On-board Analyzer Research Articles

PM Emission Measurement by On-Board Analyzer under Real Driving Conditions

PM Emission Measurement by On-Board Analyzer under Real Driving Conditions

Research for NO<sub>x</sub> Emission of Nanjing Vehicle Based on IVE Model

This paper researched on vehicles’ emissions in Nanjing based on IVE model and presented the method to quantify the main inputting parameters of IVE model. This research has collected the traffic of different types of roads in Nanjing. The light-duty vehicles, taxis, buses and trucks respectively accounted for 73.4%, 13.3%, 10.3% and 3.0% of the total traffic volume. According to vehicle driving condition data collected by GPS, the driving cycle of light-duty vehicles in Nanjing was defined. The on-road vehicles’ emission data were measured using the on-board vehicle emission analyzer made by ourselves. Then the correction factors of NOx in IVE model could be obtained using the testing emission data. The results of IVE model showed that the daily NOx emission of light-duty vehicles, taxis, buses and trucks in Nanjing city were 17.79t, 5.51t, 146.37t and 83.78t. Buses and trucks were the main emission sources of NOx, with the contribution of 57.75% and 33.06%.

Strategies for measurement of atmospheric column means of carbon dioxide from aircraft using discrete sampling

Automated flask sampling aboard small charter aircraft has been proposed as a low‐cost, reliable method to greatly increase the density of measurements of CO2 mixing ratios in continental regions in order to provide data for assessment of global and regional CO2 budgets. We use data from the CO2 Budget and Rectification‐Airborne 2000 campaign over North America to study the feasibility of using discrete (flask) sampling to determine column mean CO2 in the lowest 4 km of the atmosphere. To simulate flask sampling, data were selected from profiles of CO2 measured continuously with an onboard (in situ) analyzer. We find that midday column means can be determined without bias relative to true column means measured by the in situ analyzer to within 0.15 and better than 0.10 ppm by using 10 and 20 instantaneously collected flask samples, respectively. More precise results can be obtained by using a flask sampling strategy that linearly integrates over portions of the air column. Using less than 8–10 flasks can lead to significant sampling bias for some common profile shapes. Sampling prior to the breakup of the nocturnal stable layer will generally lead to large sampling bias because of the inability of aircraft to probe large CO2 gradients that often exist very close to the ground at night and during the early morning.

A detector for high frequency modulation in auroral particle fluxes

A high time resolution (HTR) electron detector has been developed for use in sounding rocket studies of the aurora. The detector is used to look for particle bunching in the range 50 kHz–10MHz. The design uses a Johnston Laboratory MM-1 electron multiplier and an onboard frequency spectrum analyzer. By using the onboard analyzer, the data can be transmitted back to ground on a single 93 kHz voltage-controlled oscillator. The detector covers the 50 kHz–10 MHz range six times per second and detects modulation on the order of a few percent of the total electron flux. Spectra are presented for a flight over an auroral arc.

A Remote Pulse-Height Analyzer and Telemetry Link

A system was needed for transmitting gamma-ray pulse-height information from high altitude to earth. In the system designed, a pulse-height analyzer accepts pulses from gamma-ray detectors, determines their amplitude, and transmits this information in serial form on an event-by event basis via telemetry to a ground station where it is stored on magnetic tape and in the memory of a modified multichannel analyzer. This provides a real-time visual observation of the data as it is accumulated, in addition to facilitating preflight calibration. The on-board analyzer was successfully flown at an altitude of 20 miles for 4 hours, and the telemetry translator was used to decode the magnetic tape recordings.