A method of operating an optical icing conditions sensor includes transmitting a first light beam with a first transmitter and a second light beam with a second transmitter, thereby illuminating two illumination volumes. A first receiver receives the first light beam. A second receiver receives the second light beam. A controller measures the intensity of light received by the first and second receivers. The controller compares the intensities to threshold values and determines if either intensity is greater than the threshold values. The controller determines a cloud is present if either intensity is greater than the threshold values. The controller calculates a ratio of the intensities if a cloud is present. The controller determines, using the ratio, whether the cloud contains liquid water droplets, ice crystals, or a mixture of liquid water droplets and ice crystals.

A method of operating an optical icing conditions sensor includes transmitting, with a transmitter, a light beam and thereby illuminating an illumination volume. A receiver array receives light over a range of receiving angles. The receiver array is configured to receive light having the wavelength over a receiver array field of view which overlaps with the illumination volume. A controller measures an intensity of light received by the receiver array. The controller determines that a cloud is present if the intensity is greater than a threshold value. The controller calculates scattering profile data of the light received by the receiver array if a cloud is determined to be present, which includes an angle of a scattering intensity peak within the range of receiving angles and a breadth of the scattering intensity peak. The controller estimates a representative droplet size within the cloud using the scattering profile data.

Apparatus and associated methods relate to determining an effective size, quantity, shape, and type of water particles in a cloud atmosphere based on differences in amplitudes of optical signals backscattered at different backscattering angles. Off-axis backscattering—backscattering at angles other than 180 degrees—is affected by the effective size, quantity, shape, and type of water droplets. Detected amplitudes of optical signals that are backscattered at different angles are used to indicate the effective size, quantity, shape, and type of water particles in the cloud atmosphere. In some embodiments, optical emitters and detectors are configured to measure amplitudes of optical signals backscattered at backscattering angles of both on-axis—180 degrees—and off-axis varieties.

A system includes a method and apparatus suitable for measuring planar drop sizes in a liquid spray. Measurement may involve illuminating the spray with multiple lasers and measuring the scattered intensities at several view angles using linear arrays. The system may use inverse calculation of the measured scattered intensity to estimate the local drop sizes across the entire plane in a spray. The system includes radiation detectors containing sensing elements, a lens systems, and analog to digital conversion board to convert scattered intensities to drop sizes. In addition, the system may include choppers including at least two unique filters. The filters may be selectively placed in a path between the spray and the sensing elements. By selectively placing a single array may measure both a scattered intensity and an extinction of laser light emitted from the spray.

In some examples, a system including a fluid stream monitoring system. The monitoring system includes an illumination device configured to illuminate at least some of particles suspended in a fluid stream; and an imaging device configured to image the illuminated particles at a first image plane that intersects a longitudinal axis of the fluid stream, wherein the illumination device and the imaging device are registered to the fluid stream delivery device in the first image plane, where the first image plane is substantially orthogonal to the longitudinal axis. The system includes processing circuitry configured to determine one or more physical characteristics of the fluid particles.

A differential emissivity imaging device for measuring evaporable particle properties can include a heated plate, a thermal camera, a memory device, and an output interface. The heated plate can have an upper surface oriented to receive falling evaporable particles. The evaporable particles have a particle emissivity and the upper surface has a plate surface emissivity. The thermal camera can be oriented to produce a thermal image of the upper surface. A memory device can include instructions that cause the imaging device to calculate a mass of the individual evaporable particle via heat conduction using a calculated surface area and an evaporation time.

A diagnostic device is disclosed for characterisation of particles from a patient’s airways, such as a lung, when ventilated by a ventilator, and/or for control thereof, comprising a particle detecting unit configured to be connected to a conduit for passing expiration fluid from said patient, for obtaining data related to particles being exhaled from said patent’s airways.

One variation of a method includes, during a test period: triggering release of a tracer test load into air in an environment, according to a set of release parameters, by a dispenser arranged within the environment, the first tracer test load comprising a first concentration of tracers of a first type in solution; and triggering an air sampler, located in the environment, to record a timeseries of aerosol data representing amounts of aerosol particles detected at the air sampler during the test period. The method further includes: deriving a tracer signal, representing changes in amounts of tracers in air detected at the air sampler during the test period, based on the timeseries of aerosol data and the set of release parameters; based on characteristics of the tracer signal, characterizing a set of aerosol flow metrics representing behavior of aerosols in the environment during the test period.

The present invention provides an online measuring method of particle (such as bubbles, droplets and solid particles) velocity in multiphase reactor. The method based on an online multiphase measuring instrument includes the following steps: (1) the online multiphase measuring instrument is placed into the multiphase reactor, and then a particle image produced by two or more exposures are obtained; (2) the actual size of individual pixel in the particle image is determined; (3) valid particles are determined in the depth of field; (4) then the centroid coordinates are conversed to the actual length of the coordinates (x.sub.t,i, y.sub.t,i) and (x.sub.t+Δt,i, y.sub.t+Δt,i) using the actual size of individual pixel. Thus, the instantaneous velocity of particles can be calculated by

[00001]$V_i=\sqrt{\frac{{\left(x_{t+\Delta .Math..Math.t,i}-x_{t,i}\right)}^2+{\left(y_{t+\Delta .Math..Math.t,i}-y_{t,i}\right)}^2}{\Delta .Math..Math.t}}.$

The method can realize real-time measurement of the velocity distribution of bubbles, droplets or solid particles in a multiphase reactor, and the measurement accuracy is high.

The present invention relates to systems and methods for collecting and analyzing bioaerosols, including exhaled breath aerosol from a subject. The collection system comprises an inlet portion configured to receive a gaseous fluid containing water vapor and aerosol particles. A primary passage for gaseous fluid flow is in fluid communication with the inlet portion and configured to channel the gaseous fluid flow therethrough. An outlet portion is in fluid communication with the primary passage. A sample collection region is provided, which is configured to receive from the outlet portion aerosol particles from the gaseous fluid, wherein the aerosol particles are impacted onto a layer of ice.