Methods and systems are provided for a PM sensor. In one example, a method comprises flowing exhaust gas to a cone-shaped PM sensor having a pair of openings arranged across from one another and a plurality of outlets distal to the pair of openings.

A system, apparatus, and method for accurately calibrating the detection efficiency of condensation particle counters is disclosed. An apparatus for calibrating condensation particle counters includes a container for supplying test particles of a known and constant diameter, a pump communicatively connected to the container, a nanoparticle nebulizer communicatively connected to the pump; an ion mobility classifier communicatively connected to the nebulizer, a first condensation particle counter communicatively connected to the ion mobility classifier; and a second condensation particle counter communicatively connected to the ion mobility classifier.

An apparatus and method for creating enlarged particles in a flow. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. A heater heats a first portion of the tube along a first, longitudinal portion of the tube, and a cooler cools a second, longitudinal portion of the tube along at least a second portion of the tube. The method includes heating a first portion of the tube along a first longitudinal portion of the tube, and simultaneously cooling a second portion of the tube along at least a second longitudinal portion of the tube. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

An apparatus and method for condensationally enlarging particles in a flow of air or other gas. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. The walls of the tube are wetted with a condensing fluid. The walls of the first portion of the coiled tube are held a temperature that is lower than the highest temperature in the second portion of the tube. The tube may have a third vapor recovery portion with wall temperature lower than the highest temperature in the second portion, and which optionally may not be coiled. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

Calibrated particle analysis apparatus and method are provided. In the calibrated particle analysis apparatus, a gas exchange device and several flow controllers are disposed in front of a particle analyzer. Therefore, when the calibrated particle analysis apparatus is used, gases of a sample can be exchanged with a carrier gas suggested to be used with the particle analyzer. Hence, the accuracy of analyzing the particles can be increased, and possible hazards from dangerous or toxic materials can be avoided.

Various embodiments include methods and systems to dilute a sampled particle-laden aerosol stream. In one embodiment, a system to dilute a sampled aerosol stream includes an aerosol sample inlet. A filter is coupled in fluid communication with and in parallel with a flow-monitoring device to receive the sampled aerosol stream from the aerosol sample inlet. The flow-monitoring device is configured to allow for a passage of particles contained in the sampled aerosol stream. A pressure sensor and a temperature sensor monitor the filter and the flow-monitoring device. An output from the filter and the flow-monitoring device may be directed to particle measurement or particle sizing instrumentation. An actual dilution ratio of the output sent to the particle measurement or particle sizing instrumentation is determined based on a nominal flowrate of the flow-monitoring device and thermodynamic properties of a gas comprising the aerosol stream. Other methods and apparatuses are disclosed.

A particle counting method comprises obtaining first particle information related to the gas to be measured by a first particle counter with a first particle size detection range, obtaining second particle information related to the gas to be measured by a second particle counter with a second particle size detection range, and generating particle size distribution information according to the first and second particle information. The first particle information includes a plurality of particle size ranges and a plurality of particle quantities wherein each of the plurality of particle size ranges corresponds to a respective one of the plurality of particle quantities, the second particle information includes the quantity of particles of which the size values are in the second particle size range, and the lower limit of the second particle size range is lower than that of the first particle size range.

A quantitative method of number surface area of a graphene material includes the following steps. The graphene material is mixed with a solution to form a colloidal solution containing the graphene material. The colloidal solution is atomized to form a plurality of aerosols containing the graphene material. The size of the aerosols is screened. The screened aerosols are counted to obtain a number concentration of the screened aerosols. A surface of the screened aerosols is charged and a current amount on the surface-charged aerosols is measured. The number surface area of the graphene material is calculated based on the current amount and the number concentration.

An apparatus and method for creating enlarged particles in a flow. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. A heater heats a first portion of the tube along a first, longitudinal portion of the tube, and a cooler cools a second, longitudinal portion of the tube along at least a second portion of the tube. The method includes heating a first portion of the tube along a first longitudinal portion of the tube, and simultaneously cooling a second portion of the tube along at least a second longitudinal portion of the tube. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

A system for detecting particles, including: a first device to measure concentration of particles, including an electrometer measuring device coupled to a charger and/or to an optical particle counter; a second device to measure concentration of particles, including a condensation nuclei counter; a calculation unit configured to calculate a ratio and/or a difference between a first measurement of the particle concentration in an airflow, to be performed by the first measurement device, and a second measurement of the particle concentration in an airflow, to be performed by the second measurement device, and configured to provide a comparison between the ratio and/or the difference between the first and second measurements and a threshold value to determine presence of particles of interest other than ambient air particles.