean and pure oxygen supply devices will meet the requirements of medical application and special environment safety issues. The electrochemical oxygen concentration is a device by using an electrochemical reactor of one electrode of oxygen reduction and another electrode of oxygen generation. The operation of electrochemical reactor can achieve the easy control of air oxygen from one side to another side of this thin mask structure and the materials, design and engineering of this electrochemical oxygen concentration is workable for medical application.

Abstract: The present invention provides a system for generating hydrogen gas in an aqueous solution based electrolytic or galvanic cell wherein the cathode is made from aluminum or an aluminum alloy. In a preferred arrangement the cell is a galvanic cell and cathode is made from aluminum or aluminum alloy and the anode is made from magnesium or magnesium alloy.

Abstract: The invention relates to a method for purifying water by forming in an electrolytic cell molecular halogen, hypohalic acid, hypohalite ions or combinations thereof, from halide ions dissolved in the water; and dissolving one or more soluble metal salts in the water to provide corresponding metal ions. The invention also relates to a system for purifying water, having an electrolytic cell comprising a plurality of electrodes sufficient to electrolytically convert halide ion in the water into molecular halogen, hypohalic acid, or hypohalite ions, or combinations thereof; and a metal generator, which provides concentrations of one or more metals to the water.

Abstract: The inventive method and apparatus for treating water and water systems. The apparatus and method also assures the retention of calcium in drinking water provided to an animal by suppling water to a water feed line which is connected to a drinking device, oxidizing the water to retain calcium in the water in solution, ionizing the water using copper/zinc electrodes, the ionization sanitizing the water and providing residual copper and zinc ions which act as an algicide and a biocide, and providing the ionized oxidized drinking water which retains calcium in solution to the animal for drinking.

Abstract: A device utilizing a catalytic alloy, preferably the Walker Alloy, to reduced scale and paraffin buildup in surface hydrocarbon piping is disclosed. The device is presented in a basket filter configuration for ready servicing. A series of alternate embodiments for the fundamental filter device is discussed.

Abstract: The apparatus is provided with a wire guiding means disposed in a liquid bath for turning the direction of a wire to feed the wire into and out of the bath contained by the liquid. The wire guiding means includes a tubular conduit having a first open end disposed in the liquid, a second open end disposed above the liquid, and a middle curved portion for guiding the wire through the tubular conduit. The tubular conduit can be at least partially filled with the liquid. Preferably, the treatment liquid is an electrodeposition liquid. A plurality of the tubular conduits may be disposed in the bath substantially parallel with each other. Preferably the first open end is connected to a bottom portion of the bath through a coupling such that the treatment liquid in the bath can flows into the tubular conduit. The second open end is positioned higher than the first open end.

Abstract: A system and process for cleaning a hollow interior or a passageway of a metal member including an external container having counter electrode material with a higher potential than the metal member with the counter electrode material being dc coupled to the metal member, and electrolyte passing through the container to contact the counter electrode material and fluidicly coupled into the hollow interior or the passageway of the metal member to clean same.

Abstract: A galvanizing device has at least one jet cell with a contact zone located after the jet cell in the direction of transportation of a work piece through the jet cell. At least one partition separates the jet cell from the contact zone. A seal surrounds the workpiece and is situated at an outlet of the jet cell. A pre-baffle surrounds the outlet and acts as a mount for the seal.

Abstract: A device for killing bacteria and algae in the water reservoir of an evaporative cooler. The water conditioner kills bacteria and limits algae growth by inducing a DC current on the water itself. The interaction of a zinc disk and a copper ring encircling it produces a small voltage (approximately 4-6 volts and a current in the milliamp range). The zinc acts as an anode, and the copper ring acts as a cathode. Assembly posts and end pieces act as supports and also as an insulator between the two metals of the assembly and the metal parts of the evaporative cooler. By killing bacteria present in the water and limiting the growth of algae, the water conditioner eliminates foul odors, controls rust and corrosion, and maintains the freshness of the water over long periods of time, thereby ensuring greater indoor air quality when the evaporative cooler is operated.

