Abstract: An anode assembly is disclosed for use in a cathodic protection system. The anode assembly includes an elongated housing, an electrical cable, an anode, and electrically conductive backfill. The housing has a leading end and a trailing end through which the electrical cable extends. The anode is located within the housing and is in the form of a plurality of electrically conductive segments which are spaced apart from each other and which are electrically connected to the electrical cable at respective electrically conductive joints. The backfill surrounds the anode and cable within the housing.

Abstract: A method and apparatus for monitoring an AC line for impedance change. In one embodiment, the method, includes superimposing a tone on an AC current coupled to the AC line, wherein the tone is a higher frequency than an AC voltage waveform on the AC line; applying a correlation over a sampled AC voltage waveform, obtained by sampling the AC voltage waveform, to generate a correlated signal; and determining whether at least one change in characteristic of the correlated signal occurs.

Abstract: A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.

Abstract: An anode assembly is disclosed for use in a cathodic protection system. The anode assembly includes an elongated housing, an electrical cable, an anode, and electrically conductive backfill. The housing has a leading end and a trailing end through which the electrical cable extends. The anode is located within the housing and is in the form of a plurality of electrically conductive segments which are spaced apart from each other and which are electrically connected to the electrical cable at respective electrically conductive joints. The backfill surrounds the anode and cable within the housing.

Abstract: A method for protecting a plurality of metal electrical poles and copper grounding from galvanic corrosion in corrosive soils includes electrically interconnecting the poles to a grounding grid and providing an impressed current anode for the cathodic protection of the grounding grid.

Abstract: A method of protecting a metal section in concrete. The method comprises the steps of providing a sacrificial anode and embedding the sacrificial anode in a porous matrix in the cavity; providing a source of DC power with positive and negative connections and electrically connecting one of the connections of the source of DC power to the metal section to be protected; electrically connecting the a sacrificial anode in series with the other connection of the source of DC power and spacing the source of DC power from the cavity and the connections to the source of DC power which comprise at least one of wires and cables; and driving an anode current density from the sacrificial anode in excess of 500 mA/m2. An apparatus of protecting a metal section in concrete is also disclosed.

Abstract: The present invention includes an anodic device for reducing corrosion adapted to reduce corrosion of an object subject to corrosion having a base with a thickness and surface area, and a plurality of protrusions protruding from the base each having a thickness and surface area, wherein the device is configured to allow a current to flow between the device and the object subject to corrosion. The present invention also includes methods associated with the use of such devices.

Abstract: The present disclosure pertains to methods of protecting a surface (e.g., a metal surface) from corrosion by conformably attaching a hybrid device comprising at least one multilayer energy storage device and at least one energy conversion device.

Abstract: The invention describes a method of reducing or preventing the growth of microbes on the surface of an object, wherein the object is of such material that it can act as a working electrode. The method comprises the steps of providing a counter electrode, and a reference electrode. The object is used as the working electrode. Electrical current is passed through the working and counter electrodes. The current through the counter electrode is varied such that the electric potential of the working electrode is constant relative to the electric potential of the reference electrode. Also described is an apparatus for reducing or preventing microbes on an object using a potentiostatic device.

Abstract: An impressed current cathodic protection system for a target structure susceptible to corrosion (such as of steel or cast iron) which comprises an inert mixed metal oxide anode surrounded by a tightly packed conductive zone connected to a power supply source and having an input/output regulator to control the flow of current to the target structure. The present invention relates to device and method to provide personal and/or medical details of one or more individuals in the event of an emergency.

Abstract: Cathodic protection of steel in concrete is provided by locating an anode assembly including both a sacrificial anode and an impressed current anode in contact with the concrete and providing an impressed current from a power supply to the anode. The impressed current anode forms a perforated sleeve surrounding a rod of the sacrificial anode material with an activated ionically-conductive filler material between. The system can be used without the power supply in sacrificial mode or when the power supply is connected, the impressed current anode can be powered to provide an impressed current system and/or to recharge the sacrificial anode from sacrificial anode corrosion products.

