Abstract: The subject technology receives, from a document object model, a set of nodes of a web page, each node corresponding to an element of the web page. The subject technology determines, using an intersection observer, a position and visibility of a set of first elements within a viewport of the web page. The subject technology determines, using a mutation observer, a set of new elements within the viewport that was previously hidden and now visible. The subject technology provides a set of visible elements, based at least in part on the set of new elements and the set of first element, as elements that have been seen by a user during a session. The subject technology generates an index based at least in part on the set of visible elements, the index comprising information corresponding to text that was visible to the user during the session.

Abstract: Formaldehyde is determined by electrochemical oxidation of formaldehyde at an iridium electrode while maintaining the electrode at a fixed potential and measuring the current flowing through the electrode.

Abstract: In a process for reduction or oxidation of materials in aqueous solution by assing a reagent gas through a finely porous catalyst layer into the solution, bodies of electrically conducting material which in the aggregate have a large surface are brought into electrically conducting connection with the catalyst layer on its side facing the solution in order to increase the rate of conversion of the dissolved material. The conducting bodies are distributed in the solution at least in the region of the catalyst layer and increase the effective surface for the conversion of the dissolved material. The invention is particularly useful in connection with catalyst layers provided with an electrically conducting protective cover through which gas and solution may pass on the side of the catalyst layer facing the solution as disclosed in a related application of the same inventors Ser. No. 500,941 filed June 3, 1983.

Abstract: The present invention provides an anode assembly for use on marine structures comprising an elongated sacrificial anode bar and an anode core comprising an elongated member having a straight portion embedded within the anode bar means and its end portion being mitred and which protrude from the side of the anode bar means away from the ends thereof.Preferred embodiments are directed to cores having particularly preferred mitred angles, as well as the cross-sectional configuration of the anode.

Abstract: An electrical membrane probe for the measurement of dissolved oxygen concentration in fluids, particularly designed for monitoring or control of fermentation process and characterized as follows;1. The anode metal is lined on the internal wall of the electrolytic cell which is made of metal tube.2. The vent hole for the adjustment of outer and inner pressures and the protection cover to prevent the inflow of medium into the cell are provided.3. All of parts are connected with each other mechanically then unskilled operators can exchange the especially membrane and cathode, when some of the parts are ruptured or worn out.4. The probe can maintain its ability even after repeated steam sterilization at high temperatures such as 130.degree. C.5. The deterioration of insulation is completely prevented by using glass as insulating material.6. The membrane can be removed and exchanged easily by removing the membrane holding cap.

Abstract: Method of protection of electrically conducting parts in fluoride melts through which direct current flows in the electrolysis of aluminum oxide, comprising applying such an electrical potential to said parts that the direct current flowing through the fluoride melt cannot emerge from the parts at any place within the fluoride melt.

Abstract: A batch type sodium hypochlorite generator and temporary storage unit comprising a sheet anode and a sheet cathode utilizing vertical S-shaped bipolar sheet electrodes in series therebetween, the cathode and cathodic end of each bipolar unit being substantially encircled by the anode or anodic end of the next adjacent bipolar unit and forming an electrolytic cell therebetween; said anode portion of each electrode having the surface thereof coated with a dimensionally stable electrode coating which is extremely resistant to passivation; nonconductive spacers between each such electrolytic cell to both hold the electrodes in proper alignment and to minimize stray currents between the electrolytic cells; and control means for feeding brine to such generator and discharging such sodium hypochlorite solution therefrom when required.

Abstract: This invention relates to a glass electrode structure. More specifically, the present invention relates to a glass electrode having a curved sensor tip for use in determining gas in an electrochemical membrane diffusion cell.

Abstract: A sacrificial anode and a protective coating for cathodically protecting a pipeline against corrosion especially in underground installation. The preferred anode includes a tubular shell of sacrificial anodic material electrically contacted by integral or intermediate contacts with the pipe andd having a longitudinal seam for opening and closing the anode to place it around the pipe with corrosion and electrical resistant coating material between the anode and pipe. The outer surface of the anode can have a coating of a salt material suitable for forming an electrolyte with water in the surrounding soil. In a preferred and easily installable form, the anode comprises a pair of shell halves having a coating material secured to the inner surface thereof and extending longitudinally beyond the shell halves to overlap the coating material of pipe sections at a ends of the mill-wrap coating cut-back.

Abstract: An in vivo specific ion sensor contains a specific ion electrode and surrounding reference half cell which has its immobilized electrolyte adjacent to and spaced from the specific ion electrode. The specific ion sensor is introduced, for example, into the blood stream by passing it through a cannula which perforates the subject's tissue and the underlying wall of the blood vessel.

Abstract: A method for the preparation of very accurate measuring surfaces on measuring elements such as gauge blocks, surface plates, and the like. In one embodiment of the inventive method, the measuring surface is prelapped to a level of two to five microns below the desired final level. Thereafter, the surface is sputter coated with a hard ceramic or cermet layer with a thickness of three to ten microns, and finally the surface is lapped until the final desired level is reached. The invention also comprehends measuring elements made according to the novel method.

Abstract: An apparatus and method are provided for continuous electrocoating of a conducting substrate with a coating of essentially non-conductive material. The invention is especially characterized by the provision of at least one electrode which converges towards the substrate in the direction of travel of the substrate. The electrode so converges in the direction of travel of the substrate that the rate of deposition of the non-conductive material onto the conducting substrate remains substantially constant throughout the electrocating operation.