Abstract: Water having dissolved salts therein causing scaling is treated by flowing through a passage in an elongate tubular member. The tubular member has a first metal inside surface exposed to the water. A second metal surface is positioned therein and the two surfaces have areas of 1:1 up to about 125% with the second metal being different from the first metal. The metal surfaces are electrically insulated from each other so that current flow between the two is through the water.

Abstract: In one embodiment, the electrochemical system comprises an electrochemical cell and hydrogen storage in fluid communication with the hydrogen electrode, the hydrogen storage comprising at least one of carbon nanotubes and carbon nanofibers. In one embodiment, the method for operating an electrochemical cell system, comprises introducing water to an oxygen electrode and electrolyzing the water to form oxygen, hydrogen ions and electrons, wherein the hydrogen ions migrate to a hydrogen electrode. The hydrogen ions can then be reacted with the electrons to form hydrogen gas that is stored in at least one of carbon nanotubes and carbon nanofibers.

Abstract: One embodiment of the present invention is a hydrogen generator that includes: (a) an anode material; (b) a cathode material; and (c) an electrolyte; wherein the electrolyte comprises a metal hydride, at least one stabilizing agent, and a solvent; and wherein hydrogen gas is generated whenever the anode material and the cathode material are electrically connected.

Abstract: A downhole electrical power system provides long term electrical power in a downhole environment. In a described embodiment, a downhole electrical power system includes a power source which supplies electrical power to a well tool interconnected in a tubular string. The power source includes a voltaic cell.

Abstract: A system and process for chemical milling or stripping a surface portion and/or surface deposit from metal products, such as chemically milling a metal to remove surface defects and/or stripping non-metallic deposits from a metal surface. The metal product is associated with an electrolyte, such as by being immersed in a tank filled with the electrolyte, such as a diluted acid mixture. A counter electrode having a higher potential than the metal of the metal product is also associated with the electrolyte. The counter electrode is dc coupled to the metal product, or to a conductive component in direct contact with the metal product, such that electric current flows from the metal to the counter electrode due to the difference in the natural potentials of the metal and the counter electrode. The surface portion or deposit is thereby stripped or milled from the metal product.

Abstract: A method and device for removing pollution from polluted water, consisting of a rod on which are mounted an array of spaced magnesium plates and an array of spaced copper plates. The copper plates are in contact with the magnesium plates. Polluted water passing through the plates results in precipitates of the pollutants which can be mechanically removed.

Abstract: Disclosed is A flow-through electrochemical reactor comprising a body having an internal chamber, and an inlet port and an outlet port in communication with said internal chamber to permit flow of wastewater therethrough, at least one porous anode arranged in said internal chamber such that the wastewater flowing between said inlet port and said outlet port flows through the pores of said at least one porous anode, said at least one porous anode having activity for the destruction of a target substance, and at least one cathode disposed in the internal chamber to permit an electric current to be established between said at least one cathode and said at least one anode, said electric current reducing the concentration of said target substance in the wastewater flowing through the chamber.

Abstract: This invention relates to fuel cells, and in one embodiment, to fuel cells that are especially well suited for downhole use in oil and gas wells, and for subsea use in connection with offshore wells.

Abstract: A cooling tower water purification system uses an electrical cleaning method by passing water over or through an anode and a cathode. The pH of the water is monitored and adjusted using injected CO2 gas. The water can also be mechanically filter to remove the now dead biofilm and biomass as well as any scale or other debris. An additional embodiment can use an additional device such as a water jet to “stir” the bottom of the cooling tower to increase the efficiency of the filter in removing any built up or remaining biomass, scale or the like.

Abstract: This invention discloses regeneration methods to remove carbon monoxide (CO) from reformate fuel using an adsorption and electro-catalytic oxidation (ECO) approach. One method of the invention comprises a first ECO cell and a second ECO cell, and the other method comprises a first ECO cell and a first charge storage device. Both methods eliminate the requirement of an external power supply that leads to higher cost, additional power consumption and more processor complexity for the CO removal processor.