Abstract: In some embodiments, an ICCP system includes an AC-DC rectifier receiving AC power from an AC power source and providing a DC output having a constant voltage or a constant current, a cathode connection electrically coupling the AC-DC rectifier to a structure to be protected by the ICCP system, current-emitting anodes arranged in parallel and receiving the DC output from the AC-DC rectifier, and a controller communicating with the AC-DC rectifier to set a maximum value for the constant voltage or constant current of the DC output. In other embodiments, an ICCP system includes a converter assembly including an AC-DC rectifier and a rectifier chassis enclosing and environmentally sealing the AC-DC rectifier. The ICCP system also includes an environmentally-sealed controller communicating with the AC-DC rectifier and an environmentally-protected Input-Output connection assembly.

Abstract: A multi purpose segmented Titanium Mixed Metal Oxide coated impressed current cathodic protection anode assembly (Ti MMO anode assembly). The Ti MMO anode assembly includes combinations selected from four anode components and four connection components. The various components may be assembled for different applications in liquid or soil environments for the prevention or reduction of corrosion and loss of structural integrity. For example, the Ti MMO anode assembly may be applied to protect pipelines, buried structures, piers and internal surface protection of tanks and vessels in different arrangements such as deep wells, shallow ground beds, or distributed individual anodes.

Abstract: The invention relates to a method for determining the location of the corrosion sites in reinforced concrete, wherein a value (UB, UC) of a voltage potential (UB, UC) present at each measurement location is measured at at least two measurement locations relative to a reference voltage potential (UA) present at a reference location, and information about the direction to the corrosion site (K) and/or the distance to the corrosion site (K) is determined from the location information (XB, YB, XC, YC) for each measurement location, particularly also the reference location, and the voltage potential (UA, UB, UC) present at each location.

Abstract: A method of carrying out post-treatment to a sprayed coating includes spraying aluminum-containing material onto a surface of a steel for forming a sprayed coating on the steel, and coating electrolytic aqueous solution or water base paint containing electrolytic aqueous solution therein onto the sprayed coating.

Abstract: Disclosed herein is a subsea well assembly; wherein in an example embodiment the subsea well assembly includes an umbilical attached to a power source. The power source can be on a platform. Also included is a connector for connecting the umbilical to a receptacle included with the subsea well assembly and a subsea control module delivering power and control signals to the subsea well assembly. An impressed current protection module is integrated in the subsea control module that receives power from the umbilical.

Abstract: Method and apparatus for reducing corrosion of a current bar in a corrosive environment. The non-reactive metal is fused around a reactive metal creating a shell and reducing the corrosion of the reactive metal.

Abstract: The invention relates to a superficial treatment method by electrolysis of ferrous surfaces to enhance friction or tread and seizing resistance features, wherein the surfaces provide the electrolysis anode, the electrolysis bath includes a sulphur species, primarily contains water and also contains a chloride salt and a nitrogen species in quantities which facilitates the sulphuration reaction of the surfaces.

Abstract: Embodiments include membrane restoration process. A membrane can be restored by replacing an anolyte and a catholyte of a cell with a solution having an organic acid. The cell can include an anode, a cathode and a membrane fouled with a metal. A cheleate can be formed with the metal and the organic acid of the solution and an electric current can be provided between the anode and the cathode of the cell to protect the cell from corrosion while forming the chelate.

Abstract: A cathodic protection system is provided for a subterranean well casing having an enclosed upper section of the well casing being substantially shielded by a cellar from an impressed-current cathodic protection circuit passing through earth media. The impressed-current cathodic protection circuit is provided to protect an unenclosed lower section of the well casing. To protect the enclosed upper section of the well casing, a supplemental cathodic protection circuit is provided. The supplemental cathodic protection circuit is a galvanic anode cathodic protection circuit comprising the enclosed upper section of the well casing and one or more bracelet galvanic anodes being circumferentially mounted to the enclosed upper section. The enclosed upper section of the well casing and the one or more bracelet galvanic anodes are substantially surrounded by a cellar backfill, and the galvanic anode cathodic protection circuit is equally effective throughout a broad range of non-homogeneity within the cellar backfill.

