A method and system for diagnosing a condition of an air-breathing aircraft engine are described. The method comprises obtaining a sample of lubricating fluid from the engine, filtering the sample to obtain a plurality of particles from the lubricating fluid, obtaining chemical composition data for the plurality of particles, determining a quantity of volcanic ash in the lubricating fluid by considering each one of the particles as composed partially of volcanic ash and partially of at least one other material and determining a first percentage of surface area of the particles covered by the volcanic ash and a second percentage of the surface area of the particles covered by the at least one other material, the volcanic ash having associated thereto a predetermined chemical composition, and diagnosing a condition of the engine based on the quantity of volcanic ash found in the lubricating fluid.

This application relates to apparatus and method for x-ray fluorescence analysis. There is provided an X-ray fluorescence analysis apparatus for analysing a sample, The X-ray fluorescence analysis apparatus comprises an X-ray source, a measurement chamber for holding the sample in air, and an X-ray detector. The X-ray source is arranged to irradiate the sample with a primary X-ray beam, to cause the sample to fluoresce. The X-ray detector is arranged to detect characteristic X-rays emitted by the sample and to determine a measured X-ray intensity associated with the characteristic X-rays. An X-ray filter, which transmits the primary X-ray beam, is arranged between the X-ray source and the sample. The X-ray source comprises an anode of material having an atomic number that is less than 25. The X-ray fluorescence analysis apparatus further comprises a sensor arrangement configured to sense air pressure and air temperature. A processor receives the measured X-ray intensity. The processor also receives air pressure data and air temperature data from the sensor arrangement. The processor is configured to carry out a compensation calculation for adjusting the measured X-ray intensity using the air pressure data and the air temperature data.

A method of determining one or more fuel characteristics of an aviation fuel for powering a gas turbine engine of an aircraft includes: measuring one or more trace substance parameters of the fuel, the one or more trace substance parameters each associated with a respective trace substance in the fuel; and determining one or more fuel characteristics of the fuel based on the one or more trace substance parameters. Further, a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

A method and a system for creating a reference standard for hydrogen sulfide concentrations in crude oil are described. The method includes receiving a volume of crude oil in a vessel. A hydrogen sulfide gas is flowed from a pressurized gas cylinder to the vessel to form a hydrogen sulfide gas-crude oil mixture. The hydrogen sulfide gas continues to flow from the pressurized gas cylinder to the vessel at a set pressure for a predetermined time to adjust the hydrogen sulfide concentration in the hydrogen sulfide gas-crude oil mixture to a hydrogen sulfide threshold concentration. The flow of the hydrogen sulfide gas into the vessel is stopped.

The invention relates to a novel method for diagnosing the sulfur nutrition state of a plant by measuring the content of certain mineral nutrients in the leaves.

A method of generating a maintenance schedule for an aircraft including one or more gas turbine engines powered by an aviation fuel. The method includes: determining one or more fuel characteristics of the fuel; and generating a maintenance schedule according to the one or more fuel characteristics. Also disclosed is a method of maintaining an aircraft, a maintenance schedule generation system and an aircraft.

A method and system to determine mass fraction of aromatic hydrocarbons, sulfur-multi-sulfur, sulfur-nitrogen, multi-sulfur-multi-nitrogen, and nitrogen containing aromatic compound classes present within a petroleum sample. The invention uses total sulfur determination, total nitrogen determination, and elemental formulas determination, with the latter determined through time-of-flight mass spectrometric analysis with atmospheric pressure photo ionization and Fourier-transform ion-cyclotron resonance mass spectrometric analysis with atmospheric pressure photo ionization.

The disclosure describes a method to indirectly measure the amount of elemental sulfur or amorphous dithiazine in a reservoir sample by converting them to H.sub.2S gas. The H.sub.2S is captured via caustic cyanide solution and quantified by analytical methods and correspond to the concentration of elemental sulfur or amorphous dithiazine. The method has particular applicability to determine where best to drill and avoid locations of high sulfur.

The present invention relates to method for assessing the H.sub.2S release capacity of a liquid sample containing one or more sulfur compounds which are able to be degraded into gaseous H.sub.2S with temperature. The method comprising: a) Placing a volume of the liquid sample in a purge vessel so as to obtain a liquid phase and a gaseous phase in a flask; b) Purging the gaseous phase with an inert gas stream for a determined period of time; e) Passing the purged gaseous phase through a H.sub.2S trap; d) Recovering H.sub.2S from the H.sub.2S trap; and e) Dosing the recovered H.sub.2S. The invention is also used in a method for selecting a liquid sample, in particular among a group of different liquid samples.

Systems and methods include a computer-implemented method for analyzing petroleum samples. Different boiling curves are received that are calculated for a petroleum sample using different analytical speciation techniques. The boiling curves include: 1) a detailed hydrocarbon analysis (DHA) is used for a speciation of light-end components of the petroleum sample; 2) a comprehensive 2-dimensional (2D) gas chromatography (GCxGC) is used for a speciation of a middle distillates range of the petroleum sample; and 3) a high-resolution mass spectrometry is used for a speciation of heavy-end components of the petroleum sample. A compositional coverage of the different analytical speciation techniques for the petroleum samples is determined using the different boiling curves. Each of the different analytical speciation techniques covers a different boiling range and produces a compositional model modeling a breakdown of components in the petroleum sample by carbon number, aromatic ring family, and heteroatom class.