Abstract: A system and process is provided for stripping metal oxide scale from metal products, such as stripping iron oxide scale from steel sheet and steel mill products. Steel having iron oxide scale compiling a layer of one or more iron oxide phases is associated with an electrolyte, such as by being immersed in a tank filled with the electrolyte, such as a dilute acid mixture. A counter electrode having a higher potential than steel is also associated with the electrolyte. The counter electrode is dc coupled to the steel, or to a conductive component in direct contact with the steel, such that electric current flows from the steel to the counter electrode due to the difference in the natural potentials of steel and the counter electrode. The metal oxide scale is thereby stripped from the steel.

Abstract: A water purification system and method suitable for use in swimming pools, spas, hot tubs, water storage tanks, wells and water cooling towers employs a galvanic cell having a silver or copper or zinc anode electrically connected to a cathode made from a metal of still higher electrochemical potential, normally a platinum group metal and preferably palladium. A galvanic cell of some tens of square centimeters in size and some hundreds of grams in weight liberates sufficient silver or copper ions so as to treat a multi-thousand liter body of water, such as a swimming pool, for, typically under normal contamination, some months until the anode is consumed. Copper and/or silver ions liberated from the galvanic cell suppress bacterial, fungal and/or algae growth, thus, significantly reducing the amount of chlorine, bromine or other chemicals needed to maintain water quality.

Abstract: A water and fuel conditioning device includes a core or casting made of 40-66% copper, 2-30% zinc, 10-25% nickel, 2-5% tin, 0-1.5% iron and 0-2% lead, all percentages being by weight. Water flowing in contact with this core exhibits greater electrical charge than with prior art devices. The same composition is effective as a fuel conditioner to reduce emissions. In both applications, the near absence of lead has environmental advantages.

Abstract: A method and device for removing pollution from polluted water, consisting of a rod on which are mounted an array of spaced magnesium plates and an array of spaced copper plates. The copper plates are in contact with the magnesium plates. Polluted water passing through the plates results in precipitates of the pollutants which can be mechanically removed.

Abstract: A liquid purification system comprises a flow cell housing electrodes capable of introducing ions into a liquid passing through the flow cell when a current supplied by a controller is applied across the electrodes. The controller is capable of supplying current between zero and ten amps, and at zero to one hundred volts direct current (DC) across the electrodes. The liquid purification system is easily plumbed into the pipework carrying the liquid to be purified. A by pass line is typically installed around the liquid purification system for easing of operation and maintenance. An upstream and downstream adapters are installed on the pipe and separated by a distance approximating the length of the flow cell. The flow cell is positioned between the two adapters and quick connect clamps are used to maintain a seal between the adapters and the flow cell. Removal of the flow cell can occur by stopping the liquid flow on the upstream end of the pipe or opening the by pass line around the flow cell.

Abstract: An apparatus for water treatment, and in particular for electrical water purification in combination with a filtering apparatus for providing purified water for drinking and other application common in the home, farm or business. Metal, hydrogen and oxygen ions are introduced into water to be treated by using plasma fused iridium coated titanium electrodes and copper alloy electrodes. After ionizing the water to be purified, the water is then filtered in a filter tank which contains layers of various filtration media, including granular activated carbon.

Abstract: An ion supply unit for a water system which is to have its contents purified includes a tank fed from a main water supply and an electrolytic ion generator including silver alloy electrodes. A pump circulates water from the tank through the ion generator and back into the tank at a rate of at least 1 L/s to gradually ionize the contents of the tank and generate a concentrate of silver-ion-laden water. An injector feeds the concentrate into the water system as required.

Abstract: There is disclosed a method, and the apparatus useful in the method, for the treatment of water in which the treatment unit is formed of a vessel having a treatment chamber with interior surfaces formed entirely of a nonferrous metal, preferably of copper and/or brass. Within the treatment chamber is suspended an electrode subassembly of copper cathodes and a sacrificial magnesium anode, formed of copper and magnesium plates which are oriented in substantially parallel array, spaced apart by a plurality of electrically conductive spacing elements.

Abstract: Production of air containing minus alkali ion. As shown in FIG. 2, there is shown an electric stone fine powder 20 having the grain size of 0.3 to 3 microns on the average, an electric stone carrier having the electric stone fine powder 20 uniformly mixed therewith, which is in the form of clothes having a volume intrinsic DC electric resistance of 10.sup.7 to 10.sup.10 .OMEGA..cm. This constitutes a vent contact reaction portion 2 as shown in FIG. 3. This portion 2 is located above an air intake 1a at the lower part of a box 1 and extended over the whole internal surface of the box 1. Ventilation means 3 formed from an electric fan causes the electric stone carrier 30 to subject to direct forced ventilation into contact with air, and minus alkali ion is prepared from water molecules which are moisture in air. The air containing the minus alkali ion is delivered from an air port 1b provided at the upper part of the box 1 to an installation spot.