Abstract: A method for protecting a plurality of metal electrical poles and copper grounding from galvanic corrosion in corrosive soils includes electrically interconnecting the poles to a grounding grid and providing an impressed current anode for the cathodic protection of the grounding grid.

Abstract: Apparatus for connection to a metallic structure, the apparatus comprises a transformer rectifier unit operable to output a DC current for cathodic protection of a metallic structure, and a modulator unit connected to receive a DC output from the transformer rectifier unit. The modulator unit is arranged for connection to a metallic structure, and is operable to produce a modulated current which is applied to such a metallic structure when the apparatus is in use, such that the metallic structure is detectable by a wireless locating device. The modulator unit is operable to be controlled remotely.

Abstract: An anode for cathodic protection of underwater equipment is provided. The anode comprises: a support body; sacrificial material retained by the support body; and an attachment mechanism for releasably attaching the anode to the underwater equipment.

Abstract: An apparatus and method for monitoring cathodic protection of a protected object that includes a probe with five segments in series. The cathodic protection is provided by a system with a power supply that impresses current onto the protected object. An anode is included with the system that is also connected to the power supply. The third and fifth segments are in electrical communication through a frangible connection; that over time galvanically corrodes to electrically isolate the third and fifth segments. The second segment, which is a permanent isolator, is set between the first and third segments. The third segment is selectively connected with the protected object. When the third segment is selectively disconnected from the protected object, measuring the potential difference between the third segment and the first segment yields a value for object polarization that is void of IR error.

Abstract: Modular anode assemblies are used in electrolytic oxide reduction systems for scalable reduced metal production via electrolysis. Assemblies include a channel frame connected to several anode rods extending into an electrolyte. An electrical system powers the rods while being insulated from the channel frame. A cooling system removes heat from anode rods and the electrical system. An anode guard attaches to the channel frame to prevent accidental electrocution or damage during handling or repositioning. Each anode rod may be divided into upper and lower sections to permit easy repair and swapping out of lower sections. The modular assemblies may have standardized components to permit placement at multiple points within a reducing system. Example methods may operate an electrolytic oxide reduction system by positioning the modular anode assemblies in the reduction system and applying electrical power to the plurality of anode assemblies.

Abstract: A porous metal body containing continuous pores and having a low oxygen content is provided by decomposing a porous resin body that contains continuous pores and has a layer of a metal thereon by heating the porous resin body at a temperature equal to or less than the melting point of the metal while the porous resin body is immersed in a first molten salt and a negative potential is applied to the metal layer; and a method for producing the porous metal body is provided.

Abstract: A method and system for protecting underground gas carrier pipes housed within an outer casing pipe in which a gas carrier pipe section disposed within an outer casing pipe section and having opposed ends is electrically isolated from a remaining gas carrier pipe section proximate each of the ends. An annular space between the gas carrier pipe section and the outer casing pipe section is filled with an electrolyte. At least one anode electrode is inserted into the annular space distal from each of the gas carrier pipe section and the outer casing pipe section and connected with a positive voltage lead of a cathodic protection rectifier. A negative voltage lead of the cathodic protection rectifier is connected to the gas carrier pipe section.

Abstract: A system and method for corrosion protection of measuring electrodes in electromagnetic flowmeters, wherein an electromagnetic flowmeter for measuring the flow of a medium through a measuring tube comprises first and second metallic measuring electrodes arranged on opposite sides of the measuring tube and in contact with the medium. The rate of flow of the medium in the measuring tube is measurable by output signals from the measuring electrodes representative of a potential difference between the measuring electrodes induced by the flow of the medium in the measuring tube in the presence of a magnetic field.

