Abstract: A method includes providing a cuvette containing a fluid sample having a first substance and emitting light from a light source through the cuvette containing the fluid sample for a duration of time. The cuvette is made of a material that at least partially dissolves in the presence of the first substance. Over the duration of time, the cuvette at least partially dissolves and an intensity of light that passes through the cuvette and the fluid sample changes at a rate. The method also includes receiving, by a light detector, the light that passed through the cuvette, measuring a change in intensity of the received light over the duration of time, and determining that the rate of change in intensity of the light over the duration of time is greater than a threshold rate of change.

Abstract: An apparatus includes a plate and a microheater. The plate defines a sample reservoir, component reservoirs, an outlet, a microfluidic channel, and branches. The sample reservoir is configured to hold a specified sample volume of a hydrocarbon sample. Each component reservoir is configured to hold a respective specified component volume of a different one of the hydrocarbons. The microfluidic channel extends from the sample reservoir to the outlet. Each branch connects a different one of the component reservoirs to the microfluidic channel. The microheater is an electrical resistor that is configured to provide heat to the hydrocarbon sample held in the sample reservoir. The hydrocarbon sample fractionates into the hydrocarbons, which are distributed across the component reservoirs, as the hydrocarbon sample flows from the sample reservoir to the outlet in response to receiving the heat from the microheater.

Abstract: An apparatus includes a plate and a micro-protrusion baffle. The plate defines a microfluidic channel that is configured to flow a sample of lubrication oil. The microfluidic channel has an inlet for receiving the sample of lubrication oil. The microfluidic channel has an outlet for discharging the sample of lubrication oil. The plate defines walls of the microfluidic channel. The walls extend from the inlet to the outlet. The micro-protrusion baffle is located within the microfluidic channel between the inlet and the outlet. The micro-protrusion baffle extends from any of the walls. The micro-protrusion baffle includes a cyclic olefin copolymer. Dissolution of at least a portion of the micro-protrusion baffle in response to the sample of lubrication oil flowing through the microfluidic channel indicates a presence of hydrocarbon fuel in the sample of lubrication oil.

Abstract: A system includes a microfluidic device having a substrate, a reservoir defined in the substrate a microfluidic channel formed in the substrate, a microheater, and a detector. The reservoir is configured to store a fluid sample to be tested for the presence or absence of a compound. The microfluidic channel extends from the reservoir and includes a first portion fluidically connected to the reservoir, a second portion, and a detection portion fluidically connected between the first and second portions. The microheater is arranged adjacent to the reservoir and is configured to heat the fluid sample to a temperature at which the fluid sample releases a byproduct in response to being heated. The detector is arranged in the detector portion and is configured to indicate a presence or absence of the compound in the byproduct released from the heated sample.

Abstract: Methods, systems, and apparatus to diagnose lubrication oil deterioration. In one aspect, a method includes irradiating a lubrication oil sample with a light beam to emit a light-induced fluorescence, detecting and processing the light-induced fluorescence signal to determine a temporal variation of a fluorescence intensity, identifying a steady state of the light-induced fluorescence signal, processing the temporal variation of the fluorescence intensity to determine a lubrication oil parameter, and correlating the oil parameter to a calibration curve to diagnose the lubrication oil deterioration.

Abstract: Methods, media, and devices for determining the deterioration of an oil by determining the viscosity of the oil from fluorescence rise-time are provided. A sample of an oil from a machine may be obtained. The oil sample may be irradiated using a light source such a laser to induce fluorescence in the oil sample. The induced fluorescence may be filtered and collimated before being detecting by a photodiode. The relative intensity of the fluorescence may be measured over a time period at a sample rate and used to determine the fluorescence rise-time of the oil sample. The viscosity of the oil sample may be determined from the fluorescence rise-time. The determined viscosity may be compared to viscosity threshold value to determine the deterioration of the oil.

Abstract: Methods, systems, and apparatus to diagnose lubrication oil deterioration. In one aspect, a method includes irradiating a lubrication oil sample with a light beam to emit a light-induced fluorescence, detecting and processing the light-induced fluorescence signal to determine a temporal variation of a fluorescence intensity, identifying a steady state of the light-induced fluorescence signal, processing the temporal variation of the fluorescence intensity to determine a lubrication oil parameter, and correlating the oil parameter to a calibration curve to diagnose the lubrication oil deterioration.

Abstract: Methods, systems, and apparatus to diagnose lubrication oil deterioration. In one aspect, a method includes irradiating a lubrication oil sample with a light beam to emit a light-induced fluorescence, detecting and processing the light-induced fluorescence signal to determine a temporal variation of a fluorescence intensity, identifying a steady state of the light-induced fluorescence signal, processing the temporal variation of the fluorescence intensity to determine a lubrication oil parameter, and correlating the oil parameter to a calibration curve to diagnose the lubrication oil deterioration.

Abstract: Methods, systems, and apparatus to diagnose lubrication oil deterioration. In one aspect, a method includes irradiating a lubrication oil sample with a light beam to emit a light-induced fluorescence, detecting and processing the light-induced fluorescence signal to determine a temporal variation of a fluorescence intensity, identifying a steady state of the light-induced fluorescence signal, processing the temporal variation of the fluorescence intensity to determine a lubrication oil parameter, and correlating the oil parameter to a calibration curve to diagnose the lubrication oil deterioration.

Abstract: Methods, media, and devices for determining the deterioration of an oil by determining the viscosity of the oil from fluorescence rise-time are provided. A sample of an oil from a machine may be obtained. The oil sample may be irradiated using a light source such a laser to induce fluorescence in the oil sample. The induced fluorescence may be filtered and collimated before being detecting by a photodiode. The relative intensity of the fluorescence may be measured over a time period at a sample rate and used to determine the fluorescence rise-time of the oil sample. The viscosity of the oil sample may be determined from the fluorescence rise-time. The determined viscosity may be compared to viscosity threshold value to determine the deterioration of the oil.