Abstract: Waste water is purified by passing through a vessel in which small particles of insoluble cathodes interact with anodes to form galvanic couples. During this process, chemical reduction of ions of heavy metals in the water occurs by ions and hydroxides formed during electrochemical dissolution of anodes. The hydroxides are an excellent coagulating agent which absorbs impurities contained in the water. Pressurized air can saturate the waste water simultaneously with passing through the vessel with anodes in order to produce process floatation using hydroxides as coagulant. The temperature of the waste water can be increased in order to intensity the process of treatment.

Abstract: The present industrial purification system consists of an electronic power supply and control unit, an ionization delivery unit, having at least one unique Copper/Silver electrode rods. It's objective as applied to water-based fluids in a closed-loop flow system is to prevent electrostatic materials from building up on the cathodic ionization rods and/or achieving ionization in very low conductive water-based systems which have as their medium de-ionized, ultra-purified, or reverse osmosis filtered water. The power supply and control unit requires 120 or 240 vac input at less than 1 amp, and provides an adjustable regulated dc voltage to the electrode rods, dc voltage being 50 volts. A zero center meter on the control panel indicates the actual voltage supplied to the electrodes, whereas current flowing through the electrodes is indicated by a second zero centered meter.

Abstract: In a method and apparatus for treating fluid flowing through piping so as to prevent the deposition of a calcium and magnesium scale on the piping, for example, positive and negative electrodes of electrically conductive materials having different electrochemical potentials are provided on the outer peripheral surface of an electrically insulative tubular member through which the fluid flows. Because the electrodes are disposed out of physical contact with the flowing fluid, the electrodes do not pose an obstacle to the fluid flow nor are the electrodes abraded or worn by particles that may be entrained in the fluid. Nonetheless, an electroconductive connection between the electrodes is established through the body of fluid by a capacitive effect so that the fluid is ionized.

Abstract: A water purifier capable of accomplishing water purification in a water area in which water purification is desired by merely dipping it in water without any additional operation. The water purifier includes a hollow cylindrical cell chamber member, a seal member arranged at each of both ends of the cell chamber member so as to pressedly seal the end, a terminal inserted through the seal member and electrically connected at one side thereof to each of the cells received in the cell chamber member, an annular tightening member threadedly fitted on each end of the cell chamber member to press the seal member into each end of the cell chamber member, an electrode plate connected to the other side of the terminal, and a water-permeable agent basket having a calcium fluoride agent and an iron salt agent received therein and releasably mounted on the tightening member through locking members so as to surround the electrode plate.

Abstract: The invention is an apparatus and process for recovering metal from a solution. This apparatus is a structure having an anode formed from a plurality of reducing metal elements and a cathode formed from a high surface area electrically conductive material such as metal wire. The reducing metal elements of the anode have a more negative standard state reduction potential than the metal to be recovered. This invention is also a process in which a metal is recovered by contacting a solution of a metal to be recovered with the apparatus of the invention.

Abstract: A method and apparatus produces an ionic change in fluid by causing the fluid to flow in specified sequence over electrodes having different electrochemical potentials. The last electrode which the fluid contacts is so selected as to provide the desired ionic change. The electrodes are provided in a tube of electrically insulative material such as plastic. At least some of the electrically conductive material of one of the electrodes is disposed downstream of all of the electrically conductive material of the other of the electrodes, so that fluid flowing axially through the tube sequentially contacts the electrodes and is only acted on by the downstream electrode before flowing from the tube. By appropriately selecting the material of the downstream electrode, decoloration of fluid having metal oxides or a REDOX reaction can be carried out.

Abstract: Apparatus for conditioning of fluids such as fuel compositions. The fluid to be treated is brought into contact with an alloy comprising zinc, manganese, copper, a precious metal and silicon. The alloy may be surrounded by one or more magnets to enhance operation.

