Abstract: This invention pertains generally to the field of chemical synthesis and purification, and more specifically to methods of synthesizing and purifying certain 3,7-diaminophenothiazin-5-ium compounds (referred to herein as “diaminophenothiazinium compounds”) including Methythioninium Chloride (MTC) (also known as Methylene Blue). In one embodiment, the method comprises the steps of, in order: nitrosylation (NOS); nitrosyl reduction (NR); thiosulfonic acid formation (TSAF); oxidative coupling (OC); Cr(VI) reduction (CR); isolation and purification of zwitterionic intermediate (IAPOZI); ring closure (RC); chloride salt formation (CSF); one of: sulphide treatment (ST); dimethyldithiocarbamate treatment (DT); carbonate treatment (CT); ethylenediaminetetraacetic acid treatment (EDTAT); organic extraction (OE); and recrystallisation (RX). The present invention also pertains to the resulting (high purity) compounds, compositions comprising them (e.g.

Abstract: Described is a method of reducing corrosion of a silver-containing surface comprising electro-depositing a layer of an iodine-containing material on the silver-containing surface at a charge density of about 80 mA*s (milliamps second)/cm2 or less. Also described is an electrical contact also produced by the method.

Abstract: A temperature sensor includes a membrane supported by a substrate and a circuit having elements for a substrate electrical resistance indicative of the temperature of a substrate and a membrane electrical resistance indicative of the temperature of a membrane. The substrate resistance and the membrane resistance are arranged in a bridge configuration to facilitate measurement of a differential voltage responsive to temperature change. The resulting temperature signal includes a first varying portion and a second varying portion. A controller receives a temperature signal from sensor, eliminates the second varying portion and generates a temperature value based on the based on the first varying portion. In this manner, the sensor provides an improved, fast response to changes in the surrounding temperature.

Abstract: A fuel sensor system for a vehicle includes a fuel pump adapted to be disposed in a fuel tank to pump fuel from the fuel tank to an engine of the vehicle. The fuel sensor system also includes a fuel sensor adapted to be disposed in the fuel tank to measure a property index of the fuel. The fuel sensor system further includes a jet pump connected to the fuel pump to fill the fuel sensor with a fuel sample of the fuel.

Abstract: A fuel sensor system for a vehicle includes a fuel pump adapted to be disposed in a fuel tank to pump fuel from the fuel tank to an engine of the vehicle. The fuel sensor system also includes a fuel sensor adapted to be disposed in the fuel tank to measure a property index of the fuel.

Abstract: A mass air flow sensor comprising: a sensing device with a substantially flat surface from a first point to a second point in a flow path, a heating element substantially centrally located between the first and second points, a first sensing element located between the first and second points on a first side of the heating element in the flow path direction, a second sensing element located between the first and second points on a second side of the heating element opposite the first side in the flow direction; and an air foil mounted a predetermined distance apart from the sensing device having a surface facing the heating element and the first and second sensors, wherein the air foil deflects air flow past the sensing device to be incident on the sensing device at an angle, wherein the air foil is symmetrical with respect to a line perpendicular to a center of the heating element and wherein bi-directional air flow past the sensing device is substantially free of turbulence between the first and second poin

Abstract: The present invention is directed to a single solid state thermal diffusion sensor capable of measuring both the composition and flow of gaseous vapors traveling through a duct. The sensor comprises two orthogonal sensing patterns, each having a heating element positioned equidistant between two thermistor elements. The heaters and thermistors are made from thin film platinum deposited on a thermally insulating polyimide layer having low thermal diffusivity. A sinusoidal voltage is applied to each heating element for generating oscillating thermal waves which propagate through the gaseous vapor to their respective thermistors. The thermistors of a first, transversely positioned sensing pattern are responsive to both the composition and flow of the gaseous vapor, while the thermistors of a second, longitudinally positioned sensing pattern are responsive only to the composition of the gaseous vapor.

Abstract: An apparatus comprises a sensor including a heater, an upstream detector and a downstream detector. An AC signal source excites the heater to generate propagating heat signals that are received by the upstream and downstream detectors. A first detecting circuit provides a first output signal responsive to the propagating heat signals received by the first detector and a second detecting circuit provides a second output signal responsive to the propagating heat signals received by the downstream detector. A difference circuit subtracts the first and second signals to obtain a difference signal and an output circuit provides an output signal responsive to the difference signal, which reflects both magnitude and phase. The resulting output signal has improved resolution and provides for improved sensor sensitivity.

Abstract: An airflow sensor formed on a silicon chip comprises a silicon base covered with an insulating polyimide layer, a lineal resistance heater on the chip energized with current pulses to propagate thermal waves, and a thermistor on the chip downstream of the heater to detect the arrival of each thermal wave. Circuitry determines flow rate as a function of the measured propagation time of the thermal wave. The thermistor may be replaced by a bridge of four resistive elements of which only one or two are sensitive to the thermal wave. The thermistor material is platinum, polycrystalline silicon or amorphous silicon which exhibit high temperature coefficients of resistance.

Abstract: An airflow sensor in a flat chip configuration having sensing elements on only one side is subject to causing turbulence in the airflow which has a deleterious effect on the flow signal. The turbulence is diminished or prevented and sensitivity is enhanced by tilting the plane of the sensor a few degrees to the flow direction. Flow in both directions through a passage is measured by bending the passage at the sensor location so that the flow in either direction is inclined to the surface carrying the sensing elements. Flow in both directions through a straight passage is measured by providing the sensor with sensing elements on both sides and mounting the sensor at a tilt so that flow in both directions is inclined to a surface of the sensor.

Abstract: An air flow sensor which employs a thermocouple using a film of bismuth.sub.0.92 antimony.sub.0.08 to form junctions with gold, platinum or nickel strips and a resistive strip heater of the same metal.