Abstract: A semiconductor layer (12) is caused to receive electromagnetic waves (1) to emit electrons; the emitted electrons are collected and supplied to an object to be protected against corrosion; and the electrons (3) are returned from the object to be protected against corrosion (16), to which the electrons (2) are supplied, to the semiconductor layer (12) via an electrolytic layer (14), to thereby cause an electric current to flow to the object to be protected against corrosion (16) to make a potential of the object to be protected against corrosion (16) low. In a corrosion protection structure (10), an electron supplier (13) is electrically connected to a object to be protected against corrosion (16), to thereby provide corrosion protection, the electron supplier (13) being made of a semiconductor layer (12) formed on a supporting member (11) that is capable of transmitting electromagnetic waves and has electrical conductivity.

Abstract: A method and system for protecting underground gas carrier pipes housed within an outer casing pipe in which a gas carrier pipe section disposed within an outer casing pipe section and having opposed ends is electrically isolated from a remaining gas carrier pipe section proximate each of the ends. An annular space between the gas carrier pipe section and the outer casing pipe section is filled with an electrolyte. At least one anode electrode is inserted into the annular space distal from each of the gas carrier pipe section and the outer casing pipe section and connected with a positive voltage lead of a cathodic protection rectifier. A negative voltage lead of the cathodic protection rectifier is connected to the gas carrier pipe section.

Abstract: The invention is a process for cathodic protection of electrodes wherein negative bias is applied on the electrode. The negative bias is obtained by asymmetric current pulse, which is obtained by negative phase pulsing with higher amplitude than that of the anodic phase. The asymmetric current pulse is obtained by negative phase pulsing with wider pulse width than that of the anodic phase. The asymmetric current pulse may also be obtained by negative phase pulsing with both higher amplitude and wider pulse width than that of the anodic phase. The invention further relates to a process for cathodic protection of electrodes, wherein negative bias is applied on the electrode, and the negative bias is obtained by asymmetric current pulse, where the asymmetric current pulse is obtained by negative phase pulsing with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: A sacrificial anode system and associated surface pipe system maintenance method designed to protect surface pipes and associated parts. According to a first aspect of the present invention, the sacrificial anode system is installable at an interface between a first pipe and a second pipe and comprises an insertion sleeve shaped to fit along an inner surface of the first pipe, a flange attached to the insertion sleeve and shaped to rest against an end surface of the first pipe, a sacrificial anode to be positioned within the first pipe, and a stem linking the sacrificial anode to the insertion sleeve. According to a second aspect of the present invention, a method for maintaining a surface pipe system is also provided.

Abstract: A cathodic protection system for use in an electrolyte includes a protected structure to be at least partially immersed in the electrolyte, at least one sacrificial anode to be at least partially immersed in the electrolyte and electrically connected to the protected structure, and a substantially impermeable barrier disposed between the at least one sacrificial anode and the electrolyte.

Abstract: A cadmium-free, zinc-based alloy suitable as a sacrificial anode substantially consists of 0.4-0.6% by weight of aluminum, 0.02-0.03% by weight of indium, max. 0.001% by weight of cadmium, maximum 0.005% by weight of copper, maximum 0.006% by weight of lead, maximum 0.0005% by weight of tin, maximum 0.10% by weight of other metals, in particular nickel and thallium, and balance zinc having a purity of about 99.995% The alloy shows advantageous properties with respect to resistance to cracking and breaking during post machining of the casting, especially when producing sacrificial anodes having relatively small dimensions.

Abstract: A method for corrosion protection in a marine construction including a plurality of metal elements and at least one reference electrode at least partly immerged in water, the metal elements including an anode and a metal part, the anode being provided for corrosion protection of the metal part includes measuring an electric potential of the metal part with the reference electrode as a ground reference. At least one of the metal elements and at least one of the at least one reference electrode are connected to a DC electrical power outlet so as to allow an electrical regeneration current through an electrical circuit including the at least one of the metal elements, the at least one of the at least one reference electrode and the electrolyte so that the reference electrode is anodized.