Abstract: A self-contained water treatment device to facilitate the washing of articles, such as clothes in a conventional washing machine, includes a body, a first electrode in the form of a layer of paint of an electrically conductive material integrated with the body, and a second electrode of a layer of paint of an electrically conductive material integrated with the body. The electrically conductive paints of the first and second electrodes have different electrochemical potentials and are at least in part spaced apart from one another on an electrically insulative surface of the device so as to be electrically isolated from one another. The device also has sufficient buoyancy so as to float in water. In use, the device is placed into a reservoir of water, such as the tub of a conventional clothes washing machine or dish washing machine, and the tub is filled with water and the articles to be washed.

Abstract: The present invention is drawn to a method and apparatus for treating electrically conductive fluid. Positive and negative electrodes of electrically conductive materials having different electrochemical potentials are spaced apart and electrically isolated from one another so that the only electroconductive connection that develops an electrochemical potential between the electrodes is established by fluid to be treated flowing between the electrodes. Such fluid is therefore ionized which will both prevent the precipitation of solids from the fluid which would tend to form a scale on the inner surface of piping through which the fluid flows, and aid in the removal of a previously formed scale. On the other hand, a third electrode is also provided so as to be electroconductively connected with the positive electrode but electrically isolated from the negative electrode. Therefore, the third electrode will release metal ions into the fluid.

Abstract: Apparatus and methods for conditioning of fluids such as water, aqueous solutions and fuel compositions. The fluid to be treated is brought into contact with an alloy comprising zinc, manganese, copper, a precious metal and silicon. The alloy may be electrically connected to earth ground during operation.

Abstract: The present invention is drawn to a method and apparatus for treating electrically conductive fluid. In once such apparatus, positive and negative electrodes of electrically conductive materials having different electrochemical potentials are spaced apart. At least one of the electrodes has a covering of electrically insulative material extending substantially therearound. Thus, the only electroconductive connection that develops an electrochemical potential between the electrodes is established by a capacitive effect through the fluid to be treated, which fluid is passed between the electrodes. Accordingly, when a body of electrically conductive fluid to be treated is interposed between the electrodes, an electroconductive connection between the electrodes is established through the body of fluid by a capacitive effect and the fluid is ionized.

Abstract: The present invention is drawn to a method and apparatus for treating electrically conductive fluid. Positive and negative electrodes of electrically conductive materials having different electrochemical potentials are spaced apart and electrically isolated from one another so that the only electroconductive connection that develops an electrochemical potential between the electrodes is established by fluid to be treated extending between the electrodes. Fluid passing between the electrodes is therefore ionized. Because it has been found that superior effects can be achieved when the fluid is ionized under a voltage only condition in which there is relatively little current flow through the fluid, an electrical insulator is disposed between the positive and negative electrodes as extending across any shortest direct path therebetween.

Abstract: There is disclosed a method and an apparatus for treatment of water in an electrolytic cell having stacked plates of magnesium and copper in alternating array, separated by thin metal, brass washers. The stacked plates are disposed transversely across a cylindrical treatment chamber, preferably with four stacks aligned on equally angular spacings within the chamber. The water to be treated is introduced into the chamber tangentially to the inner wall thereof and is directed over the stacked plates. The tangential introduction of water into the treatment chamber generates a vortex flow of the water across the electrolytic cells which accelerates clarification of the water by forced separation of the precipitates which are collected in the bottom of the separation chamber and periodically removed. The clarified water is removed from the treatment chamber and passed through subsequent processing.

Abstract: An autoelectrolytic hydrogen generator system constituted by one or a plurality of similar cells wherein a galvanic arrangement of magnesium and aluminum plates of sacrificial elements as anode; stainless steel as cathode and sea water as electrolyte, by its very nature is made to develop a voltage when connected in short circuit causing a current to flow within the system and hydrogen production of hydrogen in situ and on demand by the electrolytic action at one pole, the cathode, and additional hydrogen by the electrochemical reaction at the other pole, the anode. Surplus electric energy of the system applied to a optional electrolyzer will also be made to produce additional hydrogen at its two sacrificial aluminum electrodes.