Abstract: A single anode system used in multiple electrochemical treatments to control steel corrosion in concrete comprises a sacrificial metal that is capable of supporting high impressed anode current densities with an impressed current anode connection detail and a porous embedding material containing an electrolyte. Initially current is driven from the sacrificial metal [1] to the steel [10] using a power source [5] converting oxygen and water [14] into hydroxyl ions [15] on the steel and drawing chloride ions [16] into the porous material [2] around the anode such that corroding sites are moved from the steel to the anode restoring steel passivity and activating the anode. Cathodic prevention is then applied. This is preferably sacrificial cathodic prevention that is applied by disconnecting the power source and connecting the activated sacrificial anode directly to the steel.

Abstract: The present invention relates to an electrical device for impeding corrosion of a metal body. The electrical device includes a driver circuit including at least one inductive component. The driver circuit is suitable for driving one or more pads coupled to the metal body so that corrosion of the metal body is impeded. A control circuit is provided for controlling the operation of the driver circuit. A feedback circuit provides feedback from the driver circuit to the control circuit. The driver circuit can operate as a resonant circuit, owing to the at least one inductive component, and ballast energy applied to the pads.

Abstract: Disclosed herein is a composition for plasma electrolytic oxidation (PEO) treatment of magnesium alloy products, which contains a sodium hydroxide (NaOH) solution as a main component, the composition comprising, based on the weight of sodium hydroxide contained in the sodium hydroxide solution: 1-20 wt % of sodium fluoride (NaF); 1-15 wt % of trisodium phosphate (Na3PO4); 1-10 wt % of sodium pyrophosphate (Na4P2O7); 1-20 wt % of aluminum hydroxide (Al(OH)3); 1-20 wt % of sodium fluorosilicate (Na2SiF6); 1-10 wt % of potassium hydroxide (KOH); 1-15 wt % of potassium acetate (C2H3O2K); and 1-10 wt % of rare earth metal powder. The disclosed composition can form a firm, dense and uniform oxide film on the surface of a magnesium alloy product.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion, particularly space weather induced corrosion, of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process and adjust the controllable filter in response to at least one measured parameter associated with space weather effects on the conductive structure.

Abstract: An input terminal is electrically connected to a contact point. An anti-corrosion current supplying section is operable to supply an anti-corrosion current to the contact point through the input terminal so as to remove corrosion in the contact point. A series resistor is electrically interposed between the input terminal of the signal processing circuit and the contact point. The anti-corrosion current is supplied to the contact point through the series resistor.

Abstract: The present invention generally relates to synergistic corrosion management systems designed to deliver two or more different types of corrosion inhibiting compounds (e.g., two or more different types of corrosion inhibiting compounds) to an enclosure, and to method for using same. More specifically, the present invention relates to synergistic corrosion management systems designed to eliminate, manage, control and/or mitigate corrosion in containers, enclosures, cisterns and/or storage tanks (e.g., above ground storage tanks). In one embodiment, the present invention utilizes a combination of at least one cathodic-based corrosion prevention or mitigation system, at least one soluble corrosion inhibitor, and at least one volatile or vapor phase corrosion inhibitor.

Abstract: The present invention relates to a process for cathodic protection of electrode or electrode materials wherein negative bias is applied on the electrode. The negative bias is obtained by asymmetric current pulse. The asymmetric current pulse is obtained by performing negative phase with higher amplitude. The asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The asymmetric current pulse is obtained by performing negative phase with higher amplitude and with wider pulse width than that of the anodic phase. The present invention further relates to a process for cathodic protection of electrode or electrode materials, wherein negative bias is applied on the electrode, wherein the negative bias is obtained by asymmetric current pulse, wherein the asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: The invention relates to a treatment solution for producing substantially chromium(VI)-free black conversion layers on alloy layers containing zinc, the solution comprising the following: (i) at least one first carboxylic acid having 1 to 8 carbon atoms, the acid containing no polar groups with exception of the carboxyl group and being a monocarboxylic acid, (ii) at least one second carboxylic acid having 1 to 8 carbon atoms, comprising at least one further polar group that is selected from —OH, —SO3H, —NH2, —NHR, —NR2, —NR3+, and —COOH (wherein R is a C1-C6 alkyl group), (iii) 20 to 400 mmol/l Cr3+ and (iv) 50 to 2000 mmol/l NO3?, and wherein (a) the total concentration of carboxyl groups of the first carboxylic acid(s) is within a range of 5 to 150 mmol/l, (b) the total concentration of carboxyl groups of the second carboxylic acid(s) is within a range of 5 to 150 mmol/l, (c) the ratio of the concentration (in mol/l) of NO3? to Cr3+ is ?1, and (d) the following prerequisite is met (formula (I)), 0.

Abstract: A trailer coupler assembly includes a coupler grid plate, a support bracket coupled to the coupler grid plate, and a kingpin coupled to the coupler grid plate and the support bracket. The kingpin is positioned to extend below a bottom surface of the coupler grid plate. The trailer coupler assembly further includes a sacrificial anode coupled to one of the coupler grid plate and the support bracket in order to retard corrosion of one or more of the coupler grid plate, the support bracket, and the kingpin.

Abstract: The present invention relates to a process for cathodic protection of electrode or electrode materials wherein negative bias is applied on the electrode. the negative bias is obtained by asymmetric current pulse. The asymmetric current pulse is obtained by performing negative phase with higher amplitude. The asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The asymmetric current pulse is obtained by performing negative phase with higher amplitude and with wider pulse width than that of the anodic phase. The present invention further relates to a process for cathodic protection of electrode or electrode materials, wherein negative bias is applied on the electrode, wherein the negative bias is obtained by asymmetric current pulse, wherein the asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: A method for operating a system which inhibits the growth of marine organisms on a submerged surface causes a current to flow to one of two submerged surfaces over a time period that is selected as a function of the magnitude of the current and the area of the surface. In other words, the time period is determined as a function of the current density applied to the surface. In a particularly preferred embodiment the current density is maintained at approximately 35 milliamps per square foot and the time period is approximately four minutes. At the end of the time period, the current is reversed and a second submerged surface is polarized in a similar manner.

Abstract: The present invention relates to a process for cathodic protection of electrode or electrode materials wherein negative bias is applied on the electrode. the negative bias is obtained by asymmetric current pulse. The asymmetric current pulse is obtained by performing negative phase with higher amplitude. The asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The asymmetric current pulse is obtained by performing negative phase with higher amplitude and with wider pulse width than that of the anodic phase. The present invention further relates to a process for cathodic protection of electrode or electrode materials, wherein negative bias is applied on the electrode, wherein the negative bias is obtained by asymmetric current pulse, wherein the asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: Described herein are methods for diminishing or preventing in electrochemical operating systems the deposition of a metal oxide on an electrode surface. The metal oxide is formed by electrochemically assisted reduction of volatile metal oxides formed from a metallic component exposed to oxidative environments. In one example, described herein are methods for diminishing or preventing poisoning of a cathode by applying a negative protection potential to the metallic component. In another example, described herein are methods for diminishing or preventing the deposition of a metal oxide on a cathode surface by removing oxygen from the metallic component itself and thereby decreasing the amount of released volatile oxide from the metallic component by use of an auxiliary oxygen pump cell.

Abstract: An active cathodic protection system, the apparatus comprising a rectifier element with at least one electrical connection to a source of electrical current, the rectifier element associated with a direct current positive (+) output terminal for electrical connection of via an anode connector to a consumable anode, a direct current negative (?) output terminal for electrical connection via a cathode connector to the structure to be protected, grounding means for electrical grounding of the apparatus and anti-cross connection means for preventing the continuing flow of electrical current when the anode connector is associated with the negative output terminal and the cathode connector is associated with the positive output terminal. The cathodic protection system also includes a microprocessor controlled device for shutting the system if an improper current is sensed.

Abstract: A system for corrosion protection is disclosed. The system includes at least one component subject to corrosion and forming a cathode element. An anode element is disposed proximate the at least one component. A reference element is provided proximate the at least one component and configured to provide a voltage signal.